JP7162430B2 - projection exposure equipment - Google Patents

Description

The present invention relates to a projection exposure apparatus that exposes a pattern on a wafer by step-and-repeat.

A projection exposure apparatus projects a reticle pattern as an original onto a photosensitive substrate (a wafer with a resist layer formed on its surface) via a projection optical system in the lithography process, which is part of the manufacturing process for semiconductor devices and liquid crystal display devices. ). In the step-and-repeat method in which the wafer is moved and patterns are sequentially exposed, the step movement of the wafer and the exposure are alternately repeated. There is a function of not exposing a predetermined range from the edge edge when the exposure position reaches the wafer edge (periphery). Such a wafer perimeter non-exposure function is called WEM (Wafer Edge Masking).

WEM removes excess photoresist at the wafer edge during development by not exposing the periphery, for example, in the case of negative photoresist. Alternatively, in the case of a positive photoresist, WEM is used to prevent uneven exposure of the wafer edge (partial double exposure by the projection exposure apparatus and the peripheral exposure apparatus) when the wafer edge is exposed using a separate peripheral exposure apparatus. used.

As WEM technology, a mechanism for providing a light shielding plate on a wafer and a mechanism for providing a light shielding plate at a reticle conjugate position are known. For example, Patent Literature 1 describes a mechanism for loading and unloading a ring-shaped light shielding plate on a work chuck. Further, Japanese Patent Application Laid-Open No. 2002-200001 describes that a light shielding band is provided above the wafer. US Pat. No. 6,200,001 describes that the shaded strip has multiple curvatures and that the shaded strip is rotated and moved. Furthermore, Japanese Patent Application Laid-Open No. 2002-200001 describes a mechanism for providing a light shielding plate at a reticle conjugate position.

On-wafer shaded WEMs are relatively simple in construction and do not require complex controls. On the other hand, it is necessary to pay attention to parts selection, maintenance, etc. against contamination of the wafer by particles from the movable part provided on the wafer for moving the light shielding body, or damage to the wafer due to contact between the light shielding part and the wafer. there were. In addition, since the light shielding plate is provided at a distance from the wafer, there is a problem that blurring occurs at the light shielding boundary.

A WEM that shields light at a reticle conjugate position has problems in that the amount of light decreases due to an increase in the number of optical elements such as a relay lens, and that the moving mechanism and control of the light shielding plate are complicated. On the other hand, there is the advantage that there is no fear of contamination or damage to the wafer, and the blurring of the light-shielding boundary is small. Considering the characteristics of these two methods, the more highly accurate the projection exposure apparatus requires, the greater the advantage of adopting WEM at the reticle conjugate position.

Japanese Patent Publication No. 2005-505147 JP 2005-045160 A Japanese Unexamined Patent Application Publication No. 2011-233781

When changing the width of the non-exposure area of the wafer, or when the width of the non-exposure area remains the same but the diameter of the wafer changes, it is necessary to change the curvature of the boundary line of the non-exposure area. That is, it is necessary to replace the light shielding plate with one having an edge that coincides with the boundary line. However, the space at the exit of the lens for homogenizing the illumination light of the illumination optical system is narrow, and replacing the light shielding plate in this narrow space may damage the lens for homogenizing the illumination light. In addition, it is troublesome to adjust the mounting accuracy of the light shielding plate each time it is replaced.

In other words, in terms of optical design, it is ideal to set both the light blocking plate and the rod lens exit at the reticle conjugate position. However, in order to avoid interference between the movable parts, it is necessary to provide a gap between them, and it is desirable that this gap be narrow. Widening the gap has the following disadvantages.

The farther the rod lens exit is from the reticle conjugate position, the worse the illuminance distribution of the light illuminating the reticle.
As the light shielding plate moves away from the reticle conjugate position, the edges of the projected image of the light shielding plate become blurred, and the photoresist cross section becomes oblique at the blurred portion when developed.

For this reason, the mounting space for the light shielding plate at the lens outlet is narrow, and the above-described problems arise. Patent document 2 does not disclose a mechanism for rotating and moving the light shielding band, and does not give any consideration to providing the light shielding band in a narrow space.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a projection exposure apparatus in which a light shielding mechanism including a light shielding plate can be placed in a narrow space close to the exit of illumination light uniformizing means.

The present invention comprises an illumination optical system that uniformizes the illuminance of light emitted from a light source by illumination light uniformizing means and irradiates the reticle with the uniform illumination light,
Rotation having an aperture through which the light flux of the illumination light homogenizing means passes, rotating around the optical axis of the illumination light homogenizing means in the vicinity of the exit surface of the illumination light homogenizing means, and having a mounting surface perpendicular to the optical axis body and
a linear motion mechanism having a linear motion part attached to the mounting surface and moving toward or away from the optical axis;
a support plate detachably attached to the linear motion part;
a drive means provided on the support plate;
a light shielding plate located on the mounting surface and rotated by the driving means ,
a light blocking plate having a plurality of edges with different curvatures for blocking part of the light beam of the illumination optical system, one of the plurality of edges being selected by the driving means ;
This is a projection exposure apparatus in which a selected edge is used to block part of the light flux of an illumination optical system.

According to at least one embodiment, since the light blocking plate has a plurality of edges with different curvatures, it is possible to respond to changes in the width of the non-exposure region and the diameter of the wafer by switching the edges. Note that the effects described herein are not necessarily limited, and may be any effect described in the present invention or an effect different from them.

FIG. 1 is a diagram showing the configuration of an exposure apparatus according to one embodiment of the present invention. 2A and 2B are a front view, a plan view, and a side view of a light shielding plate according to an embodiment. FIG. FIG. 3 is a cross-sectional view of a light shielding mechanism in one embodiment. FIG. 4 is a diagram showing a light shielding plate moving mechanism according to one embodiment. FIG. 5 is a plan view of a wafer used for explaining the exposure operation. FIG. 6 is a front view of another example of the light shielding plate. 7A and 7B are flowcharts showing the flow of processing according to one embodiment of the present invention. 7A and 7B are flowcharts showing the flow of processing according to one embodiment of the present invention. FIG. 8 is a diagram showing another configuration example of the light shielding plate moving mechanism. FIG. 9 is a diagram showing still another configuration example of the light shielding plate moving mechanism.

Hereinafter, embodiments of the present invention and the like will be described with reference to the drawings. The description will be given in the following order.
<1. one embodiment>
<2. Variation>
The embodiments and the like described below are preferred specific examples of the present invention, and the content of the present invention is not limited to these embodiments and the like.

<1. one embodiment>
"Device configuration"
FIG. 1 is a schematic configuration diagram of one embodiment of the projection exposure apparatus of the present invention. The projection exposure apparatus has a light source 1 and an illumination optical system 4 that uses the light emitted from the light source 1 as illumination light with uniform illuminance. Illumination light from an illumination optical system 4 is applied to a reticle (photomask) 8 which is a pattern original. An image of the reticle 8 is projected onto the wafer 13 by the projection optical system 12 .

A wafer 13 is placed on an exposure stage (work chuck) 14 . The exposure stage 14 is moved by a stage moving mechanism 15 . A stage moving mechanism 15 and an optical system (light source 1, illumination optical system 4, projection optical system 12) are supported by a pedestal 16. FIG. In addition, in FIG. 1, each element is shown in a cross-sectional view along the main optical axis, and hatching at that time is omitted.

A light source 1 is a UV lamp that emits broadband light including g-, h-, and i-lines. Also, an elliptical mirror 2 is provided as a condensing mirror. Light from the light source 1 is reflected by the mirror 3 and condensed toward the entrance of the rod lens 5 of the illumination optical system 4 . A rod lens 5 is supported by a rod lens supporting portion 6 . A mercury lamp, a laser, or the like may be used as the light source 1 .

The illumination optical system 4 has a rod lens 5 and a critical illumination lens group 7 . The rod lens 5 is a transparent body having a polygonal cross section and functions as illumination light homogenizing means by internal reflection. The illumination light homogenizing means is not limited to the rod lens, but may be an internal reflecting mirror (a polygonal tube in which a plurality of mirrors are glued together facing inward).

The critical illumination lens group 7 magnifies the image of the exit surface of the rod lens 5 by a predetermined magnification (for example, 2 times) and illuminates the reticle 8 . Although the critical illumination lens group 7 is omitted in the drawing by being a square, it is composed of a plurality of lenses (for example, 10 lenses). The illumination optical system 4 also includes a light shielding mechanism (WEM mechanism) 11, which will be described later.

The reticle 8 is made of quartz glass, for example, and is a transmissive photomask on which a predetermined pattern (for example, a circuit pattern) to be transferred is drawn. A reticle 8 is supported by a reticle stage 9 . Also, an alignment camera 10 is provided, and an alignment mark provided on the reticle 8 can be imaged by the alignment camera 10 .

The projection optical system 12 is, for example, a Dyson optical system, and includes entrance and exit plane mirrors, a lens group, and a folding concave mirror. In one embodiment, the magnification of the projection optical system 12 is 1:1. Although the lens group is omitted in FIG. 1 and only one lens is shown, it is actually composed of a plurality of lenses. In one embodiment, the Dyson optical system is taken as an example, but the type, configuration, magnification, etc. of the projection optical system 12 are not limited.

The wafer 13 is, for example, a silicon wafer having a single-crystal silicon surface coated with a photoresist (photosensitive agent). In addition to those made of single crystal silicon, they may be made of glass, sapphire, or compounds. The wafer 13 has a circular shape and a diameter of, for example, 300 mm.

A photoresist is applied not only to the pattern exposure region but also to at least a part of the peripheral portion of the wafer 13 . Photoresists are photosensitive materials that are patterned using ultraviolet light. The photoresist may be either positive type or negative type. A predetermined non-exposure area is set in the peripheral portion of the wafer 13 . For example, the non-exposure area has a width of 5 mm along the entire edge of the wafer 13 . A notch or orientation flat may be provided around the wafer 13 for angular alignment of the wafer.

The exposure stage 14 holds the wafer 13 by suction. Using a robot hand (not shown), the wafer 13 is transferred from a pre-aligner (not shown) and placed on the exposure stage 14 waiting at the substrate transfer position. In FIG. 1, the substrate transfer position is indicated by a two-dot chain line. Similarly, the wafer 13 is unloaded from the exposure stage 14 at the substrate transfer position and transferred to a wafer cassette (not shown). It should be noted that the exposure stage 14 may be provided with a lift pin or the like for transferring the wafer to and from the robot hand.

The exposure stage 14 is moved in the X, Y, and θ directions by the stage moving mechanism 15 . The surface (two-dimensional plane) of the wafer 13 is defined by the X and Y directions, and the rotation direction is defined by θ. A stage moving mechanism 15 performs movement for step exposure and fine movement for wafer alignment. A mechanism for moving in the Z direction and adjusting the tilt of the exposure stage is also provided for focusing the wafer 13 . Further, the stage moving mechanism 15 moves between each position of a wafer transfer position, an alignment position (not shown), and an exposure position.

The projection exposure apparatus includes an exposure stage 14 and a mount 16 for installing an optical system. An alignment camera 10 is attached to a pedestal 16 . The projection exposure apparatus includes a wafer cassette, a wafer transfer robot, a pre-aligner, etc. (none of which are shown). The projection exposure apparatus may also have an air-conditioned chamber that encloses the entire apparatus.

"Shading plate"
In one embodiment, a light blocking plate 17 is installed on the conjugate plane of the wafer 13 of the illumination optical system 4 . Also, the light shielding plate 17 is positioned at the exit portion of the rod lens 5 . Specifically, the exit surface of the rod lens 5 is positioned close to the light shielding plate 17 . In this way, the position slightly separated from the exit surface of the rod lens 5 is called the exit part of the rod lens 5 . As for the separation distance, for example, the exit surface of the rod lens 5 is positioned at a distance of 3 mm from the light blocking plate 17 . Although the interval other than 3 mm may be used, the interval as narrow as possible is desirable. Also, the exit surface of the rod lens 5 may be aligned with the conjugate surface. 2 shows a front view, a plan view and a side view of an example of a light blocking plate 17 for blocking light along the peripheral non-exposure region of the wafer 13, and FIG. 4 shows the light shielding mechanism 11 viewed from the exit surface.

The light-shielding plate 17 is made of the same material as the reticle 8, such as quartz glass, and is coated with a black light-shielding agent. The light shielding plate 17 has an arc-shaped notch R0 on the inner peripheral side and has four arc-shaped edges R1, R2, R3 and R4 with different radii (that is, different curvatures) on the outer peripheral side. . Mounting holes 18a, 18b and 18c are also formed, through which a ring-shaped holder 19 is mounted as shown in FIG. The ring-shaped holder 19 is made of metal, for example, and the light shielding plate 17 is reinforced.

Further, the arcuate edge portion of the light shielding plate 17 has a tapered cross section corresponding to the NA (numerical aperture) of the illumination optical system. The tapered shape is for preventing a decrease in the amount of emitted light in areas other than the non-exposure area. In addition, although there are four arcuate edges of the light shielding plate in the embodiment, there is no need to limit to this. For example, a light blocking plate having two arcuate edges may be used. Since the light shielding plate 17 has edges with different curvatures, it is possible to correspond to the non-exposed areas of the wafer 13 having different radii. be.

"Light shielding plate moving mechanism"
The position of the light shielding plate 17 is displaced by the light shielding plate moving mechanism. The light shielding plate moving mechanism includes a linear motion mechanism 23, a first θ-axis mechanism, and a second θ-axis mechanism. The light shielding plate 17 and the light shielding plate moving mechanism constitute a variable light shielding means. As shown in FIG. 4, the arc-shaped notch R0 inside the light shielding plate 17 or the arc inside the ring-shaped holder 19 is attached to the rotating shaft of the arc-switching motor 20. As shown in FIG. A circular arc switching motor 20 is fixed to a base plate 21 . The base plate 21 is attached to the linear motion mechanism 23 by attaching/detaching screws 22a and 22b. That is, the base plate 21 to which the light shielding plate 17 and the arc switching motor 20 are attached in advance is detachable from the linear motion mechanism 23 . Therefore, the light shielding plate 17 is replaced integrally with the arc switching motor 20 and the base plate 21 . A mechanism for rotating the light shielding plate 17 by the arc switching motor 20 is called a 2.theta.-axis mechanism.

The linear motion mechanism 23 is a single-axis actuator such as a ball screw, and is a mechanism for linearly displacing the light shielding plate 17 and the arc switching motor 20 . The linear motion mechanism 23 moves the edge of the light blocking plate 17 toward or away from the optical axis of the illumination optical system 4 . The linear motion mechanism 23 sets the position of the edge of the light shielding plate 17 corresponding to the width of the non-exposure area.

The first .theta.-axis mechanism is a rotating mechanism that rotates the light blocking plate 17 about the optical axis of the illumination optical system. As shown in FIG. 3, a hollow motor 24 is provided by which a hollow shaft 25 is rotated. Hollow motor 24 includes a rotating cable portion 26 such as a slip ring.

A rod lens support 6 having a rod lens 5 is installed in the hollow shaft 25 . For example, the center of the hollow shaft 25 and the optical axis of the rod lens 5 are aligned. The rod lens support portion 6 is fixed to the housing on the entrance side of the rod lens 5 and supported by a bearing 27 provided in the hollow shaft 25 on the exit side. However, a cantilever structure in which the rod lens 5 and the rod lens support portion 6 are supported only on the inlet side without supporting the outlet side of the rod lens 5 by the bearing 27 may be employed.

The rod lens supporter 6 includes a rod lens cooling mechanism that cools the rod lens 5 by flowing coolant through a conduit (not shown) provided in the rod lens supporter 6 . It also has a light shielding plate cooling mechanism that cools the light shielding plate 17 by injecting gas to the light shielding plate 17 through another conduit (not shown) provided in the rod lens supporting portion 6 .

A rotary stage 28 is attached to the exit side of the rod lens 5 of the hollow shaft 25 . The rotation stage 28 is disc-shaped, and the tip of the hollow shaft 25 is fixed to the center position thereof. A linear motion mechanism 23 is attached to the rotation stage 28 via an attachment portion. For example, the radial direction of the rotary stage 28 and the direction of linear motion of the linear motion mechanism 23 are made to match. As described above, the linear motion mechanism 23 is attached with the 2.theta. Therefore, when the hollow shaft 25 is rotated by the hollow motor 24, the rotary stage 28, the direct acting mechanism 23 and the 2θ axis mechanism rotate together.

Further, the light shielding plate moving mechanism is provided with a position detection sensor 29 for the light shielding plate 17 at a position facing the light shielding plate 17 across the optical axis. The position detection sensor 29 is attached to the rotating stage 28 so as to rotate together with the light shielding plate 17, and always maintains a position facing the light shielding plate 17 to ensure that the light shielding plate 17 is in the correct position with respect to the target position. Whether there is (for example, whether the amount of protrusion of the light shielding plate 17 is as set) is confirmed by the position detection sensor 29 each time. As the position detection sensor 29, a position measurement sensor using a laser, an image recognition sensor using a camera, or the like is used.

A detection output of the position detection sensor 29 is supplied to a control section (not shown). The control unit controls the drive motor of the linear motion mechanism 23 and the like so that the light shielding plate 17 is positioned correctly with respect to the target position. By this control, the positions of the boundary of the non-exposure area MA and the edge of the light shielding plate 17 are aligned. Furthermore, the controller can control the operation and adjustment of each component of the projection exposure apparatus. The control unit is composed of, for example, a computer, is connected to each component via a transmission line, and can control each component according to a program or the like. Parameters related to the target position of the light shielding plate 17 (curvature, light shielding width, wafer size, size of the exposure range, etc.) are set in the control unit in advance. is managed in association with the position of the exposure range.

"Shading action"
FIG. 5 is a diagram showing a step-and-repeat exposure operation for the wafer 13. As shown in FIG. In the example of FIG. 5, 41 exposures are performed. A rectangle indicates a single exposure range (hereinafter referred to as a shot), and a cross indicates the center of the shot (the position of the optical axis). A single shot rectangle is basically defined by the reticle 8 . Blinds or the like may be installed to define the shot.

A non-exposure area MA having a predetermined width is set from the outer periphery of the wafer 13 to the inner boundary. The light blocking plate 17 prevents light from entering the non-exposure area MA. The peripheral shots including the non-exposure area MA are shielded from light. During the exposure operation at a position where the shot does not overlap the non-exposure area MA, the light blocking plate 17 is retracted to a position retracted from the rod lens 5 .

In FIG. 5, regarding the example of the upper left portion of the wafer 13, the light shielding area by the light shielding plate 17 is indicated by SA, and the shots covered by the non-exposure area MA are indicated by EA1 and EA2. In the shots (EA1, EA2) where the exposure area overlaps the non-exposure area MA, the light blocking plate 17 approaches the optical axis of the rod lens 5 by the amount that blocks the non-exposure area MA, blocking part of the illumination light. do. Also, the first θ-axis mechanism (having hollow motor 24 and rotary stage 28) rotates according to the angle of non-exposure area MA in shots EA1 and EA2. That is, the edge of the light shielding plate 17 is made to coincide with the arc of the inner boundary that defines the non-exposure area MA. As a result, the light shielding area SA is positioned according to the exposed areas (EA1, EA2) and the non-exposed area MA.

When changing the width of the non-exposure area MA of the wafer 13, or when replacing the wafer 13 with one having a different radius without changing the width of the non-exposure area MA, it becomes necessary to change the curvature of the light shielding area SA. . These cases can be dealt with by rotating the light shielding plate 17 by means of the 2θ axis mechanism (having the arc switching motor 20) having the arc switching motor 20 and switching the arc-shaped edge of the light shielding plate 17. . Since the light shielding plate 17 has edges with a plurality of curvatures, the curvature of the boundary defining the non-exposure area can be changed without exchanging the light shielding plate 17 .

"Another example of the shape of the shading plate"
As shown in FIG. 6, a gobo 17' having two edges of curvature R5 and R6 and having an arcuate cutout R0 inside may be used. That is, the light blocking plate must have two or more edges with different curvatures.

"Operation of projection exposure apparatus"
Operations of the projection exposure apparatus controlled by the control unit will be described with reference to the flow charts of FIGS. 7A and 7B. 7A and 7B show a series of processing flows divided into two drawings due to restrictions on the drawing space of the drawings. 7A and 7B show the operation of the exposure stage 14 and the wafer transfer device, and the process flow shown on the right shows the operation of the light shielding mechanism. Furthermore, in FIGS. 7A and 7B, reference numerals for each component are omitted due to drawing space restrictions.

Step S0: Processing is started.
Step S1: Move the exposure stage 14 to the wafer transfer position.
Step S2: The transfer arm transfers the wafer 13 to the exposure stage 14 from a predetermined direction.
Step S<b>3 : The exposure stage 14 attracts the wafer 13 .
Step S4: Move the exposure stage 14 to the alignment position.
Step S5: The alignment camera 10 detects the alignment mark of the wafer 13 and detects the position of the wafer 13. FIG.
Step S6: Move the exposure stage 14 to the initial exposure position.

The light blocking mechanism performs steps S101 and S102 in parallel with the processing of steps S1 to S6 by the exposure stage 14 and the wafer transfer device.
Step S101: The first .theta.-axis mechanism and linear motion mechanism 23 move the light shielding plate 17 to the origin.
Step S102: The first .theta.-axis mechanism and linear motion mechanism move the light blocking plate 17 to the shot start position.

The following determinations are made by the exposure stage 14 and the wafer transfer device.
Step S7: It is determined whether or not the light blocking plate 17 is stopped at the position according to the recipe with respect to the shot center of the wafer 13 .
Step S8: If the determination result in step S7 is affirmative, the exposure shutter is operated to perform exposure.
Step S103: If the determination result of step S7 is negative, the position of the light shielding plate 17 is adjusted, and the determination of step S7 is made again. Step S8 or S103 is performed according to the determination result of step S7.

Subsequently, the processing shown in FIG. 7B is performed.
Step S9: The exposure stage 14 moves to the next shot area.
Step S104: In parallel with the process of step S9, the first .theta.

The following determinations are made by the exposure stage 14 and the wafer transfer device.
Step S10: It is determined whether or not the light blocking plate 17 is stopped at the position according to the recipe with respect to the shot center of the wafer 13 .
Step S11: If the determination result in step S10 is affirmative, the exposure shutter is operated to perform exposure.
Step S105: If the determination result of step S10 is negative, the position of the light shielding plate 17 is adjusted, and the determination of step S10 is made again. Step S11 or S105 is performed according to the determination result of step S10.
Step S12: Thereafter, steps S9, S10, S11 and S105 are repeated.

Step S13: Expose the last shot.
Step S14: Move the exposure stage 14 to the wafer 13 transfer position.
Step S<b>15 : Release the wafer 13 from the exposure stage 14 .
Step S16: Transfer the wafer 13 from the exposure stage 14 by the transfer arm.

In parallel with the processing of steps S13 to S16 by the exposure stage 14 and the wafer transfer device, the light shielding mechanism performs the processing of step S106.
Step S106: Move the light shielding plate 17 to the origin position.
Step S17: The process ends.

"Other examples of linear motion mechanism"
As shown in FIG. 8, the linear motion mechanism may be arranged obliquely so that the axis (displacement direction) of the linear motion mechanism does not perpendicularly intersect the optical axis. The same reference numerals as in FIG. 4 showing the linear motion mechanism described above are used. With such an arrangement, the height of the light shielding plate moving mechanism can be reduced.

"Further examples of linear motion mechanisms"
As shown in FIG. 9 , the light shielding plate 17 , the ring-shaped holder 19 and the arc switching motor 20 are attached to one end of the arm 30 , and the other end of the arm 30 is attached to the linear motion mechanism 31 . The extending direction of the arm 30 and the axial direction (displacement direction) of the linear motion mechanism 31 are made to be perpendicular to each other. With such a configuration, the shapes of the linear motion mechanism and the 2θ-axis mechanism can be made smaller.

<2. Variation>
An embodiment of the present technology has been specifically described above, but the present invention is not limited to the above-described embodiment, and various modifications are possible based on the technical idea of the present invention. . In addition, the configurations, methods, processes, shapes, materials, numerical values, etc., given in the above-described embodiments are merely examples, and if necessary, different configurations, methods, processes, shapes, materials, numerical values, etc. may be used. good too.

As described above, according to the present invention, the variable light shielding means for forming a desired non-exposure region can be configured in a space-saving manner. Therefore, the variable light shielding means can be provided at the outlet of the illumination light homogenizing means, thereby preventing a decrease in the amount of light.

In addition, according to the present invention, the light shielding plate can be replaced in units including the edge switching portion, which facilitates replacement work, prevents damage to optical elements such as rod lenses, and increases mounting accuracy. can do.

1 light source, 4 illumination optical system, 5 rod lens,
6... Rod lens support portion, 8... Reticle, 10... Alignment camera,
11... Light shielding mechanism, 12... Projection optical system, 13... Wafer,
14... exposure stage, 15... stage movement mechanism, 17... light shielding plate,
19... Ring-shaped holder, 20... Arc switching motor, 23... Linear motion mechanism,
24... hollow motor, 25... hollow shaft, 28... rotation stage

Claims (5)

an illumination optical system that uniformizes the illuminance of light emitted from a light source by illumination light uniformizing means and illuminates the reticle;
It has an aperture through which the light flux of the illumination light homogenizing means passes, rotates about the optical axis of the illumination light homogenizing means in the vicinity of the exit surface of the illumination light homogenizing means, and is mounted perpendicular to the optical axis. a rotating body having a face;
a linear motion mechanism having a linear motion part attached to the mounting surface and moving toward or away from the optical axis;
a support plate detachably attached to the linear motion part;
a driving means provided on the support plate;
a light shielding plate located on the mounting surface and rotated by the driving means ;
the light shielding plate has a plurality of edges with different curvatures for shielding part of the light flux of the illumination optical system, one of the plurality of edges being selected by the driving means ;
A projection exposure apparatus in which a selected edge is used to block part of the light beam of said illumination optical system. 2. A projection exposure apparatus according to claim 1, wherein said exit surface and said light blocking plate are arranged at or near a conjugate position with said reticle. 3. A projection exposure apparatus according to claim 1, wherein said light shielding plate has said plurality of edges on the outer peripheral side and has an arcuate notch formed on the inner peripheral side. 4. The projection exposure apparatus according to claim 3, wherein at least three of said plurality of edges are provided on the outer peripheral side of said light shielding plate. 4. A projection exposure apparatus according to claim 3, wherein the rotary shaft of said drive means is positioned inside said arcuate cutout on said inner peripheral side of said light shielding plate.

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