JP2004158689A - Scanning aligning method and scanning aligner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To contribute to enhancement of throughput without causing any useless time in the movement of a substrate. <P>SOLUTION: A plurality of sectioned areas S1-S3 on a substrate are exposed by alternately repeating a scanning step for exposing one sectioned area S1-S3 on the substrate by moving the substrate, while scanning, in the first direction Y with respect to the illumination area A of exposing light, and a moving step for moving the substrate in the second direction X intersecting the first direction Y. During the scanning step, the substrate is driven in an oblique direction including a second direction X component with respect to the first direction Y. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is used to expose a pattern on a mask onto a photosensitive substrate in a photolithography process for manufacturing, for example, a semiconductor device, a liquid crystal display device, an imaging device (such as a CCD), or a thin film magnetic head. The present invention relates to a scanning type exposure method and a scanning type exposure apparatus which are preferably applied to a scanning type exposure method and a scanning type exposure apparatus for sequentially exposing a pattern to a plurality of divided regions on a substrate.
[0002]
[Prior art]
Conventionally, in a photolithography process for manufacturing a semiconductor element or the like, a substantially square illumination area is set on a reticle serving as a mask, and a pattern in the illumination area is set on a wafer serving as a photosensitive substrate through a projection optical system. A batch exposure type projection exposure apparatus such as a stepper for exposing on a (or a glass plate) has been frequently used. On the other hand, recently, in order to cope with an increase in the size of a chip pattern of a semiconductor element or the like, it is required to transfer a larger reticle pattern to each shot area on a wafer. However, it is difficult to design and manufacture a projection optical system in which aberrations such as distortion and field curvature are suppressed to a predetermined allowable value or less over a wide exposure field.
[0003]
Therefore, recently, a slit-shaped illumination area such as a rectangle or an arc is set on the reticle, and the reticle and the wafer are projected by the projection optical system while the pattern in the illumination area is projected onto the wafer via the projection optical system. A scanning step of sequentially exposing the reticle pattern to each shot area on the wafer while synchronously scanning the system, and a moving step of step-moving the wafer in a direction substantially orthogonal to the scanning direction, which are alternately repeated. Attention has been paid to a scanning exposure type projection exposure apparatus such as a scanning method (see Patent Document 1).
[0004]
This scanning exposure type projection exposure apparatus exposes a slit-like exposure area almost inscribed in the effective exposure field of the projection optical system while scanning the wafer, so that the diameter of the effective exposure field of the projection optical system is maximized. Besides being usable, the length of the transfer pattern in the scanning direction can be longer than the diameter of the effective exposure field, so that a large area reticle pattern can be transferred onto the wafer with a small aberration.
[0005]
FIG. 11 shows that a plurality of shot areas (partition areas) S1 to S3 on the wafer W are exposed by moving a wafer (substrate) W (and a reticle (not shown)) relative to a rectangular illumination area A of exposure light. It is a figure which shows the example of the relative movement path at the time simply. The shot areas S1 to S3 shown in this drawing have one area in which the reticle pattern is transferred in one scanning step in the Y direction, which is the scanning direction (scan direction), and the shot areas in the step movement direction (non-scan direction). Three are arranged in a certain X direction while being partitioned from each other. Note that, in practice, the wafer W (shot area) moves with respect to the illumination area A whose position is fixed, but here, for convenience, the description will be given assuming that the illumination area A moves with respect to the shot areas S1 to S3.
[0006]
In this case, the illumination area A extending in the X direction moves stepwise in the + X direction after exposing the shot area S1 by relatively moving in the + Y direction. Subsequently, the scanning direction is reversed in the −Y direction to expose the shot area S2. As described above, by repeating the scanning movement in the Y direction and the step movement in the X direction orthogonal thereto, it is possible to continuously expose the shot areas S1 to S3 on the wafer W.
[0007]
[Patent Document 1]
JP-A-4-196513
[0008]
[Problems to be solved by the invention]
However, the conventional scanning exposure method and scanning exposure apparatus as described above have the following problems.
In order to reduce the time required for the exposure processing, it is possible to realize the step movement in the X direction at the same time as the end of the scanning step. However, if the amount of step movement in the X direction is large, the movement direction is reversed with respect to the scanning direction until the next exposure start position is reached (for example, the exposure to the shot area S1 is completed and the shot area S2 is reached). Until the exposure start position is reached), the step movement in the X direction may not be completed. In such a case, it is necessary to perform the scanning movement in the Y direction after waiting for the completion of the step movement in the X direction, and there is a problem that time is wasted and the throughput is reduced.
[0009]
The present invention has been made in view of the above points, and provides a scanning type exposure method and a scanning type exposure apparatus that can contribute to an improvement in throughput without causing useless time for substrate movement. Aim.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention employs the following configuration corresponding to FIGS. 1 to 9 showing the embodiment.
In the scanning exposure method according to the present invention, the substrate (W) is moved in the first direction (Y direction) with respect to the illumination area (A) of the exposure light, so that one divided area (S1) on the substrate (W) is moved. To S3) and a moving step of moving the substrate (W) in a second direction (X direction) intersecting with the first direction (Y direction) are alternately repeated, whereby the substrate (W) is exposed. A scanning exposure method for exposing a plurality of upper partitioned regions, wherein a substrate (W) is tilted in an oblique direction including a second direction (X direction) with respect to a first direction (Y direction) during a scanning step. It is characterized by being driven.
[0011]
Further, the scanning exposure apparatus of the present invention moves the substrate (W) in the first direction (Y direction) with respect to the illumination area (A) of the exposure light, and moves the substrate (W) during the scanning movement. Is a scanning type exposure apparatus (10) having a driving device (74) for moving the first direction (X direction) in a second direction (X direction) with respect to the first direction (Y direction) during the scanning movement. And a control device (50) for controlling the driving device (74) so as to drive the substrate (W) in an oblique direction including the component.
[0012]
Therefore, in the scanning type exposure method and the scanning type exposure apparatus of the present invention, the substrate (W) is also moved in the second direction (X direction) in the scanning step. ) Will decrease by the amount moved in the scanning step. Therefore, it is possible to reduce the waiting time until the moving step is completed for the scanning step, or it is not necessary to wait until the moving step is completed, so that it is possible to reduce waste of time and improve the throughput. Can be expected.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment of a scanning exposure method and a scanning exposure apparatus according to the present invention will be described with reference to FIGS. Here, for example, a case where a scanning stepper (scanning type exposure apparatus) that transfers a circuit pattern of a semiconductor device formed on the reticle onto the wafer while synchronously moving the reticle and the wafer is used as the exposure apparatus. This will be described with reference to FIG. In these figures, the same components as those in FIG. 11 shown as a conventional example are denoted by the same reference numerals, and description thereof will be omitted.
[0014]
FIG. 1 schematically shows the overall configuration of a scanning exposure apparatus 10 according to the present invention. The exposure apparatus 10 synchronously moves a reticle R as a mask and a wafer W as a substrate in a one-dimensional direction (here, the Y-axis direction, which is the horizontal direction in FIG. Is a step-and-scan type scanning exposure apparatus that transfers the circuit pattern formed on the wafer W to each shot area on the wafer W via the projection optical system PL, that is, a so-called scanning stepper.
[0015]
An exposure apparatus 10 shown in FIG. 1 includes an illumination optical system IOP and a reticle R that illuminate a rectangular (or arc) illumination area on a reticle (mask) R with uniform illumination by exposure illumination light from a light source 12. Reticle stage (mask stage) RST that moves while holding, projection optical system PL that projects illumination light (pulse ultraviolet light) emitted from reticle R onto wafer (substrate) W, wafer that holds and moves wafer W A stage (substrate stage) WST is provided. Further, the exposure apparatus 10 includes a main body column 14 that holds a part of the illumination optical system IOP, the reticle stage RST, the projection optical system PL, and the wafer stage WST, and a vibration isolation unit that suppresses or eliminates vibration of the main body column 14. , And these control systems. Here, the optical axis direction of the projection optical system PL is defined as the Z direction, the direction of the synchronous movement of the reticle R and the wafer W is defined as the Y direction, and the direction of the asynchronous movement is defined as the X direction. The rotation directions around the respective axes are denoted by θZ, θY, and θX.
[0016]
As the light source 12, an ArF excimer laser light source that outputs pulsed ultraviolet light narrowed so as to avoid an oxygen absorption band between wavelengths 192 to 194 nm is used. It is installed on a floor FD in a clean room of a semiconductor manufacturing factory. The light source 12 is provided with a light source control device (not shown). The light source control device controls the oscillation center wavelength and the half width of the spectrum of the emitted pulse ultraviolet light, triggers the pulse oscillation, and controls the inside of the laser chamber. Gas control and the like are performed.
[0017]
As the light source 12, a KrF excimer laser light source that outputs pulsed ultraviolet light having a wavelength of 248 nm or an F light that outputs pulsed ultraviolet light having a wavelength of 157 nm is used. ₂ A laser light source or the like may be used. Further, the light source 12 may be installed in another room (service room) having a lower degree of cleanliness than the clean room, or in a utility space provided under the floor of the clean room.
[0018]
The light source 12 is not shown in FIG. 1 for convenience of drawing, but is actually connected to one end (incident end) of a beam matching unit BMU via a light-blocking bellows and a pipe. The other end (exit end) of the matching unit BMU is connected to a first illumination optical system IOP1 of the illumination optical system IOP via a pipe 16 having a relay optical system built therein. In the beam matching unit BMU, a relay optical system, a plurality of movable reflecting mirrors and the like (all not shown) are provided, and narrowed pulses incident from the light source 12 using these movable reflecting mirrors and the like. The optical path of the ultraviolet light (ArF excimer laser light) is positionally matched with the first illumination optical system IOP1.
[0019]
The illumination optical system IOP is composed of two parts, a first illumination optical system IOP1 and a second illumination optical system IOP2. The first illumination optical system IOP1 is installed on a base plate BP called a frame caster, which is a reference of an apparatus mounted horizontally on the floor FD. Further, the second illumination optical system IOP2 is supported from below by a second support column 52, which will be described later, which forms the main body column 14.
[0020]
The first illumination optical system IOP1 includes a mirror, a variable dimmer, a beam shaping optical system, an optical integrator, a condensing optical system, a vibration mirror, an illumination system aperture stop plate, a beam splitter, and a relay lens arranged in a predetermined positional relationship. And a movable reticle blind (illumination area setting device) 28J as a movable field stop constituting a reticle blind mechanism. When pulsed ultraviolet light from the light source 12 is horizontally incident on the first illumination optical system IOP1 via the beam matching unit BMU and the relay optical system, the pulsed ultraviolet light is given a predetermined peak intensity by the ND filter of the variable dimmer. After that, the cross-sectional shape is shaped by the beam shaping optical system so as to efficiently enter the optical integrator.
[0021]
Next, when the pulsed ultraviolet light is incident on the optical integrator, a surface light source, that is, a secondary light source including a large number of light source images (point light sources) is formed on the exit end side. The pulsed ultraviolet light diverging from each of these many point light sources passes through one of the aperture stops on the illumination system aperture stop plate, and then reaches the movable reticle blind 28J as exposure light.
[0022]
The movable reticle blind 28J includes, for example, two L-shaped movable blades, and an actuator (not shown) for driving the movable blades. As the movable blades, those formed in a linear shape may be independently and movably arranged in a rectangular shape. The positions of these movable blades in the direction corresponding to the scanning direction of the reticle R and the direction corresponding to the non-scanning direction orthogonal to the scanning direction are variable. The movable reticle blind 28J is provided with a movable blade at the start and end of scanning exposure to further limit an illumination area on a reticle R defined by a fixed reticle blind described later, in order to prevent unnecessary portions from being exposed. Used. The driving of the movable reticle blind 28J is controlled by a main controller 50 described later (see FIG. 2).
[0023]
The second illumination optical system IOP2 includes a fixed reticle blind, a lens, a mirror, a relay lens system, a main condenser lens, and the like (all not shown) housed in a predetermined positional relationship within the illumination system housing 17. The fixed reticle blind is disposed on a surface slightly defocused from a conjugate plane with respect to the pattern surface of the reticle R near the incident end of the illumination system housing 17 and has a predetermined shape that defines an illumination area A (see FIG. 3) on the reticle R. Opening is formed. The opening of the fixed reticle blind has a slit or rectangular shape linearly extending in the X-axis direction orthogonal to the moving direction (Y-axis direction) of the reticle R during scanning exposure at the center of the circular visual field of the projection optical system PL. It is assumed that it is formed in a shape.
[0024]
The pulsed ultraviolet light that has passed through the opening of the blade of the movable reticle blind 28J illuminates the opening of the fixed reticle blind with a uniform intensity distribution. The pulsed ultraviolet light passing through the opening of the fixed reticle blind passes through a lens, a mirror, a relay lens system, and a main condenser lens system, and passes through a predetermined illumination area (in the X-axis direction) on a reticle R held on a reticle stage RST. A linearly extending slit-shaped or rectangular illumination area A is illuminated with a uniform illuminance distribution. Here, the rectangular slit-shaped illumination light applied to the reticle R is set to be elongated in the X-axis direction (non-scanning direction) at the center of the circular projection field of view of the projection optical system PL, and the Y-axis of the illumination light is set. The width in the direction (scanning direction) is set substantially constant.
[0025]
When the first illumination optical system IOP1 and the second illumination optical system IOP2 are firmly joined, vibrations generated in the first illumination optical system IOP1 during the exposure operation due to the driving of the movable reticle blind 28J are caused in the second column. This is undesirably transmitted to the second illumination optical system IOP2 supported by the light source 52 as it is. For this reason, in the present embodiment, between the first illumination optical system IOP1 and the second illumination optical system IOP2, both can be relatively displaced, and the inside thereof can be made airtight against outside air. They are joined via an elastic bellows-like member 94 as a connecting member.
[0026]
Returning to FIG. 1, the main body column 14 includes a plurality (four in this case) of support members 40A to 40D provided on the base plate BP (however, the support columns 40C and 40D on the back side of the paper are not shown) and their support. Vibration isolating units 42A to 42D fixed to the upper parts of members 40A to 40D, respectively (however, vibration isolating units 42C and 42D on the back side of the paper surface are not shown in FIG. 1, but are substantially horizontally supported). A lens barrel base 44, a hanging column 46 hung downward from the lower surface of the lens barrel base 44, first and second support columns 48 provided on the lens barrel base 44, 52.
[0027]
The anti-vibration units 42A to 42D are configured to include an air mount and a voice coil motor (not shown) which are arranged in series (or in parallel) on the upper portions of the support members 40A to 40D and whose internal pressure is adjustable. . By these vibration isolation units 42A to 42D, micro vibrations transmitted from the floor FD to the lens barrel base 44 via the base plate BP and the support members 40A to 40D are insulated at the micro G level.
[0028]
The lens barrel base 44 is made of a casting or the like, has a circular opening in a plan view at the center thereof, and the projection optical system PL is inserted therein from above with its optical axis direction being the Z axis direction. I have. A flange FLG integrated with the lens barrel is provided on the outer periphery of the lens barrel of the projection optical system PL. As a material of the flange FLG, a material having a low thermal expansion, for example, Invar (an alloy having a low expansion of 36% nickel, 0.25% manganese, and iron containing trace amounts of carbon and other elements) is used. The flange FLG constitutes a so-called kinematic support mount that supports the projection optical system PL at three points with respect to the lens barrel base 44 via points, surfaces, and V-grooves. When such a kinematic support structure is employed, the projection optical system PL can be easily assembled to the lens barrel base 44, and the assembled lens barrel base 44 and projection optical system PL can be easily vibrated, changed in temperature, changed in posture, and the like. There is an advantage that the stress caused by the above can be reduced most effectively.
[0029]
The hanging column 46 includes a wafer base surface plate 54 and four hanging members 56 for hanging the wafer base surface plate 54 substantially horizontally. The first support column 48 includes four legs 58 (the legs on the back side of the drawing are not shown) planted on the upper surface of the lens barrel base 44 so as to surround the projection optical system PL, and these four legs. A reticle base platen 60 supported substantially horizontally by the legs 58 is provided. Similarly, the second support column 52 includes four columns 62 (the columns on the back side of the drawing are not shown) planted on the upper surface of the lens barrel base 44 so as to surround the first column 48. , And a top plate 64 supported substantially horizontally by these four columns 62. The above-described second partial optical system IOP2 is supported by the top plate 64 of the second support column 52.
[0030]
Although not shown in FIG. 1, the lens barrel base 44 constituting the main body column 14 is actually provided with three vibration sensors (for example, an accelerometer) that measure the vibration of the main body column 14 in the Z direction. ) And three vibration sensors such as an accelerometer for measuring the vibration in the XY plane direction (for example, two of these vibration sensors measure the vibration of the main body column 14 in the Y direction, and the remaining vibration sensors are (Measures the vibration of the column 14 in the X direction). In the following, these six vibration sensors are collectively referred to as a vibration sensor group 66 for convenience.
[0031]
The measurement value of the vibration sensor group 66 is supplied to the main controller 50 (see FIG. 2). Therefore, the main controller 50 can determine the vibration of the main body column 14 in the directions of six degrees of freedom based on the measurement value of the vibration sensor group 66. Then, main controller 50 removes, for example, the movement of reticle stage RST and wafer stage WST in order to remove the vibration in the six degrees of freedom direction of main body column 14 obtained based on the measurement value of vibration sensor group 66. The speed control of the vibration isolation units 42A to 42D is performed by, for example, feedback control or feedback control and feedforward control, so that the vibration of the main body column 14 can be effectively suppressed.
[0032]
The reticle stage RST is arranged on a reticle base platen 60 that forms the first support column 48 that forms the main body column 14. The reticle stage RST is driven by a reticle stage drive system 68 (not shown in FIG. 1; see FIG. 2) composed of, for example, a magnetic levitation type two-dimensional linear actuator, and moves the reticle R on the reticle base surface plate 60 in the Y-axis direction. The linear drive is performed with a large stroke in the direction, and the minute drive is also possible in the X-axis direction and the θz direction (the rotation direction around the Z-axis).
[0033]
A moving mirror 72 that reflects a length measurement beam from a reticle laser interferometer 70, which is a position detection device for measuring the position and the amount of movement, is attached to a part of the reticle stage RST. Reticle laser interferometer 70 is fixed to reticle base surface plate 60, and the position (in XY plane) of reticle stage RST (that is, reticle R) with respect to fixed mirror Mr fixed to the upper end side surface of projection optical system PL. θz rotation) is detected at a resolution of, for example, about 0.5 to 1 nm.
[0034]
Position information (or speed information) of reticle stage RST (that is, reticle R) measured by reticle laser interferometer 70 is sent to main controller 50 (see FIG. 2). Main controller 50 basically controls reticle stage drive system 68 such that the position information (or speed information) output from reticle laser interferometer 70 matches the command value (target position, target speed).
[0035]
Here, as the projection optical system PL, here, both the object plane (reticle R) side and the image plane (wafer W) side are telecentric and have a circular projection visual field, and refractive optics using quartz or fluorite as an optical glass material. A 1/4, 1/5, or 1/6 reduction magnification refracting optical system composed of only elements (lens elements) is used. For this reason, when the reticle R is irradiated with pulsed ultraviolet light, an image forming light beam from a portion of the circuit pattern area on the reticle R illuminated by the pulsed ultraviolet light enters the projection optical system PL, and the circuit pattern Is formed in a slit-like or rectangular (polygonal) shape at the center of the circular visual field on the image plane side of the projection optical system PL at each pulse irradiation of the pulsed ultraviolet light. As a result, the projected partial inverted image of the circuit pattern is reduced and transferred to the resist layer on the surface of one of the plurality of shot areas on the wafer W arranged on the imaging plane of the projection optical system PL. .
[0036]
The wafer stage WST is arranged on a wafer base platen 54 constituting the above-mentioned hanging column 46, and includes, for example, a wafer stage driving system (driving device) 74 (a driving device in FIG. 1) including a magnetic levitation type two-dimensional linear actuator or the like. (Not shown, see FIG. 2) so as to be freely driven in the XY plane.
[0037]
Wafer W is fixed to the upper surface of wafer stage WST via a wafer holder 76 by vacuum suction or the like. The XY position and the amount of rotation (the amount of yawing, the amount of rolling, and the amount of pitching) of wafer stage WST are fixed to a part of wafer stage WST with reference to reference mirror Mw fixed to the lower end of the barrel of projection optical system PL. Measurement is performed in real time at a predetermined resolution, for example, a resolution of about 0.5 to 1 nm by a wafer laser interferometer 80 that measures a change in the position of the mirror 78. The measurement value of the wafer laser interferometer 80 is supplied to the main controller 50 (see FIG. 2).
[0038]
FIG. 2 schematically shows a configuration of a control system of the above-described exposure apparatus 10. This control system is mainly configured by a main controller 50 composed of a workstation (or a microcomputer). The main control device 50 performs the various controls described above, and controls the entire device as a whole.
[0039]
Next, an exposure operation in the exposure apparatus 10 configured as described above will be described.
When wafer W is transferred onto wafer stage WST and focus adjustment is completed, reticle R and wafer W are positioned (aligned) using an alignment system (not shown). In this way, when the preparatory operation for exposure of wafer W is completed, main controller 50 controls wafer stage drive system 74 while monitoring the measurement value of wafer laser interferometer 80 based on the alignment result to control the wafer stage. Wafer stage WST is moved to a scanning start position for exposure of the first shot of W.
[0040]
Then, main controller 50 starts Y-direction scanning of reticle stage RST and wafer stage WST via reticle stage drive system 68 and wafer stage drive system 74, and both stages RST and WST reach their respective target scanning speeds. Upon reaching, the pattern area of the reticle R starts to be illuminated by the pulsed ultraviolet light, and the scanning exposure is started. Prior to the start of the scanning exposure, the light emission of the light source 12 is started, but the movement of each movable blade of the movable blind 28J constituting the reticle blind device is synchronized with the movement of the reticle stage RST by the main controller 50. Since the control is controlled, the irradiation of the pulse ultraviolet light to the outside of the pattern area on the reticle R is blocked as in the case of the ordinary scanning stepper.
[0041]
In the main controller 50, the moving speed Vr of the reticle stage RST in the Y-axis direction and the moving speed Vw of the wafer stage WST in the Y-axis direction particularly during the above-described scanning exposure are the projection magnifications of the projection optical system PL (１ ／ times, The reticle stage RST and the wafer stage WST are synchronously controlled via the reticle stage drive system 68 and the wafer stage drive system 74 so as to maintain the speed ratio according to (５ times or 1/6 times).
[0042]
Then, the pattern area of the reticle R is sequentially illuminated with the pulsed ultraviolet light, and the illumination of the entire pattern area is completed, thereby completing the scanning exposure of the first shot on the wafer W. Thus, the pattern of the reticle R is reduced and transferred to the first shot via the projection optical system PL. When the scanning exposure of the first shot is completed in this manner, main controller 50 moves wafer stage WST stepwise in the X-axis direction via wafer stage drive system 74, and starts scanning for exposure to the second shot. Moved to position. In this stepping, main controller 50 performs real-time positional displacement of wafer stage WST in the X, Y, and θz directions based on the measurement value of wafer laser interferometer 80 that detects the position of wafer stage WST (the position of wafer W). To measure. Based on the measurement result, main controller 50 controls wafer stage drive system 74 to control the position of wafer stage WST such that the XY position displacement of wafer stage WST is in a predetermined state.
[0043]
Further, main controller 50 controls reticle stage drive system 68 based on information on the displacement of wafer stage WST in the θz direction, and rotationally controls reticle stage RST so as to compensate for an error in the rotational displacement of wafer W on the wafer W side. . Then, main controller 50 performs the same scanning exposure on the second shot area as described above. In this manner, the scanning exposure (scanning step) of the shot on the wafer W and the stepping operation (moving step) for the next shot exposure are repeatedly performed, and the reticle R is exposed to all the exposure target shot areas on the wafer W. The patterns are sequentially transferred.
[0044]
Hereinafter, with reference to FIG. 3, a description will be given of a path for relatively moving the illumination area A and each shot area when exposing the plurality of shot areas S1 to S3 on the wafer W. Here, for convenience, the description will be made assuming that the illumination area A moves with respect to the shot areas S1 to S3. In addition, since reticle stage RST (reticle R) follows the movement (X, Y, θz) of wafer stage WST (wafer W), here, shot areas S1 to S3 on wafer W and illumination area are mainly used. Reference will be made to the relative movement with A.
[0045]
The illumination area A starts moving in order to perform scanning exposure on the shot area S1. Here, the illumination area A is moved along an oblique direction (direction of an angle θ with respect to the Y direction) including a component in the X direction (second direction) with respect to the Y direction (first direction).
[0046]
The relationship between time and speed of the illumination area A in the Y and X directions at this time is shown in the time chart of FIG. As shown in this time chart, in both the X direction and the Y direction, the scanning speed is accelerated to the scanning speed (Vy, Vx) in the period T1, and moves at a constant speed in the period T2. In this period T2, settling after acceleration and scanning exposure to the shot area S1 are performed. When the illumination area A moves in an oblique direction, the time required for an arbitrary point on the wafer W to pass through the illumination area A becomes longer than when the illumination area A moves in the Y direction. In the case of the same, it is necessary to provide a step of reducing the amount of illumination light in advance before the start of scanning in correspondence with the increasing scanning time.
[0047]
Subsequently, in a period T3 after the period T2, the movement in the X direction is continued at a constant speed at the speed Vx, but the movement in the Y direction is temporarily reduced to the speed 0 in order to reverse the scanning direction. When the moving speed in the Y direction reaches 0, the illumination area A is stepped to the scanning start position of the shot area S2 in the X direction while the movement in the Y direction is stopped in the period T4. Decelerate. The step moving distance at this time is shorter by the movement in the X direction in the scanning step.
[0048]
When the illumination area A reaches the scanning start position for the shot area S2, in the period T5, the movement in the Y direction accelerates to the scanning speed Vy (the opposite direction), and moves in the X direction at a constant speed Vx in the + X direction. I do. Thereafter, similarly to the above, after the period T6, the scanning step of moving the illumination area A in the Y direction at the speed Vy and in the X direction at the speed Vx in an oblique direction at an angle θ with respect to the Y direction, and only in the X direction By repeatedly and alternately performing the step of moving the step, the plurality of shot areas S1 to S3 can be sequentially exposed.
[0049]
As described above, in the present embodiment, since the illumination area A also moves in the X direction during the scanning step, the scanning step and the moving step overlap, and the moving distance in the X direction after the scanning exposure is reduced. It is possible to reduce the waste of time until the next scanning step is started. Therefore, it is possible to suppress a decrease in the throughput related to the exposure processing, and it is possible to contribute to an improvement in productivity. Further, in the present embodiment, since the amount of illumination light is reduced in advance before the start of scanning, it is possible to prevent an excessive amount of light due to the movement of the illumination area A in an oblique direction, and to manufacture a high-quality device. Will be possible.
[0050]
FIGS. 5 and 6 are views showing a second embodiment of the scanning exposure method and the scanning exposure apparatus of the present invention. In these drawings, the same components as those of the first embodiment shown in FIGS. 1 to 4 are denoted by the same reference numerals, and description thereof will be omitted. The difference between the second embodiment and the first embodiment is the moving speed of the illumination area A.
[0051]
As shown in FIG. 5, in the present embodiment, the movement of the illumination area A in the movement step is set so as to draw a curved movement locus. That is, in the present embodiment, as shown in FIG. 6, when the uniform movement in the Y direction and the X direction in the period T2 ends, the moving speed of the illumination region A is changed from Vy in the periods T3 and T5 in the Y direction. The moving direction is reversed by changing to -Vy when scanning and exposing the region S2. In the X direction, the moving speed is accelerated from Vx in the periods T3 and T5, and the scanning direction when scanning and exposing the shot region S2. By decelerating to the speed Vx, the moving steps in the X and Y directions are completed. It should be noted that the X-axis speed curve (which is shown as a straight line in the drawing, but is actually a curve) does not necessarily need to be a left-right symmetric curve centered on the Y-axis speed zero position.
[0052]
In other words, in the present embodiment, the scanning step can be started by completing the moving step in the Y direction without waiting for the moving step in the X direction to be completed. Therefore, in the present embodiment, it is possible to eliminate a useless time (corresponding to the period T4 in FIG. 4) until the next scanning step is started, and it is possible to greatly improve the throughput related to the exposure processing. become.
[0053]
7 and 8 are views showing a third embodiment of the scanning exposure method and the scanning exposure apparatus according to the present invention. In these drawings, the same components as those of the second embodiment shown in FIGS. 5 and 6 are denoted by the same reference numerals, and description thereof will be omitted. The difference between the third embodiment and the second embodiment is the attitude of the wafer W when the illumination area A moves.
[0054]
As shown in FIG. 7, the illumination area A scans and moves in an oblique direction at an angle θ with respect to the Y direction. In the present embodiment, the scan area S1 is scanned so that the arrangement direction of the shot areas S1 matches this scanning direction. At times, the wafer W is rotated around the optical axis of the illumination light. That is, as shown in the time chart of FIG. 8, the rotation of the wafer W is started via the wafer stage WST before the start of scanning, and the rotation of the angle -θ is performed in the acceleration period T1 up to the scanning speed in the Y and X directions. Let it complete. Then, scanning exposure is performed on the shot area S1 in the period T2.
[0055]
At this time, since the rectangular shot area S1 is arranged in a posture along the scanning direction, the rectangular shot area S1 is exposed with the illumination light of the same area in the illumination area A, and is exposed with the illumination light of a different area. In this case, there is no adverse effect such as a variation in aberration depending on the region. When the uniform movement in the Y direction and the X direction in the period T2 ends, the movement speed of the illumination area A is increased from Vy to -Vy (Y direction) and Vx (X direction) in periods T3 and T5. The wafer W is decelerated and rotated by the angle θ to scan and expose the shot area S2.
[0056]
Thereafter, similarly to the above, after the period T6, the scanning step of moving the illumination area A in the Y direction at the speed Vy and in the X direction at the velocity Vx in the oblique direction at an angle θ with respect to the Y direction, A plurality of shot areas S1 to S3 can be sequentially exposed by repeatedly and alternately performing the step movement in the X direction and the movement step of rotating the wafer W. As described above, in the present embodiment, since the exposure is always performed by the light source in the same area and the light amount distribution is the same, the uniformity of the exposure energy is increased, and the adverse effect on the exposure accuracy can be reduced.
[0057]
In the third embodiment, the description has been made assuming that the wafer W is rotated so that the arrangement direction matches the scanning direction, and the scanning exposure is performed in a state where the illumination area A extends in the X direction. The present invention is not limited to this. For example, as shown in FIG. 9, a driving unit PZ including a piezo element or the like is provided at an interval on one side of a fixed reticle blind RB provided in the second illumination optical system IOP2, By individually driving the driving units PZ in accordance with the posture of the wafer W during scanning, the fixed reticle blind RB can be rotated around the optical axis of the illumination light in the XY plane. Thereby, as shown by the two-dot chain line in FIG. 7, it is possible to set the illumination area A ′ inclined by the angle θ. Therefore, the time required for an arbitrary point on the wafer W to pass through the illumination area A can be shortened, and the throughput can be further improved.
[0058]
In the above embodiment, a fly-eye lens is used as an optical integrator (homogenizer). Instead, a rod integrator (internal reflection type integrator), a diffractive optical element, a microlens array, or the like may be used. You may do it. In an illumination optical system using a rod integrator, the rod integrator is arranged so that its exit surface is substantially conjugate with the pattern surface of the reticle R. Therefore, for example, the movable blind described above is close to the exit surface of the rod integrator. A movable blade of 28J is arranged. Therefore, this illumination optical system is divided into two parts by the rod integrator, and the movable blind is provided in the first portion where the rod integrator is arranged, and the fixed blind is fixed to the main body column as in the above embodiment. Provided in the second part. An illumination optical system using a rod integrator is disclosed in, for example, US Pat. No. 5,675,401. Also, a fly-eye lens and a rod integrator may be combined, or two rod integrators may be arranged in series to form a double optical integrator. Further, a double integrator may be configured by a combination of a diffractive optical element and a rod integrator or a microlens array.
[0059]
Further, in the above embodiment, the case where the active vibration isolators are used as the vibration isolators 42A to 42D is described, but it goes without saying that the present invention is not limited to this. That is, these may be passive vibration isolators.
[0060]
Further, for example, even in the case of an exposure apparatus that uses ultraviolet light as in the above-described embodiment, a reflection system including only a reflection optical element as a projection optical system, or a catadioptric system including a reflection optical element and a refraction optical element (catalogue). Dioptric system) may be used. Here, examples of the catadioptric projection optical system include, for example, Japanese Patent Application Laid-Open No. Hei 8-171504 (and corresponding US Pat. No. 5,668,672) and Japanese Patent Application Laid-Open No. Hei 10-20195 (and US Pat. A catadioptric system having a beam splitter and a concave mirror as a reflective optical element disclosed in, for example, corresponding US Pat. No. 5,835,275), or Japanese Patent Application Laid-Open No. H8-334695 (and corresponding US Pat. No. 5,334,275). 5,689,377) and JP-A-10-3039 (and corresponding US Patent Application No. 873,605 (filing date: June 12, 1997)). A catadioptric system having a concave mirror or the like can be used without using a beam splitter as an element.
[0061]
In addition, Japanese Patent Application Laid-Open No. 10-104513 (and US Pat. No. 5,488,229) discloses a plurality of refractive optical elements and two mirrors (a primary mirror which is a concave mirror, a refractive element or a parallel flat mirror). A sub-mirror, which is a back-side mirror having a reflection surface formed on the side opposite to the incident surface of the face plate, is arranged on the same axis, and an intermediate image of a reticle pattern formed by the plurality of refractive optical elements is referred to as a main mirror. A catadioptric system that re-images on the wafer with the secondary mirror may be used. In this catadioptric system, a primary mirror and a secondary mirror are arranged following a plurality of refractive optical elements, and the illumination light passes through a part of the primary mirror and is reflected in the order of the secondary mirror and the primary mirror. Part to reach the wafer.
[0062]
Further, the catadioptric projection optical system has, for example, a circular image field, is both telecentric on the object side and the image side, and has a projection magnification of 1/4 or 1/5. A reduction system may be used. Further, in the case of a scanning exposure apparatus having this catadioptric projection optical system, the irradiation area of the illumination light is substantially centered on its optical axis within the field of view of the projection optical system, and is substantially in the scanning direction of the reticle or wafer. It may be of a type defined as a rectangular slit extending along the direction orthogonal to the direction. According to the scanning exposure apparatus having such a catadioptric projection optical system, for example, the F of 157 nm wavelength is used. ₂ Even if a laser beam is used as illumination light for exposure, a fine pattern of about 100 nm L / S pattern can be transferred onto a wafer with high accuracy.
[0063]
Also, ArF excimer laser light or F ₂ A laser beam or the like is used. A single-wavelength laser beam in the infrared or visible range oscillated from a DFB semiconductor laser or a fiber laser is amplified by, for example, a fiber amplifier doped with erbium (or both erbium and yttrium). Alternatively, a harmonic converted to ultraviolet light using a nonlinear optical crystal may be used. For example, when the oscillation wavelength of the single wavelength laser is in the range of 1.51 to 1.59 μm, the 8th harmonic whose generation wavelength is in the range of 189 to 199 nm, or in the range of 151 to 159 nm, A certain tenth harmonic is output. In particular, when the oscillation wavelength is in the range of 1.544 to 1.553 μm, an eighth harmonic having a generation wavelength in the range of 193 to 194 nm, that is, ultraviolet light having substantially the same wavelength as the ArF excimer laser light is obtained. Assuming that the wavelength is in the range of 1.57 to 1.58 μm, the tenth harmonic, ie, F, in which the generated wavelength is in the range of 157 to 158 nm. ₂ Ultraviolet light having substantially the same wavelength as the laser light is obtained. When the oscillation wavelength is in the range of 1.03 to 1.12 μm, a seventh harmonic having a generation wavelength in the range of 147 to 160 nm is output. In particular, the oscillation wavelength is in the range of 1.099 to 1.106 μm. , The seventh harmonic having a generation wavelength in the range of 157 to 158 μm, that is, F ₂ Ultraviolet light having substantially the same wavelength as the laser light is obtained. In this case, for example, an ytterbium-doped fiber laser can be used as the single-wavelength oscillation laser.
[0064]
The substrate of the present embodiment is not limited to a semiconductor wafer W for a semiconductor device, but also a glass substrate for a liquid crystal display device, a ceramic wafer for a thin-film magnetic head, or an original mask or reticle used in an exposure apparatus. (Synthetic quartz, silicon wafer) and the like are applied.
[0065]
In addition to micro devices such as semiconductor elements, glass substrates or silicon wafers for manufacturing reticles or masks used in light exposure equipment, EUV exposure equipment, X-ray exposure equipment, electron beam exposure equipment, etc. The present invention can also be applied to an exposure apparatus that transfers a circuit pattern to a substrate. Here, in an exposure apparatus using DUV (far ultraviolet) light, VUV (vacuum ultraviolet) light, or the like, a transmission type reticle is generally used, and as a reticle substrate, quartz glass, fluorine-doped quartz glass, fluorite, Magnesium fluoride, quartz, or the like is used. In a proximity type X-ray exposure apparatus, an electron beam exposure apparatus, or the like, a transmission mask (stencil mask, membrane mask) is used, and a silicon wafer or the like is used as a mask substrate.
[0066]
Of course, not only an exposure apparatus used for manufacturing semiconductor elements, but also an exposure apparatus used for manufacturing a display including a liquid crystal display element, which transfers a device pattern onto a glass plate, and is used for manufacturing a thin-film magnetic head. The present invention can also be applied to an exposure apparatus that transfers a device pattern onto a ceramic wafer, an exposure apparatus used for manufacturing an imaging device (such as a CCD), and the like.
[0067]
When a linear motor (see US Pat. No. 5,623,853 or US Pat. No. 5,528,118) is used for wafer stage WST and reticle stage RST, an air floating type using air bearing is used. However, the magnetic levitation type using Lorentz force or reactance force may be used. Further, the stage may be a tie that moves along a guide, or may be a guideless type in which no guide is provided.
[0068]
As described above, the exposure apparatus 10 according to the embodiment of the present invention controls the various subsystems including the components described in the claims of the present application so as to maintain predetermined mechanical accuracy, electrical accuracy, and optical accuracy. Manufactured by assembling. Before and after this assembly, adjustments to achieve optical accuracy for various optical systems, adjustments to achieve mechanical accuracy for various mechanical systems, and various electric systems to ensure these various accuracy Are adjusted to achieve electrical accuracy. The process of assembling the exposure apparatus from the various subsystems includes mechanical connection, wiring connection of an electric circuit, and piping connection of a pneumatic circuit among the various subsystems. It goes without saying that there is an assembling process for each subsystem before the assembling process from these various subsystems to the exposure apparatus. When the process of assembling the various subsystems into the exposure apparatus is completed, comprehensive adjustment is performed, and various precisions of the entire exposure apparatus are secured. It is desirable that the exposure apparatus be manufactured in a clean room in which the temperature, the degree of cleanliness, and the like are controlled.
[0069]
As shown in FIG. 10, in the semiconductor device, as shown in FIG. 10, step 201 for designing the function and performance of the device, step 202 for manufacturing a mask (reticle) based on this design step, step 203 for manufacturing a wafer from a silicon material, and step 203 The exposure apparatus 10 according to the embodiment is manufactured through a wafer processing step 204 of exposing a reticle pattern to a wafer, a device assembling step (including a dicing step, a bonding step, and a packaging step) 205, an inspection step 206, and the like.
[0070]
【The invention's effect】
As described above, according to the present invention, it is possible to contribute to the improvement of the throughput without causing useless time for the movement of the substrate when performing the scanning exposure. Further, according to the present invention, high-quality devices can be manufactured.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing an overall configuration of a scanning exposure apparatus according to the present invention.
FIG. 2 is a block diagram showing a configuration of a control system in the scanning exposure apparatus.
FIG. 3 is a diagram illustrating the first embodiment of the present invention, and is a diagram illustrating a relative movement path between an illumination area and a shot area.
FIG. 4 is a time chart in FIG. 3;
FIG. 5 is a diagram illustrating a relative movement path between an illumination area and a shot area according to a second embodiment of the present invention.
FIG. 6 is a time chart in FIG. 5;
FIG. 7 is a diagram illustrating a relative movement path between an illumination area and a shot area according to a third embodiment of the present invention.
FIG. 8 is a time chart in FIG. 7;
FIG. 9 is a plan view of a fixed reticle blind according to another embodiment.
FIG. 10 is a flowchart illustrating an example of a semiconductor device manufacturing process.
FIG. 11 is a diagram showing a relative movement path between an illumination area and a shot area in the related art.
[Explanation of symbols]
A Lighting area
R reticle (mask)
S1 to S3 Shot area (partition area)
W wafer (substrate)
10 Scanning exposure equipment
50 Main control device (control device)
74 Wafer stage drive system (drive device)

Claims (8)

A scanning step of exposing one partitioned area on the substrate by scanning and moving the substrate in a first direction with respect to an illumination area of the exposure light; and moving the substrate in a second direction intersecting the first direction. A scanning exposure method for exposing a plurality of divided areas on the substrate by repeatedly performing the moving step and the alternating,
A scanning exposure method, comprising: driving the substrate in an oblique direction including the second direction component with respect to the first direction during the scanning step. The scanning exposure method according to claim 1,
A scanning exposure method comprising: rotating the substrate around an optical axis of the exposure light before the scanning step. The scanning exposure method according to claim 2,
A scanning exposure method, wherein the illumination area is rotated according to the rotation of the substrate. The scanning exposure method according to any one of claims 1 to 3,
A scanning exposure method, wherein the moving step is performed overlapping with the scanning step. The scanning exposure method according to any one of claims 1 to 4,
A scanning exposure method, comprising: adjusting an amount of the exposure light based on a time when an arbitrary point on the substrate passes through the illumination area in the scanning step. The scanning exposure method according to any one of claims 1 to 5,
A scanning exposure method, wherein a mask having a pattern is moved synchronously with the substrate. The scanning exposure method according to claim 6,
A scanning exposure method, wherein the pattern of the mask is transferred onto the substrate in one scanning step. A scanning exposure apparatus having a driving device that moves the substrate in a second direction during the scanning movement while moving the substrate in a first direction with respect to an illumination area of the exposure light,
A scanning device for controlling the driving device so as to drive the substrate in an oblique direction including the second direction component with respect to the first direction during the scanning movement. .

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