Holding mechanism and exposure apparatus

Abstract

To provide a holding mechanism and an exposure apparatus which are capable of achieving vacuum suction with a high degree of flatness.SOLUTION: A holding mechanism according to one embodiment of the present invention includes a suction section and a sealing section. The suction section has a suction area where a substrate is subjected to vacuum suction. The sealing section has an elastic section having a plurality of sides arranged to surround the suction area and a plurality of corners each formed between adjacent ones of the plurality of sides, and a repulsive-force-suppressing section provided in at least one of the plurality of corners.SELECTED DRAWING: Figure 2A

Description

Technical Field

[0001] The present invention relates to a holding mechanism for holding a substrate and an exposure apparatus equipped with the same.

Background Art

[0002] In the process of manufacturing printed circuit boards, semiconductor substrates, liquid crystal substrates, etc., a work stage that adsorbs and holds the substrate is used so that the substrate does not shift during processing such as exposure. As a method of adsorbing and holding the substrate, vacuum adsorption is widely used.

[0003] For example, Patent Document 1 describes a stage device that holds a substrate by vacuum adsorption. In this stage device, the substrate is vacuum-adsorbed by a thin plate member provided with a plurality of through-holes connected to a vacuum system. In addition, a sealing elastic member is provided annularly around the thin plate member. Thereby, leakage of vacuum due to warping of the substrate or the like is suppressed (paragraphs

[0015] ,

[0024] ,

[0025] of the specification of Patent Document 1, FIGS. 1, 5, etc.).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, with the miniaturization of wiring and the increase in mounting density, the flatness required for the substrate during exposure has been increasing. On the other hand, it has become difficult to improve the flatness as the size of the substrate increases. Therefore, a technique for realizing high flatness vacuum adsorption is required.

[0006] In view of the above circumstances, an object of the present invention is to provide a holding mechanism and an exposure apparatus capable of realizing high flatness vacuum adsorption. [Means for solving the problem]

[0007] To achieve the above objective, a holding mechanism according to one embodiment of the present invention comprises an adsorption portion and a sealing portion. The adsorption unit has an adsorption area for vacuum adsorption of the substrate. The sealing portion has an elastic portion having a plurality of edges arranged around the adsorption area and a plurality of corners formed between adjacent edges, and a repulsive force suppressing portion provided for at least one of the plurality of corners.

[0008] In this holding mechanism, a sealing section made of elastic material is arranged to surround the suction area where the substrate is vacuum-adsorbed. Rebound force suppressing sections are provided at the corners of the sealing section. This suppresses the rebound force at the corners, making it possible to reduce the bulging of the substrate. As a result, it becomes possible to achieve vacuum suction with a high degree of flatness.

[0009] The elastic portion may have a mounting surface on which the substrate is placed. In this case, the repulsion force suppressing portion may have a structure in which the area of ​​the mounting surface at the corner is smaller than the area of ​​the intersection region obtained by extending and intersecting the two sides connected to the corner.

[0010] The repulsive force suppressing portion may be a notch formed on the inside of the corner portion.

[0011] The planar shape of the notch may be either a rectangle or a circle.

[0012] The rebound force suppressing portion may be a stepped portion in which at least a part of the surface of the corner is lower than the surface described above.

[0013] The rebound force suppressing portion may be a low-rebound portion located at the corner and having a lower rebound force than the side portion.

[0014] The rebound force suppressing portion may be positioned so as to overlap with the intersection region formed by extending and intersecting the two sides connected to the corner portion. Alternatively, the rebound force suppressing portion may be positioned so as to be in contact with the intersection region.

[0015] The planar shape of the elastic portion may be rectangular. In this case, the plurality of corners may include four corners corresponding to the four vertices of the rectangular shape. The rebound force suppressing portion may also be provided at at least one of the four corners.

[0016] The adsorption portion may include a base having a recess for supplying vacuum and a plurality of protrusions formed within the recess, and an adsorption plate mounted on the recess having an adsorption surface forming the adsorption area and a plurality of through holes formed on the adsorption surface. In this case, the sealing portion may be attached to either the base or the adsorption plate.

[0017] The suction portion may have a mounting portion provided at a lower position than the suction surface to which the lower surface of the sealing portion is attached. In this case, the sealing portion may be configured such that, when the lower surface is attached to the mounting portion, the upper surface opposite to the lower surface protrudes higher than the suction surface.

[0018] The elastic portion may be made of rubber sponge.

[0019] An exposure apparatus according to one embodiment of the present invention comprises a light emission unit, a mask stage, and a workpiece stage. The light-emitting unit emits exposure light. The mask stage holds the patterned mask in the optical path of the exposure light. The work stage holds the workpiece to which the pattern is transferred. The work stage includes a suction portion having a suction area for vacuum-sucking the work, an elastic portion having a plurality of side portions arranged to surround the suction area and a plurality of corner portions formed between adjacent side portions of the plurality of side portions, and a seal portion having a repulsive force suppression portion provided for at least one of the plurality of corner portions.

Advantages of the Invention

[0020] As described above, according to the present invention, it becomes possible to realize vacuum suction with high flatness. Note that the effects described here are not necessarily limited, and any of the effects described in the present disclosure may be applicable.

Brief Description of the Drawings

[0021] [Figure 1] It is a schematic diagram showing a configuration example of an exposure apparatus including a work stage according to a first embodiment of the present invention. [Figure 2A] It is a schematic diagram showing a configuration example of the work stage. [Figure 2B] It is a schematic diagram showing a configuration example of the work stage. [Figure 3] It is a schematic diagram for explaining a basic configuration of the seal portion. [Figure 4] It is a schematic diagram showing a planar configuration example of the seal portion provided on the work stage. [Figure 5A] It is a schematic diagram showing an operation of vacuum suction by the work stage. [Figure 5B] It is a schematic diagram showing an operation of vacuum suction by the work stage. [Figure 6A] It is a schematic diagram showing a configuration example of the repulsive force suppression portion. [Figure 6B] It is a schematic diagram showing a configuration example of the repulsive force suppression portion. [Figure 6C] It is a schematic diagram showing a configuration example of the repulsive force suppression portion. [Figure 6D] It is a schematic diagram showing a configuration example of the repulsive force suppression portion. [Figure 6E] It is a schematic diagram showing a configuration example of the repulsive force suppression portion. [Figure 7A] This is a schematic diagram showing another example of the configuration of the rebound force suppression unit. [Figure 7B] This is a schematic diagram showing another example of the configuration of the rebound force suppression unit. [Figure 8A] This is a schematic diagram showing another example of the configuration of the rebound force suppression unit. [Figure 8B] This is a schematic diagram showing another example of the configuration of the rebound force suppression unit. [Figure 8C] Figures 8A and 8B are schematic perspective views showing the rebound force suppression section. [Figure 8D] This is a schematic diagram showing another example of the configuration of the rebound force suppression unit. [Figure 9A] This is a schematic diagram showing another example of the configuration of the rebound force suppression unit. [Figure 9B] This is a schematic diagram showing another example of the configuration of the rebound force suppression unit. [Figure 10] This is a schematic diagram showing a seal portion as an example. [Figure 11A] This is a schematic diagram showing an example of the configuration of a work stage according to the second embodiment. [Figure 11B] This is a schematic diagram showing an example of the configuration of a work stage according to the second embodiment. [Figure 12A] This is a schematic diagram showing an example of the configuration of a work stage according to another embodiment. [Figure 12B] This is a schematic diagram showing an example of the configuration of a work stage according to another embodiment. [Figure 13] This is a schematic diagram illustrating another example of the seal configuration according to a different embodiment. [Modes for carrying out the invention]

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0023] [Configuration of the lithography system] Figure 1 is a schematic diagram showing an example of the configuration of an exposure apparatus equipped with a work stage according to the first embodiment of the present invention. The exposure apparatus 100 is an exposure apparatus for exposing a workpiece W. Here, the workpiece W can be, for example, a printed circuit board. In this embodiment, the workpiece W corresponds to a substrate held by a holding mechanism. The exposure apparatus 100 includes a light irradiation unit 10, a mask M, a mask stage 11, a projection lens 12, a work stage 20, and piping L.

[0024] The light irradiation unit 10 emits exposure light. The light irradiation unit 10 includes a lamp 15, a mirror 16, and a lamp housing 17. The lamp 15 is an exposure light source that emits exposure light including ultraviolet light. The mirror 16 reflects the exposure light emitted from the lamp 15 in a predetermined direction of emission. The lamp housing 17 is a case that houses the lamp 15 and the mirror 16. Here, we will describe the case where the light source of the light irradiation unit 10 is a lamp 15, but an LED (Light Emitting Diode) or a laser light source may also be used as the light source. Furthermore, the wavelength and bandwidth of the exposure light are not limited. In this embodiment, the light irradiation unit 10 corresponds to the light emission unit that emits exposure light.

[0025] The mask M has patterns, such as circuit patterns, formed on it, which are exposed (transferred) onto the workpiece W. The mask stage 11 holds the patterned mask in the optical path of the exposure light. The projection lens 12 projects the exposure light that has passed through the mask M onto the workpiece W. For example, the projection lens 12 is configured as a reduction optical system that reduces the pattern of the mask M and forms an image on the surface of the workpiece W. In this embodiment, the case in which the exposure apparatus 100 is equipped with a projection lens 12 is described, but the present invention can also be applied to exposure apparatuses that are not equipped with a projection lens 12.

[0026] The work stage 20 holds the workpiece W onto which the pattern of the mask M is transferred. Specifically, the work stage 20 is a holding mechanism that holds the workpiece W (substrate) by vacuum suction. The work stage 20 is provided with a suction area 22 having a plurality of vacuum suction holes 29 and a sealing portion 30 arranged to surround the suction area 22. The vacuum suction holes 29 are connected to a pipe L for drawing vacuum. The specific configuration of Work Stage 20 will be explained in detail later.

[0027] Piping L is a vacuum piping with one end connected to the work stage 20 and the other end having a bifurcated branch. One branch is connected to a vacuum pump (not shown) via valve B1. The other branch is connected to an air inlet (not shown) via valve B2. Solenoid valves or the like are used as valves B1 and B2 to block the flow path.

[0028] [Basic operation of an exposure system] Here, we will explain the basic exposure operation flow of the exposure apparatus 100. In the exposure apparatus 100, a workpiece W, such as a printed circuit board, is transported by a transport means (not shown). The workpiece W is placed on the work stage 20 with its surface (the side forming the pattern) facing upwards. More specifically, the workpiece W is placed on a sealing portion 30 surrounding the adsorption area 22. At this time, a photosensitive resist is applied to the surface of the workpiece W.

[0029] When the workpiece W is placed, valve B2 of the piping L closes and valve B1 opens. As a result, vacuum is supplied to the through-hole (vacuum suction hole 29) connected to the piping L, and the workpiece W is attracted to the suction area 22. At this time, the seal portion 30 is elastically deformed as the workpiece W is vacuum-suctioned. This prevents vacuum leakage between the back surface of the workpiece W and the workpiece stage 20, and the workpiece W is securely held in place by suction.

[0030] Exposure light emitted from the light irradiation unit 10 is irradiated onto the workpiece W held by the work stage 20 via the mask M and projection lens 12. The pattern formed on the mask M is then projected onto the workpiece W, exposing the desired pattern. Vacuum is continuously supplied to the work stage 20 during the exposure process to prevent the workpiece W from moving.

[0031] When the exposure process is complete, valve B1 is closed, and the supply of vacuum to the vacuum suction hole 29 is stopped. This releases the vacuum suction of the workpiece W. Next, valve B2 is opened, and air is supplied to the vacuum suction hole 29. As a result, air is blown out of the vacuum suction hole 29, and the workpiece W is removed from the work stage 20. After that, the workpiece W is recovered by a transport means (not shown) and transported outside the exposure apparatus 100.

[0032] [Workstage Configuration] Figure 2 is a schematic diagram showing an example configuration of the work stage 20. Figure 2A is a schematic perspective view showing the work stage 20 in an disassembled state. Figure 2B is a schematic cross-sectional view showing an example configuration of the work stage 20. As shown in Figure 2, the work stage 20 has a suction portion 21 and a sealing portion 30. Hereafter, the side of the work stage 20 on which the workpiece W is held (the side on which exposure light is irradiated) will be referred to as the upper side of the work stage, and the opposite side will be referred to as the lower side.

[0033] The suction unit 21 has a suction area 22 for vacuum suction of the workpiece W. The suction area 22 is a planar region where the workpiece W is held by vacuum suction, and is located above the workpiece stage 20. While vacuum suction is being performed, the workpiece W is held in place by sticking to the suction area 22. The suction unit 21 comprises a base 23 and a suction plate 24 attached to the base 23. A suction area 22 is formed on the surface of the suction plate 24. The suction unit 21 is also provided with a mounting portion 37 for attaching the sealing portion 30.

[0034] The base 23 is a metal block that serves as the base for the suction part 21. The planar shape of the base 23, when viewed from above, is rectangular (approximately square in this case). The base 23 is typically made of an aluminum block with an electroless nickel plating treatment on its surface, but anodized aluminum or ceramics welded to it may also be used. The material of the base 23 may also be metal such as iron or copper.

[0035] A recess 25 is formed in the center of the upper surface of the base 23, and multiple protrusions 26 are formed within the recess 25 for supporting the suction plate 24. In addition, multiple vacuum introduction passages 27 are provided in the recess 25 to guide vacuum from the vacuum system (piping L) attached to the base 23 into the recess 25. The vacuum or air supplied to the piping L is guided into the recess 25 through these vacuum introduction passages 27. Thus, the base 23 has a recess 25 for supplying vacuum and a plurality of protrusions 26 formed within the recess 25.

[0036] Furthermore, the upper surface of the base 23 is finished to a highly precise flat surface. Here, the upper surface is the surface formed by the upper surface of the protrusion 26 and the upper outer surface of the base 23 (the surface surrounding the edge of the recess 25). That is, the upper surface of the protrusion 26 and the outer surface of the base 23 are at the same height, and their flatness is about 10 μm. The upper surface of the base 23 is the surface on which the suction plate 24 is placed.

[0037] The suction plate 24 is a thin, plate-like member made of a material that is large enough to completely cover the recess 25 of the base 23 and has a certain degree of flexibility so as to conform to the upper surface of the base 23. For example, a stainless steel plate with a thickness of 0.3 mm can be used as the suction plate 24. However, the thickness and material of the suction plate 24 are not limited to this, and the thickness and material of the suction plate 24 may be appropriately selected according to the size of the recess 25, for example. As shown in Figure 2, the suction plate 24 has a suction surface 28 and a plurality of vacuum suction holes 29.

[0038] The suction surface 28 is the surface that forms the suction area 22. In other words, the suction surface 28 is the surface on which the workpiece W is held during vacuum suction. The suction plate 24 is mounted on the recess 25 of the base 23 with the suction surface 28 facing upwards. In the example shown in Figure 2A, through holes for screws S are provided at the four corners of the suction plate 24, and the suction plate 24 is fixed to the base 23 by screws S. Alternatively, other fixing hardware may be used instead of screws S.

[0039] The multiple vacuum suction holes 29 are through holes formed in the suction surface 28. Each vacuum suction hole 29 is provided across the entire area that overlaps with the recess 25 of the base 23 in a plan view from above. Here, vacuum suction holes 29 having a predetermined diameter are provided in a grid pattern at regular intervals. The positions of the vacuum suction holes 29 are set so as not to coincide with the positions of the protrusions 26 of the base 23. When the suction plate 24 is attached to the base 23 and a vacuum is supplied to the base 23, the vacuum is guided to the recess 25 of the base 23 as described above, and the vacuum is also supplied to the vacuum suction holes 29 of the suction plate 24 that cover the recess 25. This makes it possible to vacuum-suction the workpiece W.

[0040] In the exposure apparatus 100, multiple suction plates 24 are prepared according to the size and shape of the workpiece W, or the position of notches or through holes provided in the workpiece W. The number, diameter, shape and arrangement of vacuum suction holes 29 provided in each suction plate 24, and the area in which the vacuum suction holes 29 are provided are set according to the workpiece W.

[0041] For example, in the example shown in Figure 2, a circular hole is provided as the vacuum suction hole 29, but it is not limited to this, and various shapes of through holes such as rectangular holes and oval holes can be provided as the vacuum suction hole 29. Furthermore, in the example shown in Figure 2, vacuum suction holes 29 are provided at regular intervals across the entire area corresponding to the recess 25 of the suction plate 24. However, the invention is not limited to this, and vacuum suction holes 29 may be provided only in a specific area depending on the size of the workpiece W. Furthermore, the size (diameter, etc.) and arrangement of the vacuum suction holes 29 can be freely set within the plane of a single suction plate 24 according to the size, softness, and degree of curvature of the workpiece W.

[0042] By configuring the suction plate 24 in this way, it becomes possible to select the optimal suction plate 24 according to the type of workpiece W to be processed, and to hold the workpiece W by suction.

[0043] The sealing portion 30 is an annular elastic member arranged to surround the suction area 22. The sealing portion 30 has a lower surface 30a and an upper surface 30b. The lower surface 30a is the surface that is attached to the base 23. The upper surface 30b is the surface opposite to the lower surface 30a. At least a portion of the upper surface 30b functions as a mounting surface 34, which will be described later.

[0044] In this embodiment, the sealing portion 30 is attached to the base 23. Specifically, the sealing portion 30 is attached so that its lower surface 30a contacts the upper surface of the base 23 and surrounds the suction plate 24. That is, the annular region on the upper surface of the base 23 surrounding the suction plate 24 becomes the mounting portion 37 to which the lower surface 30a of the sealing portion 30 is attached. As shown in Figure 2B, the mounting portion 37 is located lower than the suction surface 28 due to the thickness of the suction plate 24. In this way, the lower surface 30a of the sealing portion 30 is attached to the mounting portion 37, which is located lower than the suction surface 28.

[0045] Furthermore, the sealing portion 30 is configured such that, with its lower surface 30a attached to the mounting portion 37, its upper surface 30b protrudes higher than the suction area 22 (suction surface 28). Therefore, when a workpiece W is placed on the work stage 20, when vacuum suction is not performed, the workpiece W is held in contact with the upper surface 30b of the sealing portion 30, separated from the suction surface 28 (see Figure 5A). When vacuum suction of the workpiece W is performed, the sealing portion 30 is crushed and compressed by the workpiece W attracted to the suction surface 28, functioning as a leak suppression mechanism to suppress vacuum leaks (see Figure 5B).

[0046] The shape of the sealing portion 30 is configured such that the area in contact with the workpiece W is an annularly closed region. Typically, the shape of the outer circumference of the sealing portion 30 is set to be the same shape and size as the outer circumference of the workpiece W. The shape of the sealing portion 30 may be set as appropriate within a range that allows for proper vacuum adsorption of the workpiece W. For example, the sealing portion 30 may be configured such that its outer circumference fits inside the outer circumference of the workpiece W. Alternatively, the sealing portion 30 may be configured such that the outer circumference of the workpiece W fits between the inner and outer circumferences of the sealing portion 30.

[0047] In this configuration, where the sealing portion 30 is attached to the base 23, the suction surface 28 is positioned higher than the surface to which the sealing portion 30 is attached (the upper surface of the base 23). Therefore, during vacuum suction, when the thickness of the sealing portion 30 is compressed to the thickness of the suction plate 24, the workpiece W is held by suction on the suction surface 28. In other words, the thickness of the suction plate 24 cancels out the thickness of the sealing portion 30 when compressed. Consequently, there is no need to provide extra steps or other features on the upper surface of the base 23 to cancel out the thickness of the sealing portion 30 when compressed. This simplifies the structure of the base 23 and reduces manufacturing costs. Furthermore, since there is no need to provide extra steps or other features on the suction plate 24, it becomes possible to manufacture various types of suction plates 24 corresponding to the workpiece W at low cost.

[0048] [Structure of the sealing part] Figure 3 is a schematic diagram illustrating the basic configuration of the sealing portion 30. Figure 3 schematically shows the basic planar configuration of the sealing portion 30. Here, we will describe each part constituting the sealing portion 30 with reference to Figure 3. The sealing portion 30 has an elastic portion 31 and a rebound force suppressing portion 40.

[0049] The elastic part 31 is the main body of the sealing part 30, which is constructed using an elastic material. The elastic part 31 is constructed using, for example, a rubber sponge. The elastic portion 31 is composed of low-rebound elastic materials such as ethylene propylene diene rubber (EPDM), fluororubber, or urethane. The elastic portion 31 may be composed entirely of the same material, or it may be composed of partially different materials, as will be explained with reference to Figure 9. The planar shape of the elastic portion 31 is a band-shaped region surrounding the adsorption area 22. In Figure 3, the elastic portion 31 is provided as a rectangular band-shaped region. Therefore, the planar shape of the elastic portion 31 is rectangular. Also in Figure 3, the adsorption area 22 (the region where the adsorption plate 24 is placed) is schematically illustrated by a dotted line. The elastic portion 31 has a plurality of side portions 32, a plurality of corner portions 33, and a mounting surface 34.

[0050] Multiple edges 32 are arranged to surround the adsorption area 22. One edge 32 is, for example, an elongated rectangular region (a linear region with a certain width) extending in one direction, and forms an edge in the rectangular elastic portion 31. In the example shown in Figure 3, four straight edges 32 with a certain width are arranged to surround the top, right, bottom, and left sides of the rectangular suction area 22 in the figure.

[0051] Multiple corners 33 are formed between adjacent sides 32. One corner 33 is, for example, the part that connects two adjacent sides 32. If the two sides 32 are considered as straight lines, then the corner 33 corresponds to the vertex formed between the two straight lines. In the example shown in Figure 3, four corners 33 are positioned on the upper right, upper left, lower left, and lower right sides of the suction area 22, corresponding to the four rectangular sides 32. In other words, the multiple corners include four corners 33 that correspond to the four vertices of the rectangular shape.

[0052] In the following, when adjacent sides 32 are extended and intersect, the region where two sides 32 intersect will be referred to as the intersection region 35. For example, as shown in Figure 3, when adjacent sides 32 are arranged perpendicularly and the width of each side 32 is equal, the intersection region 35 will be a square-shaped region where one side is equal to the width of the side 32. The corner portion 33 described above can also be said to be the portion formed in the intersection region 35 of the elastic portion 31, which consists of multiple sides 32.

[0053] The mounting surface 34 is the surface on which the workpiece W is placed on the elastic portion 31. Here, the mounting surface 34 is the surface on which the workpiece W makes contact with each side portion 32 and corner portion 33 when vacuum suction is not being performed. In other words, the mounting surface 34 can also be said to be the surface that supports the workpiece W in its natural state when the elastic portion 31 (seal portion 30) is not compressed. For example, the thickness of multiple sides 32 and multiple corners 33 is set to be constant. In this case, the entire upper surface of the elastic portion 31 becomes the mounting surface 34. Also, if some of the multiple sides 32 and multiple corners 33 are made lower (see Figure 8, etc.), the upper surface of the elastic portion 31 excluding those parts becomes the mounting surface 34.

[0054] The rebound force suppression section 40 is a structural part that suppresses the rebound force generated when the elastic section 31 is compressed. When the elastic section 31, which is made of an elastic material, is compressed and deformed, it tries to return to its original shape and exerts a rebound force on the member (workpiece W) that compresses the elastic section 31. Typically, the greater the amount of compression (crushing) of the elastic section 31, the greater the rebound force from the elastic section 31. In the portion where the rebound force suppressing section 40 is provided, the rebound force is smaller compared to the portion where the rebound force suppressing section 40 is not provided.

[0055] In the sealing portion 30, the repulsion force suppressing portion 40 is provided for at least one of the multiple corner portions 33. At the corner portion 33 where the repulsion force suppressing portion 40 is provided, the repulsion force of the elastic portion 31 is reduced. In this embodiment, rebound force suppressing sections 40 are provided at all of the multiple corners 33. In the example shown in Figure 3, rebound force suppressing sections 40 are provided at each of the four corners 33. This makes it possible to reduce the rebound force at the four corners of the rectangular elastic section 31. The configuration of the rebound force suppression unit 40 will be explained in detail below.

[0056] Figure 4 is a schematic diagram showing an example of the planar configuration of the seal portion 30 provided on the work stage 20. Figure 4 shows a plan view of the work stage 20 as seen from above, as shown in Figures 2A and 2B. In the following, it is assumed that the thickness of the edges 32 and corners 33 constituting the seal portion 30 (elastic portion 31) are all set to a constant value.

[0057] Here, the rebound force suppression section 40 employs a structure that reduces the area over which the rebound force acts. Specifically, the rebound force suppression section 40 makes the area of ​​the mounting surface 34 at the corner 33 smaller than the area of ​​the intersection region 35 formed by extending and intersecting the two sides 32 connected to the corner 33. This means that the area in contact with the workpiece W by the uncompressed corner 33 is made smaller than the intersection region 35. This makes it possible to suppress the rebound force acting on the workpiece W at the corner 33.

[0058] As shown in Figure 4, a notch 41 formed on the inside of the corner portion 33 is provided as the rebound force suppression portion 40. That is, a circular notch 41 is formed in the corner portion 33, in which the inner circumference formed by the side portion 32 is cut outwards. Furthermore, a notch 41 is provided for all corner portions 33. In other words, the rectangular sealing portion 30 (elastic portion 31) is provided with four notches 41 corresponding to the four corners.

[0059] Now let's focus on the intersection region 35. Figure 4 shows the intersection region 35 of the two sides 32 that connect to the upper left corner 33 of the seal portion 30, superimposed on that corner 33. By providing the notch 41, the area of ​​the mounting surface 34 formed at the corner 33 becomes smaller than the area of ​​the intersecting region 35. This makes it possible to reduce the repulsive force generated at the corner 33 compared to a configuration where the entire intersecting region 35 becomes the mounting surface 34 in a corner 33 made of the same material as the edge 32 (see Figure 10). In Figure 4, the notch 41 cuts not only the corner 33 but also the portion of the edge 32 that connects to the corner 33 (the end of the edge 32). This makes it possible to sufficiently avoid the bulging at the corner 33, which will be explained below.

[0060] In the example shown in Figure 4, the sealing portion 30 is formed by bonding together four members 36a, 36b, 36c, and 36d. Of these, members 36a and 36c, located on the upper and lower sides in the figure, are sandwiched between members 36b and 36d, located on the right and left sides in the figure, and together they constitute the edge portion 32. On the other hand, both ends of members 36b and 36d constitute the corner portion 33 because members 36a and 36c are located adjacent to each other. In this way, even when the sealing portion 30 is composed of multiple members 36, a repulsive force suppression portion 40 (in this case, a notch 41) is provided for the portion that becomes the corner portion 33 in the planar shape. Furthermore, while certain gaps may form between the four members 36a, 36b, 36c, and 36d, these gaps are filled when compressed and deformed, so there is no need to worry about vacuum leaks occurring. Furthermore, the sealing portion 30 (elastic portion 31) is not limited to being composed of multiple members 36; for example, the sealing portion 30 may be formed integrally as a single continuous member.

[0061] [Vacuum adsorption using the sealing part] Figure 5 is a schematic diagram showing the operation of vacuum adsorption by the work stage 20. Figures 5A and 5B are cross-sectional views of the work stage 20, showing the state before and during vacuum adsorption. As shown in Figure 5A, when the workpiece W is placed on the work stage 20, the recess 25 of the base 23 is at atmospheric pressure, and the edges 32 and corners 33 of the sealing portion 30 (elastic portion 31) are hardly deformed and are in their natural state. In this case, the workpiece W is supported on the mounting surface 34 of the sealing portion 30 while floating above the suction surface 28 (suction plate 24).

[0062] As shown in Figure 5B, when vacuum is supplied to the recess 25 via the piping L, vacuum suction occurs. During vacuum suction, a force acts to press the workpiece W against the suction surface 28, which is the surface of the work stage 20, and the peripheral area of ​​the back surface of the workpiece W is pressed against the seal portion 30. As a result, the seal portion 30 receives a force in the direction of compression from the workpiece W and undergoes compressive deformation. At this time, the seal portion 30 deforms to match the shape of the peripheral area of ​​the back surface of the workpiece W, preventing the occurrence of vacuum leaks, etc. As a result, the workpiece W is pressed against the suction surface 28 with sufficient force, making it possible to firmly suction and hold the workpiece W on the suction surface 28 (suction area 22). Through this process, the workpiece W is pressed against the surface of the suction plate 24, starting with the center and then the periphery.

[0063] When the seal portion 30 is compressed in the thickness direction, it is conceivable that the seal portion 30 will bulge in the lateral direction perpendicular to the thickness direction. In this case, the lateral bulging of the two sides 32 will be concentrated at the point where the two sides 32 intersect, i.e., at the corner 33 of the seal portion 30, and the corner 33 may bulge due to the bulging having nowhere else to go. This can be said to be because the lateral deformation concentrated from each side 32 to the corner 33 is converted into a repulsive force. As a result, a locally large repulsive force acts at the four corners of the workpiece W compared to other areas, and the four corners of the workpiece W may bulge. As a result, the flatness of the workpiece W may decrease (see Figure 10).

[0064] As described above, in the example shown in Figure 4, notches 41 are provided at the four corners (four corners 33) of the seal portion 30 to suppress the repulsive force. In addition, the presence of the notches 41 allows for, for example, lateral bulging from adjacent edges 32 to escape. As a result, the workpiece W is pressed firmly against the surface of the suction plate 24 without bulging, and the workpiece W can be held on the work stage 20 with high flatness. Consequently, the exposure apparatus 100 can appropriately suppress exposure defects due to defocusing, and can effectively avoid a deterioration in yield.

[0065] [Example of the configuration of the rebound force suppression unit] Figure 6 is a schematic diagram showing an example of the configuration of the rebound force suppression section 40. Figures 6A to 6D schematically illustrate an example configuration in which the area of ​​the mounting surface 34 at the corner 33 is smaller than that of the intersecting region 35. Figure 6E schematically illustrates an example configuration in which the area of ​​the mounting surface 34 around the corner 33 is reduced. Here, the rebound force suppression section 40 provided at one of the multiple corners 33 included in the seal section 30 is shown as a representative example.

[0066] In Figure 6A, a notch 41 is provided on the inside of the corner 33 as a rebound force suppression part 40. The planar shape of the notch 41 is circular. This is the same configuration as the notch 41 shown in Figure 4. By providing a circular notch 41, it becomes possible to disperse stress concentration in the lateral direction, for example, and to sufficiently suppress the bulging at the corner 33.

[0067] In Figure 6B, a notch 41 is provided on the inside of the corner 33 as a rebound force suppression part 40. The planar shape of the notch 41 is a rectangle. The rectangle notch 41 can be easily formed, for example, by linearly cutting the elastic member that constitutes the seal part 30. This improves the manufacturability of the seal part 30 and reduces manufacturing costs.

[0068] In Figure 6C, an outer peripheral cut-off section 42 is provided as a rebound force suppression section 40, which is formed by cutting off the outer circumference of the corner 33. In the outer peripheral cut-off section 42 shown in Figure 6C, the region including the outer vertex is cut along the diagonal between the inner and outer vertices of the intersection region 35. As a result, the area of ​​the mounting surface 34 at the corner 33 becomes smaller than that of the intersection region 35. In this way, even when the outer part of the corner 33 is cut off, the surface area that contacts the workpiece W during compression is reduced, making it possible to reduce the rebound force at the corner 33.

[0069] In Figure 6D, an opening 45 is provided as the rebound force suppression part 40 so as to overlap with the corner 33 (intersecting region 35). The opening 45 is a through hole with a closed outer circumference. In Figure 6D, a circular opening 45 is provided inside the intersecting region 35. As a result, the area of ​​the mounting surface 34 at the corner 33 becomes smaller than that of the intersecting region 35. In this way, even when a through hole is provided inside the corner 33, it is possible to reduce the rebound force at the corner 33.

[0070] As shown in Figures 6A, 6B, 6C, and 6D, the repulsion force suppression section 40 is positioned to overlap with the intersection region 35. This makes it possible to directly reduce the repulsion force at the corners 33, and to sufficiently suppress the bulging of the workpiece W. As a result, it is possible to significantly improve the flatness of the workpiece W.

[0071] In Figure 6E, a notch 41 is provided on the inside of the edge 32 connected to the corner 33 as the rebound force suppressing part 40. Specifically, notches 41a and 41b are formed from the inside of the portions of the two edges 32 connected to the corner 33 that are in contact with the intersection region 35. In this way, the rebound force suppressing part 40 may be arranged to be in contact with the intersection region 35. Even in this case, the lateral bulge concentrated at the corner 33 is suppressed, and the rebound force at the corner 33 can be reduced.

[0072] Figure 7 is a schematic diagram showing another configuration example of the seal portion 30. In the sealing portion 30 described above, the corner portion 33 is formed by one of the members that make up the two adjacent side portions 32. In Figures 7A and 7B, the way in which the members that make up each part of the sealing portion 30 (the two side portions 32 and the corner portion 33) are divided differs from the example described above.

[0073] In Figure 7A, the two sides 32 and the corner 33 are made of separate members. Here, the two members that will become the sides 32 are positioned adjacent to the member that will become the corner 33. At this time, the angle between each side 32 is set to 90 degrees. Also in Figure 7A, a circular notch 41 is formed as the rebound force suppression part 40 so as to overlap the three members (the two sides 32 and the corner 33). This can also be said to be an example in which the corner 33 of the seal part 30 shown in Figure 6A is made of a different member from the sides 32.

[0074] For example, the center of the circular notch 41 is set on the line connecting the outer vertex (the upper left vertex in the figure) and the inner vertex (the lower right vertex in the figure) of the intersecting region 35. In this case, the shapes of the two edges 32 cut out by the circular notch 41 are symmetrical to each other. Thus, when the shapes of the two edges 32 are symmetrical, one edge 32 can be used as the other edge 32 by reversing its top and bottom surfaces (or its vertical or horizontal arrangement). In other words, the components that make up the edges 32 can be standardized. Similarly, the corners 33 can be used at any vertex, and the components that make up the corners 33 can also be standardized. This makes it possible to standardize the components that make up the corners 33 and edges 32, thereby reducing manufacturing costs.

[0075] In Figure 7B, a corner 33 is formed by two members that constitute two adjacent sides 32. The planar shape of the two members that form the side 32 is a long, narrow rectangle with a hypotenuse 38 at a predetermined angle to the longitudinal direction at its end. For example, as shown in Figure 7B, when the angle between the two sides 32 is set to 90 degrees, a hypotenuse 38 is formed at the end of each member, at an angle of 45 degrees to the longitudinal direction. The two members that form the side 32 are arranged so that the acute angles formed by the hypotenuses 38 face each other. In addition, an intersection region 35 is formed in the area containing the two hypotenuses 38, and the part of the two members that form the side 32 that overlaps with the intersection region 35 becomes the corner 33.

[0076] In Figure 7B, a circular notch 41 is formed as the rebound force suppression section 40, overlapping the two members that make up the two sides 32 and the corner 33. This can also be seen as an example in the seal section 30 shown in Figure 6A, where the corner 33 is formed by the two members that make up the two sides 32. In this case, similar to Figure 7A, by setting the center of the circular notch 41 on the line connecting the outer and inner vertices of the intersecting region 35, the shapes of the two members become symmetrical to each other. This makes it possible to use the same two members to constitute the edge portion 32 and the corner portion 33, and to reduce the number of parts.

[0077] Figures 7A and 7B illustrate an example in which a circular notch 41 is provided as the repulsion force suppression part 40, but the invention is not limited to this example. For example, instead of a circular notch 41, a square notch 41 may be provided, as in Figure 6B. Also, an outer perimeter cutout portion 42 may be provided by cutting off the outer perimeter of the corner portion 33, as in Figure 6C. Also, an opening 45 may be provided so as to overlap with the corner portion 33, as in Figure 6D. Also, a notch 41 may be provided on the inside of the side portion 32 connected to the corner portion 33, as in Figure 6E. In either case, by making the planar shape of the edge portion 32 a line-symmetric shape, it is possible to make the two members common to each other.

[0078] Figure 8 is a schematic diagram showing another example of the configuration of the rebound force suppression unit. In Figure 8, a stepped portion 43 is used as the repulsion force suppressing portion 40, in which at least a part of the surface of the corner portion 33 is lower than the mounting surface 34. The stepped portion 43 is a step created by recessing all or part of the upper surface of the corner portion 33 relative to other parts.

[0079] Figures 8A and 8B schematically illustrate plan views showing the stepped portion 43 formed across the entire surface of the intersection region 35. The shaded area in the figures represents the stepped portion 43, which is set to the same size as the intersection region 35. Figure 8C schematically illustrates a perspective view showing the stepped portion 43 shown in Figures 8A and 8B. As shown in Figure 8C, the portion that becomes the stepped portion 43 is a region recessed to a predetermined depth relative to the mounting surface 34 formed by the adjacent edges 32.

[0080] In Figure 8A, the two side portions 32 and the corner portion 33 are made of separate members. In this case, the thickness of the member making up the corner portion 33 is set to be smaller than the thickness of the member making up the side portion 32. As a result, a step portion 43 is formed on the upper surface of the corner portion 33 that is lower than the upper surface (mounting surface 34) of the side portion 32. For example, when forming a corner 33 on a part of the edge 32, processing such as partially reducing the thickness of the edge 32 is required. In contrast, by constructing the corner 33 from a separate component from the edge 32, processing such as creating the corner 33 on the edge 32 becomes unnecessary, and it becomes possible to easily manufacture the components that will become the corner 33 and the edge 32.

[0081] In Figure 8B, a corner portion 33 is formed on one of the members that make up the two sides 32. In this case, the thickness of the portion that becomes the corner portion 33 is set to be smaller than the thickness of the other portions. As a result, a stepped portion 43 is formed at the portion that becomes the corner portion 33, which is lower than the mounting surface 34. In this way, the edge portion 32 and the corner portion 33 may be formed integrally. This makes it possible to reduce the number of components.

[0082] In its natural state, the thickness of the stepped portion 43 is set to be smaller than the thickness of the position that becomes the mounting surface 34 (edge ​​portion 32), and larger than the thickness of the sealing portion 30 (in this embodiment, the thickness of the suction plate 24) when compressed and deformed during vacuum suction. In this case, since the thickness of the stepped portion 43 is smaller than that of the position that becomes the mounting surface 34, the repulsive force is reduced. This makes it possible to directly reduce the repulsive force at the corner portion 33, and to sufficiently suppress the bulging of the workpiece W. Furthermore, when compressed and deformed, the stepped portion 43 will also be compressed to some extent, so it will be in close contact with the workpiece W, making it possible to suppress the occurrence of vacuum leaks.

[0083] Figure 8D schematically illustrates a plan view showing an example of a stepped portion 43 formed in a part of the intersection region 35. The shaded area in Figure 8D represents the stepped portion 43. Here, the stepped portion 43 is formed in the region of the intersection region 35 that overlaps with the corner portion 33, including the outer vertex, which is divided by the diagonal line between the inner and outer vertices. The region including the inner vertex is set to the same thickness as the edge portion 32 and functions as a mounting surface 34. In Figure 8D, the corner portion 33 is made of a separate component from the edge portion 32, but the corner portion 33 may also be integrally formed with the edge portion 32.

[0084] Thus, even with a configuration in which only a portion of the intersecting region 35 is made into a stepped portion 43, it is possible to reduce the repulsive force generated at the corner portion 33, thereby suppressing the bulging of the workpiece W. In addition to the stepped portion 43, a mounting surface 34 is also formed at the corner portion 33. As a result, the corner portion 33 is in close contact with the workpiece W, and the occurrence of vacuum leakage can be sufficiently suppressed.

[0085] Figure 9 is a schematic diagram showing another example of the configuration of the rebound force suppression unit. In Figure 9, a low-rebound section 44 is used as the rebound force suppression section 40, and is located at the corner 33 and is made of an elastic material with lower rebound force than the edge 32. The low-rebound section 44 is made using an elastic material that has lower rebound than the elastic material that makes up the edge 32. For example, a rubber sponge with a higher porosity than the material used for the edge 32 to reduce rebound force can be used as the low-rebound section 44.

[0086] In Figure 9A, the two side portions 32 and the corner portion 33 are made of separate members, and the sealing portion 30 is formed by individually attaching each member. A member with lower rebound than the side portions 32 is used to make up the corner portion 33, so that the entire corner portion 33 becomes a low-rebound portion 44. In this case, it is possible to easily manufacture the members that will become the corner portion 33 and the side portions 32 by processing materials with different rebound forces. In Figure 9B, a corner portion 33 is formed integrally with one of the members constituting the two sides 32. For example, a less resilient member is bonded to the portion of the member constituting the side 32 that will become the corner portion 33 to form a less resilient portion 44. In this case, it is possible to reduce the number of members that need to be attached.

[0087] For example, the thickness of the low-rebound portion 44 (corner portion 33) is set to be equal to the thickness of the edge portion 32. In this case, the upper surface of the low-rebound portion 44 functions as the mounting surface 34 together with the upper surface of the edge portion 32. Furthermore, when the workpiece W is placed and vacuum suction is performed, the low-rebound portion 44 (corner portion 33) and the edge portion 32 are compressed and deformed by the same amount of displacement. At this time, since the rebound force in the low-rebound portion 44 (corner portion 33) is lower than that in the edge portion 32, it is possible to suppress the bulging of the corners of the workpiece W.

[0088] The position and shape of the low-rebound portion 44 are not limited. For example, in addition to the corner portion 33, the low-rebound portion 44 may also be provided on the parts of the two sides 32 that are in contact with the corner portion 33. Alternatively, the low-rebound portion 44 may be provided on at least one of the corner portions 33. In this case as well, the rebound force at the corner portion 33 is suppressed, making it possible to suppress the bulging of the workpiece W.

[0089] As explained with reference to Figures 6 to 9, in this embodiment, the corners 33 formed in the sealing portion 30 are provided with repulsion force suppressing portions 40 such as notches 41, stepped portions 43, and low-rebound portions 44. By configuring the sealing portion 30 to hold the workpiece W by vacuum suction, it is possible to suppress the bulging of the four corners of the workpiece W when vacuum suction is applied. As a result, it is possible to properly hold the workpiece W in a flat position.

[0090] In the work stage 20 according to this embodiment, a seal portion 30 made of an elastic portion 31 is arranged to surround the suction area 22 for vacuum adsorption of the workpiece W. Repulsion force suppression portions 40 are provided at the corners 33 that constitute the seal portion 30. This suppresses the repulsion force at the corners 33, making it possible to reduce the bulging of the workpiece W. As a result, it becomes possible to achieve vacuum adsorption with a high degree of flatness.

[0091] Figure 10 is a schematic diagram showing a seal portion 50 as a comparative example. The corner portion 33 provided in the seal portion 50 shown in Figure 10 is made of the same material as the edge portion 32, has the same thickness as the edge portion 32, and each edge is set to the same width as the edge portion 32. In other words, the corner portion 33 is made of the same material as the edge portion 32 and covers the entire surface of the intersection region 35 of the two edge portions 32. In this case, if the seal portion 30 is compressed and deformed in the thickness direction, the lateral bulging of the two edge portions 32 is concentrated in the corner portion 33, and it is conceivable that the corner portion 33 will bulge.

[0092] The work stage 20 is required to securely hold the placed workpiece W by suction, and for the workpiece W to remain flat while held by suction. However, in the example shown in Figure 10, the four corners of the vacuum-suctioned workpiece W may bulge, potentially reducing the flatness of the workpiece W. In recent years, with the miniaturization of wiring and the increase in mounting density, the patterns exposed on the workpiece W have become finer. Therefore, even if the bulging of the workpiece W is slight, defocusing occurs in the bulged areas and their surroundings during processing such as exposure, resulting in exposure failure. As a result, there has been a problem of reduced yield.

[0093] In this embodiment, a repulsive force suppressing section 40 is provided for the corners 33 of the sealing section 30, which are prone to bulging. For example, notches 41 provided at the four corners, stepped sections 43, and low-rebound sections 44 serve as the repulsive force suppressing sections 40. These repulsive force suppressing sections 40 suppress the repulsive force acting from the corners 33 to the workpiece W.

[0094] In this way, by introducing the seal section 30 equipped with the repulsion force suppression section 40, when the work stage 20 holds the workpiece W by vacuum suction, it is possible to suppress the bulging of the four corners when the workpiece W is vacuum-suctioned, and to hold the workpiece W with good flatness. As a result, exposure defects due to defocusing and the like can be sufficiently suppressed, and the yield can be improved.

[0095] One example of a workpiece W that is held by adsorption on the work stage 20 and processed is a printed circuit board. Printed circuit boards are manufactured by forming patterns such as circuits on a resin substrate such as glass epoxy. In recent years, the fields in which printed circuit boards are applied have expanded, and various types of substrates are now being used, such as soft and easily deformable substrates and substrates with complex shapes and numerous notches and through holes. In addition, printed circuit boards are getting larger year by year, making them more susceptible to warping and deformation.

[0096] According to the work stage 20 of the present invention, even with workpieces W that are prone to significant warping and deformation, it is possible to suppress the bulging of the four corners of the workpiece W and properly maintain the flat surface of the workpiece W. Furthermore, an exposure apparatus using such a work stage 20 can achieve high-precision exposure. In addition, since exposure defects are suppressed, it is possible to improve the yield.

[0097] <Second Embodiment> A work stage according to a second embodiment of the present invention will now be described. In the following description, parts that are similar to the configuration and operation of the work stage 20 described in the above embodiment will be omitted or simplified.

[0098] Figure 11 is a schematic diagram showing an example configuration of a work stage according to the second embodiment. Figure 11A is a schematic perspective view showing the work stage 220 in an disassembled state. Figure 11B is a schematic cross-sectional view showing an example configuration of the work stage 220. As shown in Figure 11, the work stage 220 has a suction section 221 composed of a base 223 and a suction plate 224, and a sealing section 230. Of these, the base 223 is configured in the same way as the base 23 described with reference to, for example, Figure 2.

[0099] As shown in Figure 11A, in the work stage 220, the sealing portion 230 is attached to the suction plate 224. Here, the sealing portion 230 is positioned above the rectangular suction plate 224, which completely covers the recess 25 of the base 223, so as to surround the suction surface 28 (suction area 22). In addition, each of the four corners 33 of the sealing portion 230 is provided with a repulsion force suppressing portion 40 (in this case, a circular cutout 41). This makes it possible to suppress bulging at the four corners.

[0100] Furthermore, mounting portions 37 are provided around the suction area 22 to which the lower surface 230a of the sealing portion 230 is attached. The mounting portions 37 are configured as a step lower than the suction surface 28, so the lower surface 230a of the sealing portion 230 is attached at a lower position than the suction surface 28. In addition, the sealing portion 30 is configured such that when the lower surface 230a is attached to the mounting portions 37, the upper surface 230b protrudes higher than the suction surface 28. With this configuration, the thickness of the sealing portion 230 during compression is canceled out, making it possible to properly vacuum-suction the workpiece W.

[0101] As described above, the configuration of providing a sealing portion 230 on the suction plate 224 expands the size of the workpiece W that can be handled. For example, the shape of the suction area 22 and the sealing portion 230 are configured to match the shape of the workpiece W placed on the workpiece stage 220. This makes it possible to properly vacuum-suction even workpieces W that are smaller than the planar shape of the recess 25 of the base 223 with high flatness.

[0102] <Other Embodiments> The present invention is not limited to the embodiments described above, and various other embodiments can be realized.

[0103] In the above embodiment, a work stage configured to have a suction plate screwed to a base was described (see Figures 2 and 11). The method of fixing the suction plate is not limited, and for example, a method of fixing the suction plate using vacuum suction may be used.

[0104] Figure 12A is a schematic diagram showing an example of the configuration of a work stage according to another embodiment. The work stage 320 has a suction section 321, which is composed of a base 323 and a suction plate 324, and a sealing section 330. Of these, the configuration of the base 323 and the suction plate 324 differs from that of the work stage described above. Also, in Figure 12A, the sealing section 330 is attached to the base 323 so as to surround the suction plate 324.

[0105] The base 323 has a first recess 325, a first protrusion 326, a first vacuum introduction path 327, a second recess 355, a second protrusion 356, and a second vacuum introduction path 357. A first recess 325 is formed in the center of the upper surface of the base 323, and a plurality of first protrusions 326 and a second protrusion 356 for supporting the suction plate 324 are formed within the first recess 325. The second protrusion 356 is an annular projection provided in the center of the first recess 325, and a second recess 355 is formed inside it.

[0106] The first recess 325 is provided with a plurality of first vacuum introduction passages 327. Each first vacuum introduction passage 327 is connected to a first vacuum system (piping L1) attached to the base 323. Vacuum or air supplied to piping L1 is guided from the first vacuum introduction passages 327 to the first recess 325. The second recess 355 is provided with a plurality of second vacuum introduction passages 357. Each second vacuum introduction passage 357 is connected to a second vacuum system (piping L2) attached to the base 323. Vacuum or air supplied to piping L2 is guided from the second vacuum introduction passages 357 to the second recess 355. Furthermore, the introduction of vacuum or air into piping L1 (first vacuum system) and piping L2 (second vacuum system) can be controlled independently.

[0107] Furthermore, the upper surface of the base 323 is finished to a highly precise flat surface. Here, the upper surface is the surface formed by the upper surface of the first protrusion 326, the upper surface of the second protrusion 356, and the upper outer surface of the base 323 (the surface surrounding the edge of the first recess 325). In other words, the upper surface of the first protrusion 326, the upper surface of the second protrusion 356, and the outer surface of the base 323 are at the same height.

[0108] The first recess 325, the first protrusion 326, and the first vacuum introduction passage 327 correspond, for example, to the recess 25, protrusion 26, and vacuum introduction passage 27 shown in Figure 2. Therefore, it can be said that the base 323 is configured by providing the second recess 355, the second protrusion 356, and the second vacuum introduction passage 357 to the base 23 shown in Figure 2, and connecting the piping L2, which is the second vacuum system.

[0109] The suction plate 324 is a thin, plate-like member that completely covers the first recess 325 of the base 323. The suction plate 324 has a suction surface 28 and a plurality of vacuum suction holes 29. The adsorption surface 28 forms the adsorption area 22 and is the surface on which the workpiece W is held during vacuum adsorption. The multiple vacuum suction holes 29 are through holes formed in the suction surface 28. Each vacuum suction hole 29 is provided across the entire area of ​​the region that overlaps with the first recess 325 in a plan view from above, excluding the fixing region 60 (the area indicated by the dotted line in the figure) that overlaps with the second protrusion 356. The fixing region 60 does not have through holes and completely covers the second protrusion 356 (second recess 355).

[0110] The operation of the work stage 320 will now be described. In the work stage 320, with piping L1 and L2 closed and no vacuum or air supply, the suction plate 324 is placed on the upper surface of the base 323. At this time, the suction plate 324 is positioned so that the fixing area 60 and the second protrusion 356 overlap. With the suction plate 324 in place, vacuum is supplied to the piping L2. As a result, vacuum is introduced into the second recess 355 via the second vacuum introduction passage 357, and the suction plate 324 is vacuum-adsorbed. This makes it possible to fix the suction plate 324 to the base 323.

[0111] With the suction plate 324 fixed, the workpiece W is placed on the suction plate 324 (suction surface 28). At this time, the workpiece W is supported by the mounting surface 34 of the seal portion 330 while floating above the suction surface 28. With the workpiece W placed in this position, vacuum is supplied to the piping L1. As a result, vacuum is introduced into the first recess 325 via the first vacuum introduction passage 327, and the workpiece W is vacuum-adsorbed to the suction surface 28 via the vacuum suction hole 29. This makes it possible to fix the workpiece W to the suction plate 324. Furthermore, once the exposure or other processing on the workpiece W is complete, air is supplied to the piping L1, and the vacuum suction of the workpiece W is released.

[0112] In this way, vacuuming is performed by the piping L2 during the period when vacuum suction of the workpiece W is being performed, and also during the period when vacuum suction of the workpiece W is released, so that the suction plate 324 is continuously fixed to the base 323. Furthermore, when replacing the suction plate 324, the vacuuming by piping L2 is stopped, and air or other fluids are supplied from piping L2. This makes it possible to easily remove the suction plate 324. Furthermore, since there are no through holes or the like in the fixing area 60 of the suction plate 324, the workpiece W will not be attracted by vacuum drawn by the piping L2. In other words, the vacuum attraction of the suction plate 324 and the vacuum attraction of the workpiece W can be performed completely independently.

[0113] Figure 12B is a schematic diagram showing an example of the configuration of a work stage according to another embodiment, in which the arrangement of the sealing portion 330 is changed from that in Figure 12A. In the work stage 420 shown in Figure 12B, the sealing portion 330 is attached to the suction plate 324 so as to surround the suction surface 28. Even with this configuration in which the sealing portion 330 is attached to the suction plate 324, the vacuum suction of the suction plate 324 and the vacuum suction of the workpiece W can be performed completely independently.

[0114] Furthermore, in the work stage 420, the planar shape of the suction plate 324 is set to be the same shape and size as, for example, the planar shape of the outer circumference of the base 323 when viewed from above. This makes it possible to vacuum-suction a larger workpiece W than when the sealing portion 330 is placed on the base 323.

[0115] In this way, in work stages 320 and 420, the suction plate 324 is vacuum-adsorbed to the base 323 from the back side. This eliminates the need for screws or other fasteners, and allows the entire suction surface 28 to be used, including the outer edge of the suction plate 324 (or base 323). Furthermore, when replacing the suction plate 324, screw fastening and other such work are unnecessary, making it possible to easily replace the suction plate 324 even in confined spaces.

[0116] The above describes a configuration in which a repulsion force suppressing portion 40 is provided at all four corners 33 of a sealing portion with a rectangular planar shape. It is not necessarily required to provide a repulsion force suppressing portion 40 at all four corners 33; for example, depending on the material and thickness of the workpiece W, a repulsion force suppressing portion 40 may be provided at at least one of the four corners 33. Even with such a configuration, it is possible to suppress the bulging of the workpiece W at the corner 33 where the repulsion force suppressing portion 40 is provided.

[0117] Furthermore, each corner 33 may be provided with a rebound force suppressing section 40 of different characteristics and types. For example, each corner 33 may be provided with a notch 41 of different size and shape as the rebound force suppressing section 40. Alternatively, different types of rebound force suppressing sections 40, such as notches 41, stepped sections 43, and low-rebound sections 44, may be provided in combination. In addition, the selection of the corners 33 on which the rebound force suppressing section 40 is provided, as well as the characteristics and types of the rebound force suppressing section 40 provided at each corner 33, are not limited and may be set appropriately according to the type of workpiece W and the required flatness.

[0118] Figure 13 is a schematic diagram illustrating an example of the configuration of a sealing portion according to another embodiment. The above primarily described a sealing section with a rectangular planar shape. However, the shape of the sealing section is not limited.

[0119] Figure 13 schematically illustrates a deformed polygonal seal portion 430 in which a concave region 51 (the area indicated by the dotted line in the figure) is formed on one side of the rectangular shape. Here, the concave region 51 is configured as a rectangular area enclosed by four corners 33. In this case, the seal portion 430 has a total of eight corners 33, including the corners 33 formed in addition to the concave region 51.

[0120] Even in such cases, by providing a repulsion force suppressing section 40 (in this case, a circular notch 41) at each corner 33, the repulsion force at the corners 33 is suppressed, making it possible to suppress the bulging of the workpiece W. As a result, even workpieces W with complex shapes, such as notches on the outer circumference, can be properly vacuum-suctioned with high flatness.

[0121] The workpiece W may be positioned to cover the concave region 51. In this case, the concave region 51 can be used as a space for a jig or the like to be inserted when transporting the workpiece W. Thus, even if the shape of the sealing portion 430 deforms to introduce a transport system or the like, the repulsion force suppression portion 40 makes it possible to sufficiently suppress the bulging of the workpiece W in the deformed portion (concave region 51).

[0122] Furthermore, the shape of the sealing portion is not limited. The present invention can be applied to any shape as long as corners are formed. For example, the angle of the corners (the angle of intersection of the sides) does not have to be 90 degrees, and a rhombus or parallelogram-shaped sealing portion may be formed. Alternatively, a polygonal sealing portion such as a triangle or pentagon may be formed. The shape of the sides is also not limited, and for example, part of the side may be formed as a curve.

[0123] The rebound force suppression section described with reference to Figure 6, etc., mainly involves forming notches or steps at the corners to reduce the mounting surface (contact area with the workpiece) at the corners. However, it is not limited to this; for example, a slope or groove may be formed on the upper surface of the corner to reduce the mounting surface at the corner. Alternatively, while leaving the mounting surface at the corner intact, a cavity or cut may be formed inside the material constituting the corner to reduce the rebound force at the corner. In addition, any structure capable of suppressing the rebound force at the corner may be used as the rebound force suppression section.

[0124] In the above embodiment, a work stage (holding mechanism) mainly used in an exposure apparatus was described as an example. However, the work stage (holding mechanism) according to the present invention can be used in any apparatus that processes a substrate by vacuum adsorption and holding it, even if it is not an exposure apparatus. For example, this holding mechanism may be used in apparatus that performs various processing operations such as deposition, etching, sputtering, polishing, and cutting. As a result, the workpiece W is held with high flatness, making it possible to perform each processing operation with high precision.

[0125] In this disclosure, words such as "abbreviated," "almost," and "approximately" are used as appropriate to facilitate understanding of the explanation. However, there is no clear distinction defined between using and not using these words. In other words, in this disclosure, concepts that define shape, size, positional relationships, state, etc., such as "center," "central," "uniform," "equal," "same," "orthogonal," "parallel," "symmetrical," "extending," "axial," "cylindrical," "cylindrical shape," "ring shape," and "annular shape," include concepts such as "substantially centered," "substantially central," "substantially uniform," "substantially equal," "substantially the same," "substantially orthogonal," "substantially parallel," "substantially symmetrical," "substantially extending," "substantially axial," "substantially cylindrical," "substantially cylindrical shape," "substantially ring shape," and "substantially annular shape." For example, this includes states that fall within a predetermined range (e.g., a range of ±10%) based on criteria such as "perfectly centered," "perfectly central," "perfectly uniform," "perfectly equal," "perfectly the same," "perfectly orthogonal," "perfectly parallel," "perfectly symmetrical," "perfectly extending," "perfectly axial," "perfectly cylindrical," "perfectly cylindrical shape," "perfectly ring shape," and "perfectly annular shape." Therefore, even if words like "abbreviated," "almost," or "approximately" are not added, the concept may still include what could be expressed by adding such words. Conversely, when a state is expressed with words like "abbreviated," "almost," or "approximately," it does not necessarily mean that a complete state is excluded.

[0126] In this disclosure, expressions using "greater than A" such as "greater than A" and "less than A" are expressions that comprehensively include both concepts that include cases where something is equivalent to A and concepts that do not include cases where something is equivalent to A. For example, "greater than A" is not limited to cases where something is not equivalent to A, but also includes "greater than or equal to A". Similarly, "less than A" is not limited to "less than A", but also includes "less than or equal to A". When implementing this technology, you should appropriately adopt specific settings and other elements from the concepts included in "greater than A" and "less than A" so that the effects described above are achieved.

[0127] It is also possible to combine at least two of the feature features of the present technology described above. In other words, the various feature features described in each embodiment may be combined arbitrarily, regardless of the specific embodiment. Furthermore, the various effects described above are merely examples and not limiting, and other effects may also be exhibited. [Explanation of symbols]

[0128] W...work 10...Light-irradiating section 11…Mask Stage 20, 220, 320, 420… Work Stages 21, 221, 321...Adsorption part 22…Adsorption area 23, 223, 323... base 24, 224, 324...Adsorption plate 30, 230, 330, 430... Seal part 31...Elastic part 32…edge 33... Corner 34… Mounting surface 35… Crossing region 40... Rebound force suppression part 100… Exposure equipment

Claims

1. A suction unit having a suction area for vacuum adsorption of a substrate, A seal portion having a plurality of edges arranged around the adsorption area and a plurality of corners formed between adjacent edges, which compresses and deforms so as to reduce the thickness when the substrate is vacuum adsorbed with the direction perpendicular to the adsorption area as the thickness direction, and a repulsion force suppressing portion provided for at least one of the plurality of corners to suppress the repulsive force generated in the thickness direction of the elastic portion due to the compressive deformation. It is equipped with, The elastic portion includes a plurality of elastic members arranged adjacent to each other at the corner portion where the rebound force suppressing portion is provided. Retention mechanism.

2. A holding mechanism according to claim 1, The plurality of elastic members are arranged spaced apart from each other so as to form a gap that is closed by the compressive deformation. Retention mechanism.

3. A holding mechanism according to claim 1, The elastic portion has a mounting surface on which the substrate is placed, The aforementioned repulsive force suppressing portion has a structure in which the area of ​​the surface to be placed at the corner is smaller than the area of ​​the intersection region obtained by extending and intersecting the two sides connected to the corner. Retention mechanism.

4. A holding mechanism according to claim 3, The aforementioned repulsion force suppressing portion is a notch formed on the inside of the corner portion. Retention mechanism.

5. A holding mechanism according to claim 4, The planar shape of the aforementioned notch is either a rectangle or a circle. Retention mechanism.

6. A holding mechanism according to claim 3, The aforementioned repulsion force suppressing portion is a stepped portion in which at least a part of the surface of the corner is lower than the aforementioned surface. Retention mechanism.

7. A holding mechanism according to claim 1, The rebound force suppressing portion is a low-rebound portion located at the corner and composed of an elastic material with lower rebound force than the side portion. Retention mechanism.

8. A holding mechanism according to any one of claims 1 to 7, The rebound force suppressing portion is positioned so as to overlap with the intersection region formed by extending and intersecting the two sides connected to the corner, or so as to be in contact with the intersection region. Retention mechanism.

9. A holding mechanism according to any one of claims 1 to 7, The planar shape of the elastic part is rectangular. The aforementioned plurality of corners include four corners corresponding to the four vertices of the rectangular shape. The repulsive force suppressing portion is provided at at least one of the four corners. Retention mechanism.

10. A holding mechanism according to any one of claims 1 to 7, The adsorption unit comprises a base having a recess for supplying vacuum and a plurality of protrusions formed within the recess, and an adsorption plate having an adsorption surface forming the adsorption area and a plurality of through holes formed on the adsorption surface, which is mounted on the recess. The sealing portion is attached to either the base or the suction plate. Retention mechanism.

11. A holding mechanism according to claim 10, The adsorption portion has a mounting portion that is located lower than the adsorption surface and to which the lower surface of the sealing portion is attached. The sealing portion is configured such that, when the lower surface is attached to the mounting portion, the upper surface opposite to the lower surface protrudes higher than the suction surface. Retention mechanism.

12. A holding mechanism according to any one of claims 1 to 7, The elastic part is constructed using rubber sponge. Retention mechanism.

13. A light-emitting section that emits exposure light, A mask stage that holds a patterned mask on the optical path of the exposure light, A work stage that holds a workpiece onto which the aforementioned pattern is transferred, It is equipped with, The aforementioned work stage is A suction unit having a suction area for vacuum adsorption of the workpiece, An elastic portion having a plurality of edges arranged around the adsorption area and a plurality of corners formed between adjacent edges among the plurality of edges, which compresses and deforms so that the thickness decreases when the workpiece is vacuum adsorbed with the direction perpendicular to the adsorption area as the thickness direction, and a repulsive force suppressing portion provided for at least one of the plurality of corners to suppress the repulsive force generated in the thickness direction of the elastic portion due to the compressive deformation, It has, The elastic portion includes a plurality of elastic members arranged adjacent to each other at the corner portion where the rebound force suppressing portion is provided. Exposure apparatus.

14. A suction unit having a suction area for vacuum adsorption of a substrate, An elastic portion having a plurality of edges arranged around the adsorption area and a plurality of corners formed between adjacent edges among the plurality of edges, which compresses and deforms so that the thickness decreases when the substrate is vacuum adsorbed with the direction perpendicular to the adsorption area as the thickness direction, and a seal portion having a repulsive force suppressing portion provided for at least one of the plurality of corners to suppress the repulsive force generated in the thickness direction of the elastic portion due to the compressive deformation. It is equipped with, The elastic portion has a mounting surface on which the substrate is placed, The aforementioned repulsion force suppressing portion is a stepped portion in which at least a part of the surface of the corner is lower than the aforementioned surface. Retention mechanism.

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