JP2019148693A - Projection exposure apparatus - Google Patents

Abstract

To provide a projection exposure apparatus capable of responding to changes in a width of an unexposed area and changes in a wafer diameter by switching edges.SOLUTION: The projection exposure apparatus includes an illumination optical system for equalizing the illuminance of emitted light of a light source and irradiating a reticle with the light, and a variable light-shielding unit disposed in the illumination optical system and having a movable light-shielding plate 17. The variable light-shielding unit includes: a rotation drive part having a rotation part that rotates around the optical axis of the illumination optical system; a linear motion drive part having a linear motion part mounted on the rotation part of the rotation drive part via a support member and moving to be nearer to or apart from the optical axis of the illumination optical system; and a switching part mounted on the linear motion part of the linear motion drive part and rotating the light-shielding plate on a plane perpendicular to the optical axis of the illumination optical system. The light-shielding plate has a plurality of edges having different curvatures to block a part of a luminous flux of the illumination optical system, and one of the plurality of edges is used to block a part of the luminous flux of the illumination optical system.SELECTED DRAWING: Figure 2

Description

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

  In a lithography process included in a manufacturing process of a semiconductor device, a liquid crystal display device, or the like, a projection exposure apparatus converts a reticle pattern as an original plate into a photosensitive substrate (a wafer having a resist layer formed on the surface) via a projection optical system. ). In the step-and-repeat method in which the wafer is moved and the pattern is sequentially exposed, step movement and exposure of the wafer are alternately repeated. When the exposure position comes to the wafer edge (peripheral part), there is a function of not exposing a predetermined range from the edge end. Such a wafer peripheral non-exposure function is referred to as WEM (wafer edge masking).

  In the case of WEM, for example, in the case of a negative photoresist, the peripheral photoresist is not exposed so that excess photoresist on the wafer edge is removed during development. Alternatively, in the case of a positive photoresist, a WEM is used to prevent wafer edge exposure unevenness (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 a technique of WEM, 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 Document 1 describes a mechanism for carrying in and out a ring-shaped light shielding plate on a work chuck. Japanese Patent Application Laid-Open No. H10-228561 describes that a light shielding band is provided above the wafer. Patent Document 2 describes that a light shielding band has a plurality of curvatures and rotates and moves the light shielding band. Further, Patent Document 3 describes a mechanism for providing a light shielding plate at a reticle conjugate position.

  A WEM that shields light on a wafer has a relatively simple structure and does not require complicated control. On the other hand, it is necessary to pay attention to component selection, maintenance, etc. against wafer contamination due to particles from the movable part that moves on the wafer and moves the light shield, or wafer damage due to contact between the light shield and the wafer. there were. Further, since the light shielding plate is provided apart from the wafer, there is a problem that blur occurs at the light shielding boundary.

  The WEM that shields light at the reticle conjugate position has a problem that the amount of light decreases due to an increase in optical elements such as a relay lens, and the movement mechanism and control of the light shielding plate are complicated. On the other hand, there are no worries about contamination and damage of the wafer, and there is an advantage that there is little blurring of the light shielding boundary. Considering the features of these two methods, the merit of employing the WEM at the reticle conjugate position is greater as the projection exposure apparatus requires higher precision exposure.

JP 2005-505147 A Japanese Patent Laid-Open No. 2005-045160 JP 2011-233781 A

  When the width of the non-exposed area of the wafer is changed or the width of the non-exposed area does not change, the curvature of the boundary line of the non-exposed area needs to be changed when the diameter of the wafer changes. That is, it is necessary to replace the light shielding plate with an edge that coincides with the boundary line. However, the space of the exit portion of the lens for homogenizing the illumination light of the illumination optical system is narrow, and in this narrow space, replacing the light shielding plate may damage the lens for equalizing the illumination light, Further, it is troublesome to adjust the mounting accuracy of the light shielding plate every time it is replaced.

  That is, from the viewpoint of optical design, it is ideal that both the light shielding plate and the rod lens exit are installed at the reticle conjugate position. However, in order to avoid interference of the movable part, it is necessary to provide a gap between them, and it is desirable that this gap be narrow. When the gap is widened, the following disadvantages occur.

The farther the rod lens exit is from the reticle conjugate position, the worse the illuminance distribution of the light that irradiates the reticle.
The farther the light shielding plate is from the reticle conjugate position, the more blur occurs at the edge portion of the projected image of the light shielding plate, and the photoresist cross section becomes an oblique shape at the blurred portion when developed.

  For this reason, the space for attaching the light shielding plate at the lens exit portion becomes narrow, and the above-described problems occur. Patent Document 2 does not disclose a mechanism for rotating and moving the light shielding band, and no consideration is given to providing the light shielding band in a narrow space.

  Accordingly, an object of the present invention is to provide a projection exposure apparatus in which a light shielding mechanism including a light shielding plate can be arranged in a narrow space close to the exit of the illumination light uniformizing means.

The present invention provides an illumination optical system that irradiates a reticle with uniform illuminance of light emitted from a light source, and
Provided in the illumination optical system, comprising a variable light-shielding part having a movable light-shielding plate,
The variable shading part
A rotation drive unit having a rotation unit that rotates about the optical axis of the illumination optical system;
A linear motion drive unit that is attached to the rotation unit of the rotation drive unit via a support member and has a linear motion unit that moves so as to approach or separate from the optical axis of the illumination optical system;
A switching unit that is attached to the linear motion unit of the linear motion drive unit and rotates the light shielding plate on a plane perpendicular to the optical axis of the illumination optical system;
The light shielding plate has a plurality of edges with different curvatures for shielding a part of the light beam of the illumination optical system, and uses one of the edges to shield a part of the light beam of the illumination optical system. It is an exposure apparatus.

  According to at least one embodiment, since the light shielding plate has a plurality of edges having different curvatures, switching of the edges can cope with a change in the width of the non-exposure region and a change in the diameter of the wafer. In addition, the effect described here is not necessarily limited, The effect described in this invention or an effect different from them may be sufficient.

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

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The description will be given in the following order.
<1. Embodiment>
<2. Modification>
The embodiments described below are preferred specific examples of the present invention, and the contents of the present invention are not limited to these embodiments.

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

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

  The light source 1 is a UV lamp that emits broadband light including g, h, and i rays. An elliptical mirror 2 is provided as a condensing mirror. The 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. The rod lens 5 is supported by a rod lens support portion 6. A mercury lamp, a laser, or the like may be used as the light source 1.

  The illumination optical system 4 includes 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 uniformizing means by internal reflection. The illumination light uniformizing means is not limited to a rod lens, and an internal reflection mirror (a polygonal cylinder in which a plurality of mirrors are bonded inward) may be used.

  The critical illumination lens group 7 expands the image of the exit surface of the rod lens 5 at a predetermined magnification (for example, 2 times) and irradiates the reticle 8. In the figure, the critical illumination lens group 7 is omitted in a square shape, but it is composed of a plurality of lenses (for example, 10 lenses). The illumination optical system 4 includes a light shielding mechanism (WEM mechanism) 11 described later.

  The reticle 8 is made of, for example, quartz glass, and is a transmissive photomask on which a predetermined pattern (for example, a circuit pattern) to be transferred is drawn. The reticle 8 is supported by a reticle stage 9. In addition, 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 an entrance and exit plane mirror, a lens group, and a folded concave mirror. In one embodiment, the magnification of the projection optical system 12 is equal. In FIG. 1, the lens group is omitted and only one lens is shown, but it is actually composed of a plurality of lenses. In the 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 in which a photoresist (photosensitive agent) is applied on the surface of single crystal silicon. In addition to those made of single crystal silicon, they may be made of glass, sapphire, or a compound. The shape of the wafer 13 is circular and the diameter is, for example, 300 mm.

  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. A photoresist is a photosensitive material that forms a pattern using ultraviolet rays. The photoresist may be either positive type or negative type. A predetermined non-exposure area is set in the periphery of the wafer 13. For example, a width of 5 mm is set as a non-exposure area over the entire edge of the wafer 13. A notch or orientation flat for wafer angle alignment may be provided around the wafer 13.

  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). The exposure stage 14 may be provided with lift pins or the like for transferring the robot hand and the wafer.

  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 direction and the Y direction, and the rotation direction is defined by θ. The stage moving mechanism 15 performs movement for step exposure and minute movement for wafer alignment. In addition, a mechanism for moving in the Z direction and adjusting the tilt of the exposure stage is provided for focusing the wafer 13. The stage moving mechanism 15 moves between the wafer transfer position, the alignment position (not shown), and the exposure position.

  The projection exposure apparatus includes a gantry 16 for installing an exposure stage 14 and an optical system. An alignment camera 10 is attached to the gantry 16. Although the projection exposure apparatus includes a wafer cassette, a wafer transfer robot, a pre-aligner, and the like (all not shown), these may be installed on the gantry 16 or may be installed separately from the gantry 16. The projection exposure apparatus may have an air conditioning chamber that covers the entire apparatus.

"Shading plate"
In one embodiment, a light shielding plate 17 is installed on the conjugate surface of the wafer 13 of the illumination optical system 4. Further, the light shielding plate 17 is located at the exit of the rod lens 5. Specifically, the exit surface of the rod lens 5 is positioned near the light shielding plate 17. In this way, the position from the exit surface of the rod lens 5 to a position slightly separated from the exit surface is referred to as the exit portion of the rod lens 5. For example, the exit surface of the rod lens 5 is positioned at an interval of 3 mm with respect to the light shielding plate 17. An interval other than 3 mm may be used, but an interval as narrow as possible is desirable. Further, the exit surface of the rod lens 5 may coincide with the conjugate surface. 2 shows a front view, a plan view, and a side view of an example of a light shielding plate 17 for shielding light along the peripheral non-exposed region of the wafer 13. FIG. 3 shows an enlarged view of the light shielding mechanism 11. 4 shows the light-shielding mechanism 11 viewed from the exit surface.

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

  Furthermore, the arc-shaped edge portion of the light shielding plate 17 has a tapered cross section corresponding to the NA (aperture ratio) of the illumination optical system. The taper shape is for preventing a decrease in the amount of emitted light outside the non-exposed region. Although there are four arc-shaped edges of the light shielding plate in the embodiment, it is not necessary to limit to this. For example, a light shielding plate having two arc-shaped edges may be used. Since the light shielding plate 17 has edges with different curvatures, the light shielding plate 17 can correspond to the non-exposed areas of the wafer 13 having different radii, and there is an advantage that the light shielding plate 17 does not need to be replaced according to the radius of the non-exposed areas of the wafer 13. is there.

"Shading 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 variable light shielding means. As shown in FIG. 4, an arcuate cutout R <b> 0 inside the light shielding plate 17 or an arcuate inside the ring-shaped holder 19 is attached to the rotation shaft of the arc switching motor 20. An arc switching motor 20 is fixed to the 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 referred to as a second θ-axis mechanism.

  The linear motion mechanism 23 is a single-axis actuator such as a ball screw, and is a mechanism that linearly displaces the light shielding plate 17 and the arc switching motor 20. By the linear motion mechanism 23, the edge of the light shielding plate 17 is approached or separated 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 θ-axis mechanism is a rotation mechanism that rotates the light shielding plate 17 around the optical axis of the illumination optical system. As shown in FIG. 3, a hollow motor 24 is provided, and a hollow shaft 25 is rotated by the hollow motor 24. The 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 matched. The rod lens support portion 6 has an inlet side of the rod lens 5 fixed to the housing and an outlet side supported by a bearing 27 provided in the hollow shaft 25. However, a cantilever structure in which the rod lens 5 and the rod lens support portion 6 are supported only on the entrance side without supporting the exit side of the rod lens 5 by the bearing 27 may be employed.

  The rod lens support unit 6 includes a rod lens cooling mechanism that cools the rod lens 5 by flowing a coolant through a conduit (not shown) provided in the rod lens support unit 6. In addition, a light shielding plate cooling mechanism for cooling the light shielding plate 17 by injecting gas to the light shielding plate 17 through another guide path (not shown) provided in the rod lens support portion 6 is provided.

  A rotary stage 28 is attached to the exit side of the rod lens 5 of the hollow shaft 25. The rotary stage 28 has a disk shape, and the tip of the hollow shaft 25 is fixed to the center position thereof. A linear motion mechanism 23 is attached to the rotary stage 28 via an attachment portion. For example, the radial direction of the rotary stage 28 and the direction of the linear motion of the linear motion mechanism 23 are made to coincide. As described above, the second θ-axis mechanism having the light shielding plate 17 and the arc switching motor 20 is attached to the linear motion mechanism 23. Therefore, when the hollow shaft 25 is rotated by the hollow motor 24, the rotary stage 28, the linear motion mechanism 23, and the second θ-axis mechanism rotate integrally.

  Further, in the light shielding plate moving mechanism, a position detection sensor 29 of the light shielding plate 17 is provided at a position facing the light shielding plate 17 with the optical axis interposed therebetween. The position detection sensor 29 is attached to the rotary stage 28 so as to rotate together with the light shielding plate 17, and always maintains a position facing the light shielding plate 17, so that the light shielding plate 17 is in a correct position with respect to the target position. Whether or not there is (for example, whether the protruding amount of the light shielding plate 17 is as set value) 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.

  The detection output of the position detection sensor 29 is supplied to a control unit (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 boundary of the non-exposure area MA and the edge position of the light shielding plate 17 are matched. Further, the operation and adjustment of each component of the projection exposure apparatus can be controlled by the control unit. The control unit is configured by, for example, a computer and is connected to each component via a transmission path, and can control each component according to a program or the like. In addition, parameters (curvature, light shielding width, wafer size, exposure range size, etc.) related to the target position of the light shielding plate 17 for the control unit are set in advance for the control unit. Are managed in association with the position of the exposure range.

"Shading operation"
FIG. 5 is a diagram showing a step-and-repeat exposure operation for the wafer 13. In the example of FIG. 5, 41 exposures are performed. A single exposure range (hereinafter appropriately referred to as a shot) is indicated by a rectangle, and the cross indicates the center of the shot (the position of the optical axis). The rectangle of one shot is basically determined by the reticle 8. You may install the blind etc. for prescribing | regulating a shot.

  A non-exposure area MA having a predetermined width from the outer periphery of the wafer 13 to the inner boundary is set. The light shielding plate 17 prevents light from entering the non-exposed area MA. Light shielding is performed in peripheral shots including the non-exposed area MA. In the exposure operation at a position where the shot does not reach the non-exposure area MA, the light shielding plate 17 is retracted to a position where it is 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 represented by SA, and the shot in which the non-exposure area MA is represented is represented by EA1 and EA2. In shots (EA1, EA2) in which the exposure area is applied to the non-exposure area MA, the light shielding plate 17 approaches the optical axis of the rod lens 5 as much as the non-exposure area MA is shielded, and part of the illumination light is shielded. To do. Further, the first θ-axis mechanism (having the hollow motor 24 and the rotary stage 28) rotates according to the angle of the non-exposure area MA in the shots EA1 and EA2. That is, the edge of the light shielding plate 17 coincides 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 exposure areas (EA1, EA2) and the non-exposure area MA.

  When the width of the non-exposure area MA of the wafer 13 is changed, or when the wafer 13 is replaced with one having a different radius without changing the width of the non-exposure area MA, it is 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 the second θ-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 a plurality of curvature edges, the curvature of the boundary defining the non-exposure region can be changed without replacing the light shielding plate 17.

"Other examples of shading plate shapes"
As shown in FIG. 6, a light shielding plate 17 'having two curvatures R5 and R6 edges and having an arcuate cutout R0 on the inside may be used. That is, the light shielding plate needs to have two or more different curvature edges.

"Operation of projection exposure system"
The operation of the projection exposure apparatus performed under the control of the control unit will be described with reference to the flowcharts of FIGS. 7A and 7B. FIG. 7A and FIG. 7B show the flow of a series of processes divided into two drawings due to the limitation of the drawing space of the drawings. Further, the processing flow shown on the left side in FIGS. 7A and 7B shows the operation of the exposure stage 14 and the wafer transfer apparatus, and the processing flow shown on the right side shows the operation of the light shielding mechanism. Furthermore, in FIG. 7A and FIG. 7B, the reference symbol regarding each component is abbreviate | omitted on restrictions of drawing space.

Step S0: Processing is started.
Step S1: The exposure stage 14 is moved to the wafer transfer position.
Step S2: The transfer arm transfers the wafer 13 from the predetermined direction to the exposure stage 14.
Step S3: The exposure stage 14 sucks the wafer 13.
Step S4: Move the exposure stage 14 to the alignment position.
Step S5: The alignment camera 10 detects the alignment mark on the wafer 13, and detects the position of the wafer 13.
Step S6: Move the exposure stage 14 to the first exposure position.

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

The following determination is made by the exposure stage 14 and the wafer transfer device.
Step S7: It is determined whether or not the light shielding 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 and exposure is performed.
Step S103: If the determination result in step S7 is negative, the position of the light shielding plate 17 is adjusted, and the determination in step S7 is made again. Step S8 or S103 is performed according to the determination result of step S7.

Subsequently, the process 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 θ-axis mechanism and the linear motion mechanism 23 move the light shielding plate 17 to the light shielding position of the next shot.

The following determination is made by the exposure stage 14 and the wafer transfer device.
Step S10: It is determined whether or not the light shielding 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 in step S10 is negative, the position of the light shielding plate 17 is adjusted, and the determination in step S10 is made again. Step S11 or S105 is performed according to the determination result of step S10.
Step S12: Hereinafter, steps S9, S10, S11, and S105 are repeated.

Step S13: The last shot is exposed.
Step S14: The exposure stage 14 is moved to the wafer 13 transfer position.
Step S15: The wafer 13 suction on the exposure stage 14 is released.
Step S16: The wafer 13 is transferred from the exposure stage 14 by the transfer arm.

The light shielding mechanism performs the process of step S106 in parallel with the processes of steps S13 to S16 by the exposure stage 14 and the wafer conveyance device.
Step S106: The light shielding plate 17 is moved to the origin position.
Step S17: The process ends.

"Other examples of linear motion mechanisms"
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 intersect the optical axis perpendicularly. The same reference numerals as those in FIG. 4 showing the linear motion mechanism described above are attached. With such an arrangement, the height of the light shielding plate moving mechanism can be reduced.

"Still another example of linear motion mechanism"
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 side of the arm 30, and the other end side of the arm 30 is attached to the linear motion mechanism 31. The extension direction of the arm 30 and the axial direction (displacement direction) of the linear motion mechanism 31 are orthogonal to each other. With this configuration, the shapes of the linear motion mechanism and the second θ-axis mechanism can be reduced.

<2. Modification>
Although one embodiment of the present technology has been specifically described above, the present invention is not limited to the above-described embodiment, and various modifications based on the technical idea of the present invention are possible. . Further, the configurations, methods, steps, shapes, materials, numerical values, and the like given in the above-described embodiments are merely examples, and different configurations, methods, steps, shapes, materials, numerical values, and the like are used as necessary. Also good.

  As described above, according to the present invention, the variable light-shielding means for forming a desired non-exposure region can be configured to save space. Therefore, the variable light-shielding means can be provided at the exit of the illumination light uniformizing means, and the light quantity can be prevented from decreasing.

  In addition, according to the present invention, it is possible to replace the light shielding plate in units including the edge switching unit, thereby facilitating the replacement work, preventing damage to the optical element such as the rod lens, and increasing the mounting accuracy. can do.

DESCRIPTION OF SYMBOLS 1 ... Light source, 4 ... Illumination optical system, 5 ... Rod lens,
6 ... Rod lens support, 8 ... Reticle, 10 ... Alignment camera,
11 ... light shielding mechanism, 12 ... projection optical system, 13 ... wafer,
14... Exposure stage, 15... Stage moving mechanism, 17.
19 ... Ring-shaped holder, 20 ... Arc switching motor, 23 ... Linear motion mechanism,
24 ... Hollow motor, 25 ... Hollow shaft, 28 ... Rotation stage

Claims (6)

An illumination optical system that irradiates a reticle with uniform illuminance of light emitted from a light source, and a variable light-shielding unit that is provided in the illumination optical system and has a movable light-shielding plate,
The variable light shielding portion is
A rotation drive unit having a rotation unit that rotates about the optical axis of the illumination optical system;
A linear motion drive unit that is attached to the rotation unit of the rotation drive unit via a support member and has a linear motion unit that moves so as to approach or separate from the optical axis of the illumination optical system;
A switching unit that is attached to the linear motion unit of the linear motion drive unit and rotates the light shielding plate on a plane perpendicular to the optical axis of the illumination optical system;
The light-shielding plate has a plurality of edges with different curvatures for shielding a part of the light beam of the illumination optical system, and a part of the light beam of the illumination optical system using one of the plurality of edges Projection exposure apparatus that shields light.   The projection exposure apparatus according to claim 1, wherein the light shielding plate has the plurality of edges on an outer peripheral side, and an arc-shaped notch is formed on an inner peripheral side.   The projection exposure apparatus according to claim 2, wherein at least three of the plurality of edges are provided on an outer peripheral side of the light shielding plate.   The projection exposure apparatus according to claim 2, wherein a rotation actuator of the switching unit is located inside an arcuate cutout on the inner peripheral side of the light shielding plate.   The projection exposure apparatus according to any one of claims 1 to 4, wherein the light shielding plate and the switching unit are integrated with each other and can be attached to the linear motion mechanism.   The projection exposure apparatus according to claim 1, further comprising a measurement unit that is attached to a rotation unit of the rotation drive unit and measures a position of the light shielding plate with respect to the rotation unit.

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