JPWO1999027569A1 - Exposure apparatus, exposure method, and device manufacturing method - Google Patents

Abstract

(57) [Abstract] With illumination light from illumination optical systems IOP1 and IOP2 irradiating a mask on mask stage RS1 and a mask on mask stage RS2, respectively, mask stage RS1 and substrate stage WS1 are moved synchronously, and mask stage RS2 and substrate stage RS2 are also moved synchronously. By moving mask stage RS1 and mask stage RS2 in opposite directions, reaction forces against a base plate 18 caused by stage movement can be canceled, thereby suppressing vibration of the exposure apparatus. Throughput can be improved by performing alignment operations on substrate stages WS3 and WS4 in parallel with these exposure operations.

Description

Detailed Description of the Invention

TECHNICAL FIELD The present invention relates to an exposure apparatus, an exposure method, and a device manufacturing method, and more particularly
or an exposure apparatus that transfers a pattern formed on a mask onto a substrate via a projection optical system.
and a method for manufacturing a microdevice using the same.
BACKGROUND ART Conventionally, when semiconductor elements or liquid crystal display elements are manufactured by a photolithography process,
Various exposure tools are used for this purpose, but currently, photomasks or reticles are used.
The pattern of the reticle (hereafter referred to as "reticle") is projected onto the surface through a projection optical system.
A substrate such as a wafer or glass plate coated with a photosensitive material such as photoresist (hereinafter referred to as
Generally, a projection exposure apparatus is used to transfer the pattern onto a photosensitive substrate (hereinafter referred to as a "sensitive substrate").
In recent years, the projection exposure equipment has become a type that can move the sensitive substrate two-dimensionally.
The substrate is placed on a substrate stage, and the substrate is moved stepwise (stepping) by this substrate stage.
The reticle pattern is transferred sequentially to each shot area on the photosensitive substrate.
A step-and-repeat type reduction projection exposure apparatus that repeats exposure operations.
Recently, the stepper has been improved to become a static exposure device.
and scan type projection exposure apparatus (for example, Japanese Patent Laid-Open Publication No. 7-176468)
and the corresponding scanning exposure apparatus described in U.S. Pat. No. 5,646,413.
This step-and-scan method has become relatively popular.
Compared to steppers, projection exposure equipment using the holographic method uses a large field with smaller optical
This makes it easy to manufacture the projection optical system and allows for large-field exposure.
High throughput can be expected due to the reduction in the number of light shots.
On the other hand, scanning the reticle and wafer relative to each other has an averaging effect, and distortion is reduced.
It has the advantage of being able to improve the depth of focus and the image quality.
The integration density of DRAM will increase from 16M (mega) bits to 64M bits, and in the future
As the speed increases over time, to 256Mbit, 1G (gigabit),
Since a large field is required, scanning projection exposure equipment is used instead of steppers.
This type of projection exposure apparatus is primarily used as a mass production machine for semiconductor devices, etc.
Therefore, it is important to consider how many wafers can be exposed in a given time.
In this regard, in the case of a step-and-scan projection exposure apparatus, the large field
As mentioned above, when exposing a field, the number of shots to be exposed in a wafer is
This reduces the number of steps required, so throughput is expected to improve. However, exposure requires a reticle and a wafer.
Since this is done during uniform speed movement by synchronous scanning,
An acceleration/deceleration area is required, and if the shot size is the same as that of a stepper,
When exposing a dot, the throughput may be lower than that of a stepper.
The process flow in this type of projection exposure apparatus is roughly as follows: First, a wafer is loaded onto the wafer table using a wafer loader.
Next, a search and alignment mechanism is used to roughly detect the wafer position.
This search alignment process is specifically
For example, the outer shape of the wafer is used as a reference, or the search area on the wafer is used as a reference.
Next, fine alignment is performed to accurately determine the position of each shot area on the wafer.
This fine alignment process is generally called EGA (Enhanced Alignment).
This method uses a method called "Stand-Alignment" (Stand-Alignment Global Alignment) for the alignment of the wafer.
A plurality of sample shots are selected, and the associated
The positions of the alignment marks (wafer marks) are measured sequentially, and the measurement results are compared with the shot
Based on the design values of the matrix, statistical calculations are performed using the least squares method, etc.
, which obtains data on the arrangement of all shots on a wafer (Japanese Patent Laid-Open Publication No. 61-4442
(See U.S. Pat. No. 4,780,617 and its corresponding U.S. Pat. No. 4,780,617, etc.)
Next, the coordinate position of each shot area obtained by the EGA method or the like can be calculated with a relatively high degree of accuracy.
Based on the measured baseline amount, each shot area on the wafer is sequentially set to the exposure position.
Next, while positioning the wafer, the reticle pattern is transferred onto the wafer via the projection optical system.
Next, the exposed wafer on the wafer table is unloaded using a wafer unloader.
The wafer unloading step is then performed.
This step is carried out simultaneously with the wafer loading step described above.
Thus, the wafer exchange process is completed. In this way, in the conventional projection exposure apparatus, the wafer exchange process is completed in the following order: wafer exchange → search alignment → front
Fine alignment → exposure → wafer exchange... four major operations are combined into one
The throughput THOR [sheets/hour] of this type of projection exposure apparatus is
The wafer exchange time is T1 [sec], and the search alignment time is T2 [sec].
The fine alignment time is T3 [sec], and the exposure time is T4 [sec].
In this case, it can be expressed as the following formula (1): THOR=3600/(T1+T2+T3+T4) (1) The operations of T1 to T4 are performed in the order of T1 → T2 → T3 → T4 → T1... (
Therefore, the individual elements T1 to T4 are repeatedly executed.
By speeding up the element, the denominator becomes smaller, and the throughput THOR can be improved.
However, the above-mentioned T1 (wafer exchange time) and T2 (search alignment time)
The effect of improvement is small because only one operation is performed for one wafer.
is relatively small. In addition, in the case of T3 (fine alignment time),
When using the EGA method, it is possible to reduce the number of shots sampled or to
Reducing the measurement time can improve throughput, but on the other hand,
T3 cannot be easily shortened because it will degrade the accuracy of the experiment.
T4 (exposure time) is the wafer exposure time and the stepping time between shots.
For example, scanning projection such as step-and-scan
In the case of an exposure tool, the relative position of the reticle and wafer is adjusted to shorten the wafer exposure time.
It is necessary to increase the scanning speed, but the synchronization accuracy will deteriorate, so it is not recommended to increase the scanning speed too quickly.
In addition to the throughput mentioned above, other important requirements for this type of projection exposure apparatus are
are the resolution, depth of focus (DOF), and line width.
The resolution R is determined by the exposure wavelength λ and the numerical aperture of the projection lens.
If N.A. (Numerical Aperture), then λ/N.A.
The depth of focus (DOF) is proportional to λ/(N.A.) ² Therefore, in order to improve the resolution R (reduce the value of R), the exposure wavelength λ is
It is necessary to shorten the lens or increase the numerical aperture (N.A.).
The density of semiconductor devices is increasing, and the device rule is 0.2 μmL/S (laser
In and space) and below, these patterns
For exposure, a KrF excimer laser is used as the illumination light source.
Therefore, as mentioned above, it is inevitable that the integration density of semiconductor elements will increase further in the future.
Therefore, it is desirable to develop a device equipped with a light source with a shorter wavelength than the KrF excimer laser.
As a candidate for next-generation devices with shorter wavelength light sources such as ArF excimer lasers,
Typical examples include devices that use a laser as a light source and electron beam exposure devices.
In the case of an optical device, the throughput is significantly lower than that of an optical exposure device.
Another method to increase the resolution R is to increase the numerical aperture N.A.
However, increasing the N.A. reduces the DOF of the projection optical system.
This DOF is called UDOF (Usable Depth of Field).
Focus: The part used by the user (pattern step, resist thickness, etc.) and the equipment
Up until now, the ratio of UDOF has been large.
Therefore, the main focus of development of exposure equipment was to increase the DOF.
As a technique for increasing F, for example, modified illumination has been put to practical use. In order to manufacture devices, L/S (line and space)
), isolated L (line), isolated S (space), and CH (contact hole), etc.
It is necessary to form a pattern on the wafer that combines the above L/S,
The exposure parameters for optimal exposure differ for each pattern shape, such as an isolated line.
For this reason, conventionally, ED-TREE (excluding CHs with different reticles)
Using this method, the resolution line width is within a predetermined tolerance for the target value, and
Common exposure parameters (coherence factor σ) that provide a predetermined DOF are
, N.A., exposure control accuracy, reticle drawing accuracy, etc.) are calculated and used as the
However, in the future, the following technical
It is believed that there is a trend. Improvements in process technology (planarization on wafers) have led to lower pattern steps and thinner resists.
The decrease will continue, and there is a possibility that UDOF will decrease from the 1 μm range to 0.4 μm or less. The exposure wavelength will change from 9 lines (436 nm) to i (365 nm) to KrF excimer laser (
However, in the future, the wavelength will be shortened to 248 nm.
3 nm), and F ₂ Only light sources up to laser (157 nm) have been considered.
The technical hurdles are also high. After that, we will move to EB exposure. Instead of static exposure such as step and repeat,
Scanning exposure like this is expected to become the mainstream of projection exposure equipment.
The technology allows large-field exposure with a small diameter projection optical system (especially for scanning
With the above technological trends as a background, two-dimensional imaging is being developed as a method to improve the limiting resolution.
The double exposure method was reviewed, and this double exposure method was used in an ArF exposure device, and 0.1 μmL/
Attempts to expose up to S are being considered. Generally, there are three types of double exposure methods:
(1) L/S and isolated lines with different exposure parameters are formed on separate reticles, and
Double exposure is performed on the same wafer under optimal exposure conditions. (2) When a phase shift method is introduced, L/S is more limited than isolated lines at the same DOF.
By utilizing this, all patterns can be measured with one reticle.
The isolated line is formed by L/S and the L/S is thinned out by the second reticle.
(3) Generally, isolated lines can obtain higher resolution with smaller N.A. than L/S.
(However, the DOF becomes smaller.) Therefore, all patterns are formed with isolated lines.
The combination of isolated lines formed by the first and second reticles.
The double exposure method described above has two effects: improving resolution and DOF. However, the double exposure method requires multiple exposure processes using multiple reticles.
Therefore, the exposure time (T4) is more than double that of conventional devices, and the throughput is
In reality, the double exposure method is no longer used because of the inconvenience of significant deterioration of the image.
Until now, the use of shorter exposure wavelengths, modified illumination, and phase shift
However, when the double exposure method described above is used in an ArF exposure apparatus, the resolution and depth of focus (DOF) can be improved to 0.1 μm.
By realizing exposure up to L/S, 256Mbit and 1Gbit DRA
There is no doubt that this is a promising option for the development of the next generation of mass-produced M.
A new technology to improve throughput, which is a bottleneck in the double exposure method,
In this regard, the four operations mentioned above, namely wafer exchange, search alignment,
, fine alignment, and exposure operations can be performed simultaneously, even if only partially.
If these four operations can be performed in parallel, it will be faster than if they were performed sequentially.
It is thought that the throughput can be improved by using this method.
This is based on the premise that multiple pages must be set up, which seems simple in theory, but in reality
In fact, in order to provide sufficient effect by using multiple substrate stages,
For example, the substrate on one of the substrate stages
While scanning exposure is being performed on one substrate, alignment exposure is being performed on the other substrate stage.
When the substrate stage and the reticle stage are
The reaction force caused by the acceleration and deceleration of one stage acts as a disturbance on the other stage,
In order to achieve high-precision overlay,
After performing alignment on the substrate on the substrate stage,
The results are used to align the mask pattern with the sensitive substrate and perform exposure.
Therefore, it is necessary to simply use one of the two substrate stages for exposure, for example, and the other for other purposes.
The present invention was made under such circumstances, and its first object is to improve throughput.
A second object of the present invention is to provide an exposure apparatus and an exposure method that can improve throughput and
An exposure apparatus and an exposure method that can realize highly accurate exposure of fine patterns
A third object of the present invention is to provide a method for manufacturing a microdevice at low cost.
Disclosure of the Invention An exposure apparatus according to a first aspect of the present invention transfers a pattern formed on a mask onto a substrate.
An exposure apparatus for transferring a pattern onto a first surface,
a first mask stage (RS1) and a second mask stage (RS2) movable in the direction of the mask;
An illumination system (12A, 12B, BMU1, BMU2, IOP1,
IOP2); and a mask for projecting illumination light emitted from each of the masks onto a substrate (W1, W2).
a first projection optical system (PL1) and a second projection optical system (PL2) that project light therethrough;
are arranged on the first and second mask stage sides, and the substrates (W1, W2) are
a first and a second substrate stage (WS1, WS2) that can hold and move the substrate;
The first mask stage and the first substrate stage are projected at a magnification of the first projection optical system.
and moving the second mask in the first direction at a speed ratio corresponding to the speed of the first mask.
and the second substrate stage at a speed according to the projection magnification of the second projection optical system.
The illumination system includes a driving device (22, 40) for synchronously moving the mask on the first mask stage and the second mask stage in the first direction at a ratio of 1/2 to 1/4.
The masks on the two mask stages are irradiated, and in this state, the driving device
The first mask stage and the first substrate stage are adjusted in accordance with the projection magnification of the first projection optical system.
The second mask stage and the second substrate stage are moved synchronously in the first direction at a speed ratio.
The stage is moved synchronously in the first direction at a speed ratio according to the projection magnification of the second projection optical system.
Then, the pattern of the mask on the first mask stage is projected onto the first substrate by the first projection optical system.
The patterns are transferred sequentially onto the substrate on the plate stage, and at the same time, the patterns are transferred onto the mask on the second mask stage.
The patterns are sequentially transferred onto a substrate on a second substrate stage by a second projection optical system.
That is, two substrates, one on the first substrate stage and one on the second substrate stage, are
The mask pattern is transferred to the plate in parallel, which reduces throughput.
In this case, from the viewpoint of simultaneous parallel processing of two substrates,
The direction of movement of each stage during the phase movement is not particularly limited.
As shown, the first mask stage (RS1) and the second mask stage (RS2) during the synchronous movement
The movement directions of the two sensors (RS2) are opposite to each other in the first direction.
The movement of the first substrate stage (WS1) and the second substrate stage (WS2) during the period of movement
The moving directions may be opposite to each other in the first direction.
The reaction forces generated when accelerating and decelerating before and after the synchronized movement of each mask stage are mutually
The mask stages are moved synchronously, and the
Since the reaction forces generated during acceleration and deceleration cancel each other out to some extent,
and reducing the force in the first direction applied to the body of the exposure device including the support member.
This makes it possible to reduce synchronization errors between the stages of each set.
In this case, there is a risk that a certain amount of rotational moment will act on the body.
However, almost no force is generated in the direction perpendicular to the first direction within the stage movement plane.
For example, compared to preventing six degrees of freedom of movement (or vibration) of the body,
In the exposure apparatus, the mask stages (RS1, RS2) and the substrates (RS1, RS2) are
It is desirable that the plate stages (WS1, WS2) move on the same plane.
In this case, the above-mentioned motion is performed by a so-called two-dimensional linear actuator (planar motor) or the like.
It is possible to configure a drive system for four stages, and the support for each stage is
Only rotational moments in the same plane act on the body including the support member (pitch
Since no bending or rolling occurs, vibrations can be easily suppressed.
In the above exposure apparatus, the first and second substrate stages (WS1, WS2) are the same
a third substrate stage (WS3) that moves on one surface; and a positioning member formed on the substrate.
The apparatus may further include a first mark detection system (28A) for detecting the alignment mark.
In such a case, the substrates on the first and second substrate stages are scanned as described above.
While the mask pattern is being transferred by exposure, the substrate on the third substrate stage
The alignment marks formed on the substrate can be detected by the first mark detection system.
Therefore, the exposure operation for the substrates on the two substrate stages and the exposure operation for the substrates on one substrate stage are performed.
The mark position detection operation (alignment operation) for the substrate on the
In this case, the driving device (22, 40) drives the first substrate stage (
WS1) or the second substrate stage (WS2), instead of the third substrate stage
(WS3) to the first mask stage (RS1) or the second mask stage (
In such a case, the mark position detection
The third substrate stage on which the above has been completed is inserted into the first substrate stage or the second substrate stage.
By switching the stage, the exposure operation for the substrate on the first and second substrate stages is completed.
After that, a scanning exposure for transferring a mask pattern to the substrate on the third substrate stage is performed.
In this case, the alignment of the substrate on the third substrate stage is performed by
The exposure time for the substrates on the first and second substrate stages completely overlaps.
Since the substrate is mounted on the first and second substrate stages, alignment and exposure are performed.
In the exposure apparatus, the first, second and third substrate stages are arranged to hold the substrate, and the throughput can be further improved compared to when the light is sequentially and repeatedly applied.
The fourth substrate stage (WS4) moves on the same plane as the other substrates (WS1, WS2, WS3).
a second mark detection system (2) for detecting an alignment mark formed on the substrate;
8B). In this case, the first and second substrate stages
The mask pattern is transferred onto the substrate by scanning exposure as described above.
While the alignment mark formed on the substrate on the third substrate stage is being aligned with the first mark,
The detection system detects the alignment marks formed on the substrate on the fourth substrate stage.
The first mark detection system can detect the alignment marks on the two substrates.
The exposure operation for the substrate on the stage and the master operation for the substrate on the two substrate stages
In this case, the driving device (22, 40) drives the first substrate stage (
WS1), the second substrate stage (WS2), instead of the third substrate stage (WS
3), the fourth substrate stage (WS4) is connected to the first mask stage (RS1),
It may be possible to move them in synchronization with the second mask stage (RS2).
In this case, the third substrate stage and the first substrate stage after the mark position detection are completed.
After the mark position detection is completed, the fourth substrate stage and the second substrate stage are swapped.
By switching the positions, the exposure operation for the substrates on the first and second substrate stages can be performed.
Immediately after the completion of the process, the substrate on the third substrate stage and the substrate on the fourth substrate stage are
This allows scanning exposure for transferring the mask pattern.
The alignment time for the substrate on the first substrate stage and the substrate on the fourth substrate stage is
, which completely overlaps with the exposure time for the substrate on the second substrate stage.
Then, alignment and exposure are sequentially repeated for the substrates on the first and second substrate stages.
In the above exposure apparatus, the mask stages (RS1, RS2) are arranged at approximately the same time.
and each of the substrate stages (WS1, WS2) has approximately the same mass.
In such a case, it is desirable to have a first mask stage and a first substrate stage.
The synchronous movement of the first mask stage and the second substrate stage is performed simultaneously.
When scanning at the same target speed, the acceleration and deceleration of each stage
The reaction forces are canceled out between the mask stages and between the substrate stages,
No force in the first direction acts on the body including the support member that supports the stage.
In the above exposure apparatus, the projection optical systems (PL1, PL2) are the same.
a projection magnification, and the mass of each mask stage (RS1, RS2) is equal to or larger than the mass of each substrate
The mass of the stage (WS1, WS2, WS3, WS4) is multiplied by the projection magnification.
In this case, it is desirable to move the first mask stage and the first substrate by the driving device.
stage (or the third substrate stage) moves at a speed according to the projection magnification of the first projection optical system.
The second mask stage and the second substrate stage are moved synchronously in the first direction.
the second projection optical system (or the fourth substrate stage) at a speed ratio according to the projection magnification of the second projection optical system.
When moved synchronously in one direction, each stage moves without contact with the support member.
(Driven by a linear motor, etc.)
The law of conservation of momentum holds between the image sensor and the substrate stage, and the synchronization control circuit and the actuator
Scanning can be performed with almost zero synchronization error without the need for special equipment such as an anti-vibration device.
In the above exposure apparatus, the drive device drives the first and second mask stages (R
The first and second substrate stages (WS1, WS2) are aligned in the same straight line.
In such a case, it is desirable to drive the exposure device in the same way as the exposure device described above.
The reaction forces during stage acceleration and deceleration are mutually proportional between stages and substrate stages.
The force in the first direction is not applied to the body including the support members that support each stage.
In addition, the rotation moment will no longer be applied, so the synchronous control circuit and
Scanning with almost zero synchronization error is possible without installing special equipment such as an active vibration isolation device.
In the exposure apparatus, the mask on the first mask stage (RS1) and the
A mask exchange mechanism (20) for exchanging the mask with the mask on the second mask stage (RS2)
In such a case, for example, the first mask stage may further include a
A mask on which a first resolution pattern is formed is placed, and a second resolution pattern is formed on a second mask stage.
With a mask on which a pattern is formed placed, the first group is exposed by scanning exposure.
The substrate on the plate stage, the first decomposition pattern, and the second decomposition pattern are
After transferring the two-part pattern, the first mask stage is replaced by the mask exchange mechanism.
The mask on the first mask stage is replaced with the mask on the second mask stage, and each is used for scanning exposure.
The second separation plate is then moved relative to the substrate on the first substrate stage and the substrate on the second substrate stage.
By transferring the first decomposition pattern and the second decomposition pattern,
A composite pattern of the first decomposed pattern and the second decomposed pattern is then transferred to the substrate on the first substrate stage,
It is possible to transfer onto a substrate on a plate stage.
Therefore, the double exposure can be easily realized simultaneously.
In addition, the improvement of resolution and depth of focus allows for the production of fine patterns.
Each projection optical system is a catadioptric optical system, and the wavelength of the illumination light is 20
In such a case, it is not necessary to increase the size of the projection optical system.
This enables highly accurate transfer of fine patterns on the submicron order or less without any need for a
The exposure method according to the second aspect of the present invention includes: exposing a pattern formed on a mask to a substrate;
The exposure method for transferring a first mask (R1) and a first substrate (W1) is
While moving synchronously in the first direction at a speed ratio according to the projection magnification of the projection optical system (PL1),
The first mask is irradiated with illumination light (EL) to form a pattern on the first mask.
The pattern is transferred onto a first divided area on the first substrate via the first projection optical system.
A first step; and simultaneously with the first step, a second mask (R2) and a second substrate (W2)
is synchronously moved in the first direction at a speed ratio according to the projection magnification of the second projection optical system (PL2).
While moving the mask, the second mask is irradiated with illumination light (EL), and a pattern is formed on the second mask.
The formed pattern is projected onto a second divided area on the second substrate via the second projection optical system.
and a second step of transferring the first divided area on the first substrate by the scanning exposure in the first step.
The pattern of the first mask is transferred to the second area on the second substrate by scanning exposure in the second process.
The pattern of the second mask is transferred to the image area at the same time.
The mask pattern is transferred simultaneously to two substrates, the first substrate and the second substrate.
In this case, the first and second substrates are formed on the substrates different from the first and second substrates at the same time as the first and second steps.
The alignment marks formed on the third substrate (WS3) and the fourth substrate (WS4) are
The method may further include a third step of detecting the peak.
Exposure operation for the plate and mark position detection operation for the two substrates (alignment
In this case, the alarm for the third and fourth boards is
The exposure time for the first and second substrates was completely overlapped.
In the above exposure method, after the first and second steps are completed,
The second mask (R2) and the first substrate (W1) are projected by the first projection optical system (PL).
While moving the object in the first direction synchronously at a speed ratio according to the speed ratio, the object is illuminated by an illumination light (EL).
The second mask is irradiated with light and the pattern formed on the second mask is projected onto the first projection optical system (
PL1) to be transferred onto the first partitioned region on the first substrate (W).
and a third step, wherein the first mask (R1) and the second substrate (W
2) in the first direction at a speed ratio according to the projection magnification of the second projection optical system (PL2).
While moving the first mask synchronously, the first mask is irradiated with illumination light, and a pattern is formed on the first mask.
The pattern thus formed is projected onto the second divided area of the second substrate via the second projection optical system.
In this case, for example, a first decomposed pattern is formed on a first mask in advance, and a second decomposed pattern is transferred onto the second mask.
By forming the second decomposition pattern on the mask, the scanning exposure in the first and second steps can be performed.
The first decomposition plate is formed by the light in the first divided area of the first substrate and the second divided area of the second substrate.
After the first and second decomposition patterns are transferred simultaneously, the third and fourth scanning steps are performed.
By exposure, a second resolved pattern is formed in the first divided area on the first substrate, and a second resolved pattern is formed in the second substrate.
The first decomposed pattern is transferred to each of the second divided areas.
The composite pattern of the first decomposition pattern and the second decomposition pattern is simply formed on the first section of the first substrate.
The image area can be transferred to the second divided area of the second substrate.
Double exposure of two substrates can be easily achieved simultaneously.
It is possible to improve throughput and also improve resolution and depth of focus.
The exposure apparatus according to the third aspect of the present invention is a photolithography apparatus for manufacturing microdevices.
An exposure apparatus used in a lithography process, which holds a first mask (R1).
a first mask stage (RS1); and at least two reflective optical elements (M1, M2
, M3), and a first projection optical system (PL1) having a front surface in front of the first projection optical system;
A first substrate stage (WS) for holding the first substrate (W1) on the first mask stage side
1); a second mask stage (RS2) that holds a second mask (R2); and
a second projection optical system (PL) having at least two reflective optical elements (M1, M2, M3);
2) and a second substrate (W) on the second mask stage side with respect to the second projection optical system.
a second substrate stage (RS2) for holding the first and second substrates;
When scanning and exposing, the first and second substrate stages are moved relative to each other along a predetermined direction.
and a driving device (22, 40) for driving the first mask in the opposite direction. According to this, when the first and second substrates are subjected to scanning exposure, the first mask is exposed by the illumination light.
The mask on the stage and the mask on the second mask stage are illuminated.
In this state, the first and second substrate stages are moved relative to each other along a predetermined direction by a driving device.
This allows the mask patterns on the first and second substrates to be
Since the transfer of the patterns is performed simultaneously in parallel, throughput can be improved.
In this case, the body of the exposure apparatus includes the support members for the first and second substrate stages.
The force applied to the first mask stage in a predetermined direction can be reduced.
Synchronization error between the first mask stage and the first substrate stage, and between the second mask stage and the second substrate stage
The exposure method according to the fourth aspect of the present invention is a method for transferring a device pattern onto a substrate.
In the exposure method, a first mask (R1) is positioned on the first projection optical system (PL1).
The first substrate (W1) is placed, and the first mask and the first substrate are moved synchronously.
a first step of transferring a pattern of the first mask onto the first substrate; and a second projection optical system.
A second substrate (W2) is placed on the second mask (R2) side with respect to the system (PL2),
The second mask and the second substrate are moved synchronously to transfer the pattern of the second mask to the
and a second step of transferring the patterned image onto a second substrate, the first and second steps being carried out substantially simultaneously.
and the first and second substrates are moved in opposite directions along a predetermined direction.
According to this, in the first and second steps, the first mask is projected by the first projection optical system.
At approximately the same time that the pattern is transferred onto the first substrate, a second mask is projected onto the first substrate by the second projection optical system.
In this case, the first and second substrates are aligned in a predetermined direction.
Since the two are moved in opposite directions along the same axis, the same principle as in the invention described in claim 16 is applied.
Therefore, the synchronization error between the first mask and the first substrate, and the synchronization error between the second mask and the second substrate can be reduced.
In the above exposure method, from the viewpoint of improving throughput, the movement of the first and second masks can be improved.
Therefore, for example, the first mask may be moved along the predetermined direction.
The second mask is moved in the opposite direction to the first substrate along the predetermined direction.
The first substrate may be moved in the opposite direction to the second substrate.
According to the invention of claim 19, the first and second masks and the first and second substrates
In the above exposure method, it is desirable that the first mask (R1) and the first substrate (W1) are moved on the same straight line.
and the reaction force generated by the synchronous movement of the second mask (R2) and the second substrate (W
2) and the reaction force generated by the synchronized movement may be made to cancel each other out.
In the above exposure method, after the first and second steps, the first substrate and
The second substrate and the second substrate are arranged in opposite directions along a direction perpendicular to the predetermined direction.
In such a case, for example, in the first and second steps,
For example, the pattern of the first mask is applied to one shot area on each of the first and second substrates.
After transferring the patterns of the first and second masks, the first and second substrates are
When stepping to the scanning start position of each next shot area,
There is a reaction force due to the acceleration/deceleration of the first substrate and a reaction force due to the acceleration/deceleration of the second substrate during rotation.
A device manufacturing method according to a fifth aspect of the present invention includes the steps of:
The method is characterized by including a lithography process using an optical device.
The exposure apparatus according to the above inventions makes it possible to improve throughput, and as a result,
The device manufacturing method according to the sixth aspect of the present invention is a method for manufacturing a device using the exposure method according to the second and fourth aspects.
According to a seventh aspect of the present invention, an exposure method is used.
An exposure apparatus for irradiating a line and exposing an object to the pattern, comprising: a plurality of mask stages each capable of holding a mask and being movable; a plurality of object stages each capable of holding an object to be exposed and being movable; and a common base for movably supporting the plurality of mask stages and the plurality of object stages.
a base plate for projecting the energy beam emitted from each of the masks onto the corresponding object to be exposed;
and a plurality of projection systems for synchronously moving each mask stage and its corresponding object stage with respect to each projection system.
The object is exposed to the pattern of each mask by moving the mask.
According to this exposure apparatus, a mask stage, an object stage, and a projection system are provided.
The exposure device has multiple subunits that are operated simultaneously.
For example, the first mask of the first sub-unit can be exposed.
the stage and the second mask stage of the second sub-unit are connected to respective projection systems.
The first and second mask stages can be moved simultaneously relative to each other.
Since both are supported on a common base plate, the movement directions of the mask stages are the same.
By controlling the mask stages so that they are in the opposite direction, the movement of each mask stage, especially the movement
The reaction force against the base plate that occurs when accelerating and decelerating to start and finish (scanning)
In addition, the movement directions of the first and second mask stages can be canceled.
By controlling the first and second mask stages to be in opposite directions,
The corresponding first and second object stages also move in opposite directions,
The velocity generated during the movement of each object stage, especially during acceleration and deceleration at the start and end of the movement,
Therefore, the reaction force against the base plate can be canceled.
The reaction force generated by the stage movement in the two subunits is canceled within the device.
This reduces the vibration of the device body and the synchronization error between stages that results from it.
Furthermore, it is possible to perform exposure operations simultaneously in a plurality of exposure apparatus subunits.
In this specification, the term "common base plate" refers to a base plate having a single flat surface.
Not only the plate-like member that moves one mask stage to the other, but also the
A plate-like structure having multiple movably supported surfaces, each surface having a different height.
That is, multiple mask stages and multiple object stages may be included.
Each of the disk-shaped members is movably supported on at least a portion of the disk-shaped member.
Any component may be used, and its shape, structure and material may be selected.
The reaction force when the mask stages move in opposite directions is cancelled out,
In terms of easily achieving the purpose of suppressing vibrations,
The mask stage and the object stage have a flexible surface on which the mask stage and the object stage can move freely.
In the exposure apparatus of the present invention, the mask stage and the object stage are mounted on a base plate.
Furthermore, the exposure apparatus can be supported by the plurality of mask stages and the plurality of
A drive that can support and move the object stage on the base plate without contact.
The exposure apparatus may further comprise a drive device, for example a linear actuator.
and a controller for controlling the at least two
The mask stages can be controlled so that they move in opposite directions. The exposure apparatus of the present invention may further include a support table, and the base plate can be attached to the support table.
Alternatively, the exposure apparatus may further include a surface plate as shown in FIG.
The base plate is supported movably on the surface plate, and a mask stage and
When the object stage moves, the stage movement may affect the base plate.
The base plate may be configured to move relative to the surface plate in response to the applied reaction force.
This configuration allows for the movement of a single mask stage or multiple masks.
When the stage moves and the reaction force against the base plate does not cancel out
Even if the base plate is moved, it can move relative to the surface plate in response to the residual reaction force.
At this time, the momentum of the base plate is equal to the momentum of the stage, and the average center of gravity of the stage
Even if the position changes and an unbalanced load occurs, the unbalanced load is balanced by shifting the center of gravity of the base plate.
Therefore, the center of gravity of the entire exposure apparatus can be maintained at a predetermined position.
This allows for the movement of stages, especially when multiple stages are moving along complex trajectories.
Even if the exposure device is moved, the exposure device itself is prevented from vibrating.
When supporting the workpiece, it is possible to do so without contact, for example by using a linear actuator on a surface plate.
In addition, the exposure device irradiates the backside of the base plate with energy rays from the irradiation system.
The mask stage is supported on the surface of the base plate and is configured to transmit light through the mask.
The exposure apparatus may further include a plurality of projection systems for irradiating the energy beam onto each projection system.
The exposure apparatus may further include a base plate for the plurality of mask stages and the plurality of object stages, and the plurality of projection systems may be symmetrically arranged on the base plate.
In this case, the mask stage may be provided with an interferometer for measuring the position on the stage.
A plurality of object stages each reflect the beams transmitted from the interferometer.
Furthermore, the two-dimensional position on the base board may be
Cartesian coordinates defined by a predetermined first axis and a second axis perpendicular to the first axis on the base plate
the plurality of mask stages and the plurality of object stages when the plurality of mask stages and the plurality of object stages are determined using a system
At least one stage of the first axis and the second axis is aligned along a third axis direction intersecting the third axis direction.
The interferometer may include a reflecting surface extending therefrom, the interferometer irradiating the beam onto the reflecting surface to measure the beam intensity.
By receiving the reflected light, the position of the one stage in the third axis direction can be measured.
The exposure apparatus further determines whether the one stage is located on the basis of the measured position in the third axis direction.
A calculator that calculates position coordinates on a Cartesian coordinate system defined by the first and second axes of the page.
For example, the interferometer may be reset when the measurement beam of the interferometer is first irradiated onto the reflecting surface.
The stage position at this time is defined by the first axis (Y axis) and the second axis (X axis).
The position after the stage has moved (
X, Y) are the distance traveled in the third axis direction measured by the interferometer and the distance traveled when the reflecting surface is moved in the first axis direction.
Alternatively, it can be calculated from the angle at which it intersects with the second axis.
By using only the measurement value of the first interferometer, the first axis and the second axis of the stage are defined.
It is possible to calculate the position coordinates on the Cartesian coordinate system.
It is sufficient to provide only a reflecting surface in a direction intersecting the coordinate axes of the above-mentioned Cartesian coordinate system, so
A reflector is provided on each movable body along the orthogonal axis of the orthogonal coordinate system, and the orthogonal axis is
In the conventional method, the position of the movable body in the axial direction was measured using multiple interferometers.
Compared to optical devices, the number of interferometers and reflecting surfaces is reduced, resulting in a simpler exposure device.
It is also possible to measure the position of an object to be exposed, such as a photosensitive substrate, and
Position control can also be simplified. In addition, the degree of freedom in arranging the reflecting surface is improved.
As a result, the degree of freedom in designing the stage shape is improved.
It is no longer necessary to use a rectangular stage such as a square or rectangular stage.
When a reflecting surface is placed obliquely on such a rectangular stage,
The outer section can be removed to create a triangular stay as shown in Figure 16.
Therefore, it is possible to hold a mask or an object and move it two-dimensionally.
The exposure apparatus is used in a lithography process for manufacturing a device.
A projection exposure apparatus, particularly a scanning projection exposure apparatus, is preferred. In this case, the object to be exposed is
For example, light or electromagnetic waves of any wavelength such as visible light, ultraviolet light, or X-rays, electrons, etc.
According to an eighth aspect of the present invention, the first object having a pattern is irradiated with an energy beam of a particle beam.
1. An apparatus for exposing a second object to energy rays, comprising: a first base plate on which a first object is mounted for moving the first object relative to the energy rays;
a plurality of first movable bodies capable of holding the first object, and a plurality of first movable bodies that move in synchronization with the movement of the first object relative to the energy beam during scanning exposure of the second object;
The second object is placed on the first base plate so as to move the second object relatively.
a plurality of first movable bodies capable of holding a first object; and a first movable body for irradiating the first object held by each of the first movable bodies with the energy beam.
At least one optical element is disposed on the opposite side of the first object with respect to the first base plate.
According to a ninth aspect of the present invention, there is provided an exposure apparatus comprising: an illumination system for exposing a substrate to an energy beam irradiated onto a mask;
a first mask for scanningly exposing a first substrate and a second substrate to the energy beam, respectively;
The mask and the first substrate are moved synchronously, and the second mask and the second substrate are moved synchronously.
and the first and second masks or the first and second substrates are moved to the same plane.
and the first mask and the second mask are moved in opposite directions.
The synchronous movement with the first substrate and the simultaneous movement of the second mask and the second substrate are
The first and second masks and the first and second substrates may be formed substantially simultaneously.
The first and second masks and the first and second substrates may be disposed on one surface.
According to a tenth aspect of the present invention, a pattern formed on a mask is transferred onto a substrate.
a first mask stage and a second mask stage each of which holds a mask and is movable in a first direction;
providing an illumination system for irradiating each mask with illumination light; and providing first and second projection optics for projecting the illumination light emitted from each mask onto a substrate.
providing a first and second projection optical system on the same side as the first and second mask stages, respectively;
and a first and a second substrate stage, each of which is capable of holding and moving the substrate.
and providing the first mask stage and the first substrate stage in a projection system of the first projection optical system.
The second mass is moved synchronously in the first direction at a speed ratio corresponding to the shadow magnification.
the projection stage and the second substrate stage in accordance with the projection magnification of the second projection optical system.
providing a drive for synchronously moving the exposure device in the first direction at a speed ratio;
According to an eleventh aspect of the present invention, there is provided a method for manufacturing a photolithography device.
A method for manufacturing an exposure apparatus used in a lithography process, comprising the steps of: providing a first mask stage that holds a first mask; providing a first projection optical system having at least two reflective optical elements; and providing a first substrate stage that holds a first substrate on the first mask stage side relative to the first projection optical system.
providing a stage; providing a second mask stage that holds a second mask; providing a second projection optical system having at least two reflective optical elements; and providing a second substrate stage that holds a second substrate on the second mask stage side relative to the second projection optical system.
providing a stage; and moving the first and second substrate stages when scanning and exposing the first and second substrates, respectively.
providing drive devices that drive in opposite directions along a predetermined direction;
According to a twelfth aspect of the present invention, there is provided a method for manufacturing an optical device, comprising: applying energy to an exposure pattern formed on a mask;
A method for manufacturing an exposure apparatus for irradiating a .lambda.-ray and exposing an object to be exposed with the pattern.
The method includes providing a plurality of movable mask stages each holding a mask.
and providing a plurality of movable object stages each holding an object to be exposed.
a common base that movably supports a plurality of mask stages and a plurality of object stages;
a step of providing a base plate; and a step of projecting the energy beams emitted from each of the masks onto a corresponding object to be exposed.
and providing a plurality of projection systems for each of the projection systems, respectively; wherein the exposure apparatus provides a mask stage and a corresponding object stage for each of the projection systems.
By synchronously moving the mask and the image, the object is exposed to the pattern of each mask.
BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will now be described with reference to Figures 1 to 14. Figure 1 shows a schematic configuration of an exposure apparatus 10 according to one embodiment, and Figure 2 shows a schematic configuration of an exposure apparatus 10 according to one embodiment.
1 shows a plan view of the exposure apparatus 10 with the projection optical system removed.
The exposure apparatus 10 is a scanning exposure type of the so-called step-and-scan method.
It is a projection exposure system that uses the step-and-scan projection exposure method.
The effective projection of a reduced projection optical system with a circular projection field using a laser beam as illumination light is
The shadow area is limited to a polygon (hexagon), and both ends of the effective projection area in the non-scanning direction are
A method of partially overlapping the images, known as scan and stitching, is used.
For example, Japanese Patent Application Laid-Open No. 2-229423 and the corresponding U.S. Pat.
In addition, the scanning exposure method is disclosed in US Pat. No. 4,924,257.
Such a projection exposure apparatus is disclosed in, for example, Japanese Patent Laid-Open No. 4-196513 and its corresponding publications.
U.S. Pat. No. 5,473,410, Japanese Patent Application Laid-Open No. 4-277612, and
Corresponding U.S. Pat. No. 5,194,893, Japanese Patent Application Laid-Open No. 4-307720, and
The corresponding patents are also disclosed in U.S. Pat. No. 5,506,684 and the like.
The exposure method can also be applied to the exposure apparatus and exposure method of the present invention.
Insofar as the national laws of the designated or elected States in the international application permit,
The exposure apparatus 10 includes a pair of excimer laser light sources 12A and 12B and a
The excimer laser light sources 12A and 12B are beam matching units BMU1 and BMU2.
1, the excimer laser light sources 12A and 12B and the exposure device main body 14 are shown as
Although the exposure apparatus main body 14 is shown in close proximity, in reality, it is installed in an ultra-clean room.
The interior space is highly dustproof and has highly accurate temperature control.
The excimer laser beam is housed in an environmental chamber (not shown).
The sources 12A and 12B are located in a separate room (with a high degree of cleanliness) isolated from the ultra-clean room.
The exposure apparatus main body 14 is installed in a horizontal position by a plurality of (four in this example) vibration isolation pads 16.
The supported base plate 18 is used as a substrate (first and second substrates).
The first wafer W1 and the second wafer W2 are held and moved independently in the XY two-dimensional plane.
, first and second wafer stages WS1 and WS2 as second substrate stages, and a base
On the board 18, first and second reticles R1 and R2 are placed as first and second masks, respectively.
The scanning direction is mainly the Y-axis direction (the left and right directions in the plane of the drawing in FIG. 1).
a first reticle stage and a second reticle stage as a first mask stage and a second mask stage, respectively, which move in a direction
Stages RS1 and RS2, above stage WS1 and RS1, and stage WS2 and RS
2, the first and second projection optical systems PL1 and PL2, and the base plate
18, and illuminate the reticles R1 and R2 from below.
The base board 18 is equipped with optical systems IOP1 and IOP2, a control system, etc. As shown in FIG.
That is, the third and fourth wafer stages WS3 and WS4 serve as the third and fourth substrate stages.
Also, on the base board 18, a lever as a mask exchange mechanism is provided.
A tickle exchange mechanism 20 is also provided. The excimer laser light sources 12A and 12B are used as exposure light sources.
Here, pulsed ArF excimer laser light with a wavelength of 193 nm is emitted.
The excimer laser light sources 12A and 12B emit pulsed ultraviolet laser light for exposure.
The lighting used is 256M (mega) bit to 4G (giga) bit class.
A microcomputer with the integration level and fineness equivalent to that of semiconductor memory elements (D-RAM)
The minimum line width required for mass production of circuit devices is approximately 0.25 to 0.10 μm.
This is to obtain pattern resolution. The exposure illumination light is ArF excimer laser.
The present invention is not limited to KrF excimer laser light, but may also be applied to other lasers, such as KrF excimer laser light with a wavelength of 248 nm or KrF excimer laser light with a wavelength of 1
F of 57 nm ₂ Excimer laser light, or high-energy lasers such as copper vapor lasers and YAG lasers
Harmonics, ultraviolet emission lines from ultra-high pressure mercury lamps (g-line, i-line, etc.),
Light in the soft X-ray region (EUV light) with a wavelength of 5 to 15 nm may also be used.
To achieve a width of 0.10 μm, F ₂ Using excimer laser light, EUV light, etc.
It is desirable that the wavelength width of the ArF excimer laser light (pulse laser light) is
chromatic aberration caused by the various refractive optical elements that make up the projection optical systems PL1 and PL2
The absolute value of the center wavelength to be narrowed and
The value of the narrowing width (between 0.2 pm and 300 pm) is displayed on the operation panel (not shown).
The settings can be adjusted as needed and fine-tuned from the operation panel.
The operation panel also allows you to select pulse emission mode (typically self-oscillation, external trigger)
An example of an exposure apparatus using an excimer laser as a light source is disclosed in Japanese Patent Application Laid-Open No. 57-1982.
No. 98631 (corresponding to U.S. Pat. No. 4,458,994), JP-A-1-2
No. 59533 (corresponding to U.S. Pat. No. 5,307,207), JP-A-2-1
No. 35723 (corresponding to U.S. Pat. No. 5,191,374), JP-A-2-2
94013 (corresponding U.S. Pat. No. 5,383,217), etc.
An exposure device that uses an excimer laser light source for step-and-scan exposure.
Examples include the aforementioned Japanese Patent Application Laid-Open No. 2-229423 (corresponding U.S. Pat. No. 4,924,
257), JP-A-6-132195 (corresponding U.S. Pat. No. 5,477,
304), JP-A-7-142354 (corresponding U.S. Pat. No. 5,534,
Therefore, in the exposure apparatus 10 of FIG.
Apply the basic technology disclosed in each patent publication as is or with partial modifications.
It is possible to apply the national laws of the designated States or elected States designated in this international application.
To the extent permitted by law, the above publications and U.S. patents are incorporated herein by reference.
The laser light from the excimer laser light sources 12A and 12B passes through BMU1 and BMU2.
The first and second illumination optical systems IPO1 and IPO2 are each provided with a beam expander,
A plurality of ND filters with different transmittances are placed in such a way that one of them is positioned in the illumination light path.
a turret plate for holding the light source, a (double) fly-eye lens system, and an oscillating mirror.
Uniform power optical system, relay lens system, fixed blinds, movable blinds, etc.
The double fly-eye lens system and the oscillating mirror are
The combined configuration is described, for example, in Japanese Patent Laid-Open No. 1-235289 and
U.S. Pat. No. 5,307,207 and Japanese Patent Application Laid-Open No. 7-142354 correspond to the above.
and its corresponding U.S. Pat. No. 5,534,970.
and, to the extent permitted by the domestic laws of the designated countries, incorporates the disclosures contained in the main text.
Here, the operation of the illumination optical systems IPO1 and IPO2 will be briefly explained.
The laser light emitted from the laser light sources 12A and 12B enters the illumination optical system,
The beam is shaped to an appropriate diameter by a beam expander and enters an optical system for uniforming illumination.
Here, speckle is reduced and illumination is made uniform, and the lens system
Passing through a movable blind installed at a position conjugate with the reticle R (reticle R1, R2)
A fixed blank is placed at a position slightly defocused from the conjugate plane of the reticle R.
It reaches India, where its cross-sectional shape is determined to a predetermined shape, and then it is used as a relay lens system.
and passes through a bending mirror MO to form uniform illumination light (exposure light) EL, which is then incident on a reticle R
The predetermined shape defined by the fixed blinds, here a rectangular slit shape
The illumination area IAR (see FIG. 6) is illuminated.
The exposure light EL is incident on the first and second projection optical systems PL1 and PL2, which will be described later.
In this embodiment, these illumination optical systems IPO1, IPO2, and beam
The beam matching units BMU1 and BMU2 and the laser light sources 12A and 12B
The base plate 18 is provided with a bending mirror MO.
Apertures 18a and 18b are formed in the respective holes 18a and 18b to allow the emitted illumination light EL to pass therethrough.
The illumination light EL passes through the openings 18a and 18b and reaches the reticle stage RS.
The reticles R1 and R2 held on the base plate 1 and the base plate 2 are reached.
8 may be made of a light-transmitting material, and the openings 18a and 18b may be omitted.
The vibration isolation pad 16 is an air damper, which absorbs vibrations from the installation floor.
The four wafer stages WS1, WS2, WS3, and WS4 are square flat surfaces.
and their mass (more precisely, each wafer stage WS and wafer W)
The sum of the masses m1, m2, m3, and m4 are all almost equal.
The mass of each wafer stage is determined so that m1, m2, m3, m4 = m.
These four wafer stages WS1, WS2, WS3, and WS4 are set
is a magnetically levitated two-dimensional linear actuator 22 (
1, see FIG. 5) to maintain a gap of several microns between the bases.
It is supported by floating on the board 18 and driven two-dimensionally independently within the XY plane.
To explain this in more detail, the wafer stages WS1, WS2, WS3, and WS4 are
A magnet (not shown) is provided on the bottom surface, and the inside of the base board 18 is
The coils (which make up the X, Y, and Z circuits) are arranged at regular intervals over almost the entire surface.
The coil and the wafer stages WS1, WS2, WS3,
The magnets on the bottom of the WS4 act as a two-dimensional linear actuator.
In this case, the wafer stage WS
WS1, WS2, WS3, and WS4 are magnetically coupled to the magnets on their bottom surfaces and the Z
The magnetic force in the Z direction is generated by the current flowing through the coil that makes up the circuit.
The base plate 18 is supported in a floating state.
By controlling the current flowing through the coil using a control circuit (not shown in FIG. 5),
Wafer stages WS1, WS2, WS3, and WS4 can be independently moved within the XY two-dimensional plane.
It can be freely driven and can also be finely driven in the Z-axis direction and in the tilt direction relative to the XY plane.
This allows the wafer stages WS1, WS2, WS3,
The wafer stages WS1, WS2, WS3, and WS4 are configured to be capable of controlling the position and attitude of the wafer in six degrees of freedom.
The first, second, third and fourth wafers W1, W2, W3 and W4 are vacuum-sucked through the holder.
The wafer stages WS1, WS2, WS3, and W
On the upper surface of S4, various reference marks (for example, a first reference mark and a pair of reference marks described later) are provided.
1, FM2, FM3, FM4, FM5, FM6, FM7, FM8, FM9, FM10, FM11, FM12, FM13, FM14, FM15, FM16, FM17, FM18, FM19, FM20, FM21, FM22, FM23, FM24, FM25, FM26, FM27, FM
4 is set at approximately the same height as the wafers W1, W2, W3, and W4.
These fiducial mark plates FM1, FM2, FM3, and FM4 are, for example,
Used to detect the reference position of the wafer stage, during reticle alignment, etc.
In addition, both sides of the X axis direction and the Y axis direction of the wafer stages WS1, WS2, WS3, and WS4 are
The surfaces on both sides (i.e., the four sides) are mirror-finished reflective surfaces.
These reflecting surfaces are used for the interferometer beams of each measurement axis that make up the interferometer system described later.
The reflected light is received by each interferometer, and the reference
Position (generally, a fixed mirror is placed on the side of the projection optical system or the alignment optical system)
The displacement from the reference plane is measured, and the wafer stage
The two-dimensional positions of WS1, WS2, WS3, and WS4 can now be measured.
The structure of the measurement axis of the interferometer system will be described in detail later. The first and second reticle stages RS1 and RS2 have a square planar shape.
, by a magnetic levitation type two-dimensional linear actuator provided on the base board 18
The substrate is supported by floating on the base plate 18 with a gap of several microns maintained.
The motor is driven independently in the axial direction (left and right directions on the paper in Figure 1) and the X-axis direction.
In addition, these reticle stages RS1 and RS2 are magnetically levitated secondary stages.
The original linear actuator allows for fine movement in the X-axis and θ-axis directions.
To explain this in more detail, the bottom surfaces of the reticle stages RS1 and RS2 are provided with a non-illustrated
A magnet is provided, and a coil (X circuit,
Y circuit and Z circuit) and on the bottom of the reticle stages RS1 and RS2
Each of the magnets constitutes a part of the two-dimensional linear actuator 22.
In this case, the reticle stages RS1 and RS2 are provided on the bottom surfaces thereof.
Z generated by the magnetic force of the magnet and the current flowing through the coil that makes up the Z circuit
The magnetic field acts in the direction of the axis of the magnet, and the magnet is supported on the base plate 18.
The current flowing through the coil is controlled by a control device 40 (see FIG. 5).
The tickle stages RS1 and RS2 are independently driven in the Y direction at a predetermined stroke.
At the same time, it is also minutely driven in the X direction and in the rotational direction around the Z axis.
This allows for position control of the reticle stages RS1 and RS2 in the XY plane.
The reticle stages RS1 and RS2 are vacuum-attached to the reticle stages R1 and R2.
In this embodiment, the mass of the reticle stage RS1 (e.g.
More precisely, the total mass of the reticle stage RS1 and the reticle R1 (M1) and the reticle
The mass of the reticle stage RS2 (more precisely, the mass of the reticle stage RS2 and the reticle
The mass of the element R1 is approximately equal to the mass of the element M2. That is, M1 = M2 =
The mass of each reticle stage is set so that M holds.
In this embodiment, the projection magnification of the projection optical systems P1 and P2 described later is β, and the reticle stage
The mass M of the wafer stage is set to the projection magnification β times the mass m of the wafer stage.
, M=βm, the mass of the reticle stage M and the mass of the wafer stage M are set.
The mass m of each of the reticle stage RS1 and the reticle stage RS2 is determined.
One side (the side facing the paper in Figure 1) is a reflective surface with a mirror finish.
Similarly, on the other side of the reticle stage RS2 in the Y direction (the right side in FIG. 1),
The side surface and the side surface on one side in the X direction (the front side of the paper in FIG. 1) are mirror-finished.
These reflecting surfaces are used to form the interferometer system described later.
The interferometer beams of each measuring axis are projected, and the reflected light is received by each interferometer.
The reference position of each reflecting surface (generally, a fixed mirror is placed on the side of the projection optical system, and the
is the reference plane), and the displacement of the reticle stage RS1,
The two-dimensional position of RS2 is measured.
The first and second projection optical systems PL1 and PL2 are integrated with their respective lens barrels PP.
The projection optical system is supported by a main body column 24 provided on the base plate 18.
PL1 and PL2 are both mirrors with openings at the reticle-facing surface and the wafer-facing surface.
The tube PP and the entire optical system constitute a reduction optical system (projection magnification β (β is, for example, 1/4)).
Four lens groups GL1 to GL4 and three reflective optical elements (concave mirror and plane mirror) M1
3 shows a specific example of the configuration of the optical system that constitutes the first projection optical system PL1.
As shown in FIG. 3, the first lens group GL1 is located above the reticle R1.
A convex lens (or a common optical axis A in the Z-axis direction) is arranged in the
The second lens group GL2 is made up of a plurality of lenses each having a first lens element and a second lens element.
is a common Z-axis direction lens arranged above the first lens group GL1 along the Z-axis direction.
It is composed of a plurality of concave and convex lenses having an optical axis AX.
The four-lens group GL4 is a common Z lens group arranged along the Z axis above the wafer W1.
The second lens group GL2 is composed of a plurality of concave and convex lenses having an optical axis in the axial direction. A concave mirror M1 is disposed above the second lens group GL2.
In addition, a mirror is positioned below the second lens group GL2 at the pupil plane of the projection optical system PL1.
The reflecting surface of the fourth lens group GL4 is obliquely disposed above the fourth lens group GL4.
A relatively large plane mirror M3 is installed at an angle, and a Z axis is provided between the mirror M2 and the plane mirror M3.
a third lens group GL3 consisting of a plurality of lenses having an optical axis in a direction perpendicular to the
In FIG. 3, the distance between the reticle R1 and the first lens group GL1 is
aberration correction plate 2 for correcting non-rotationally symmetric aberrations, such as distortion;
The projection optical systems PL1 and PL2 are, for example, those disclosed in Japanese Patent Application Laid-Open No. 2003-200544.
No. 5,220,454 and corresponding U.S. Pat. No. 5,220,454.
The refractive optical elements and reflective optical elements (concave mirrors, beam splitters, etc.)
A combined system (catadioptric system) can also be used.
No. 8-304705 and corresponding U.S. Pat. No. 5,691,802.
Optical systems may be improved and used to the extent permitted by the domestic laws of the designated countries.
The disclosures of the publications and U.S. patents by the same authors are incorporated herein by reference. According to the projection optical system PL1, as shown in FIG.
The exposure light EL transmitted upward from the projection optical system PL1 passes through the first lens group GL1, the second lens group GL2, and the third lens group GL3 in the projection optical system PL1.
The light passes through the right half of the second lens group GL2 and reaches the concave mirror M1, where it is
The light is reflected in a direction symmetrical with respect to the optical axis AX and passes through the left half of the second lens group GL2.
Then, the exposure light EL is reflected by the mirror M2 and reaches the third mirror M3.
The exposure light passes through the upper half of the lens group GL3 and reaches the plane mirror M3.
The light is reflected by the mirror M3, passes through the right half of the fourth lens group GL4, and reaches the wafer W1.
In this way, the projection optical system PL1 is a double-telecentric reduction magnification optical system as a whole.
The second projection optical system has a reduction ratio (projection magnification) β (β is, for example, 1/4).
The optical system PL2 is also identical to the projection optical system PL1 (however, the arrangement of each optical element is
The lens is bilaterally symmetrical, and as a whole, it has a bilaterally telecentric reduction magnification (projection
The optical system is configured with a reduction magnification of β (β is, for example, 1/4).
During scanning exposure, the wafer stages WS1 and WS2 (or wafer stage WS
The movement speed of the reticle stages RS1 and RS2 in the scanning direction is
On the other side of the projection optical systems PL1 and PL2 in the X-axis direction (the far side of the paper in FIG. 1),
Although not shown in FIG. 1, in reality, as shown in the plan view of FIG.
Off-axis (off-axis) with the same function as the first and second mark detection systems
is) type alignment systems 28A and 28B are arranged to align the first and second projection optical systems PL1,
The left and right symmetrical positions are separated by the same distance in the Y direction based on the X axis passing through the boundary of PL2.
These alignment systems 28A and 28B are installed at the same position (see FIG. 4).
LSA (Laser Step Alignment) system, FIA (Filed
Image Alignment) system, LIA (Laser Interfe)
Three types of alignment sensors are available:
These are used as reference marks on the reference mark plate and as alignment marks on the wafer.
It is possible to measure the position of the alignment mark in two dimensions (X and Y).
The alignment systems 28A and 28B are, for example, those described in Japanese Patent Laid-Open No. 7-321030.
As disclosed in the FIA publication and corresponding U.S. Pat. No. 5,721,605,
An off-axis system that combines the LIA system and the LIA system by sharing part of the optical system.
The above alignment sensors may also be used, and the designated or elected States designated in this international application
The disclosures in this publication and the U.S. patent are incorporated by reference to the extent permitted by the domestic laws of the selected countries.
Here, the LSA system irradiates a mark with laser light and utilizes the diffracted and scattered light.
It is the most versatile sensor that measures the mark position using a
The FIA system is used for process wafers.
By illuminating the mark with broadband light and processing the image of this mark,
This is a sensor that measures the mark position, and it can measure asymmetric marks on the aluminum layer or wafer surface.
In addition, the LIA system can be used to slightly change the frequency of a diffraction grating mark.
The laser beams are irradiated from two directions, and the two diffracted beams are made to interfere with each other.
This is a sensor that detects the position information of the mark from the phase of the
In this embodiment, these three types of alignment sensors are used appropriately according to the purpose.
The wafer's approximate position is measured by detecting the positions of three one-dimensional marks on the wafer.
and so-called search alignment, which performs accurate positioning of each shot area on the wafer.
In this case, the alignment system 28A is mounted on the wafer stage WS3 (or WS1).
Alignment marks and fiducial mark plate F on the held wafer W3 (or W1)
It is used to measure the position of a reference mark formed on M3 (or FM1).
The alignment system 28B is held on the wafer stage WS4 (or WS2).
The alignment marks and fiducial mark plate FM4 (or W2) on the wafer W4 (or W2)
are used to measure the position of a reference mark formed on the FM2.
The information is sent to the alignment control device 30 (see FIG. 5).
The control unit 30 converts the information from each of the alignment sensors into digital data.
The digitized waveform signal is processed to detect the mark position.
The position detection result is sent to the main controller 40, which then responds to the result.
The magnetically levitated two-dimensional linear actuator 22 is controlled by the
Although not shown in FIG. 1, the wafer-facing side of the first projection optical system PL1
Near the end of the wafer W1, there is an inclined lens for detecting the Z-direction position of the wafer W1 with the lens barrel PP as the reference.
An incident light type focus sensor 32A (see FIG. 5) is provided.
As shown in FIG. 4, the gas sensor 32A is attached to the lens barrel PP via a holding member (not shown).
The wafer W1 is fixed in place, and a detection beam FB is irradiated obliquely onto the surface of the wafer W1.
The optical system 34a is fixed to the lens barrel PP via a holding member (not shown), and the wafer W
and a light receiving system 34b that receives the detection beam FB reflected by the surface 1.
A focus sensor 32A is also provided in the vicinity of the end of the second projection optical system PL2 on the wafer-opposing surface side.
A focus sensor 32B (see FIG. 5) having the same configuration is provided.
The measurement values of these focus sensors 32A and 32B are supplied to the main control device 40.
The focus sensors 32A and 32B allow the main controller 40 to
It is possible to detect (calculate) not only the Z-direction position but also the inclination.
These focus sensors 32A and 32B are described in, for example, Japanese Patent Application Laid-Open No. 6-2834.
The multi-point focal positioning system disclosed in U.S. Pat. No. 5,448,332 and the corresponding U.S. Pat. No. 5,448,332 is also disclosed.
The position detection system and the corresponding U.S. Pat. No. 5,473,422
The focus leveling system disclosed in the International Application No. 2004/0024449 and other publications is used.
To the extent permitted by the national laws of the designated or elected States,
The publications and U.S. patents are incorporated herein by reference.
The alignment sensors may also be provided in the alignment systems 28A and 28B.
When measuring the alignment marks using the alignment systems 28A and 28B, the same process is performed as during exposure.
Focus and leveling measurement and control for autofocus/autoleveling
By performing this measurement, highly accurate alignment measurement becomes possible.
, the offset due to the attitude of the wafer stage between exposure and alignment (
Also, instead of a focus sensor with oblique incidence light, e.g.
For example, Japanese Patent Application Laid-Open No. 7-321030 and the corresponding U.S. Patent No. 5,721,605
As disclosed in the above, the objective optical system of the off-axis alignment system
A TTL type focus sensor is used to detect the position of the wafer in the Z direction.
to the extent permitted by the national laws of the designated States or elected States designated in this international application.
The disclosures of these publications and U.S. patents are incorporated herein by reference. Furthermore, in the exposure apparatus 10 of this embodiment, the first and second illumination optical systems IOP1,
Inside the IOP2, the projection optical systems PL1 and PL2 project the light on the reticle.
The tickle mark (not shown) and the marks on the fiducial mark plates FM1 to FM4 are simultaneously
Through the Reticle (TTR) using the exposure wavelength for observation
le) a pair of reticle alignment microscopes 36A consisting of alignment optics;
36B (not shown in FIG. 1, see FIG. 5).
The alignment microscopes 36A and 36B are, for example, those disclosed in Japanese Patent Laid-Open No. 7-176468.
and corresponding U.S. Pat. No. 5,646,413.
These detection signals are sent to the alignment control device 30.
The relative positional relationship between the fiducial mark on the fiducial mark plate and the reticle mark is
The calculation result is supplied to the main control device 40.
Insofar as the national laws of the designated or elected States in the international application permit,
The wafer stages WS1, WS2, WS3, and WS4 and the reticle stage WS1, WS2, WS3, and WS4 are as follows:
Regarding the interferometer system 38 (see FIG. 5) that manages the positions of RS1 and RS2,
2. Here, in FIG. 2, the components constituting the interferometer system 38 are
The measurement axis of each laser interferometer is used to represent the corresponding laser interferometer.
As shown in FIG. 2, the interferometer system 38 is
, RS2 in the XY plane.
Y6, RIX1 to RIX4, and the positions of wafer stages WS1 to WS4 in the XY plane
A total of 20 laser interferometers WIY1 to WIY10, WIX1 to WIX
In FIG. 2, a measurement beam parallel to the measurement beam of the interferometer RIY1 is projected in the Y-Z plane.
An interferometer RIY5 is provided to irradiate the reflecting surface of the reticle stage RS1.
Divide the difference between the measurement values of the two interferometers RIY1 and RIY5 by the interferometer axis spacing in the Z direction.
This makes it possible to detect the rotation angle of the reticle stage RS1 around the X axis.
Similarly, for the reticle stage RS2, the length measurement beam of the interferometer RIY3 is
An interferometer RIY6 is provided, which uses a measurement beam parallel to the X axis.
In addition, a measurement beam parallel to the measurement beam of the interferometer RIX1 in the X-Z plane is detected.
An interferometer RIX3 is also installed to illuminate the reflecting surface of the cruise stage RS1.
The difference between the measurement values of the interferometers RIX1 and RIX3 is divided by the interferometer axis spacing in the Z direction.
This makes it possible to detect the rotation angle around the Y axis of the reticle stage RS1.
Similarly, for the reticle stage RS2, the measurement beam of the interferometer RIX3
An interferometer RIY4 is provided that uses a measurement beam parallel to the Y axis to detect the rotation angle around the Y axis.
The interferometer RIY1 emits a measurement beam in the Y direction onto the reflecting surface of the reticle stage RS1.
By projecting the beam and receiving the reflected light, the reticle at the projection position of the measurement beam is measured.
Similarly, the interferometer RIY2 measures the position of the lens stage RS1 in the Y direction.
The Y-direction measurement beam is projected onto the reflecting surface of the tickle stage RS1, and the reflected light is received.
By illuminating the reticle, the Y axis of the reticle stage RS1 at the projection position of the measurement beam is
The position in the direction is measured by the measurement beams of the two interferometers RIY1 and RIY2.
The center of the illumination position is the center of the illumination area IAR (see FIG. 6) (the center of the reticle R1 in the X direction).
Therefore, the average of the measurements from these two interferometers is
The value is the Y-direction position of the reticle stage RS1, and the difference between the two measurement values is the X-direction interferometer axis.
Dividing this by the distance gives the rotation angle of the reticle stage RS1 around the Z axis.
The measurement values of these interferometers RIY1 and RIY2 are supplied to the main controller 40.
The main controller 40 calculates the average value, the rotation angle, and the velocity information. The interferometer RIX1 projects a measurement beam in the X direction onto the reflecting surface of the reticle stage RS1.
By projecting and receiving the reflected light, the X direction of the reticle stage RS1
The measurement value of this interferometer RIX1 is supplied to the main control device 40.
The interferometer RIY3 projects a measurement beam in the Y direction onto the reflecting surface of the reticle stage RS2.
By projecting the beam and receiving the reflected light, the reticle at the projection position of the measurement beam is measured.
Similarly, the interferometer RIY4 measures the position of the lens stage RS2 in the Y direction.
The Y-direction measurement beam is projected onto the reflecting surface of the tickle stage RS2, and the reflected light is received.
By illuminating the reticle, the Y axis of the reticle stage RS2 at the projection position of the measurement beam is
The position in the direction is measured by the measurement beams of the two interferometers RIY3 and RIY4.
The center of the illumination position is the center of the illumination area IAR (see FIG. 6) (the center of the reticle R2 in the X direction).
Therefore, the average of the measurements from these two interferometers is
The value is the Y-direction position of the reticle stage RS2, and the difference between the two measurement values is the X-direction interferometer axis.
Dividing this by the distance gives the rotation angle of the reticle stage RS2 around the Z axis.
The measurement values of these interferometers RIY3 and RIY4 are supplied to the main controller 40.
The main controller 40 calculates the average value, the rotation angle, and the velocity information. The interferometer RIX2 projects a measurement beam in the X direction onto the reflecting surface of the reticle stage RS2.
By projecting and receiving the reflected light, the X direction of the reticle stage RS2
The measurement value of this interferometer RIX2 is supplied to the main control device 40.
In FIG. 2, the measurement beam of the interferometer WIY1 is parallel to the measurement beam of the interferometer WIY2 in the Y-Z plane.
An interferometer WIY9 is provided to irradiate the reflecting surface of the wafer stage WS1 (or WS3).
The difference between the measurement values of these two interferometers WIY1 and WIY9 is the interferometer in the Z direction.
By dividing by the axis spacing, the rotation of wafer stage WS1 (or WS3) around the X axis is calculated.
The rotation angle can be detected.
The measurement beam parallel to the long beam is reflected by the reflecting surface of the wafer stage WS1 (or WS3).
An interferometer WIX9 is also provided to irradiate the beam.
The difference between the measured values is divided by the distance between the interferometer axes in the Z direction to obtain the wafer stage WS1
(or WS3) around the Y axis.
This is for managing the position of the wafer stage WS1 (or WS3) at the exposure position.
Therefore, the interferometer WIY1 is located at the wafer stage WS1 (or WS3) at the exposure position.
By projecting a measurement beam in the Y direction onto the reflecting surface of the
The position of the wafer stage WS1 (or WS3) in the Y direction is measured.
The irradiation position of the measurement beam Y1 is the exposure area on the wafer corresponding to the illumination area IRA.
The interferometer WIX1 is positioned opposite the wafer stage WS1 (or WS3) at the exposure position.
By projecting a measurement beam in the X direction onto the projection surface and receiving the reflected light, the measurement
The position of the wafer stage WS1 (or WS3) in the X direction at the projection position of the long beam is
The optical axis of the measurement beam of this interferometer WIX1 corresponds to the illumination area IRA.
It is arranged to coincide with the center of the exposure area IA (see FIG. 6) on the wafer in the X direction.
The interferometer WIX2 is also mounted on the reflecting surface of the wafer stage WS1 (or WS3).
By projecting a measurement beam in the X direction and receiving the reflected light, the measurement beam
The position of the wafer stage WS1 (or WS3) in the X direction at the projection position of the system is measured.
The measurement values of these two interferometers WIX1 and WIX2 are supplied to the main controller 40.
The main controller 40 determines the wattage at the time of exposure based on the measurement value of the interferometer WIX1.
Manages the X-direction position of the stage WS1 (or WS3). Also, the main control device
In 40, the difference between the measurement values of the interferometers WIX1 and WIX2 is divided by the interferometer axis interval in the Y direction.
In FIG. 2, the measurement beam of the interferometer WIY2 is parallel to the measurement beam of the wafer stage WS1 (or WS3) in the Y-Z plane.
An interferometer WIY10 is provided to irradiate the reflecting surface of the wafer stage WS2 (or WS4).
The difference between the measurement values of the two interferometers WIY2 and WIY10 is used as the interference in the Z direction.
By dividing by the interferometer axis interval, the X-axis rotation of wafer stage WS2 (or WS4)
The rotation angle of the interferometer WIX3 can be detected in the X-Z plane.
The measurement beam parallel to the measurement beam is reflected by the wafer stage WS2 (or WS4).
An interferometer WIX10 is also provided to illuminate the surface, and these two interferometers WIX3 and WIX
The difference between the ten measurements is divided by the spacing between the interferometer axes in the Z direction to calculate the wafer stage.
Similarly, the interferometers WIY2, WIY3, WIY10, WIX4, and WIX10 are configured to detect the rotation angle of the interferometer WS2 (or WS4) around the Y axis.
, mainly to manage the position of wafer stage WS2 (or WS4) at the exposure position.
The interferometer WIY2 is used to measure the wafer stage WS2 (
Alternatively, a measurement beam in the Y direction is projected onto the reflecting surface of WS4) and the reflected light is received.
In this way, the position of wafer stage WS2 (or WS4) in the Y direction is measured.
The irradiation position of the measurement beam of the interferometer WIY2 is the wafer corresponding to the illumination area IRA.
The interferometer WIX3 is positioned opposite the wafer stage WS2 (or WS4) at the exposure position.
By projecting a measurement beam in the X direction onto the projection surface and receiving the reflected light, the measurement
The position of the wafer stage WS2 (or WS4) in the X direction at the projection position of the long beam is
The optical axis of the measurement beam of this interferometer WIX3 corresponds to the illumination area IRA.
It is arranged to coincide with the center of the exposure area IA (see FIG. 6) on the wafer in the Y direction.
The interferometer WIX4 is also mounted on the reflecting surface of the wafer stage WS2 (or WS4).
By projecting a measurement beam in the X direction and receiving the reflected light, the measurement beam
The position of the wafer stage WS2 (or WS4) in the X direction at the projection position of the system is measured.
The measurement values of these two interferometers WIX3 and WIX4 are supplied to the main controller 40.
The main control device 40 controls the WX3 at the time of exposure based on the measurement value of the interferometer WIX3.
Manages the X-direction position of the stage WS2 (or WS4). Also, the main control device
In 40, the difference between the measurement values of the interferometers WIX3 and WIX4 is divided by the interferometer axis interval in the Y direction.
The interferometers WIY4 and WIX6 measure the rotation angle of the wafer stage WS3 (or WS4) around the Z axis.
(or WS1), and the interferometer WIY4 is used to manage the position of the alignment
The measurement beam in the Y direction is projected onto the wafer stage WS3 (or WS1) at the target position.
By receiving the reflected light, the wafer size at the projection position of the measurement beam can be measured.
The position of the stage WS3 (or WS1) in the Y direction is measured.
For simplicity, only one measuring axis is shown in Figure 2, but in reality,
A two-axis interferometer with two measurement axes is used, and the central axis of the optical axis of the two measurement beams
passes through the detection center of the alignment system 28A. Each measurement axis from this interferometer WIY4
The measurement values are supplied to the alignment control device 30 and the main control device 40.
The control device 40 controls the alignment (on the wafer) based on the measurement value of the interferometer WIY4.
When detecting the alignment mark, the Y direction of the wafer stage WS3 (or WS1)
The interferometer WIX6 controls the orientation position and the θ rotation in the X-Y plane.
1) by projecting a measurement beam in the X direction onto the object and receiving the reflected light.
The position of the wafer stage WS3 (or WS1) in the X direction at the projection position of the long beam is
The optical axis of the measurement beam of the interferometer WIX6 is aligned with the detection axis of the alignment system 28A.
The measurement value of this interferometer WIX6 is
The interferometers WIY7 and WIX8 are connected to the wafer stage WS3 at the alignment position.
(or WS1), and the interferometer WIY7 is used to manage the position of the alignment
The Y-direction measurement beam is projected onto the wafer stage WS4 (or WS2) at the target position.
By receiving the reflected light, the wafer size at the projection position of the measurement beam can be measured.
The position of the stage WS4 (or WS2) in the Y direction is measured.
For simplicity, only one measuring axis is shown in Figure 2, but in reality,
A two-axis interferometer with two measurement axes is used, and the central axis of the optical axis of the two measurement beams
passes through the detection center of the alignment system 28B. Each measurement axis from this interferometer WIY7
The measurement values are supplied to the alignment control device 30 and the main control device 40.
The control device 40 controls the alignment (on the wafer) based on the measurement value of the interferometer WIY7.
When detecting the alignment mark, the Y direction of the wafer stage WS4 (or WS2)
The interferometer WIX8 controls the orientation position and the θ rotation in the X-Y plane.
2) by projecting a measurement beam in the X direction onto the object and receiving the reflected light.
The position of the wafer stage WS4 (or WS2) in the X direction at the projection position of the long beam is
The optical axis of the measurement beam of the interferometer WIX8 is aligned with the detection axis of the alignment system 28B.
The measurement value of this interferometer WIX8 is
The signal is supplied to the main controller 40. The interferometer W used for position control of the wafer stage WS3 (or WS1)
IY4 is a two-axis interferometer, but in the Y-Z plane, one of the two measurement axes is parallel to the
It is a three-axis interferometer that also has a length measurement axis and detects the rotation angle around the X axis (in the Y-Z plane).
Furthermore, the interferometer WIX6 may be arranged in two parallel directions in the X-Z plane.
The Y axis of the wafer stage WS3 (or WS1) is
The rotation angle (in the X-Z plane) may be detected.
Regarding the interferometers WIY7 and WIX8 used for position control of the stage WS4 (WS2)
Even if there are two measuring axes, one is added to each, and the X axis and
Even if the rotation angle around the Y axis (in the Y-Z plane and the X-Z plane) is detected,
As is clear from the above, in this embodiment, the exposure is performed by the interferometer system 38.
During both the light and alignment, the main control device 40
The XY two-dimensional position of each wafer stage is managed without any Abbe error.
In particular, during exposure, the reticle stage, which is movable with six degrees of freedom,
The position of the X-axis, Y-axis and Z-axis of the wafer stage and the position of the X-axis, Y-axis and Z-axis of the wafer stage are measured.
The interferometers WIY5 and WIX5 are mainly used to detect the wafer exchange position (loading position).
7) (or WS3) in the wafer stage WS1 (see FIG. 7)
The interferometer WIY5 is used to measure the wafer stage WS1 (or WS3).
By projecting a measurement beam in the direction and receiving the reflected light, the wafer stage
The position of WS1 (or WS3) in the Y direction is measured.
The measurement beam in the X direction is projected onto the stage WS1 (or WS3) and the reflected light is
By receiving the light, the position of the wafer stage WS1 (or WS3) in the X direction is measured.
The measurement values of these interferometers WIY5 and WIX5 are supplied to the main controller 40.
Similarly, the interferometers WIY8 and WIX7 are mainly used at the wafer exchange position (loading position).
The position of wafer stage WS2 (see FIG. 7) (or WS4) in the
The interferometer WIY8 is used to control the wafer stage WS2 (or WS
4) by projecting a length measurement beam in the Y direction onto the wafer and receiving the reflected light.
The position of the stage WS2 (or WS4) in the Y direction is measured.
7 projects a length measurement beam in the X direction onto the wafer stage WS2 (or WS4) and
By receiving the reflected light, the X direction of the wafer stage WS2 (or WS4)
The measurement values of these interferometers WIY8 and WIX7 are transmitted to the main control device 4.
In this example, the wafer is supplied to the loading position.
Interferometers WIX5, WIY5 or WIX7, WIY8 are used for position control.
Instead of the interferometer, an encoder is used to measure the position of the wafer stage.
The remaining interferometer WIY3 may be configured to perform position control when the wafer stages WS1 and WS3 are exchanged.
The interferometer WIY6 is installed for the purpose of controlling the position of the wafer stage.
It is provided for the purpose of managing the positions of these stages when exchanging WS2 and WS4.
The wafer stage movement control method, including the use of these interferometers, is also
The interferometers RIY1 to RIY2 measure the positions of the reticle stages RS1 and RS2.
Y6 is higher than the upper surface of the wafer stages WS1 and WS2 (or WS3 and WS4).
There is a measurement beam (length measurement beam) at the wafer stage WS1, WS2 (or
The beam is not blocked by the movement of the reticle stages RS1 and RS2.
Interferometers RIY1, RIY2, RIY5 or RIY3 for controlling the position of the direction,
A pair of double-pass interferometers may be used as RIY4 and RIY6, respectively.
That is, for example, one side in the Y direction of the reticle stage RS1 (the left side in FIG. 1)
A pair of corner cube mirrors are installed in the
A pair of double-pass interferometers irradiates the reticle stage RS1 with a measurement beam.
In this way, each double-pass interferometer can be used to control the reticle position in the Y direction.
It is no longer affected by the rotation (yawing) of the cruise stage, so it allows for more accurate reticle.
Next, the reticle exchange mechanism 20 will be described.
, two articulated robot arms 20b, 2 for reticle loading and unloading
0c and a driving device 21 for these robot arms.
The exchange mechanism 20 is a part of the reticle transport system and includes a robot arm 20b,
20c connects a reticle loader (not shown) to the reticle stages RS1 and RS2.
The reticle is handed over between the reticle stages RS1 and RS2.
The reticle is also exchanged between the reticle stages RS1 and RS2.
Reticle exchange is mainly performed during double exposure. In addition, the exposure apparatus 10 of this embodiment is provided with two wafer exchange mechanisms (not shown).
Each wafer exchange mechanism is attached to the wafer stage in the loading position.
Between wafer stage WS1 (or WS3) and wafer stage WS2 (or WS4),
Next, the control system of the exposure apparatus 10 will be described with reference to FIG.
a workstation (or microcomputer) that controls the entire device;
As shown in FIG. 5, the main controller 40 includes an interferometer system 38, a focus
The sensors 32A and 32B, the alignment control device 30, etc. are connected.
The main control unit 40 includes the magnetic levitation type two-dimensional linear actuator 22 and
The exposure amount control device 42 is connected to the shutter.
Here, the exposure apparatus 10 according to this embodiment will be described with reference to the operation of each of the above-mentioned components of the control system.
The exposure amount control device 42 controls the reticles R1 and R2 and the wafers W1 and W2 (or W3,
Before the synchronous scanning with W4 is started, an instruction is sent to the shutter driving device 44.
This opens shutters (not shown) provided at the emission ends of the light sources 12A and 12B.
Furthermore, the shutter driver 44 adjusts the scanning positions of the reticles R1 and R2.
The movable blinds arranged in the illumination optical systems IOP1 and IOP2 are driven.
This allows the pattern area of the reticle to be scanned immediately before the start and end of scanning exposure.
The illumination light passing through the outside does not unnecessarily expose areas other than the shot area on the wafer to be scanned and exposed.
After this, the main control device 40 controls the reticle via the two-dimensional linear actuator 22.
Reticle R1 and wafer W1, reticle R2 and wafer W2, i.e., reticle stage
RS1 and wafer stage WS1, reticle stage RS2 and wafer stage WS
The synchronous scanning (scan control) of the interferometer 2 is started.
Interferometers RIY1, RIY2, RIX1, RIX5, and WI constitute the system 38.
Y1, WIY9, WIX1, WIX2, WIX9 and interferometers RIY3, RIY4
, RIY6, RIX2, WIY2, WIY10, WIX3, WIX4, WIX1
While monitoring the measured value of 0, the main control device 40 controls the two-dimensional linear actuator.
That is, in this embodiment, the main control unit
and a two-dimensional linear actuator 22 controlled by the same.
The reticle stage RS1, the wafer stage WS1, and the reticle stage
When wafer stage RS2 and wafer stage WS2 are controlled to move at a constant speed within a predetermined tolerance,
In this regard, the exposure amount control device 42 controls the amount of light emitted from the excimer laser light sources 12A and 12B.
The laser control device 46 is instructed to start pulse emission.
The pattern is cross-sectionally illuminated by illumination light (exposure light) EL from the optical systems IOP1 and IOP2.
On the reticles R1 and R2, which are coated with aluminum, a rectangle defined by fixed blinds is formed.
The illumination area IAR is illuminated, and an image of the pattern in the illumination area is projected onto the projection optical system PL.
1. It was reduced to 1/4 by PL2 and photoresist was applied to its surface.
The scanning exposure is performed by projecting the light onto the wafers W1 and W2. FIG. 6 shows an explanatory diagram of the principle of this scanning exposure.
In the exposure apparatus 10, as shown in FIG. 6, a reticle R (R1 or
R2) is a rectangle (strip) whose longitudinal direction is perpendicular to the scanning direction (Y direction).
The reticle R is illuminated by an illumination area IAR (like a slit), and the reticle R is exposed.
The illumination area IAR (centered on the optical axis AX) is scanned at a speed VR in the Y direction.
The wafer W (W1 or W2) is projected onto the wafer W (W3 or W4) via the projection optical system PL (PL1 or PL2).
is projected onto W2) to form a slit-shaped exposure area (projection area) IA.
Since the wafer W has an inverted image relationship with the reticle R, the wafer W moves in the direction of the velocity VR.
In the opposite direction (+Y direction), the laser beam moves in synchronism with the reticle R on the same straight line as the reticle R.
The entire surface of the shot area (divided area) SA on the wafer W can be exposed.
The ratio of the scanning speeds VW/VR is precisely proportional to the reduction magnification of the projection optical system PL.
The pattern in the pattern area PA of the reticle R is formed on the wafer W.
The image is accurately reduced and transferred onto the upper shot area SA.
When the size of the shot area SA in the scanning direction changes due to the
The ratio is actively changed from the reduction magnification to reduce the magnification error between the shot area SA and the transferred image.
The longitudinal width of the illumination area IAR can be adjusted by adjusting the pattern on the reticle R.
It is wider than the turn area PA and narrower than the maximum width including the light-shielding area ST.
By scanning, the entire surface of the pattern area PA is illuminated.
As is clear from FIG. 2, in this embodiment, the first
The second reticle stages RS1 and RS2 are aligned in the same direction in the Y direction in opposite directions.
The reticle stages RS1 and RS2 move in synchronization with each other.
The rear stage WS1 (or WS3) and WS2 (or WS4) are facing in opposite directions.
The main controller 40 controls each stage so that it moves in the same straight line along the Y direction.
Returning to the previous explanation of the operation, the exposure amount control device 4
Reference numeral 2 denotes an illuminance uniforming optical system (not shown) that constitutes the illumination optical systems IOP1 and IOP2.
The driving of the vibrating mirror is controlled so that the pattern area on the reticle R is completely illuminated in the illumination area IA.
R (see FIG. 6), that is, until the image of the entire surface of the pattern reaches the wafer surface.
This control is continued until the light is formed in the dot area.
The pulsed light emitted by the laser control device 46 is incident on the wafers W1 and W2.
Any point on the image plane passes through the illumination field width (w) n times (n is a positive integer).
Since light emission is required, the oscillation frequency is set to f and the wafer scanning speed is set to V.
The following equation (2) must be satisfied: f/n=V/w (2) Furthermore, the irradiation energy of one pulse irradiated onto the wafer is P, and the resist sensitivity is
Assuming that the irradiation energy P and the oscillation frequency f are variable, the following equation (3) must be satisfied: nP=E (3) In this way, the exposure amount control device 42 controls the irradiation energy P and the oscillation frequency f.
The laser control unit 46 is then given a command to operate the laser.
The applied voltage (or charging voltage) to the light sources 12A and 12B and the generation of the trigger pulse
By adjusting the oscillation interval, the irradiation energy P and oscillation frequency f can be changed.
, and is configured to control the shutter driver 44 and the mirror driver.
If the sensitivity of the photoresist on the wafer varies greatly, multiple ND filters may be used.
The ND filter in the illumination light path is replaced by rotating the turret that holds the
In other words, the intensity of the pulsed light on the reticle (wafer) can be adjusted by changing the transmittance.
Furthermore, the exposure amount control device 42 adjusts the exposure amount depending on the sensitivity of the photoresist on the wafer W.
In this case, not only the voltage applied to the light source but also the settings in the illumination optical system must be adjusted.
The turret plate holding multiple ND filters is rotated to place them in the illumination light path.
By changing the ND filter placed inside the lens, i.e., by changing the transmittance, the reticle
The main controller 40 also controls the intensity of the illumination light (pulsed light) on the wafer (or the wafer).
When correcting the movement start position (synchronization position) of the tickle stage and wafer stage,
The two-dimensional linear actuator 22 drives each stage according to the correction amount.
Next, the stage position is corrected. Next, referring to FIGS. 2 and 7 to 10, the four wafers which are the feature of this embodiment will be described.
The parallel processing by stages WS1 to WS4 will be explained.
The wafer stages WS1 and WS2, and the wafer stages WS3 and WS4 have the same movement.
Since the work is done simultaneously in parallel, in the following, unless otherwise necessary, we will refer to the base board 1 in Figure 2.
Only the operation of wafer stages WS1 and WS3, which operate on the left half side of 8, will be explained.
First, normal exposure is performed on each wafer on the wafer stage.
In the following description, the wafer exchange time is Tc, and the alignment time is Td.
The alignment time (including search alignment and fine alignment) is Ta,
The light time is Te. The reticle R1 is a 9-inch reticle, and the wafer W
The following description will be given assuming that a 14-inch wafer is used as W3. In this case, the exposure time Te for one wafer, the wafer exchange time Tc, and the alignment time are
The relationship between the time Ta and the total time (Tc+Ta) is Te>(Tc+Ta).
Therefore, for the wafer on one wafer stage, for example, wafer stage WS1,
While exposure is being performed on the other wafer stage, e.g.
Naturally, there will be a waiting time for WS3. Therefore, let this waiting time be Tw.
FIG. 10 shows the flow of processing for wafer stages WS1 and WS3 in this case.
In step 101 of FIG. 10, wafer exchange is performed on wafer stage WS1.
That is, the wafer stage is in the loading position shown in FIG.
The exposed wafer W1 on WS1 and the new unexposed wafer (hereinafter, this wafer
For convenience, the wafer W1 is replaced with the wafer W2 by a wafer replacement device (not shown).
The position of the wafer stage WS1 at this loading position is
The main controller 40 manages the alignment based on the measured values of IY5 and WIX5. Then, in step 102, the alignment operation is performed on the wafer stage WS1.
Before this, the wafer stage WS1 is moved to the loading position shown in FIG.
8. The alignment system 28A is positioned in the vicinity of the alignment position shown in FIG.
The reference mark plate FM1 is moved to a position below the reference mark plate FM1.
The position of the wafer stage WS1 was initially determined based on the measurements of the interferometers WIY5 and WIX5.
The measurement beams from these interferometers are then transferred to the wafer stage WS.
Since the beam no longer hits the target 1, the main control device 40 controls the interferometers WIY5, WIX5, and
The measurement beams of the interferometers WIY4 and WIX6 are simultaneously reflected by the reflecting surface of the wafer stage WS1.
When the interferometer WIY5 is irradiated with the light, the correspondence between the measured values of the interferometer WIY4 and the interferometer WIY5 is
The measurement values of the interferometers WIX5 and WIX6 are then correlated.
For example, the alignment system 28 detects the fiducial mark plate FM1 and calculates its positional deviation.
The wafer stage WS1 is positioned at a position where the amount becomes a predetermined value (for example, zero).
Then, the measurement value of the interferometer WIY4 becomes equal to the measurement value of the interferometer WIY5, and the interferometer
The measurement value of the interferometer WIX6 is set to be equal to the measurement value of the interferometer WIX5.
Preset the measurement values of WIX4 and WIX6.
Instead of presetting each measurement, it is also possible to simply reset the measurement.
Furthermore, when associating the measurement values of the interferometers WIY5 and WIY4, the interferometer WIY3
The measurement beam of the wafer stage WS1 is also irradiated onto the reflecting surface of the wafer stage WS2.
It is preferable to preset the measurement values of the interferometer WIY3 together with the measurement values of the interferometer WIY4.
This allows, for example, an interferometer having the detection center of the alignment system 28A as the origin to
The wafer stage W is located on the (X6, Y4) coordinate system defined by WIY4 and WIX6.
As the alignment operation in step 102, first, the main control unit 40
The wafer stage WS1 is moved to the origin position on the coordinate system (X6, Y4), and the alignment is performed.
The first index mark on the fiducial mark plate FM1 is detected by the alignment system 28A (the index mark therein).
The relative positional relationship between the reference mark and the alignment system 28A is measured.
For example, the first reference mark is detected by a sensor of the FIA system that constitutes the alignment system 28A.
The image is captured, and the alignment control device 30 performs a first alignment with the index center as a reference.
The position of the reference mark is measured on the coordinate system (X6, Y4), and this measurement result is used as the main control
Next, search alignment is performed on wafer W1 on wafer stage WS1.
This search alignment is a pre-alignment performed during the transfer of the wafer W1.
Since the position error is large when only the first step is performed, the second step is performed on the wafer stage WS1.
Specifically, the wafer placed on the stage WS1 is pre-aligned.
The positions of three search alignment marks (not shown) formed on the wafer W1 are
Measurement is performed using the LSA system of the alignment system 28A, and the U is determined based on the measurement results.
The wafer W1 is aligned in the X, Y, and θ directions.
The operation of each part is controlled by the main controller 40. After this search alignment is completed, the arrangement of each shot area on the wafer W1 is
Here, the EGA method is used to perform the desired fine alignment.
is designed while managing the position of the wafer stage WS1 on the coordinate system (X6, Y4).
Based on the shot arrangement data (alignment mark position data) above,
While the stage WS1 is moved in sequence, the wafer W1 is
At least three selected shot areas SA are used as sample shots.
The alignment mark position is measured by the FIA system of the alignment system 28A.
Based on the results and the design coordinate data of the shot arrangement, statistical calculations were performed using the least squares method.
This calculates all shot arrangement data.
Y4), the coordinate position of each shot area SA is calculated.
The operation of each part is controlled by the main control unit 40, and the above calculations are
The EGA measurement is carried out by, for example, the method disclosed in Japanese Patent Laid-Open No. 61-44429 and
The corresponding patent is disclosed in U.S. Patent No. 4,780,617.
The disclosures of these documents are incorporated herein by reference to the fullest extent permitted by law. The main control device 40 then calculates the coordinate position of each shot based on the first reference mark.
By subtracting the coordinate position of the first reference mark, the relative position of each shot with respect to the first reference mark is calculated.
The wafer exchange and alignment operations are performed on the wafer stage WS1 side.
While this is happening, as shown in step 111 of FIG. 10, wafer stage WS3
On the other hand, exposure is carried out continuously by the step-and-scan method (see Figure 1).
7 and 8). Specifically, in the same manner as the wafer W1 side described above, the reference mark plate FM3 is
The relative positional relationship of each shot with respect to the first reference mark is calculated.
The results of the above and the reference arc plate FM by the reticle alignment microscopes 36A and 36B
The projection of the pair of second reference marks on the reticle 3 and the corresponding marks on the reticle on the wafer surface.
Based on the results of the relative position detection of the image (which will be described in detail later),
While sequentially positioning the shot areas on W3 below the optical axis of the projection optical system PL1,
Each time each shot area is exposed (the pattern of the reticle R1 is transferred), the reticle stage
By synchronously scanning the wafer stage RS1 and the wafer stage WS3 in the scanning direction (Y direction),
In this case, scanning exposure is performed for one shot on wafer W3.
When the transfer of the pattern of the reticle R1 to the shot area is completed, the exposure of the next shot area is started.
Because of the light, the wafer stage WS3 must be at least X
During this exposure, the main controller 40
Based on the measured values of RIY1, RIY2 and RIX1, the reticle stage RS1
and manages the position and speed of the interferometers WIY1, WIX1, and WIX2.
While managing the position and speed of the wafer stage WS1 based on
Furthermore, the main controller 40 controls the reticle signals obtained from the interferometers RIY1 and RIY2.
The rotation amount (yawing amount) of stage RS1 and the interferometers WIX1 and WIX2 are obtained.
Based on the amount of rotation (yawing amount) of the wafer stage WS3, the reticle R
The linear actuator 22 is arranged to offset the relative rotation error between the wafer W1 and the wafer W1.
This allows for a small gap between the reticle stage RS1 and the wafer stage WS3 in the XY plane.
At least one of the reticle stages is rotated.
is set to the center of the illumination area IAR, which coincides with the optical axis of the projection optical system PL1, as the center of rotation,
When the wafer stage WS3 is rotated, it is aligned with the optical axis of the projection optical system PL1.
It is desirable to set the center of the exposure area IA as the center of rotation. Furthermore, during scanning exposure, the main controller 40 determines whether the surface of the wafer W1 is projected within the exposure area IA.
The detection of the focus sensor 32A is set within the focal depth of the shadow optical system PL1.
The results are shown in Table 1. The results are obtained from the interferometers RIY1 and RIY5 and the interferometers RIX1 and RIX3.
Based on the rotation amounts of the stage WS3 around the X and Y axes obtained, the linear alignment is calculated.
The actuator 22 controls the Z-direction position and tilt angle of the wafer stage WS3.
At this time, the interferometers RIT1 and RIY5 and the interferometers RIX1 and RIX3 are
The rotation amounts of the reticle stage RS1 around the X-axis and Y-axis obtained from
Position control of wafer stage WS3, i.e., focus and leveling control of wafer W1
Also, the X-axis and Y-axis rotation of the reticle stage RS1 can be used to control the
Based on the amount of rotation, the imaging characteristics of the projection optical system PL1 that may occur due to this rotation are calculated.
the projection optical system to compensate for changes in properties (e.g., aberrations such as distortion).
At least one optical element of the PL1 may be moved.
This focus sensor is installed on the cruise stage RS1 side and is used to measure the scanning exposure or
Based on the Z-direction position and tilt angle of the reticle R1 detected before scanning exposure,
The linear actuator 22 is operated to offset the position change and tilt.
The movement of the reticle stage RS1 may be controlled by the
The focus sensor on the reticle stage RS1 detects the focus of the reticle stage RS1.
Using the detection results of the sensor, the linear actuator 22 moves the wafer stage W
The movement of S3 is controlled to perform focus and leveling control of the wafer W1.
In this embodiment, the exposure time Te is the wafer exchange time and the alignment time.
Since the total time is longer than the total time of wafer stage WS3,
Then, when the exposure operation on the wafer stage WS3 side is completed, the wafer stage W
S3 moves to the loading position as shown in FIG.
The movement is performed while the Y coordinate is almost fixed based on the measurement values of the interferometers WIX1 and WIX2.
This is performed by the main controller 40. Then, when the wafer stage WS3 moves to the loading position,
The wafer stage WS1, which has already been aligned, is at the exposure position shown in FIG.
During this movement, the wafer stage WS1 is initially moved to the position where the interference
It is managed based on the total WIY4 (and WIY3) and WIY6 measurements,
During this movement, the measurement beams from the interferometers WIY4 and WIX6 are incident on the wafer stage.
However, before that, the measurement beam from interferometer WIY3
When the wafer is in contact with the wafer stage WS1, the signals from the interferometers WIX1 and WIX2 are
Since the measurement beam hits the wafer stage WS1, the main controller 40
At that point, the interferometers WIX1 and WIX2 are reset, and thereafter, the three interferometers WIX
Y3, and the X of wafer stage WS1 based on the measurement values of interferometers WIX1 and WIX2.
The position in the Y plane is controlled and the object is moved toward the exposure position.
Before the measurement beam from the interferometer WIY3 does not hit the wafer stage WS1,
The measurement beams from the interferometers WIY1 and WIY9 are directed to the wafer stage WS1.
Therefore, the main controller 40 controls the length measurement beam to
By resetting the interferometers WIY1 and WIY9 when they hit the wafer 1,
The position of the first stage WS1 is measured using interferometers WIY1 (WIY9), WIX1, and WIX2.
It becomes possible to manage the coordinate system (Xe, Ye) that is specified.
In this example, the interferometers WIX1 and WIX2 and the interferometers WIY1 and WIY9 are linked in time series.
It was supposed to be set up with six interferometers: WIX1, WIX2, WIX6, and WIXY.
The measurement beams WIY1, WIY3, and WIY9 are irradiated onto the wafer stage WS1.
In this state, the interferometers WIX1 and WIX2 and the interferometers WIY1 and WIY9 are rotated almost simultaneously.
That is, the six interferometers WIX1, WIX2, W
Each measurement beam of IX6, WIY1, WIY3, and WIY9 is on wafer stage WS1.
In the state where the light is irradiated to the reticle alignment microscopes 36A and 36B,
Therefore, a pair of second fiducial marks on the fiducial mark plate FM1 and a corresponding reticle
The pair of marks on the reticle alignment microscope 36 are then detected.
The positions of the second reference mark and the mark on the reticle detected by 36A and 36B, respectively
The wafer stage WS1 is positioned at a position where the amount of deviation is a predetermined value (for example, zero).
In this state, the measurement values of the interferometers WIX1, WIX2, and the interferometers WIY1, WIY9 are
In this case, the interferometers WIX1, WIX2, and WI are reset simultaneously.
The position information of the reticle stage RS1 when Y1 and WIY9 are reset is
The position information is detected by interferometers RIX1, RIY1, and RIY2, and the main control unit
The data is stored in the internal memory of the interferometers WIX1, WIX2, and WIX40.
a wafer-side orthogonal coordinate system (Xe, Ye) defined by IY1, an interferometer RIX1,
The coordinate system is related to the reticle-side orthogonal coordinate system defined by RIY1 and RIY2.
This means that tickle alignment is not required in this example, which will be described later.
During scanning exposure, the control device 40 uses this stored position information and the interferometers RIX1 and RIX3.
, RIY1, and RIY2, the reticle stage RS1 is moved.
In addition, the measurement values of the interferometers WIX1, WIX2, and the interferometers WIY1, WIY9 are
Instead of resetting the interferometers WIX1 and WIX2, the measurement values of the interferometers WIX
The measurement values of the interferometers WIY1 and WIY9 are equal to the measurement values of the interferometers W
Interferometers WIX1, WIX2, and WIX3 are set to the same value as the measurement value of IY3.
The measured values of IY1 and WIY9 may be preset.
The coordinate system (X6, Y
4) The coordinate position on the coordinate system is determined by the interferometers WIX1, WIX2, and WIY1.
It can be used as a coordinate position on the system (Xe, Ye) as it is.
, the coordinate position of each shot area on the wafer determined by the EGA method as described above.
By subtracting the coordinate position of the first fiducial mark on fiducial mark plate FM1 from
The relative positional relationship of each shot area on the wafer with respect to the first reference mark is obtained.
In this way, when the movement of the wafer stage WS1 to the exposure position is completed,
The exposure of wafer W1 on wafer stage WS1 shown in step 104 of FIG.
The exposure is carried out in the same manner as above, but prior to this exposure, the reticle alignment is carried out as follows.
A pair of second fiducials on the fiducial mark plate FM1 by the alignment microscopes 36A and 36B
Detecting the relative position of the mark and the corresponding projected image of the reticle mark on the wafer surface (
That is, main controller 40 sets the coordinate system (Xe, Ye) at the origin position on the coordinate system.
The wafer stage WS1 is moved to position the reticle alignment microscopes 36A and 36B.
The pair of second reference marks on the reference mark plate FM1 are exposed to the exposure light.
The relative positions of the projected images of the corresponding reticle marks on the wafer surface are detected.
2. Coordinate positions of the reference marks and coordinates of the projected image of the mark RMK on the reticle R on the wafer surface
The difference between these two positions determines the exposure position (the projection position of the projection optical system PL1).
The relative coordinate positions of the pair of second fiducial marks on the fiducial mark plate FM1 and the center of the shadow
Then, the main control device 40 calculates the first reference mark on the reference mark plate FM1.
The relative positional relationship of each shot to the work, the exposure position and the position on the fiducial mark plate FM1
The relative coordinate position of the pair of second reference marks determines the exposure position and the position of each shot.
Based on the result, the relative positional relationship of each shot on wafer W1 is calculated.
As mentioned above, high-precision alignment is possible even if the interferometer is reset.
The reason is that the first fiducial mark on the fiducial mark plate FM1 is aligned by the alignment system 28A.
After measuring the alignment marks of each shot area on wafer W1,
By this, the virtual position calculated by measuring the first reference mark and the wafer mark is
This is because the distance between the first reference mark and the second reference mark is calculated using the same sensor.
Since the relative positional relationship (relative distance) between the work and the position to be exposed is required,
Before exposure, the exposure position and the second reference are determined by the reticle alignment microscopes 36A and 36B.
The positional relationship with the first reference mark is known.
For example, by adding the relative distance to that value, the beam of the interferometer is
Even if the power is cut off during the movement of the page and reset again, high-precision exposure operation is performed.
The first fiducial mark and the pair of second fiducial marks are always on the same fiducial mark plate.
Therefore, if the drawing error is calculated in advance, there is no fluctuation factor as long as only the offset is managed.
In addition, the pair of second fiducial marks may also have an offset due to a reticle drawing error.
For example, Japanese Patent Laid-Open No. 7-176468 and the corresponding U.S. Pat. No. 5,629,995 are known.
As disclosed in US Pat. No. 646,413, multiple marks are used during reticle alignment.
Either use a laser to reduce the drawing error, or measure the reticle mark drawing error in advance.
If the designated country or countries designated in this international application are not included, offset management alone can be used.
incorporates by reference this publication and the U.S. patent to the extent permitted by the domestic laws of the selected elected countries.
The applicant has used two wafer stages and
While the other wafer stage performs the exposure operation, the other wafer stage performs the wafer exchange and alignment.
An exposure method and an exposure apparatus for performing this exposure are disclosed in International Publication W98/24115.
This international publication also describes the interference that occurs when aligning two wafer stages.
If the wafer stage moves over a range that cannot be tracked by a single measurement beam,
In this case, a method for resetting the interferometer and a method for using a reference mark formed on the stage are also provided.
A method for tracking the position of a wafer stage using a laser is disclosed, and this method is incorporated into the present invention.
The method may also be applied to the designated States designated in the present international application or the selected States.
To the extent permitted by the domestic laws of the selected countries, International Publication WO 98/24115 is incorporated by reference.
In this way, reticle alignment is performed, and the reticle is aligned on the wafer stage WS1.
While the exposure is being performed, the wafer stage WS3 is simultaneously
The wafer exchange, alignment, and waiting are the same as those on the wafer stage WS1 side.
After the exposure in step 104 is completed, the same parallel processing as above is performed.
In the exposure apparatus 10 of this embodiment, the wafer stages WS1 and WS3 are
Simultaneously with this parallel operation, the remaining wafer stages WS2 and WS4 also perform similar parallel operations.
However, the movements of wafer stages WS1 and WS2, and WS3 and WS4 are completely symmetrical.
As a result of calculations by the inventors using a simple simulation, this exposure apparatus 10
The basic configuration adopted by the company is a double reticle stage + double wafer stage.
By this configuration, the exposure time Te is equal to the wafer exchange time and the alignment time by the normal exposure described above.
When the total processing time (Tc + Ta) is doubled, the
The throughput is improved by about three times, and the exposure time Te is equivalent to the time (Tc + Ta).
It was concluded that in some cases the throughput could be improved by about four times. Next, double exposure was performed using the first reticle R1 and the second reticle R2 described above.
In this case, the first reticle R1 has a pattern to be transferred.
A first decomposition pattern (referred to as pattern A) is formed on the second reticle R2.
A second decomposition pattern (referred to as pattern B) of the pattern to be transferred is formed.
FIG. 11 shows the flow of processing for wafer stages WS1 and WS3 in this case.
In steps 121 and 122 of FIG. 11, in the case of the normal exposure described above,
Similarly, wafer exchange and alignment operations are performed on wafer stage WS1.
At this time, on the wafer stage WS3 side, the step-up is performed in the same manner as described above.
The pattern of the first reticle R1 is transferred onto the wafer W3
The pattern is transferred to each shot area in sequence (step 131). During the exposure in step 131, the wafer stage WS1 is in a waiting state.
In this case, even after the exposure in step 131 is completed, the wafer stage
On wafer stage WS3, wafer exchange is not performed immediately, so
While the exposure operation in step 131 is being performed, the wafer stage
At the same time, on wafer stage WS4 side, the step
The pattern of the second reticle R2 is then transferred onto the wafer W.
3, and the exposure operation is completed in step 131.
At approximately the same time, the exposure operation on the wafer stage WS4 side is also completed. Then, when these exposure operations are completed, the reticle is replaced by the reticle replacement mechanism 20.
Reticle R1 on reticle stage RS1 and reticle R2 on reticle stage RS2
The reticle is exchanged (step 132 in FIG. 11).
This reticle exchange is performed by the robot arms 20b and 20c.
When this is completed, the reticle alignment is performed on the wafer stage WS3 side in the same manner as described above.
A step-and-scan exposure is then performed,
The pattern of the second reticle R2 is transferred sequentially to each shot area on the wafer W3.
(Step S131). As a result, in step S131,
The drawn first resolved pattern is transferred to each shot area on wafer W3.
The second resolved pattern drawn on the second reticle R2 is transferred in an overlapping manner.
In parallel with the operations of steps 132 and 133, the wafer stage WS
On side 4, reticle alignment and step-and-scan exposure are performed.
At the same time as step S131, the second resolved pattern on the second reticle R2 is
The first reticle R1 is transferred to each shot area on the wafer W4.
The decomposed patterns are transferred in an overlapping manner.
On the WS1 side, the waiting state continues as shown in step 123 of FIG.
In this case, the specific exposure sequence for double exposure on wafer W3 is as shown in FIG.
), each shot area of the wafer W3 is projected onto the reticle R1 (pattern A).
) to perform scanning exposure from A1 to A12 in order, and then, as shown in FIG.
Sequential scanning is performed using reticle R2 (B pattern) in the order of B1 to B12.
When the double exposure operation on the wafer stage WS3 side is completed, the wafer
The stage WS3 moves to the loading position.
The same process is carried out as in the case of normal exposure. Then, when the wafer stage WS3 moves to the loading position,
The wafer stage WS1, which has already been aligned, moves to the exposure position as described above.
In this way, when the movement of the wafer stage WS1 to the exposure position is completed,
The pattern of the reticle R2 is transferred onto the wafer W1 on the wafer stage WS1 (step
(step 124), reticle exchange (step 125), reticle for wafer W1
The pattern transfer of R1 (step 126) is carried out in the same manner as described above. In this way, while double exposure is being carried out on the wafer stage WS1,
In parallel with this, on the wafer stage WS3 side, the wafer stage WS1 described above
The wafer exchange, alignment, and waiting are performed in the same manner as on the other side (steps 134 to 136).
) operation is performed. After the exposure in step 126 is completed, the same parallel processing as above is performed.
The operations of the various parts during the double exposure are also controlled by the main controller 40. In the exposure apparatus 10 of this embodiment, the wafer stages WS1 and WS3 are
Simultaneously with this parallel operation, the remaining wafer stages WS2 and WS4 also perform similar parallel operations.
However, the movements of wafer stages WS1 and WS2, and WS3 and WS4 are completely symmetrical.
As a result of calculations by the inventors using a simple simulation, this exposure apparatus 10
The basic configuration adopted by the company is a double reticle stage + double wafer stage.
By the above-mentioned double exposure, the exposure time Te for one wafer is
is set to twice the sum of the wafer exchange time and alignment time (Tc+Ta) and
If the lens exchange time is set to about half of the exposure time Te, the throughput is
It was concluded that the output was improved by approximately 2.4 times. Thus, the exposure apparatus 10 of this embodiment is the best in comparison with the conventional double exposure.
This will dramatically improve the throughput, which has been a major issue, as explained earlier.
By using the various double exposure methods described above, the high resolution and DOF can be improved.
It is now possible to achieve exposure of up to 0.1 μmL/s, and achieve a high throughput of 25
In the above description, steps 103 and 114 in FIG.
The explanation was given on the assumption that there are waiting times such as steps 123 and 136 in step 1.
This waiting time does not contribute to the production of the device, so it is important to make effective use of this waiting time.
The method to use is to use a sample shot of EGA and/or a single sample.
One possible solution is to increase the number of alignment marks detected in a shot.
This will improve alignment accuracy and result in less wasted waiting time.
For example, in the case of normal exposure as explained above, the sample shot is taken when the waiting time is
Furthermore, according to the exposure apparatus 10 of this embodiment, in addition to the effect of improving the throughput,
In addition, the following various effects can be obtained. For example, by simply using two wafer stages, it is possible to perform exposure operations and other operations, such as alignment.
When processing the image in parallel, the scanning exposure on one wafer stage side
The reaction force generated when the reticle stage or wafer stage is accelerated or decelerated is applied to the base plate 1.
The body including the wafer stage 8 is vibrated, and the vibration causes the alignment of the other wafer stage.
However, in this embodiment, the following reasons are considered:
In other words, the first and second reticle stages RS1 and RS2 have approximately the same mass M.
At the same time, the first, second, third, and fourth wafer stages WS1, WS2, W
S3 and WS4 have almost the same mass m, and the first reticle stage RS1 and the second
2 reticle stage RS2 are facing in opposite directions, and therefore wafer stage WS1 and
WS2 also moves in the same direction in the opposite direction and performs scanning exposure at the same scanning speed.
Therefore, when accelerating and decelerating the reticle stage RS1 and the reticle stage RS2,
The reaction forces generated on the wafer stage WS1 and the wafer stage WS2 cancel each other out.
The reaction forces generated on the base board 18 during acceleration and deceleration of S2 cancel each other out.
In this case, the reticle stages RS1 and RS2 and the wafer stages WS1 and WS2 are the same.
Since the base plate 18 moves along the same straight line on the surface, it is possible to rotate θ and
Therefore, the scanning exposure operation of wafer stages WS1 and WS2 and the wafer stage WS
3. Although the alignment operation of WS4 is performed simultaneously, the body
This ensures that problems such as poor alignment accuracy caused by vibrations in the
In addition, the alignment operation of the wafer stages WS3 and WS4 can also be performed.
The center of gravity of the body including the base plate 18 moves almost simultaneously with these stages.
By moving in a sequence and along a path that avoids vibration, the vibration-isolating pad 16
Passive air pads are used to isolate the vibrations from the installation floor at the micro-G level.
Therefore, there is no need for a synchronous control circuit or active
Both alignment and exposure accuracy are improved without the need for special equipment such as vibration isolation devices.
The two reticle stages RS1 and RS2 can be moved up and down with almost zero synchronization error.
In this embodiment, the first and second projection optical systems PL1 and PL2 have the same projection magnification.
The mass M of the reticle stages RS1 and RS2 is equal to the mass M of each wafer stage (W
Since the projection magnification is β times the mass m of each of the elements (WS1, WS2, WS3, WS4),
Even if the scanning speeds of the reticle stages RS1 and RS2 are different, the main control unit
The reticle stage RS is moved by the two-dimensional linear actuator 22.
At least one of the wafer stages RS1 and RS2, and the wafer stages WS1 (or WS3), WS
2 (or WS4) and adjust the acceleration distance (deceleration distance)
The acceleration (deceleration) of the reticle stages RS1 and RS2 and the wafer stage
The acceleration (deceleration) of stages WS1 (or WS3) and WS2 (or WS4)
By controlling the movement so that the reticle stages RS1 and RS2 are approximately equal,
The wafer stage WS1 (or WS3) is set to the projection magnification β of the first projection optical system PL1.
The reticle stage RS1 and the reticle stage RS2 move synchronously in the first direction at a speed ratio according to the reticle stage RS1.
The projection stage WS2 (or WS4) is adjusted in accordance with the projection magnification β of the second projection optical system PL2.
The reticles are moved synchronously with each other by moving synchronously in the first direction at a speed ratio that matches the speed ratio.
The law of conservation of momentum holds between the stage and the wafer stage, and a synchronous control circuit and
Scanning with almost zero synchronization error is possible without installing special equipment such as an active vibration isolation device.
In this embodiment, the projection optical systems PL1 and PL2 are catadioptric systems including three mirrors.
Because it is a folding optical system, the projection optical system can be controlled using illumination light with a wavelength of 200 nm or less.
High precision of fine patterns on the submicron order or less without increasing the size too much
Furthermore, according to this embodiment, the high through-put transfer as described above is possible.
Since a larger put can be obtained, the off-axis alignment system can be made larger than the projection optical system PL.
Even if they are installed far apart, the impact of the degradation of throughput is almost eliminated.
Therefore, we designed a cylindrical optical system with high N.A. (numerical aperture) and small aberrations.
However, the exposure apparatus and exposure method according to the present invention
Of course, this is not limited to the above embodiment. For example, the first reticle stage RS1 and the wafer stage WS (or WS3)
The mass ratio does not have to be equal to the projection magnification of the first projection optical system PL1.
Similarly, the mass ratio between the reticle stage RS2 and the wafer stage WS2 (or WS4) is
The magnification of the first projection optical system PL1 does not have to be equal to that of the second projection optical system PL2.
Even if the reticle stage RS1 and the first wafer stage WS1 are moved in opposite directions,
and the reaction force remaining without being cancelled out during acceleration and deceleration of the second reticle stage RS2 and the second reticle stage RS3.
Even if the wafer stage WS2 is moved in the opposite direction, the acceleration and deceleration are not canceled out and remain.
Specifically, the first and second forces are set to cancel each other out.
The mass of the reticle stages RS1 and RS2 and the mass of the first and second wafer stages WS1
, WS2 and at least one of the masses is different, the first reticle stem
The first wafer stage RS1 and the second reticle stage WS1, and the second reticle stage RS2 and
The acceleration and deceleration speeds are made different between the second wafer stage WS1 and the second wafer stage WS2, and the reaction force generated during the acceleration and deceleration
At this time, the first reticle stage R
S1 and first wafer stage WS1, and second reticle stage RS2 and second
The acceleration and deceleration speeds of the WS2 and WS3 are adjusted to suit the run-up distance and acceleration before and after scanning exposure.
The masses of the first and second reticle stages RS1 and RS2 are adjusted, and the masses of the first and second reticle stages RS1 and RS2 are adjusted.
The masses of the two wafer stages WS1 and WS2 do not have to be equal to each other.
In this case, even if the first and second reticle stages RS1 and RS2 are moved in opposite directions,
The reaction force that remains uncounted during acceleration and deceleration, and the first and second wafer stages WS
1. Even if WS2 is moved in the opposite direction, the reaction force remains without being canceled out during acceleration and deceleration.
For example, the first reticle stage RS1 and the second reticle stage RS2 are
The mass ratio of the first wafer stage WS1 to the first projection optical system PL1 is set to be approximately equal to the magnification of the first projection optical system PL1.
Comb and mass ratio between second reticle stage RS2 and second wafer stage WS2
is set to be approximately equal to the magnification of the second projection optical system PL2. Alternatively, the mass of the first reticle stage RS1 and the first wafer stage WS1 may be set to
Ratio, magnification of the first projection optical system PL1, second reticle stage RS2 and second wafer
At least one of the mass ratio of the stage WS2 and the magnification of the second projection optical system PL2 is
If they are different, the first reticle stage RS1 and the first wafer stage W
The acceleration/deceleration of S1, the second reticle stage RS2, and the second wafer stage WS2
The reaction force generated during acceleration and deceleration is made approximately equal to cancel it out.
At this time, the first reticle stage RS1 and the first wafer stage
The first reticle stage RS1, the second reticle stage RS2, and the second wafer stage WS2 are
The run-up distance before and after scanning exposure and the acceleration start position are adjusted according to the acceleration and deceleration speeds.
Furthermore, the sensitivity characteristics of the photoresist differ between the first wafer W1 and the second wafer W2.
Even in this case, scanning exposure is performed on the first wafer W1 and the second wafer W2.
The moving speeds of the first and second wafer stages W are kept the same without being different.
The first and second wafer stages S1 and S2 are driven under the same conditions.
The acceleration during the run-up period before scanning exposure of WS1 and WS2 is the same, and at the start of acceleration
The time can also be the same for the first wafer W1 and the second wafer W2.
The scanning exposure end time is the same, and the deceleration start time can be matched.
Furthermore, when the throughput is taken into consideration, the first and second
2. Set the scanning speed of wafers W1 and W2 to the maximum moving speed of the wafer stage.
However, the first and second wafers W1 have different photoresist sensitivity characteristics.
When the scanning speeds of the first and second wafers W1 and W2 are set to be the same,
In order to give an appropriate exposure dose according to the sensitivity characteristics of the photoresist,
Based on the sensitivity characteristics of the resist and the scanning speed, the first and second wafers W1 and W2
At least one of the scanning exposure conditions is also changed.
In some cases, the intensity of the illumination light on the wafer and the width of the illumination light on the wafer in the scanning direction
If the exposure illumination light is pulsed light, then it is sufficient to adjust at least one of the following:
The intensity of the illumination light on the wafer, the width of the illumination light on the wafer in the scanning direction, and the pulsed light
It is only necessary to adjust at least one of the masses of the first and second reticle stages RS1 and RS2 and the oscillation frequency of the first and second reticle stages RS1 and RS2.
When at least one of the masses of the second wafer stages WS1 and WS2 is different
As described above, during the pre-scanning of the first wafer W1 and the second wafer W2,
The reaction force generated by the two objects should be approximately equal if the acceleration is changed.
Furthermore, the scanning exposure start time is set to be the same for the first wafer W1 and the second wafer W2,
In addition, the first and second wafers are spaced apart so as to minimize the time difference between the generation of the reaction force.
It is desirable to adjust the run-up distance or acceleration start position of at least one of the wafers.
The scanning exposure time per shot between the first wafer W1 and the second wafer W2, i.e., the scanning exposure time
The exposure end time may also be different. For example, the scanning exposure end time of the first wafer W1 is
If the scanning exposure of the second wafer W1 ends earlier than the scanning exposure of the second wafer W2, the first wafer W1 will continue to be scanned even after the scanning exposure is completed.
The first wafer W1 continues to move at the same speed as during scanning exposure, and the second wafer W2 is scanned and exposed.
At approximately the same time as the start of deceleration after the end of the light, the first wafer W1 starts to decelerate.
, the first and second reticle stages RS1 and RS2, and the first and second wafer stages
The deceleration of the first and second wafers after scanning exposure is determined according to the masses of WS1 and WS2.
This allows the reaction forces generated during the deceleration period to be almost cancelled out.
The sensitivity characteristics of the photoresist are the same for the first wafer W1 and the second wafer W2.
However, if the width of the shot area in the scanning direction is different,
The scanning exposure time per shot differs between the first wafer W1 and the second wafer W2.
Similarly to the above, the scanning speed of at least one of the first and second wafers W1 and W2 is
It is desirable to adjust the scanning exposure time to match the first and second scanning exposure times.
The scanning speed is adjusted to provide the second wafer with the correct exposure dose.
The scanning speed is adjusted based on the sensitivity of the photoresist and the first and second wafers.
In the above embodiment, the first and second projection optical systems PL1 and PL2 are both reticles.
The case where a partial inverted image of a lens pattern is projected onto a wafer has been described.
The first projection optical system PL1 projects a partial erect image of the pattern of the first reticle R1 onto the first wafer.
It is also possible to project onto W1. In such a case, the first projection optical system
The first reticle R1 and the first wafer W1 are moved in the Y direction at a speed ratio according to the magnification of PL1.
In this case, the second projection optical system PL2 moves in the same direction along the
A partial erect image of the second reticle pattern is also projected onto the second wafer W2,
The second reticle R2 and the second wafer W2 are moved in the same direction along the Y direction.
At the same time, the moving direction is opposite to the moving direction of the first reticle R1 and the first wafer W1.
This allows the first reticle R1 and the first wafer W1 to be aligned in the same direction.
The reaction force generated by the synchronous movement and the synchronous movement of the second reticle R2 and the second wafer W2
By the way, when the first wafer W1 is sequentially applied to a plurality of divided areas (shot areas) on the first wafer W1, the reaction force generated by the movement of the first wafer W1 is almost cancelled out.
The pattern of the tickle R1 is transferred to a plurality of divided areas (short
When the pattern of the second reticle R2 is transferred to the first and second reticle R1 in succession,
The exposure stages WS1 and WS2 each complete scanning exposure of one divided area.
The laser beam is moved in the direction (X direction) perpendicular to the scanning direction (Y direction).
The first and second wafer stages WS1 and WS2 are rotated in opposite directions along the X direction.
This makes it possible to minimize the reaction force generated in the X direction.
However, in this case, the first and second wafer stages WS1
, WS2 are not stepped on the same straight line, so the base plate 18 has a rotary motor.
This generates vibrations, but the first and second wafer stages WS1 and WS2
In addition to the vibration isolation pad 16 on which the base board 18 on which the vibration isolation pad 16 is placed is placed,
A frame is provided on the floor (or base plate) on which the 16 is installed, and the base plate
For example, a voice coil motor is disposed between the rotor 18 and the frame, and the rotation moment is
In the above embodiment, the shot area of the first wafer W1 and the second wafer W2 is
On the assumption that the number of wafers is the same, the first wafer stage WS1 and the second wafer stage WS2 are
In the above description, the first wafer WS2 always operates in the same manner.
The number of shot areas (divided areas) to which patterns are to be transferred on the first wafer W1 and the second wafer W2
For example, if the number of divided regions on the first wafer W1 is different from the number of divided regions on the second wafer W2,
When the number of divided areas on the second wafer W2 is greater than the number of divided areas on the first wafer W1,
Even after the transfer of the pattern of the second reticle R2 is completed, all of the patterns on the first wafer W1 remain.
The first reticle R1 is not transferred until the transfer of the pattern of the first reticle R1 to the divided area is completed.
In parallel with the synchronous movement of the first wafer stage WS1 and the second stage RS1,
2. Drive the reticle stage RS2 and the second wafer stage WS2 (idle movement)
It is desirable to cancel out this reaction force. The exposure apparatus of the present invention can also be constructed as shown in the modified example in FIG.
In the exposure apparatus 10 shown in FIG. 1, the base plate 18 is supported by four vibration isolation pads 16.
However, in the exposure apparatus 200 shown in FIG. 15, four vibration isolation pads
16 is provided with a surface plate 190 supported horizontally by the base plate 180.
190. That is, the exposure apparatus shown in FIG.
In this position, the wafer stages WS1 to WS4 and the reticle stages RS1 and RS2 are
The base is moved by a two-dimensional linear actuator (first linear actuator 22).
In the past, the base plate (18) was supported by floating, but in this modified example, the base plate 180 is also supported by floating.
The surface plate 190 is supported by a second linear actuator (not shown).
The second linear actuator is similar to the first linear actuator.
In addition, a plurality of magnets embedded in the bottom surface of the base plate 180 and the entire surface plate 190
The base plate can be made of a coil embedded across the entire surface.
180 and the surface plate 190 have openings 18 at the portions through which the illumination light EL passes.
In the exposure apparatus 200 shown in FIG.
When either the reticle stage RS1 or RS2 moves, the stage movement
In response to this reaction force, the base plate 180 moves to the surface plate.
At this time, the base plate moves relative to the system including the base plate and the stage.
The momentum of the stage moves so that it is equal to the momentum of the stage, and the average of the stages
Even if the center of gravity position changes and an unbalanced load occurs on the base plate 180, the unbalanced load is absorbed by the base plate 180.
This can be canceled by moving the center of gravity of the platen 180.
The center of gravity of the entire 200 can be kept at a predetermined position, and exposure can be performed by moving the stage.
This prevents the device itself from vibrating. In particular, in this modified example, when one of the reticle stages moves, or when two
Or, when multiple reticle stages are moved, the base of the reticle stage
When the reaction forces against the base plate do not cancel, for example, the reticle moves in opposite directions.
Even when the stage does not move or when the weights of the reticle stages are different,
The base plate 180 moves relative to the surface plate 190 in response to the reaction force generated on the base plate 180.
This makes it possible to prevent vibration of the exposure apparatus 200.
Therefore, this type of exposure apparatus 200 has multiple reticle stages and wafer stages.
When moving the stage, the reaction forces generated by multiple stages are carried by each other.
There is no need to adjust the stage movement path or speed between stages to cancel the
Relaxing sequence control when performing exposure using multiple subunits of an exposure device
Therefore, the exposure apparatus 200 of this modified example can accommodate a large number of stages.
Indeed, the more complex the stage movement path, the more effective this becomes. Also, when a pattern formed in one divided area on the wafer is defective,
Normally, the patterns of the next layer and subsequent layers are not transferred to the partitioned area.
In the exposure apparatus 10 of the embodiment, in order to cancel out the reaction force, the area where the defective pattern is formed is
Even in the image area, the reticle and wafer are moved synchronously to transfer the reticle pattern to the wafer.
Transfer to the divided area, or move the reticle stage and wafer stage by idle movement.
In the exposure apparatus 10 of the above embodiment, for example, one divided area on the wafer
When a reticle pattern is transferred to one divided area and another divided area in sequence,
the wafer stage is stopped between the scanning exposure of the divided area and the scanning exposure of the other divided area.
Furthermore, it is desirable to move the wafer between the scanning exposures without moving it.
It is desirable for the movement locus to be parabolic (or U-shaped).
In this case, the wafer stage moves in the stepping direction during deceleration of the reticle stage.
Acceleration begins and decreases during acceleration for the next shot of the reticle stage.
At this time, the first wafer stage WS1 and the second wafer stage WS2 are
The stepping direction is reversed with WS2, and the acceleration/deceleration timing is
In the above embodiment, four wafer stages are provided that move on the same plane.
However, the present invention is not limited to this case. For example,
A third wafer stage that moves on the same plane as the second wafer stages WS1 and WS2.
WS3 is provided, and there is only one alignment system to detect the alignment mark.
Even in such a case, the first and second wafer stages WS
1. As described above, the reticle is exposed by scanning exposure to the wafers W1 and W2 on WS2.
While the pattern is being transferred, the pattern formed on the wafer W3 on the third wafer stage
The alignment marks can be detected by the alignment system.
The exposure operation for the wafer on one wafer stage and the exposure operation for the wafer on the other wafer stage
The mark position detection operation (alignment operation) for the wafer is performed simultaneously in parallel.
In this case, the driving device (22, 40) drives the two wafer stages.
After the exposure operation for the wafer on the page is completed, the third wafer for which the mark position detection is completed is
Wafer stage WS3 and first wafer stage WS1 or second wafer stage WS2
and the third wafer stage WS3 is replaced with the first reticle stage RS1 or the third reticle stage RS2.
The second reticle stage RS1 can be moved in synchronization with the second reticle stage RS2.
1. Immediately after the exposure operation for the second wafers W1 and W2 is completed, the third wafer stage
Scanning exposure for transferring a reticle pattern onto wafer W3 on WS3 is possible.
In this case, the alignment time for the third wafer W3 is 1/2 times the time for the first and second wafers W1 and W2.
The exposure time for the wafer is completely overlapped, so the throughput is much faster than with conventional methods.
In the above embodiment, the wafer stages WS1 to WS4 are square wafer stages.
Although the case where an EH stage is used has been exemplified, the present invention is not limited to this.
Instead, for example, a triangular wafer stage may be used.
The wafer is scanned using an interferometer with a length measurement axis tilted at a predetermined angle relative to the X and Y axes.
Since the stage position can be managed, the alignment end position can be easily changed to the exposure position.
It is thought that this will make it easier to manage the position of the wafer stage when moving to a new position. An example of a triangular stage is shown in FIG. 16. FIG. 16 shows a triangular stage.
The first, second, and third interferometers 76X1, 76Y constitute the position measurement system.
76X2 and the beams RIX1, RIY, and RIX2 from the three interferometers,
FIG. 1 is a plan view showing the triangular wafer stage TWST.
The stage TWST is formed in the shape of an equilateral triangle in plan view, and each of its three sides has a
The first, second and third reflecting surfaces 60a, 60b and 60c are mirror-finished.
The second interferometer 76Y is formed by detecting the position of the wafer stage TWST during scanning exposure.
The interferometer beam RIY in the Y-axis direction (first axis direction) is reflected by the second reflecting surface 60b.
The reflected light is received by irradiating the wafer stage TWST perpendicularly.
The first interferometer 76X1 measures the position in the Y-axis direction.
The interferometer beam RIX1 inclined at a fixed angle θ1 is irradiated perpendicularly onto the first reflecting surface 60a.
The reflected light is received, and the third interferometer beam RIX1 is reflected by the
The position (or velocity) in the axial direction is measured.
The total 76X2 is the interferometer beam RI in the direction inclined at a predetermined angle θ2 with respect to the Y-axis direction.
X2 is irradiated perpendicularly to the third reflecting surface 60c, and the reflected light is received to obtain interference.
The position in the fourth axis direction, which is the direction of the measurement beam RIX2, is measured.
Stage position in the third axis direction and/or fourth axis direction and angle θ1 and/or θ2
Using this value, the stage position in the X-axis direction (second axis direction) perpendicular to the Y-axis is calculated.
Alternatively, the stage position in the third axis direction and the angle θ1 can be calculated as follows:
Using this, the X-axis and Y-axis positions of the stage can be calculated.
By using such a triangular stage, the X-axis and Y-axis
The stage can be made smaller and lighter than conventional stages equipped with reflecting mirrors,
As in the exposure apparatus of the present invention, a plurality of mask stages and a plurality of substrate stages are shared.
In the above embodiment, for the sake of convenience, most of the components constituting the interferometer system are
Although we have explained the case where a single-axis interferometer is used as an interferometer, it is also possible to measure yawing, etc.
Of course, a multi-axis interferometer may be used. The exposure illumination light is an ArF excimer laser with a wavelength of about 200 nm or less.
Or F ₂ It is not limited to vacuum ultraviolet light (VUV light) such as laser, but also includes light with a wavelength of 2
Ultraviolet light of about 1000 nm or more (KrF excimer laser, i-line, g-line, etc.)
Alternatively, the wavelength may be 5 to 15 nm, for example 13.4 nm or 11.5 nm.
The light may be EUV light (XUV light) in the soft X-ray region, which is 1000 nm.
Silver lamp, excimer laser, or F ₂ Instead of a laser, a DFB semiconductor laser or
refers to a single wavelength laser in the infrared or visible range emitted from a fiber laser, e.g.
For example, erbium (or both erbium and ytterbium) doped fiber
The harmonic wave is amplified by a fiber amplifier, and converted to ultraviolet light using a nonlinear optical crystal.
For example, the oscillation wavelength of the single wavelength laser may be set to a range of 1.51 to 1.59 μm.
and an eighth harmonic having a wavelength in the range of 189 to 199 nm, or an eighth harmonic having a wavelength in the range of
The 10th harmonic wave in the range of 151 to 159 nm is output.
If the range is 1.544 to 1.553 μm, then the range is 193 to 194 nm.
The eighth harmonic, that is, ultraviolet light with almost the same wavelength as the ArF excimer laser, is obtained.
If the oscillation wavelength is within the range of 1.57 to 1.58 μm, the range of 157 to 158 nm
The tenth harmonic within the range, i.e., F ₂ In addition, if the oscillation wavelength is set within the range of 1.03 to 1.12 μm, the generated wavelength will be 14
The seventh harmonic wave in the range of 7 to 160 nm is output, and in particular, the oscillation wavelength is set to 1.09
If the wavelength is within the range of 157 to 158 μm,
The seventh harmonic of F ₂ Ultraviolet light with almost the same wavelength as the laser is obtained.
A ytterbium-doped fiber laser is used as the single wavelength oscillation laser.
Furthermore, the present invention is applicable not only to exposure devices used in the manufacture of semiconductor devices, but also to liquid crystal displays.
Used in the manufacture of displays including display elements, etc., device patterns are printed on glass.
Exposure equipment for transferring patterns onto plates, devices used in the manufacture of thin-film magnetic heads
An exposure device that transfers a pattern onto a ceramic wafer, and an image sensor (such as a CCD)
The present invention can also be applied to exposure equipment used in the manufacture of semiconductor devices.
Not only microdevices such as electron beams, but also optical exposure equipment, EUV exposure equipment, X-ray exposure equipment
To manufacture reticles or masks used in equipment, electron beam exposure equipment, etc.
Also, it is used in exposure equipment that transfers circuit patterns onto glass substrates or silicon wafers.
The present invention can be applied to the above-mentioned light sources.
In exposure devices using a transmissive reticle, a transmissive reticle is generally used.
are silica glass, fluorine-doped silica glass, fluorite, magnesium fluoride,
Also, proximity type X-ray exposure equipment or electric
In sagittal beam exposure equipment, a transmission mask (stencil mask, membrane mask) is used.
A silicon wafer is used as the mask substrate.
The reticle is placed so that its pattern surface faces downward (facing the illumination system in Figure 1).
The reticle is held on the stage, but the pellicle, for example, prevents foreign particles from getting on the pattern surface.
If adhesion is prevented, the pattern surface faces upward (projection light
The reticle may be held on the reticle stage so that it faces the optical system.
The light is vacuum ultraviolet light or ultraviolet light with a wavelength of about 200 nm or more (KrF excimer
When using a laser, i-line, g-line, etc., the reticle is a reflective type, and
A beam splitter is disposed between the chip and the projection optical system.
The illumination optical system is configured so that the exposure illumination light is irradiated onto the reticle through the
In the above embodiment, the case where double exposure is performed has been described as an example.
The pattern of the first reticle and the pattern of the second reticle are placed in different shot areas on the same wafer.
Alternatively, the area may be larger than the range of one scanning exposure.
To obtain larger devices, multiple reticle patterns are placed next to each other on the same wafer.
The image is transferred to adjacent shot areas, so-called stitching exposure is performed.
In this case, similarly to the above-mentioned multiple exposure, the first reticle is exposed by the first scanning exposure operation.
After transferring the circle pattern, the wafer is not subjected to development processing, and the first scanning exposure operation is performed.
Following this, a second scanning exposure operation is performed, and a transfer image of the first reticle pattern is formed.
A transfer image of the second reticle pattern is formed on the photoresist on the wafer.
In the above-described embodiment, the illumination optical systems IOP1 and IOP2 are mounted on the base 18.
Although it is assumed that the base 18 or the base plate 190 is fixed, the base 16 supporting the base 18 or the base plate 190 is disposed.
Alternatively, the exposure apparatus may be placed on a floor on which the exposure apparatus itself is placed.
In a room separate from the clean room where the equipment is installed (such as the utility space under the floor),
The exposure light sources 12A and 12B may be arranged together with the projection optical systems PL1 and PL2.
L2 is supported on the base 18 or the surface plate 190 via the frame 24.
However, the projection light is projected on a stand other than the stand 16 that supports the base 18 or the surface plate 190.
In the exposure apparatus described in the above embodiment, the wavelength of the exposure illumination light is 20.
When using vacuum ultraviolet light of about 0 nm or less, a laser light source, a light transmitter including a BMU,
The inside of the optical system, illumination optical system, and projection optical system are filled with inert gas such as nitrogen or helium.
In addition, the wavelength of the exposure illumination light is 5 to 15 nm.
When EUV light (XUV light) is used, the wafer is heated from an SOR or laser plasma light source.
It is preferable to keep the optical path up to C in a nearly vacuum state. In addition, EUV light (XUV light) with a wavelength of 5 to 15 nm is used as the exposure illumination light.
In this case, as mentioned above, a reflective reticle is used, so the illumination optics
The system is arranged on the same side of the reticle as the projection optical system, and the EUV light is the main light.
The line is configured to be incident on the reticle at an angle relative to a direction perpendicular to the reticle.
The projection optical system is composed of only a plurality of reflective optical elements.
In addition, the reticle side can be made into a non-telecentric optical system. Also, the first scanning exposure using the first reticle and the second scanning exposure using the second reticle can be performed.
The scanning exposure is adjusted in accordance with the patterns formed on the first and second reticles.
The light conditions may be different from each other.
, the plane that has a Fourier transform relationship with the pattern plane of the reticle in the illumination optical system (pupil plane)
For example, if the first reticle has a dense pattern (
A line and space pattern is formed on the second reticle, and contact holes are formed on the second reticle.
When a rule pattern is formed, the first illumination optical system IOP1
The intensity distribution of the illumination light on the pupil plane is higher outside than in the center.
The second illumination optical system IOP2 employs a holographic illumination method, and the intensity distribution of the holographic illumination is centered on the optical axis.
A conventional illumination method can be employed, which is generally constant within a generally circular (or rectangular) area.
In addition, as a modified illumination method, the intensity distribution described above is set approximately at the center of the optical axis of the illumination optical system.
The annular illumination method, in which the light source is higher than the inside of the band area, and the optical axis of the illumination optical system
The four local regions are separated by approximately equal distances from each other.
There are also methods such as the SHRINC method, which increases the temperature within a given area.
Both the bright optical system and the normal illumination method are used, and the size (cross-sectional area) of the illumination light on the pupil plane, i.e.
That is, the ratio of the numerical aperture of the illumination light incident on the reticle to the numerical aperture of the projection optical system on the reticle side.
It is also possible to change the so-called coherence factor (σ value).
Alternatively, an annular illumination method is used in one of the first and second illumination optical systems, and SHR is used in the other.
The INC method may be used. Furthermore, the scanning exposure conditions include the aperture number of the projection optical system, and the first and second projection optical systems
The numerical apertures of the systems PL1 and PL2 may be different.
As a scanning exposure condition, the relationship between the pattern surface of the reticle in the projection optical system and the Fourier transform is
The presence or absence of a pupil filter placed on the relevant plane (corresponding to the pupil plane), and the presence or absence of a pupil filter placed on the relevant plane (corresponding to the pupil plane) during scanning exposure
While a point on the shot area crosses the illumination light, the image plane of the projection optical system and the wafer are
The presence or absence of so-called progressive focus methods (such as the FLEX method) that move relative to the optical axis of the
The pupil filter is also used for projection optics.
A central blocking type that blocks the light beam distributed within a circular area centered on the optical axis of the system, or
is the light beam that passes through a circular area centered on the optical axis of the projection optical system, and the light beam that passes outside the circular area.
There are pupil filters that reduce the coherence of the light beam passing through.
A reticle having a conventional chrome pattern was used as the first reticle, and a
Phase shift reticle with phase shifter (halftone type, spatial frequency modulation type)
In the above-described embodiment, the first and second illumination optical systems IOP1 and IOP2 are the same.
Illumination light of wavelength (ArF excimer laser, or F ₂ laser) onto the reticle.
That is, the same light source was used as the exposure light sources 12A and 12B, but the first
The illumination optical system and the second illumination optical system may use illumination light sources with different wavelengths.
For example, in the illumination optical system, an ArF excimer laser is used to produce a 130 nm line array.
The land-space pattern is transferred onto the wafer, and the second illumination optical system is used to illuminate the F ₂ laser,
Or, 100 nm line and space patterns can be created using EUV (XUV) light.
The first and second projection optical systems P
L1 and PL2 may be the same in structure or resolution, or may be different.
Furthermore, the first and second illumination optical systems may have the same configuration.
<Device Manufacturing Method> Next, a device manufacturing method using the above-described exposure apparatus and exposure method in a lithography process will be described.
13 shows an embodiment of a manufacturing method for a device (semiconductor chip such as IC or LSI, liquid crystal panel, CCD
The flowchart shows an example of manufacturing a semiconductor device (e.g., a thin film magnetic head, a micromachine, etc.).
As shown in FIG. 13, first, in step 201 (design step),
, device function and performance design (e.g., circuit design of semiconductor devices),
A pattern is designed to realize the function.
In the mask fabrication step, a mask is fabricated on which the designed circuit pattern is formed.
On the other hand, in step 203 (wafer manufacturing step), a material such as silicon
Next, in step 204 (wafer processing step), the wafer is manufactured by using the
The mask and wafer prepared in step 203 are used to perform lithography, as will be described later.
Next, in step 20, actual circuits and the like are formed on the wafer by a printing technique or the like.
In step 5 (device assembly step), the wafer processed in step 204 is used.
This step 205 includes a dicing process, a bonding process, and a semiconductor device assembly process.
The process may include processes such as chip sealing and packaging (chip encapsulation) as required.
Finally, in step 206 (inspection step), the
The devices are then inspected for functionality and durability.
After going through these steps, the device is completed and shipped. Figure 14 shows a detailed flow of step 204 in the case of a semiconductor device.
In FIG. 14, in step 211 (oxidation step),
In step 212 (CVD step), the surface of the wafer is oxidized.
In step 213 (electrode formation step), an insulating film is formed on the wafer surface.
In step 214 (ion implantation step), electrodes are formed on the wafer by evaporation.
In step 211, ions are implanted into the wafer.
Each of the steps 214 constitutes a pre-processing step for each stage of wafer processing.
At each stage of the wafer process, once the above pre-processing steps are completed, the following steps are performed:
In this manner, the post-processing step is carried out. In this post-processing step, first, step 215
In the resist formation step, a photosensitive agent is applied to the wafer.
In step 216 (exposure step), the exposure apparatus and exposure method described above are used.
In this way, the circuit pattern of the mask is transferred onto the wafer.
In step 218 (etching), the exposed wafer is developed.
In step (3), the exposed member in the portion other than the portion where the resist remains is etched.
Then, in step 219 (resist removal step),
After etching, the unnecessary resist is removed.
By repeating the process and post-processing, multiple circuit patterns are formed on the wafer.
By using the device manufacturing method of this embodiment described above,
216), the exposure apparatus 100 is used, thereby improving throughput.
This allows for cost reductions and improved resolution, especially when double exposure is used.
The improved DOF allows highly integrated devices that were previously difficult to manufacture to be manufactured at low cost.
In addition, the exposure according to each aspect of the present invention described above can be performed.
The exposure apparatus is manufactured by assembling each component according to the method for manufacturing an exposure apparatus of the present invention.
INDUSTRIAL APPLICABILITY As described above, the exposure apparatus according to the present invention (manufactured by the manufacturing method of the present invention) can be manufactured by the above method.
According to the exposure apparatus and exposure method, throughput can be improved.
In addition, it is possible to improve productivity per a certain amount of occupied floor space. In particular, the exposure apparatus and exposure method of the present invention can improve throughput.
This makes it possible to realize highly accurate exposure of fine patterns.
Furthermore, the device manufacturing method according to the present invention allows microdevices to be manufactured at high throughput.
This has the excellent effect of enabling quick and low-cost production.

[Brief explanation of the drawings]

FIG. 1 is a diagram schematically illustrating the configuration of an exposure apparatus according to an embodiment of the present invention. FIG. 2 is a plan view of the main body of the exposure apparatus from which the projection optical system constituting the exposure apparatus of FIG. 1 has been removed. FIG. 3 is a diagram illustrating a specific configuration example of the projection optical system of FIG. 1. FIG. 4 is an enlarged view of the vicinity of the first wafer stage of the apparatus of FIG. 1. FIG. 5 is a diagram illustrating the schematic configuration of a control system of the apparatus of FIG. 1. FIG. 6 is a diagram illustrating the principle of scanning exposure in the apparatus of FIG. 1. FIG. 7 is a diagram illustrating parallel processing using four wafer stages WS1 to WS4, illustrating a state in which scanning exposure and wafer exchange are performed simultaneously. FIG. 8 is a diagram illustrating parallel processing using four wafer stages WS1 to WS4, illustrating a state in which scanning exposure and alignment are performed simultaneously. FIG. 9 is a diagram illustrating parallel processing using four wafer stages WS1 to WS4, illustrating a state in which wafer exchange and alignment are performed simultaneously. FIG. 10 is a diagram illustrating the flow of parallel processing using wafer stages WS1 and WS3 when normal exposure is performed. 11 shows the flow of parallel processing on wafer stages WS1 and WS3 when double exposure is performed. FIG. 12 shows the state of double exposure on wafer W3 ((A) and (B)).
Fig. 13 is a flowchart for explaining an embodiment of a device manufacturing method according to the present invention. Fig. 14 is a flowchart showing the processing in step 204 of Fig. 13. Fig. 15 is a modified example of the exposure apparatus of the present invention shown in Fig. 1, and shows the schematic configuration of an exposure apparatus in which a surface plate supported by vibration isolation pads is provided and a base plate is supported so that it can float above the surface plate. Fig. 16 is a schematic plan view showing a triangular stage and its position measurement system that can be used in the exposure apparatus of the present invention.

──────────────────────────────────────────────────── Continuation of front page (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE), OA (BF, BJ , CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP(GH, GM, K E, LS, MW, SD, SZ, UG, ZW), UA (AM ,AZ,BY,KG,K Z, MD, RU, TJ, TM) ,AL,AU,BA,BB,BG,BR,CA,CN, CU, CZ, EE, GD, GE, HR, HU, ID, I L, IS, JP, KR, LC, LK, LR, LT, LV , MG, MK, MN, MX, NO, NZ, PL, RO, SG, SI, SK, SL, TR, TT, UA, US, U Z, VN, YU (72) Inventor Yutaka Ichihara Nikon Corporation, 3-2-3 Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Hideo Mizutani Nikon Corporation, 3-2-3 Marunouchi, Chiyoda-ku, Tokyo (Note) This publication is based on the publication published internationally by the International Bureau of Patents (WIPO). The effect of the international publication of the Japanese patent application (Japanese utility model registration application) related to this publication arises pursuant to Article 184-10, Paragraph 1 of the Patent Act (Article 48-13, Paragraph 2 of the Utility Model Act) and is unrelated to this publication.

Claims (97)

[Claims] [Claim 1] An exposure apparatus that transfers a pattern formed on a mask onto a substrate, comprising: first and second mask stages that can move in a first direction while holding a mask; an illumination system that irradiates each of the masks with illumination light; first and second projection optical systems that project the illumination light emitted from each of the masks onto the substrate; first and second substrate stages that are arranged on the first and second mask stage sides of the first and second projection optical systems and can move while holding the substrate, respectively; and a drive device that moves the first mask stage and the first substrate stage synchronously in the first direction at a speed ratio corresponding to the projection magnification of the first projection optical system, and moves the second mask stage and the second substrate stage synchronously in the first direction at a speed ratio corresponding to the projection magnification of the second projection optical system. [Claim 2] An exposure apparatus as described in claim 1, characterized in that the movement directions of the first mask stage and the second mask stage during the synchronous movement are opposite to each other in the first direction, and the movement directions of the first substrate stage and the second substrate stage during the synchronous movement are opposite to each other in the first direction. 3. An exposure apparatus according to claim 1, wherein each of said mask stages and each of said substrate stages move on the same plane. 4. An exposure apparatus according to claim 1, further comprising a common base plate on which the first and second mask stages and the first and second substrate stages are movably supported. 5. An exposure apparatus according to claim 4, wherein the drive device is a linear actuator that levitates and moves the first and second mask stages and the first and second substrate stages on the common base plate. [Claim 6] An exposure apparatus as described in claim 1 or 2, further comprising a base plate which is movably supported on the base plate, and which can move in response to a reaction force generated by movement of at least one of the first and second mask stages and the first and second substrate stages. 7. An exposure apparatus according to claim 6, further comprising a linear actuator for supporting said base plate on said surface plate in a non-contact manner. [Claim 8] An exposure apparatus according to any one of claims 1 to 3, further comprising: a third substrate stage that moves on the same plane as the first and second substrate stages; and a first mark detection system that detects an alignment mark formed on the substrate. 9. An exposure apparatus according to claim 4, wherein the driving device moves the third substrate stage synchronously with the first mask stage or the second mask stage, instead of the first substrate stage or the second substrate stage. [Claim 10] An exposure apparatus as described in claim 8, further comprising: a fourth substrate stage that holds the substrate and moves on the same plane as the first, second, and third substrate stages; and a second mark detection system that detects alignment marks formed on the substrate. [Claim 11] An exposure apparatus as described in claim 1, characterized in that the driving device moves the third substrate stage and the fourth substrate stage synchronously with the first mask stage and the second mask stage, respectively, instead of the first substrate stage and the second substrate stage. 12. The exposure apparatus according to claim 1, wherein each of said mask stages has approximately the same mass, and each of said substrate stages has approximately the same mass. 13. An exposure apparatus according to claim 2, 9, 11 or 12, wherein each of the projection optical systems has the same projection magnification, and the mass of each of the mask stages is the projection magnification times the mass of each of the substrate stages. 14. An exposure apparatus according to claim 12, wherein said drive device drives said first and second mask stages and said first and second substrate stages on the same straight line. 15. An exposure apparatus according to claim 1, further comprising a mask exchange mechanism that exchanges the mask on said first mask stage with the mask on said second mask stage. 16. An exposure apparatus according to claim 1, wherein each of said projection optical systems is a catadioptric system, and the wavelength of said illumination light is 200 nm or less. [Claim 17] An exposure method for transferring a pattern formed on a mask onto a substrate, comprising: a first step of irradiating the first mask with illumination light while synchronously moving a first mask and a first substrate in a first direction at a speed ratio corresponding to the projection magnification of a first projection optical system, and transferring the pattern formed on the first mask to a first divided area on the first substrate via the first projection optical system; and a second step of irradiating the second mask with illumination light while synchronously moving a second mask and a second substrate in the first direction at a speed ratio corresponding to the projection magnification of a second projection optical system, simultaneously with the first step, and transferring the pattern formed on the second mask to a second divided area on the second substrate via the second projection optical system. 18. The method of claim 17, wherein a third substrate different from the first and second substrates is formed simultaneously with the first and second steps.
18. The exposure method according to claim 17, further comprising a third step of detecting alignment marks formed on the first substrate and the fourth substrate, respectively. [Claim 19] The exposure method described in claim 17 further includes a third step, after completion of the processing of the first and second steps, of irradiating the second mask with illumination light and transferring the pattern formed on the second mask onto the first divided area on the first substrate via the first projection optical system while synchronously moving the second mask and the first substrate in a first direction at a speed ratio corresponding to the projection magnification of the first projection optical system; and a fourth step, simultaneously with the third step, of irradiating the first mask with illumination light and transferring the pattern formed on the first mask onto the second divided area on the second substrate via the second projection optical system while synchronously moving the first mask and the second substrate in the first direction at a speed ratio corresponding to the projection magnification of the second projection optical system. [Claim 20] An exposure method described in any one of claims 17 to 19, characterized in that the first substrate and the second substrate are moved using a first substrate stage and a second substrate stage, respectively, on which reference marks are formed, and the exposure areas defined in the first substrate and the second substrate are determined based on the reference marks. [Claim 21] An exposure apparatus used in a photolithography process for manufacturing microdevices, comprising: a first mask stage that holds a first mask; a first projection optical system having at least two reflective optical elements; a first substrate stage that holds a first substrate on the first mask stage side relative to the first projection optical system; a second mask stage that holds a second mask; a second projection optical system having at least two reflective optical elements; a second substrate stage that holds a second substrate on the second mask stage side relative to the second projection optical system; and a drive device that drives the first and second substrate stages in opposite directions along a predetermined direction when scanning and exposing the first and second substrates, respectively. 22. The exposure apparatus of claim 21, further comprising a common base plate on which the first and second mask stages and the first and second substrate stages are movably supported. 23. An exposure apparatus according to claim 22, wherein the drive device is a linear actuator that moves the first and second mask stages and the first and second substrate stages by levitating the common base plate above the common base plate. [Claim 24] An exposure apparatus as described in claim 21 or 22, further comprising a base plate which is movably supported on the base plate, and which can move in response to a reaction force generated by movement of at least one of the first and second mask stages and the first and second substrate stages. 25. An exposure apparatus according to claim 24, further comprising a linear actuator for supporting said base plate on said surface plate in a non-contact manner. [Claim 26] An exposure method for transferring a device pattern onto a substrate, comprising: a first step of placing a first substrate on the first mask side relative to a first projection optical system, and moving the first mask and the first substrate synchronously to transfer the pattern of the first mask onto the first substrate; and a second step of placing a second substrate on the second mask side relative to a second projection optical system, and moving the second mask and the second substrate synchronously to transfer the pattern of the second mask onto the second substrate, wherein the first and second steps are performed almost simultaneously, and the first and second substrates are moved in opposite directions to each other along a predetermined direction. 27. An exposure method according to claim 26, wherein the first mask is moved in a direction opposite to the first substrate along the predetermined direction, and the second mask is moved in a direction opposite to the second substrate along the predetermined direction. 28. The exposure method according to claim 27, wherein the first and second masks and the first and second substrates are moved on the same straight line. [Claim 29] An exposure method described in any one of claims 26 to 28, characterized in that the reaction force generated by the synchronous movement of the first mask and the first substrate and the reaction force generated by the synchronous movement of the second mask and the second substrate cancel each other out. 30. An exposure method according to claim 29, wherein after the first and second steps, the first substrate and the second substrate are moved in opposite directions along a direction perpendicular to the predetermined direction. [Claim 31] An exposure method described in any one of claims 26 to 28, characterized in that the first substrate and the second substrate are moved using a first substrate stage and a second substrate stage, respectively, on which reference marks are formed, and the exposure areas defined in the first substrate and the second substrate are determined based on the reference marks. 32. A device manufacturing method comprising a lithography process using the exposure apparatus according to claim 1, 2, or 21. Description: 33. A device manufacturing method, comprising using the exposure method according to any one of claims 17 to 19 and 26. Description: [Claim 34] An exposure apparatus for irradiating an exposure pattern formed on a mask with an energy beam to expose an object to be exposed with the pattern, comprising: a plurality of mask stages each capable of moving and holding a mask; a plurality of object stages each capable of moving and holding an object to be exposed; a common base plate for movably supporting the plurality of mask stages and the plurality of object stages; and a plurality of projection systems for projecting the energy beam emitted from each of the masks onto a corresponding object to be exposed, wherein the exposure apparatus exposes the object to be exposed with the pattern of each mask by synchronously moving each mask stage and its corresponding object stage relative to each projection system. 35. An exposure apparatus according to claim 34, further comprising a drive device for moving the mask stage and the object stage while floating above the base board. 36. The exposure apparatus according to claim 35, wherein the drive device is a linear actuator. 37. An exposure apparatus according to claim 35, further comprising a controller for controlling the drive device, the controller controlling the drive device so that at least two mask stages move in directions opposite to each other. 38. An exposure apparatus according to claim 34, further comprising a support table, the base plate being fixed to the support table. [Claim 39] An exposure apparatus as described in Claim 35, further comprising a base plate which is movably supported on the base plate, and which can move in response to a reaction force generated by movement of at least one of the mask stage and the object stage. 40. An exposure apparatus according to claim 39, wherein the base plate is supported on the surface plate in a non-contact manner. 41. An exposure apparatus according to claim 40, further comprising a linear actuator for supporting said base plate on said surface plate in a non-contact manner. 42. An exposure apparatus according to claim 34, wherein the energy beam from the irradiation system is irradiated from the rear surface of the base plate and passes through a mask on a mask stage supported on the surface of the base plate. 43. The exposure apparatus according to claim 34, further comprising a plurality of irradiation systems for irradiating the energy beam onto each projection system. 44. The exposure apparatus according to claim 43, further comprising two projection systems, the projection systems being arranged symmetrically on the base plate. 45. The method according to any one of claims 34 to 4, further comprising an interferometer for measuring the positions of the plurality of mask stages and the plurality of object stages on the base plate.
2. The exposure apparatus according to claim 1. 46. The exposure apparatus of claim 45, wherein the plurality of mask stages and the plurality of object stages each have a reflecting member for reflecting the beam transmitted from the interferometer. 47. The exposure apparatus of claim 46, wherein the plurality of mask stages and the plurality of object stages each have a reflecting member for reflecting the beam transmitted from the interferometer. [Claim 48] An exposure apparatus as described in claim 47, wherein the two-dimensional position on the base plate is determined using an orthogonal coordinate system defined by a predetermined first axis and a second axis perpendicular to the first axis on the base plate, at least one stage of the multiple mask stages and multiple object stages has a reflective surface extending along a third axis direction intersecting the first axis and the second axis, the interferometer measures the position of the one stage in the third axis direction by irradiating a beam toward the reflective surface and receiving the reflected light, and further comprises a calculator that calculates position coordinates on the orthogonal coordinate system defined by the first axis and the second axis of the one stage based on the measured position in the third axis direction. 49. The exposure apparatus according to claim 34, wherein the object to be exposed is a sensitive substrate, and the exposure apparatus is a projection exposure apparatus used in a lithography process for manufacturing a device. 50. The method of claim 34, wherein a reference mark is formed on each object stage, and an exposure area defined on the object to be exposed is determined based on the reference mark.
42. An exposure apparatus according to any one of claims 1 to 41. [Claim 51] An apparatus for exposing a second object with an energy beam irradiated onto a first object having a pattern, comprising: a plurality of first movable bodies capable of holding the first object, arranged on a first base plate, for moving the first object relative to the energy beam; a plurality of second movable bodies capable of holding the second object, arranged on the first base plate, for moving the second object relative to the energy beam in synchronization with the movement of the first object during scanning exposure of the second object; and an illumination system in which at least one optical element is arranged on the opposite side of the first object with respect to the first base plate, for irradiating the energy beam onto the first object held by each first movable body. 52. An exposure apparatus according to claim 51, further comprising a second base plate that supports the first base plate so that the first base plate moves in response to movement of at least one of the plurality of first and second movable bodies. 53. An exposure apparatus according to claim 52, wherein said second surface plate is provided with a second linear actuator that supports said first surface plate in a non-contact manner. 54. The first base plate is provided with a first linear actuator for supporting each of the first and second movable bodies in a non-contact manner.
54. The exposure apparatus according to any one of claims 1 to 53. 55. An exposure apparatus according to claim 54, wherein said first linear actuator drives said plurality of first and second movable bodies with six degrees of freedom, respectively. [Claim 56] An exposure apparatus as described in Claim 51 or 52, further comprising an actuator provided on the first base plate to move two of the plurality of first movable bodies in opposite directions to each other during scanning exposure of the second object. 57. An exposure apparatus according to claim 56, wherein the actuator moves two second movable bodies corresponding to the two first movable bodies in directions opposite to each other. 58. An exposure apparatus according to claim 57, wherein said actuator is characterized by moving one of said two first movable bodies and the corresponding second movable body in mutually opposite directions. 59. The actuator includes: two first movable bodies and two second movable bodies;
59. An exposure apparatus according to claim 57 or 58, characterized in that the movable body moves substantially in the same straight line. 60. A plurality of first movable bodies for respectively detecting position information of the plurality of first movable bodies.
53. The exposure apparatus of claim 51 or 52, further comprising an interferometer. [Claim 61] An exposure apparatus as described in Claim 60, wherein each of the multiple first interferometers has multiple first measurement axes used to detect position information regarding a first axis direction in which the first object is moved during the scanning exposure and a second axis direction perpendicular to the first axis direction. [Claim 62] An exposure apparatus as described in Claim 61, characterized in that the multiple first measurement axes include a measurement axis used to detect information regarding the rotation of the first movable body relative to a third axis perpendicular to the first and second axes. 63. The plurality of first measurement axes include at least one axis used to detect information relating to the rotation of the first movable body about at least one of the first and second axes.
63. The exposure apparatus of claim 62, comprising two measurement axes. 64. A plurality of second movable bodies for respectively detecting position information of the plurality of second movable bodies.
61. The exposure apparatus of claim 60, further comprising an interferometer. [Claim 65] An exposure apparatus as described in Claim 64, characterized in that each of the multiple second interferometers has multiple second measurement axes used to detect position information regarding a first axis direction in which the second object is moved during the scanning exposure and a second axis direction perpendicular to the first axis direction. [Claim 66] An exposure apparatus as described in Claim 65, characterized in that the multiple second measurement axes include a measurement axis used to detect information regarding the rotation of the second movable body relative to a third axis perpendicular to the first and second axes. 67. The plurality of second measurement axes include at least one axis used to detect information relating to the rotation of the second movable body about at least one of the first and second axes.
67. The exposure apparatus of claim 66, comprising two measurement axes. 68. An exposure apparatus according to any one of claims 51 to 53, wherein the number of said plurality of second movable bodies is at least one more than the number of said plurality of first movable bodies. [Claim 69] An exposure apparatus as described in Claim 68, further comprising a first linear actuator provided on the first base for synchronously moving each of the plurality of first movable bodies and the corresponding plurality of second movable bodies, and for moving at least one of the second movable bodies independently of the synchronous movement. [Claim 70] An exposure apparatus as described in Claim 69, further comprising: a plurality of second interferometers having two second measurement axes that intersect at least within the irradiation area of the energy beam to detect the position information of each of the plurality of second movable bodies that are moved synchronously; and a third interferometer having two third measurement axes that intersect at least outside the irradiation area to detect the position information of at least one of the second movable bodies. [Claim 71] An exposure apparatus as described in Claim 70, wherein one of the plurality of second interferometers and the third interferometer are positioned so that one of the plurality of second movable bodies is simultaneously detected by at least one second measurement axis of that one second interferometer and at least one third measurement axis of the third interferometer. [Claim 72] An exposure apparatus as described in Claim 70 or 71, further comprising a mark detection system having a detection center approximately at the intersection of the two third measurement axes for detecting a mark on a second object held by at least one second movable body. 73. The first linear actuator includes a second movable body that moves synchronously with one of the plurality of first movable bodies, and a second movable body that moves independently of the synchronous movement.
70. The exposure apparatus according to claim 69, wherein the movable bodies are exchanged after completion of scanning exposure of the second object held by the one second movable body. [Claim 74] A method for exposing a substrate with energy rays irradiated onto a mask, characterized in that in order to scan and expose a first and second substrate, respectively, with the energy rays, a first mask and the first substrate are moved synchronously, and a second mask and the second substrate are moved synchronously, and the first and second masks, or the first and second substrates, are moved in opposite directions on the same plane. 75. The method of claim 7, wherein the synchronous movement of said first mask and said first substrate and the synchronous movement of said second mask and said second substrate are carried out substantially simultaneously.
5. The exposure method according to claim 4. 76. An exposure method according to claim 74 or 75, wherein the first and second masks and the first and second substrates are arranged on the same plane. 77. An exposure method according to any one of claims 74 to 76, wherein the first and second masks, and the first and second substrates are moved in opposite directions, respectively. 78. An exposure method according to claim 77, wherein the first mask and the first substrate are moved in opposite directions. 79. An exposure method according to claim 78, wherein said first and second masks and said first and second substrates are moved substantially on the same straight line. 80. The first substrate is subjected to a first scanning exposure using the first mask followed by a second scanning exposure using the second mask.
76. The exposure method according to any one of items 76 to 78. 81. The exposure method according to claim 80, wherein the first mask is exchanged for the second mask before the second scanning exposure. 82. The method according to claim 80 or 81, wherein the first substrate is subjected to multiple exposure by the first and second scanning exposures. 83. The first substrate is exposed to the first and second scanning exposures.
82. The exposure method according to claim 80 or 81, wherein the first pattern of the mask and the second pattern of the second mask are transferred to different regions. 84. A method according to any one of claims 74 to 83, wherein marks on a third substrate are detected in parallel with the scanning exposure operation of the first substrate, and marks on the first mask are detected before the scanning exposure of the third substrate, and the detection results are used for the scanning exposure of the third substrate.
76. The exposure method according to any one of items 76 to 78. 85. An exposure method according to claim 84, wherein the marks on said first mask are detected together with a reference mark provided on a movable body that holds said third substrate. 86. An exposure method according to claim 85, wherein different interferometers are used for detecting the mark on said third substrate and for detecting said reference mark. 87. A length measurement axis of an interferometer used to detect marks on said third substrate; and
87. An exposure method according to claim 86, wherein when the movable body is simultaneously detected by the length measurement axes of the interferometers used to detect the reference marks, the measurement values of the two interferometers are correlated. 88. An exposure method according to any one of claims 74 to 76, characterized in that the scanning exposure conditions for the first substrate and the scanning exposure conditions for the second substrate are made different. [Claim 89] An exposure method according to Claim 88, characterized in that the scanning exposure conditions include the intensity distribution of the energy beam on the pupil plane of an illumination optical system that emits the energy beam and the numerical aperture of a projection optical system through which the energy beam passes. [Claim 90] An exposure method described in any one of claims 74 to 76, characterized in that the first and second masks are transmission masks, and the energy rays are irradiated onto the first and second masks, respectively, from opposite sides of a base on which the first and second masks are placed. 91. An exposure method according to claim 90, wherein said energy rays are vacuum ultraviolet rays having a wavelength of about 200 nm or less. [Claim 92] An exposure method described in any one of claims 74 to 76, characterized in that the first and second masks are reflective masks, and the energy rays are irradiated onto the first and second masks respectively from the same side of a base on which the first and second masks are placed. 93. An exposure method according to claim 92, wherein said energy beam is EUV light having a wavelength within a range of 5 to 15 nm, and the chief ray thereof is tilted with respect to a direction perpendicular to said first and second masks. 94. A device manufacturing method, comprising using the exposure method according to any one of claims 74 to 76. Description: [Claim 95] A method for manufacturing an exposure apparatus that transfers a pattern formed on a mask onto a substrate, comprising the steps of: providing first and second mask stages, each capable of holding a mask and moving in a first direction; providing an illumination system that irradiates illumination light onto each mask; providing first and second projection optical systems that project the illumination light emitted from each mask onto a substrate; providing first and second substrate stages, each positioned on the same side of the first and second projection optical systems as the first and second mask stages, each capable of holding the substrate and moving; and providing a drive device that moves the first mask stage and the first substrate stage synchronously in the first direction at a speed ratio corresponding to the projection magnification of the first projection optical system, and moves the second mask stage and the second substrate stage synchronously in the first direction at a speed ratio corresponding to the projection magnification of the second projection optical system. [Claim 96] A method for manufacturing an exposure apparatus used in a photolithography process for manufacturing microdevices, comprising the steps of: providing a first mask stage that holds a first mask; providing a first projection optical system having at least two reflective optical elements; providing a first substrate stage that holds a first substrate on the first mask stage side relative to the first projection optical system; providing a second mask stage that holds a second mask; providing a second projection optical system having at least two reflective optical elements; providing a second substrate stage that holds a second substrate on the second mask stage side relative to the second projection optical system; and providing a drive device that drives the first and second substrate stages in opposite directions along a predetermined direction when scanning and exposing the first and second substrates, respectively. [Claim 97] A method for manufacturing an exposure apparatus that irradiates an exposure pattern formed on a mask with an energy beam to expose an object to be exposed with the pattern, comprising the steps of: providing a plurality of movable mask stages each holding a mask; providing a plurality of movable object stages each holding an object to be exposed; providing a common base plate that movably supports the plurality of mask stages and the plurality of object stages; and providing a plurality of projection systems for projecting the energy beam emitted from each of the masks onto a corresponding object to be exposed; wherein the exposure apparatus exposes the object to be exposed with the pattern of each mask by synchronously moving each mask stage and its corresponding object stage relative to each projection system.