JPH06163353A - Projection exposure device - Google Patents

Abstract

PURPOSE:To prevent a supporting part of a stage whereon a wafer or a reticle is mounted from generating tilting or deformation due to reaction of its driving force when the stage is accelerated. CONSTITUTION:Columns 12A, 12B are mounted on a base 1 with vibration proof springs 2A, 2B between, stage systems 4, 5 of a wafer 6 are arranged inside the first column 12A and a stage system 9 of a reticle 11 is arranged on the second column 12B. Force is applied to permanent magnet buried parts 15A, 19A of the columns 12A, 12B from electromagnetic parts 15a, 19A of a fixed column 13 planted on the base 1 by a linear motor method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection exposure apparatus for exposing an image of a reticle pattern onto a wafer by, for example, a so-called slit scan exposure method.

[0002]

2. Description of the Related Art When a semiconductor device, a liquid crystal display device, or the like is manufactured by a lithography process, a pattern image of a photomask or reticle (hereinafter referred to as "reticle") is exposed under exposure light through a projection optical system. A projection exposure apparatus that projects on a photosensitive substrate is used. In such a projection exposure apparatus, there is an increasing demand for a larger field in which an image of a larger chip pattern on a reticle is exposed on a photosensitive substrate. In order to meet the demand for a large field, a so-called slit scan exposure method in which a reticle and a photosensitive substrate are scanned in synchronization with, for example, a slit-shaped or arc-shaped illumination area is effective. As a result, an image of a pattern wider than the illuminated area on the reticle can be exposed on the photosensitive substrate.

FIG. 4 shows a conventional projection exposure apparatus of the slit scan exposure system. In FIG. 4, a first column made of Invar (alloy having a low expansion coefficient) is mounted on a base 1 via vibration-proof springs 2A and 2B. 3 is placed. A Y stage 4 and an X stage 5 are mounted inside the first column 3, and a wafer 6 as a photosensitive substrate is held on the X stage 5. A lens barrel 7 is fixed to the upper part of the first column 3, and the projection optical system PL is housed inside the lens barrel 7. The Y stage 4 positions the wafer 6 in a direction perpendicular to the paper surface of FIG. 4 in a plane (horizontal plane) perpendicular to the optical axis of the projection optical system PL, and the X stage 5 moves perpendicular to the Y axis in the horizontal plane. The wafer 6 is positioned in the X direction. Although not shown, the wafer 6 is placed between the X stage 5 and the wafer 6.
A Z stage and the like for locating in the Z direction, which is the optical axis direction of the projection optical system PL, is also interposed.

A second column 8 made of Invar is fixed on the first column 3, a reticle scanning stage 9 slidable in the X direction is placed on the second column 8, and transferred onto the reticle scanning stage 9. The reticle 11 on which a pattern for use is formed is held. The pattern on the reticle 11 is illuminated by the exposure light IL emitted from the illumination optical system 10,
The pattern image on the reticle 11 is projected and exposed on the wafer 6 via the projection optical system PL. In this case, the illumination optical system 1
The illumination area on the reticle 11 by 0 is, for example, a rectangular slit shape, and the entire pattern area on the reticle 11 is not illuminated only by the illumination area.

Therefore, during exposure, by driving the reticle scanning stage 9, the reticle 11 is scanned at a constant speed V1 in the X direction, which is the direction perpendicular to the longitudinal direction of the illumination region. In sync with this, X
By driving the stage 5, the wafer 6 is scanned in the −X direction at a constant speed V2 with respect to the reticle image in the illumination area. If the projection magnification from the reticle 11 to the wafer 6 by the projection optical system PL is β, the velocity V2 is β · V1. In this manner, by synchronously scanning the reticle 11 and the wafer 5, the image of the entire pattern of the reticle 11 is projected and exposed on the wafer 6. Then, by driving the Y stage 4 and the X stage 5, the wafer 6
The next exposure area above moves into the exposure field of the projection optics PL.

At this time, the vibration generated by driving the reticle scanning stage 9, the Y stage 4, and the X stage 5 is damped by the first column 3 and the second column 8. Further, vibration from the floor side where the base 1 is installed is absorbed by the vibration-proof springs 2A and 2B and hardly transmitted to the first column 3 side.

[0007]

In the conventional technique as described above, it is necessary to scan the reticle 11 and the wafer 6 at the same speed, and from the stationary state of the stage to the constant speed scanning, or It is necessary to apply a predetermined driving force from the first column 3 and the second column 8 supporting the X stage 5 and the reticle scanning stage 9, respectively, from the constant velocity scanning to the stage stationary state. .

For example, as shown in FIG. 5A, the mass of the reticle scanning stage 9 and the mass of the X stage 5 are M respectively.
Assuming that the accelerations given to the reticle scanning stage 9 and the X stage 5 are g1 and g2, respectively, as 1 and M2, the driving forces given to the reticle scanning stage 9 and the X stage 5 are represented by M1.g1 and M2.g2, respectively. (For the sake of simplicity, the error due to friction is excluded). The driving force continues to be applied until the respective stages reach a constant scanning speed. In this process, due to the reaction, the corresponding forces F1 (= -M1 · g1) and F2 (= −M2 · g) are applied to the corresponding second column 8 and first column 3, respectively.
2) will be added, and the entire first column 3 and second column 8 may be tilted. Further, as shown in FIG. 5B, when the force F3 is applied to the second column 8 in order to apply the acceleration g3 to the reticle scanning stage 9, the weak portions 8a and 8b of the second column 8 are deformed. There was also a risk of doing it.

Thus, the first column 3 and the second column 8
If the tilt of the reticle 11 or the deformation of the second column 8 occurs, the relative positional relationship between the reticle 11 and the wafer 6 changes, and the pattern on the reticle 11 is superimposed on the circuit pattern already formed on the wafer 6. There is a disadvantage that the overlay accuracy at the time of exposure is deteriorated. Further, if the first column 3 and the second column 8 are made to have a high rigidity structure in order to prevent this, it is difficult to design the columns, and the columns become complicated and large. Further, there is also a disadvantage that the vibration due to the inclination and deformation of each column becomes an external force, which deteriorates the position controllability between the reticle 11 and the wafer 6.

In view of the above point, the present invention, even when the stage supporting a wafer or a reticle is accelerated, even if the supporting portion of the stage receives a force in the opposite direction due to the reaction of its driving force, An object of the present invention is to provide a projection exposure apparatus in which the support portion does not tilt or deform.

[0011]

A projection exposure apparatus according to the present invention holds an illumination optical system (10) for illuminating an illumination area having a predetermined shape and a mask (11), as shown in FIG. Mask scanning means (9) for relatively scanning the mask (11) with respect to the illumination area, and mask scanning means (9)
And the mask base (12B) on which is placed, and the image of the pattern on the mask (11) in the illumination area is formed on the photosensitive substrate (6).
The projection optical system (PL) for projecting onto the upper surface and the photosensitive substrate (6) are held, and the photosensitive substrate (6) is attached to the conjugate image of the illuminated area.
A substrate scanning means (5) for relatively scanning the substrate and a substrate base (12A) on which the substrate scanning means (5) is mounted,
By synchronously scanning the mask (11) and the photosensitive substrate (6) relative to the illuminated area, an image of a pattern of an area on the mask (11) wider than the illuminated area is formed on the photosensitive substrate (6). ) In the projection exposure apparatus for projecting onto a fixed member (1) arranged independently of the substrate base (12A).
Substrate base urging means (15A, 17A) for applying an urging force to the substrate base (12A) is provided in 3), and the substrate is used when the photosensitive substrate (6) is relatively scanned with respect to the conjugate image of the illumination area. A force having the same magnitude in the opposite direction to the force applied to the base (12A) is applied to the substrate base urging means (15A, 17).
A) is applied to the substrate base (12A).

In this case, the mask base (12B) is placed on the substrate base (12A), and the mask base urging means (19A, 21A) for applying the urging force to the fixing member (14) with respect to the mask base (12B). ) Is provided and the mask (11)
The mask base urging means (19A, 21A) applies to the mask base (12B) a force having the same magnitude in the opposite direction to the force applied to the mask base (12B) when scanning is performed relative to the illumination area. Is desirable.

The substrate base urging means (15A, 17)
A) and the mask base biasing means (19A, 21A) are
It is desirable to apply a biasing force to the substrate base (12A) and the mask base (12B) in a non-contact manner. An example of the non-contact substrate base urging means (15A, 17A) and the mask base urging means (19A, 21A) is a linear motor.

[0014]

According to the present invention, when the substrate scanning means (5) is driven, the substrate base urging means (15A, 17A) of the fixing member (13) separate from the substrate base (12A) is used. , The substrate base (12A) with the same magnitude as the reaction given to the substrate base (12A) and the forces in the opposite directions synchronized.
Therefore, the substrate base (12A) is not tilted or deformed. Therefore, the overlay accuracy of the conjugate image of the mask (11) and the photosensitive substrate (6) is improved.

Further, when the fixing member (13) is provided with mask base urging means (19A, 21A) for applying an urging force to the mask base (12B), when the mask scanning means (9) is driven. To the mask base (12B) by applying a reverse force to the mask base (12B) with the same magnitude as the reaction applied to the mask base (12B).
2B) does not tilt or deform. Therefore, the overlay accuracy and the like are further improved.

The substrate base urging means (15A, 17)
A) and the mask base urging means (19A, 21A)
When a biasing force is applied to the substrate base (12A) and the mask base (12B) without contacting each other, the fixing member (1
Vibration and the like on the 3) side are not transmitted to the substrate base (12A) side. In particular, those substrate base urging means (15A, 1
7A) and the mask base biasing means (19A, 21A) are of linear motor type, the fixing member (13)
To substrate base (12A) and mask base (12B)
No new vibration is transmitted to. And the fixing member (13)
Even when the fixing member (13) is distorted or deformed by the force applied to the fixing member (13) and the substrate base (12A).
It is supported by an anti-vibration stand etc. Therefore, when the power of the linear motor is turned off, the influence of the distortion of the fixing member (13) directly affects the substrate base (12A).
There is no transmission to.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the projection exposure apparatus according to the present invention will be described below with reference to FIGS. In this embodiment, the present invention is applied to a slit scan exposure type projection exposure apparatus, and in FIGS. 1 to 3, the portions corresponding to those in FIG. 4 are denoted by the same reference numerals and detailed description thereof will be omitted.

FIG. 1 shows a projection exposure apparatus according to the present embodiment. In FIG. 1, vibration damping springs 2A and 2B are mounted on a base 1.
The first column 12A made of Invar (alloy having a low expansion coefficient) is placed via the above, and the second column 12B made of Invar is fixed on the first column 12A. A wafer 6 is held inside the first column 12A via a Y stage 4 and an X stage 5, and a projection optical system PL is held above the first column 12A via a lens barrel 7. Further, the reticle 11 is held above the second column 12B via the reticle scanning stage 9. The illumination optical system 10 of the present example also illuminates the slit-shaped illumination area on the reticle 11, and scans the wafer 6 in the −X direction in synchronization with scanning the reticle 11 in the X direction with respect to the illumination area. As a result, the image of the pattern of the reticle 11 is exposed on the wafer 6 by the slit scan exposure method.

In this embodiment, a fixed column 13 made of Invar is planted on the peripheral edge of the base 1. Then, three permanent magnet embedding portions 14A to 14C are formed on the upper surface of the convex portion 12a on one side surface in the X direction of the first column 12A (only 14A appears in FIG. 1), and these permanent magnet embedding portions are formed. Three electromagnet portions 15A to 15C are formed on the bottom of the convex portion 13a of the fixed column 13 so as to face 14A to 14C (only 15A appears in FIG. 1). In contrast to this, the convex portion 1 on the other side surface in the X direction of the first column 12A
Three permanent magnet embedded portions 16A to 16C on the upper surface of 2b
(Only 16A is shown in FIG. 1) to face the permanent magnet embedded portions 16A to 16C,
Three electromagnet parts 1 are provided on the bottom of the convex portion 13b of the fixed column 13.
7A to 17C are formed (only 15A is shown in FIG. 1). Three sets of linear motors are configured by the permanent magnet embedded portions 14A to 14C and the corresponding electromagnet portions 15A to 15C.

Further, two permanent magnet embedding portions 1 are provided on the upper surface of the one convex portion 12c in the X direction at the upper end of the second column 12B.
8A and 18B are formed (only 18A is shown in FIG. 1), and two electromagnet parts 19A are provided at the bottom of the convex part 13c at the upper end of the fixed column 13 so as to face the permanent magnet embedding parts 18A and 18B. And 19B (only 19A appears in FIG. 1). In contrast to this, the second
Two permanent magnet embedding portions 20A and 20B are formed on the upper surface of the other convex portion 12d in the X direction at the upper end of the column 12B (only 20A appears in FIG. 1), and these permanent magnet embedding portions 20A and 20B are formed. Two electromagnet parts 2 are provided at the bottom of the protrusion 13d at the upper end of the fixed column 13 so as to face each other.
Form 1A and 21B (only 21A appears in FIG. 1).

FIG. 2 is a sectional view taken along the line AA of FIG.
As shown in FIG. 2, the three embedded permanent magnets 14
A to 14C are arranged in the Y direction. Then, in the permanent magnet embedded portions 14A and 14C at both ends, the N pole portion 22A, the S pole portion 23 and the N pole portion 22 of the permanent magnet are sequentially arranged in the X direction.
B is embedded, and Y is embedded in the central permanent magnet embedded portion 14B.
22A, S pole 23 and N of the permanent magnet in the direction
The pole portion 22B is embedded. The electromagnet portion 15A of FIG. 1 is formed by arranging electromagnets in the X direction, and the electromagnet portions facing the permanent magnet embedding portions 14B and 14C are formed by arranging electromagnets in the Y direction and the X direction, respectively.

Therefore, by the linear motor including the permanent magnet embedding portion 14A and the electromagnet portion 15A and the linear motor including the permanent magnet embedding portion 14C and the corresponding electromagnet portion, an arbitrary force F4A is applied to the first column 12A in the X direction. And F4C can be applied, and an arbitrary force F4B can be applied to the first column 12A in the Y direction by the linear motor including the central permanent magnet embedding part 14B and the corresponding electromagnet part.

Further, permanent magnets are embedded in the permanent magnet embedding portions 16A to 16C on the right side of the first column 12A in the same arrangement as that of the permanent magnet embedding portions 14A to 16C, and the corresponding electromagnet portions 17A to 17C are respectively arranged. Electromagnets are arranged in the arrangement direction of the facing permanent magnets. And
Applying an arbitrary force F5A in the X direction, an arbitrary force F5B in the Y direction, and an arbitrary force F5C in the X direction to the first column 12A by a linear motor including the permanent magnet embedded portions 16A, 16B, and 16C, respectively. You can Therefore, a force in an arbitrary direction can be applied to the first column 12A within the horizontal plane (XY plane) by the three sets of left side linear motors and the three sets of right side linear motors. An arbitrary rotational force can also be applied to. Therefore, when the reaction is applied to the first column 12A when the acceleration is applied to the X stage 5 and the Y stage 4 during slit scan exposure or the like,
A force that cancels the reaction is applied to the first column 12A from the six sets of linear motors.

On the other hand, in FIG. 1, permanent magnets are embedded in the two left permanent magnet embedding portions 18A and 18B on the second column 12B in the X direction, and the corresponding electromagnet portions 19A and 19B are also arranged in the X direction. It is configured by arranging electromagnets. In addition, the two right permanent magnet embedding portions 20A and 20B on the second column 12B are respectively provided with Xs.
The permanent magnets are embedded in the direction, and the corresponding electromagnet portions 21A and 21B are also configured by arranging the electromagnets in the X direction. Therefore, the second column 12 is formed by the two linear motors each including the permanent magnet embedded portions 18A and 18B.
An arbitrary force in the X direction is applied to B, and an arbitrary force in the X direction is also applied to the second column 12B from the two linear motors each including the permanent magnet embedded portions 20A and 20B.

In this embodiment, since the reticle 11 is scanned by the reticle scanning stage 9 in the X direction, the reaction on the second column 12B acts in the X direction. Therefore, the force applied from the linear motor to cancel the reaction to the second column 12B is only the force in the X direction. When the reticle 11 is also driven in the Y direction, linear motors for independently applying a force in the Y direction may be mounted in parallel.

Next, the operation of this embodiment will be described with reference to FIG. When slit scan exposure is started in this embodiment, acceleration g1 in the X direction is applied to the reticle 11 and acceleration g in the −X direction is applied to the wafer 6, as shown in FIG.
2 is added, and as a reaction between them, the −X direction force F1 is applied to the second column 12B, and the X direction force F2 is applied to the first column 12A. Therefore, by the linear motor including the permanent magnet embedding portion 18A and the electromagnet portion 19A and the other three linear motors above the second column 12B, a total of F in the X direction with respect to the second column 12B.
Give 1 power.

Further, the linear motor and the first column 12 comprising the permanent magnet embedded portion 14A and the electromagnet portion 15A.
The other five linear motors on the side surface of A apply a total force of F2 to the first column 12A in the -X direction. Since the permanent magnet portion 14A and the like and the electromagnet portion 15A and the like are fixed, the actual movement is not performed even when a force is generated as a linear motor. This allows
The forces acting on the first column 12A and the second column 12B become zero, and the first column 12A and the second column 12B
Of the reticle 11 and the wafer 6 are maintained with high accuracy.

Further, as shown in FIG. 2, when the center of gravity of the stage system is deviated from the optical axis of the projection optical system PL by the position of the Y stage 4 and the position of the X stage 5, the Y stage 4 is also driven. In such a case, two types of force vectors <FY> and <FX> act on the stage system.
In such a case, the force vector applied to the first column 12A by the three linear motors on the left side in FIG. 2 is <FA>, and the force vector applied to the first column by the three linear motors on the right side is <FA>. As FB>, these force distributions are as follows. <FA> + <FB> = <FX> + <FY> As a result, the twisting force acting on the first column 12A becomes zero.

Although the linear motor generates a relatively large amount of heat, the linear motor of this example is arranged away from the projection exposure unit including the reticle 11, the projection optical system PL, and the wafer 6, so its influence is ignored. It is possible. However, the influence of heat generation can be further reduced by mounting a heat generation prevention mechanism such as an air cooling type or a liquid cooling type on each of the linear motors.

In the above embodiment, the first column 12A is used.
And the force is applied to the second column 12B from the fixed column 13 by the linear motor method, but the force is applied to the first column 12A and the second column 12B by a method of blowing compressed air, for example. May be. Further, for example, a compression coil spring may be interposed between the fixed column 13 and the first column 12A, and a force may be applied to the first column 12A from the fixed column 13 side via the compression coil spring. . When the compression coil spring is used, it is possible to prevent the vibration and the like on the fixed column 13 side from being transmitted to the first column 12A, almost like the non-contact type.

Although the fixed column 13 is arranged on the base 1 in the above-mentioned embodiment, if there is a member other than the base 1 that does not vibrate when the stages 4, 5, 9 are evaluated, this The fixed column 13 may be fixed to the member. Further, in the above-described embodiment, the wafer side electromagnet portions 15A to 15C and 17A to 17C and the reticle side electromagnet portions 19A to 19C and 21A to 21C are both fixed columns 1.
However, the electromagnet part on the wafer side and the electromagnet part on the reticle side may be fixed to different fixed columns.

Also, in the embodiment of FIG. 1, the first column 12
Y stage 4 and X stage 5 are housed inside A,
Anti-vibration springs 2A and 2B are interposed between the bottom portion and the base 1, but the first column 12A is expanded left and right around the holding portion of the lens barrel 7, and the portion thus expanded. The vibration-proof springs 2A and 2B may be interposed between the base 1 and the base 1, respectively. In this case, a U-shaped column is preferably attached as a metal piece under the holding portion of the lens barrel 7 of the first column, and the Y stage 4 and the X stage 5 are mounted on the U-shaped column. Should be placed. With such a configuration, the influence of vibration is further reduced.

As described above, the present invention is not limited to the above-described embodiments, and various configurations can be adopted without departing from the gist of the present invention.

[0034]

According to the present invention, since the force applied to the substrate base in the opposite direction to the force applied to the substrate base is applied from the substrate base urging means to the substrate base, the inclination or deformation of the substrate base is prevented. There is an advantage that it does not occur and the relative positional relationship between the mask and the photosensitive substrate does not easily change. Further, when the mask base urging means applies a force having the same magnitude in the opposite direction to the force applied to the mask base to the mask base, it is possible to suppress the inclination and deformation of the mask base, There is an advantage that the relative positional relationship between the mask and the photosensitive substrate can be maintained more stably. Further, since the force applied to the substrate base and the mask base becomes zero, it is possible to use a member having relatively small rigidity as the substrate base and the mask base, which is advantageous in design and manufacturing.

Further, when the substrate base urging means and the mask base urging means apply the urging force to the substrate base and the mask base in a non-contact manner, the vibration or the like on the fixed member side causes the substrate base to oscillate. And it is not transmitted to the mask base. In particular, when the substrate base urging means and the mask base urging means are linear motors, respectively, the overall configuration can be simplified.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a projection exposure apparatus according to the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is an explanatory view showing forces acting on a first column 12A and a second column 12B in the embodiment of FIG.

FIG. 4 is a configuration diagram showing a conventional projection exposure apparatus.

5A is a diagram showing a state in which the projection exposure apparatus of FIG. 4 is inclined when the stage is driven, and FIG. 5B is a diagram showing a state in which a column of the projection exposure apparatus of FIG. 4 is deformed when the stage is driven.

[Explanation of symbols]

 1 Base 2A, 2B Anti-Vibration Spring 4 Y Stage 5 X Stage 6 Wafer PL Projection Optical System 7 Lens Tube 9 Reticle Scanning Stage 10 Illumination Optical System 11 Reticle 12A First Column 12B Second Column 13 Fixed Column 14A, 16A, 18A, 20A Permanent magnet embedded part 15A, 17A, 19A, 21A Electromagnet part

Claims (4)

[Claims] 1. An illumination optical system for illuminating an illumination area of a predetermined shape, a mask scanning means for holding a mask and scanning the mask relative to the illumination area, and a mask scanning means for mounting the mask. A mask base, a projection optical system for projecting an image of a pattern on the mask in the illuminated area onto a photosensitive substrate, and holding the photosensitive substrate to hold the photosensitive substrate with respect to a conjugate image of the illuminated area. A substrate scanning unit that relatively scans, and a substrate base on which the substrate scanning unit is placed, and by synchronously scanning the mask and the photosensitive substrate relative to the illumination region, In a projection exposure apparatus for projecting an image of a pattern of an area on the mask wider than the illumination area onto the photosensitive substrate, a fixing member arranged independently of the substrate base applies a biasing force to the substrate base. To And a force substantially equal in magnitude in the opposite direction to the force applied to the substrate base when the photosensitive substrate is relatively scanned with respect to the conjugate image of the illumination area. A projection exposure apparatus characterized in that it is applied to the substrate base from a means. 2. The mask base is placed on the substrate base, and the fixing member is provided with mask base urging means for applying an urging force to the mask base. 2. The projection exposure apparatus according to claim 1, wherein a force which is substantially equal in magnitude in a direction opposite to the force applied to the mask base during scanning is applied from the mask base urging means to the mask base. . 3. The projection exposure apparatus according to claim 2, wherein the substrate base biasing means and the mask base biasing means apply a biasing force to the substrate base and the mask base in a non-contact manner, respectively. 4. The projection exposure apparatus according to claim 3, wherein each of the substrate base urging means and the mask base urging means is a linear motor.