JP2023098194A - Substrate holding member - Google Patents

Abstract

To provide a substrate holding member capable of keeping the strength of an annular convex part while reducing a ratio of a contact between a substrate and an upper end surface of the annular convex part.SOLUTION: A substrate holding member 100 comprises: a flat-plate substrate 10 having one or a plurality of ventilation holes 14 opened to an upper surface 12; a plurality of pin-like convex parts 22 formed projecting upward from the upper surface 12 of the substrate 10; and an annular convex part 24 projecting upward from the upper surface 12 of the base body 10, and is formed in an annular shape along an outer periphery of the upper surface 12. The annular convex part 24 has a concave part 26 having a bottom part 26a at a position closer to the upper surface 12 of the base body 10 than an upper end surface 24a of the annular convex part, and a length in a radial direction of the upper end surface 24a of the annular convex part is different depending on the position of the annular convex part 24.SELECTED DRAWING: Figure 2

Description

The present invention relates to substrate holding members.

2. Description of the Related Art Conventionally, substrate holding members for supporting substrates such as silicon wafers and glass have been used in semiconductor manufacturing apparatuses and the like. Since the substrate constituting the substrate holding member supports the back surface of the substrate, the substrate is supported by evacuating through the vent holes formed in the surface of the substrate. In recent years, ultra-miniaturization and ultra-high precision of semiconductor products are progressing. If particles are interposed between the base and the substrate, local swelling of the substrate occurs, causing problems such as short-circuiting of the circuit pattern formed on the substrate in the circuit pattern forming process by exposing the substrate. As a result, the yield of semiconductor products decreases. Therefore, it is necessary to avoid such a problem. In order to reduce the risk of such particles being caught, a substrate holding member is used in which a plurality of pin-shaped projections are used as a region for supporting the substrate, thereby reducing the contact area between the substrate and the base.

In Patent Document 1, one main surface of a ceramic base has a recessed portion, the bottom surface of the recessed portion is provided with a plurality of protrusions, and the top surface of the protrusion and one main surface of the ceramic base are formed. is used as the holding surface, in order to minimize the generation of particles caused by contact between the vacuum adsorption device and the substrate, the projections are tapered to reduce the contact ratio with the substrate. An apparatus is disclosed.

Patent Document 2 discloses a technique in which a plurality of pin-shaped projections are arranged substantially uniformly in a negative pressure area that becomes a negative pressure when a substrate is sucked, and constitute a support surface for a substrate, and a pin-shaped convex portion that seals the negative pressure area from the outside air. and the upper surface of the sealing edge is slightly lower than the support surface so as not to come into contact with the substrate when the substrate is adsorbed. A substrate suction and holding device is disclosed that further reduces the effect of particle generation due to contact with the edge bank.

JP-A-10-242255 Japanese Patent Application Laid-Open No. 2001-185607

The vacuum suction device described in Patent Document 1 is formed so that the top surfaces of the plurality of projections and the top surface of the seal wall are positioned on the same plane, and the top surfaces of the plurality of projections and the top surface of the seal wall hold the substrate. , the rate of contact between the substrate and the top surface of the seal wall increases, increasing the risk of foreign matter such as particles getting caught in that portion.

In the substrate adsorption and holding device described in Patent Document 2, since the height of the sealing edge portion is lower than the height of the pin-shaped convex portion by a certain degree, the air is always flowing in from the outside during the substrate adsorption operation. This may allow foreign matter such as particles to enter at the same time as the inflow of air. If the particles allowed to enter at this time adhere to the back surface of the substrate, they may contaminate the substrate, and if they adhere between the holding surface and the substrate, the planarity accuracy of the substrate will be impaired. Further, even if the height of the sealing edge portion is made lower than the height of the pin-shaped protrusion, the substrate may come into contact with the sealing edge portion.

In addition, if the overall width of the annular protrusion (seal wall, etc.) is uniformly reduced for the purpose of reducing the contact rate with the substrate, the strength of the annular protrusion will be reduced, and particles will be generated due to damage to the annular protrusion. increased risk of On the other hand, if the width of the annular convex portion is uniformly increased to ensure strength, the contact rate is directly increased, and the risk of foreign matter such as particles getting caught increases.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and provides a substrate holding member in which the contact ratio between the substrate and the upper end surface of the annular protrusion is reduced and the strength of the annular protrusion is maintained. for the purpose.

(1) In order to achieve the above objects, the present invention provides a substrate holding member comprising a plate-like substrate having one or more vent holes opening on the top surface, and and an annular protrusion protruding upward from the upper surface of the base body and formed in a ring shape along the outer periphery of the upper surface, wherein the annular protrusion is the A concave portion having a bottom portion is provided at a position closer to the upper surface of the base body than the upper end surface of the annular protrusion, and the length of the upper end surface of the annular protrusion in the radial direction varies depending on the position of the annular protrusion. there is

Thus, the annular protrusion has a recess having a bottom portion closer to the upper surface of the base body than the upper end surface of the annular protrusion, and the radial length of the upper end surface of the annular protrusion is equal to the position of the annular protrusion. , the contact ratio between the substrate and the upper end surface of the annular protrusion is reduced, and the strength of the annular protrusion is maintained.

(2) Further, in the substrate holding member of the present invention, the upper end of the pin-shaped protrusion and the upper end surface of the annular protrusion are characterized by forming the same plane.

In this way, when the upper end of the pin-shaped protrusion and the upper end surface of the annular protrusion form the same plane, the upper end surface of the annular protrusion is always in contact with the substrate. The effect of reducing the contact ratio with the upper end face of the annular projection and the effect of maintaining the strength of the annular projection are more exhibited.

(3) Further, in the substrate holding member of the present invention, at least a part of the concave portion is connected to an inner region of the annular convex portion.

In this way, by connecting the concave portion to the inner region of the annular convex portion, the suction force can be generated also on the upper surface of the concave portion, so that the substrate can be stably attracted. In addition, when the substrate is vacuum-sucked, the atmosphere in the inner region and the recess can be kept in the same pressure state, which makes it easier to ensure the flatness accuracy of the substrate.

(4) Further, in the substrate holding member of the present invention, at least a part of the concave portion is connected to an outer region of the annular convex portion.

Since the recess is connected to the outer region of the annular protrusion in this manner, the atmosphere in the recess becomes the atmospheric state, so that the separation of the substrate is ensured when the substrate is attached and detached. In addition, since the recess is not connected to the inner region, it is possible to prevent the foreign matter from entering the inner region when the foreign matter remains in the recess.

According to the substrate holding member of the present invention, the contact rate between the substrate and the upper end surface of the annular protrusion is reduced, and the strength of the annular protrusion is maintained.

It is a schematic diagram showing an example of the upper surface of the substrate holding member according to the embodiment of the present invention. 1(a) and 1(b) are partial cross-sectional views each showing an example of a substrate holding member according to an embodiment of the present invention; FIG. 4A to 4C are partial cross-sectional views each showing an example of a radial cross-section of an annular convex portion of a substrate holding member according to an embodiment of the present invention; FIG. 4A to 4C are partial cross-sectional views each showing an example of a radial cross-section of an annular convex portion of a substrate holding member according to an embodiment of the present invention; FIG. It is a partial schematic diagram showing a modification of the upper surface of the substrate holding member according to the embodiment of the present invention. 4(a) and 4(b) are partial schematic diagrams respectively showing modifications of the upper surface of the substrate holding member according to the embodiment of the present invention. FIG. 4(a) and 4(b) are partial schematic diagrams respectively showing modifications of the upper surface of the substrate holding member according to the embodiment of the present invention. FIG.

Next, embodiments of the present invention will be described with reference to the drawings. In order to facilitate understanding of the description, the same reference numerals are given to the same components in each drawing, and overlapping descriptions are omitted. In addition, in the configuration diagram, the size of each component is conceptually represented, and does not necessarily represent the actual size ratio.

[Embodiment]
A substrate holding member according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. FIG. 1 is a schematic diagram showing an example of the top surface of a substrate holding member according to an embodiment of the present invention. 2(a) and 2(b) are partial cross-sectional views each showing an example of a substrate holding member according to an embodiment of the present invention. The substrate holding member 100 includes a substantially flat substrate 10 for holding a substrate (wafer) W by suction. The substrate 10 is made of a ceramic sintered body and has a substantially flat plate shape. The base body 10 may have various shapes such as a substantially disk shape, a polygonal plate shape, an elliptical plate shape, and the like.

Substrate 10 has one or more vent holes 14 opening into top surface 12 . When there are a plurality of vent holes 14 , the vent holes 14 may communicate with each other through a vent path passing through the interior of the base 10 . Vent 14 is connected to a vacuum suction device (not shown). The position, shape, and size of the vent holes 14 are determined by the shape of the suction surface area determined by the annular convex portion 24, which will be described later, the shape and type of the substrate W, the suction force when vacuum suction is performed, and the like. Varies according to design.

The base 10 has an annular projection 24 that protrudes upward from the upper surface 12 and is annularly formed along the outer circumference of the upper surface 12 . For example, when the base body 10 is formed in a disk shape, the annular projection 24 is formed at a position spaced from the outer periphery of the upper surface 12 of the base body 10 toward the center by a predetermined distance, and is annularly continuous when viewed from above. preferably formed.

The substrate 10 has a plurality of pin-shaped protrusions 22 formed to protrude upward from the upper surface 12 . A plurality of pin-shaped protrusions 22 are formed inside the annular protrusion 24 . The pin-shaped protrusion 22 may be formed outside the annular protrusion 24 . The plurality of pin-shaped protrusions 22 support the substrate W. As shown in FIG. The upper ends 22a of the plurality of pin-shaped protrusions are formed substantially flush. That is, a plane (reference plane) 30 formed by the upper ends 22a of the plurality of pin-shaped protrusions is determined. As a result, the upper ends 22a of the plurality of pin-shaped protrusions and the substrate W come into contact with each other, and the substrate W is supported. In addition, among the plurality of pin-shaped protrusions 22 , there may be one whose upper end does not come into contact with the substrate W. FIG. This is because even if such pin-shaped protrusions 22 are present, it is possible to support the substrate W depending on the arrangement of the pin-shaped protrusions 22 therearound.

The shape of the pin-shaped protrusion 22 may be cylindrical, prismatic, truncated cone, truncated pyramid, or the like, or may have a stepped shape such that the cross-sectional area of the upper portion is smaller than that of the lower portion. Moreover, the pin-shaped convex portion 22 may have a steep truncated cone shape with a high aspect ratio. It is preferable that the upper end 22a of the pin-shaped protrusion is a flat surface of a predetermined size. In that case, the maximum diameter of the plane of the upper end 22a of the pin-shaped protrusion is preferably 100 μm or more and 500 μm or less, and the surface roughness of the plane of the upper end 22a of the pin-shaped protrusion is Ra of 0.01 μm or more and 0.50 μm or less. is preferred.

The arrangement of the pin-shaped protrusions 22 may be a regular arrangement such as a triangular lattice, a square lattice, or a concentric circle, or may be an irregular arrangement such that the arrangement is locally uneven. The height of the pin-shaped protrusions 22 is preferably 50 μm or more and 200 μm or less. The height of the pin-shaped protrusion 22 means the distance from the upper surface 12 of the base 10 to the upper end 22a of the pin-shaped protrusion. Further, it is preferable that the distance between the centers of adjacent pin-shaped protrusions 22 is 1.5 mm or more and 8 mm or less.

The upper end 22a of the pin-shaped protrusion and the upper end face 24a of the annular protrusion preferably form the same plane. That is, the height of the annular projection 24 is preferably the same as the height of the pin-shaped projection 22 . Thus, when the upper end 22a of the pin-shaped protrusion and the upper end surface 24a of the annular protrusion form the same plane, the upper end surface 24a of the annular protrusion always contacts the substrate W, so that the annular protrusion 24 becomes the recess 26. The effect of reducing the contact ratio between the substrate W and the upper end surface 24a of the annular protrusion and the effect of maintaining the strength of the annular protrusion 24 are further exhibited.

The height of the annular protrusion 24 is the distance from the upper surface 12 of the base 10 to the upper end surface 24a of the annular protrusion. The radial length (width) of the annular protrusion 24 is preferably 0.05 mm or more and 4 mm or less, and more preferably 0.1 mm or more and 1.0 mm or less. The width of the annular protrusion 24 is preferably equal to or less than the distance between the centers of adjacent pin-shaped protrusions 22 . Moreover, the surface roughness of the upper end surface 24a of the annular protrusion is preferably Ra of 0.01 μm or more and 0.50 μm or less.

The upper end surface 24a of the annular projection may be positioned closer to the upper surface 12 of the base 10 than the upper end 22a of the pin-shaped projection. That is, the height of the annular projection 24 may be lower than the height of the pin-shaped projection 22 . In this case, the atmosphere always flows in from the outside of the base body 10 during the adsorption operation of the substrate W, and the Bernoulli effect can be exhibited in the vicinity of the annular convex portion 24 to suppress the edge of the substrate W from sinking. , the substrate W may come into contact with the upper end surface 24a of the annular protrusion due to the shape of the substrate W, warpage, or the like. Therefore, by applying the configuration of the present invention, the contact ratio between the substrate W and the upper end surface 24a of the annular protrusion is reduced, and the strength of the annular protrusion 24 is maintained.

When the height of the annular protrusion 24 is lower than the height of the pin-shaped protrusion 22, the height of the annular protrusion 24 is preferably lower than the height of the pin-shaped protrusion 22 by 1 μm or more and 5 μm or less. For example, when the pin-shaped protrusion 22 has a height of 100 μm, the annular protrusion 24 preferably has a height of 95 μm or more and 99 μm or less.

FIG. 2A is a partial cross-sectional view of a radial cross section of the substrate holding member 100 including the annular protrusion 24 at a position where the recess 26 is not formed. FIG. 2B is a partial cross-sectional view of a radial cross section of the substrate holding member 100 including the annular convex portion 24 at the position where the concave portion 26 is formed. As shown in FIGS. 1 and 2(a) and (b), the annular protrusion 24 has a recess 26 having a bottom 26a at a position closer to the upper surface 12 of the base 10 than the upper end surface 24a of the annular protrusion. However, the radial length L of the upper end face 24 a of the annular protrusion varies depending on the position of the annular protrusion 24 . The position of the annular protrusion 24 is the position of the annular protrusion 24 when the substrate holding member 100 is viewed from the upper surface 12 side. As a result, the contact ratio between the substrate W and the upper end surface 24a of the annular protrusion is reduced, and the strength of the annular protrusion 24 is maintained. The radial length L of the upper end face 24a of the annular protrusion will be described later.

The concave portion 26 has a bottom portion 26a at a position closer to the upper surface 12 of the base 10 than the upper end surface 24a of the annular convex portion. As a result, the radial length L of the upper end surface 24a of the annular convex portion differs at least between the position where the concave portion 26 is not formed and the position where the concave portion 26 is formed.

3A to 3C are partial cross-sectional views each showing an example of a cross section in the radial direction of the annular convex portion 24 of the substrate holding member 100 according to the embodiment of the present invention. The position of the annular projection 24 where the recess 26 is not formed as shown in FIG. The radial length L of the upper end surface 24a of the annular projection is expressed as the upper end surface 24a of the annular projection on the radial cross section. is the length of one line segment to be

On the other hand, at the position of the annular projection 24 where the concave portion 26 is formed near the center of the annular projection 24 as shown in FIG. , is the sum of the lengths of two or more line segments divided and represented as the upper end face 24a of the annular projection on the radial cross section. In the example of FIG. 3(c), L=L1+L2. The width of the upper end surface 24a of the annular protrusion at the position where the recess 26 is formed (the width of each of the two or more parts when the recess is divided into two or more) is preferably 0.02 mm or more, and the width of the part 0.05 mm or more is more preferable from the viewpoint of further ensuring the strength of.

The width of the upper surface of the concave portion 26 (difference between the radial length of the upper end surface 24a of the annular convex portion in which no concave portion is formed and the radial length of the upper end surface 24a of the annular convex portion in which the concave portion 26 is formed) is Although it depends on the width of the annular protrusion 24, in order to maintain the strength of the annular protrusion 24, it should be 50% or less of the radial length of the upper end surface 24a of the annular protrusion where the recess 26 is not formed. preferable. The width of the upper surface of the concave portion 26 may differ for each position of the annular convex portion 24 .

4A to 4C are partial cross-sectional views each showing an example of a cross section in the radial direction of the annular convex portion 24 of the substrate holding member 100 according to the embodiment of the present invention. The depth D of the concave portion 26 depends on the height of the annular convex portion 24, but is set so that it can play its role even when the annular convex portion 24 is worn, or when particles remain in the concave portion 26. Furthermore, in order to prevent particles from adhering to the substrate W, the height H is preferably 20% or more of the height H of the annular projection 24 . On the other hand, the depth D of the concave portion 26 is preferably 70% or less of the height H of the annular convex portion 24 in order to maintain the strength of the base 10 and the annular convex portion 24 .

The depth D of the concave portion 26 is the vertical distance from the upper end surface 24a of the annular convex portion to the bottom portion 26a of the concave portion 26. As shown in FIG. The bottom 26a of the recess 26 may not be flat. If the bottom 26a of the recess 26 is not flat, the depth D of the recess 26 is the largest of the vertical distances from the top surface 24a of the annular protrusion to the bottom 26a of the recess 26. The depth D of the concave portion 26 may differ for each position of the annular convex portion 24 .

In addition, as shown in FIG. 4C, the recess 26 is located at the inner or outer end of the annular protrusion 24, and the depth D of the recess 26 is the same as the height H of the annular protrusion 24. , the radial length L of the upper end face 24a of the annular projection at a certain position is different from that of the annular projection at another position, although it is not known from the relevant portion alone whether the annular projection 24 has the recess 26 or not. If the radial length L′ of the upper end surface 24a of the convex portion is different, that is, if the radial length of the upper end surface 24a of the annular convex portion is different depending on the position of the annular convex portion 24, it is within the scope of the present invention. included.

A corner portion connecting the upper end surface 24a of the annular convex portion and the side surface of the concave portion 26 may be provided with a chamfered portion such as a C surface or an R surface. As a result, the friction against the substrate W can be reduced when the substrate W is attached and detached, and the risk of particle generation can be reduced. Further, the inside of the concave portion 26 may be mirror-finished. As a result, adhesion of foreign matter and generation of particles in the concave portion 26 can be suppressed.

The side surface of the concave portion 26 and the side surface of the annular projection 24 may not be flat and may not be perpendicular to the upper end surface 24a of the annular projection. However, in order to prevent the contact rate from increasing rapidly when the annular projection 24 wears, it is preferable that the annular projection intersects the upper end surface 24a of the annular projection at a vertical angle or at an angle close thereto. For example, the angle formed by the upper end surface 24a of the annular projection and the side surface of the recess 26 or the side surface of the annular projection 24 is preferably 90° or more and 130° or less.

Although the circumferential length of one concave portion 26 is not particularly limited, it is preferable that the concave portions 26 have symmetrical arrangement and length in order to hold the substrate W evenly and flatly as a whole. However, if there is a peculiarity in the peripheral shape of the substrate W to be supported (for example, a substrate W that partially differs in thickness, a substrate W that is partially warped, etc.), the recesses 26 may be arranged or arranged according to the shape of the substrate W. You can design the length.

FIG. 5 is a partial schematic diagram showing a modification of the top surface of the substrate holding member according to the embodiment of the present invention. 5 to 7 omit the pin-shaped projection 22 and the vent hole 14. As shown in FIG. As shown in FIG. 5 , adjacent recesses 26 may communicate with narrower recesses 26 . If the concave portion 26 is formed so that the width of the annular convex portion 24 extending in the circumferential direction is constant, the width of the annular convex portion 24 as a whole becomes uniformly small, which leads to a decrease in the strength of the annular convex portion 24. This is not preferable because the risk of particle generation due to damage to the convex portion 24 increases.

6A and 6B are partial schematic diagrams showing modifications of the upper surface 12 of the substrate holding member 100 according to the embodiment of the present invention, respectively. As shown in FIGS. 6(a) and 6(b), at least some of the recesses 26 are preferably connected to the inner region of the annular protrusion 24. As shown in FIGS. In this way, by connecting the concave portion 26 to the inner region of the annular convex portion 24, an attraction force can be generated even on the upper surface of the concave portion, so that the substrate W can be stably attracted. Further, when the substrate W is vacuum-sucked, the atmosphere in the inner region and the recess 26 can be kept in the same pressure state, so that the flatness accuracy of the substrate W can be easily ensured.

When the concave portion 26 is connected to the inner region of the annular convex portion 24, as shown in FIG. Alternatively, as shown in FIG. 6B, a concave portion 26 is formed near the center of the annular convex portion 24, and a portion of the concave portion 26 is formed to communicate with the inner region. , may be connected to the inner region.

7A and 7B are partial schematic diagrams showing modifications of the upper surface 12 of the substrate holding member 100 according to the embodiment of the present invention, respectively. As shown in FIGS. 7(a) and 7(b), at least some of the recesses 26 are preferably connected to the outer region of the annular protrusion 24. As shown in FIGS. Since the recess 26 is connected to the outer region of the annular protrusion 24 in this manner, the atmosphere in the recess 26 becomes the atmospheric state, so that the substrate W can be easily released when the substrate W is detached. In addition, since the concave portion 26 is not connected to the inner region, it is possible to prevent the foreign matter from entering the inner region when the foreign matter remains in the concave portion 26 .

When the concave portion 26 is connected to the outer region of the annular convex portion 24, as shown in FIG. Alternatively, as shown in FIG. 7B, a concave portion 26 is formed near the center of the annular convex portion 24, and a portion of the concave portion 26 is formed to communicate with the outer region. , may be connected to the outer region.

The substrate holding member 100 of the present invention may be constructed by combining the modifications shown in FIGS. However, the concave portion 26 is not configured to connect the inner region and the outer region of the annular convex portion 24 .

In the substrate holding member of the present invention, the contact ratio between the substrate and the upper end surface of the annular protrusion is reduced, and the strength of the annular protrusion is maintained.

[Manufacturing method of substrate holding member]
By a well-known method, a flat plate-like compact is produced from the raw material powder, and the plate-like ceramic sintered compact is obtained by sintering this compact. Although the disk-shaped substrate holding member is illustrated in FIG. 1 and the like, any shape such as a polygonal shape or an elliptical shape may be used. Silicon carbide, aluminum oxide, aluminum nitride and the like are used as the ceramic sintered body.

Next, a vent hole, a pin-shaped protrusion, an annular protrusion, and the like are formed on the upper surface of the ceramic sintered body. As a forming method, it is possible to form by grinding, blasting, milling, laser processing, or the like. Further, after forming the pin-shaped protrusions and the annular protrusions, the upper end surfaces of the respective protrusions may be polished.

A plurality of pin-shaped protrusions are formed. The arrangement, shape, protrusion height, etc. of the pin-shaped protrusion are not particularly limited. Any known form or similar form may be used. For example, the arrangement may be a regular arrangement such as a triangular lattice, a square lattice, or a concentric circle, as well as an irregular arrangement such as local sparseness. It may be placement. Moreover, the shape may be a columnar shape or a conical shape, or may be a stepped shape such that the cross-sectional area of the upper portion is smaller than that of the lower portion. The upper ends of the plurality of pin-shaped protrusions are formed substantially flush. For example, the pin-shaped protrusion has a protrusion amount of 50 μm or more and 200 μm or less, and when the upper end is formed with a flat surface, the diameter of the upper end surface is 100 μm or more and 500 μm or less, and the distance between adjacent pin-shaped protrusions is 1.5 mm or more and 8 mm or less. is preferably designed according to conditions such as the substrate to be adsorbed.

The annular projection is annularly formed along the outer periphery of the upper surface of the base. It is preferable that the amount of protrusion of the annular protrusion from the upper surface of the base is determined according to the amount of protrusion of the pin-shaped protrusion from the upper surface of the base. Depending on the design of the substrate holding member, the upper end surface of the annular projection and the upper ends of the plurality of pin-shaped projections are formed substantially flush, or the upper end surface of the annular projection is formed by a plurality of pin-shaped projections. It is formed so as to have an upper end surface at a position closer to the upper surface of the substrate than the upper end of the portion. When the upper end surface of the annular protrusion is formed to have the upper end surface at a position closer to the upper surface of the base than the upper ends of the plurality of pin-shaped protrusions, for example, the height of the pin-shaped protrusions is 1 μm or more and 5 μm. It is preferable that it is formed as low as below. Moreover, it is preferable that the width of the annular convex portion is formed in the range of 0.05 mm or more and 4 mm or less.

The concave portion is preferably formed after the annular convex portion is formed, but may be formed at the same time as the annular convex portion. Although the concave portion can also be formed by the above processing method, it is preferable to use laser processing in that the concave portion can be easily formed on the narrow annular convex portion.

In this manner, the substrate holding member of the present invention can be manufactured in which the contact ratio between the substrate and the upper end surface of the annular protrusion is reduced and the strength of the annular protrusion is maintained.

It goes without saying that the present invention is not limited to the above-described embodiments, but extends to various modifications and equivalents within the spirit and scope of the present invention. Also, the structure, shape, number, position, size, etc. of the constituent elements shown in each drawing are for convenience of explanation, and may be changed as appropriate.

10 Base 12 Upper surface 14 Ventilation hole 16 Center of base 22 Pin-shaped protrusion 22a Upper end 24 of pin-shaped protrusion Annular protrusion 24a Upper end surface 26 of annular protrusion Recess 26a Bottom 30 Reference surface 100 Substrate holding member W Substrate

Claims (4)

A substrate holding member,
a flat plate-like substrate having one or more air holes opening in the upper surface;
a plurality of pin-shaped protrusions formed so as to protrude upward from the upper surface of the base;
an annular protrusion projecting upward from the upper surface of the base body and formed in an annular shape along the outer periphery of the upper surface;
The annular protrusion has a recess having a bottom at a position closer to the upper surface of the base than the upper end surface of the annular protrusion, and the length in the radial direction of the upper end surface of the annular protrusion is A substrate holding member characterized by being different depending on the position. 2. The substrate holding member according to claim 1, wherein the upper end of said pin-shaped projection and the upper end surface of said annular projection form the same plane. 3. The substrate holding member according to claim 1, wherein at least part of said concave portion is connected to an inner region of said annular convex portion. 3. The substrate holding member according to claim 1, wherein at least part of said concave portion is connected to an outer region of said annular convex portion.

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