Substrate holding member

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

Technical Field

[0001] The present invention relates to a substrate holding member.

Background Art

[0002] Conventionally, in semiconductor manufacturing apparatuses and the like, a substrate holding member that supports a substrate such as a silicon wafer or glass has been used. The base body constituting the substrate holding member supports the back surface of the substrate, and the substrate is supported by evacuating through vent holes formed on the surface of the base body. In recent years, the miniaturization and ultra-high precision of semiconductor products have been progressing. If particles intervene between the base body and the substrate, local swelling of the substrate occurs, and in the circuit pattern formation process by exposing the substrate, problems such as short circuits in the circuit pattern formed on the substrate occur, and the yield of semiconductor products decreases. Therefore, it is necessary to avoid such problems. In order to reduce the risk of particle biting, a substrate holding member with a reduced contact area between the substrate and the base body by using a plurality of pin-shaped convex portions as the region for supporting the substrate has been used.

[0003] Patent Document 1 discloses a vacuum adsorption device having a concave portion on one main surface of a ceramic base, a plurality of protrusions provided on the bottom surface of the concave portion, and using the top surface of the protrusion and one main surface of the ceramic base as a holding surface. In order to minimize the generation of particles caused by the contact between the vacuum adsorption device and the substrate, a vacuum adsorption device with a reduced contact ratio with the substrate is disclosed by making the protrusions tapered.

[0004] Patent Document 2 discloses a substrate adsorption and holding device provided with a plurality of pin-shaped convex portions that are substantially evenly arranged in a negative pressure region that becomes a negative pressure when the substrate is adsorbed and that constitute the support surface of the substrate, and a sealing edge bank portion for sealing the negative pressure region from the outside air and configuring the inside thereof. By making the upper surface of this sealing edge bank portion slightly lower than the support surface so as not to contact the substrate when the substrate is adsorbed, the influence of particle generation due to the contact between the substrate and the sealing edge bank portion is further reduced.

Prior Art Documents

[0005] [Patent Document 1] Japanese Patent Application Publication No. 10-242255 [Patent Document 2] Japanese Patent Publication No. 2001-185607 [Overview of the project] [Problems that the invention aims to solve]

[0006] The vacuum suction device described in Patent Document 1 is formed such that the top surfaces of the multiple protrusions and the top surface of the sealing wall are located on the same plane. Since the substrate is held by the top surfaces of the multiple protrusions and the top surface of the sealing wall, the contact rate between the substrate and the top surface of the sealing wall is increased, and the risk of foreign matter such as particles becoming trapped in that area increases.

[0007] In the substrate adsorption and holding device described in Patent Document 2, the height of the sealing rim is a certain degree lower than the height of the pin-shaped protrusions. As a result, air is constantly flowing in from the outside during the substrate adsorption operation, and this air inflow may allow foreign matter such as particles to enter. If these particles adhere to the back surface of the substrate, they can cause contamination of the substrate, and if they adhere between the holding surface and the substrate, the flatness accuracy of the substrate will be impaired. Furthermore, even if the height of the sealing rim is lower than the height of the pin-shaped protrusions, the substrate may still come into contact with the sealing rim.

[0008] Furthermore, if the overall width of the annular protrusions (such as sealing walls) is uniformly reduced in order to decrease the contact rate with the substrate, it leads to a decrease in the strength of the annular protrusions, increasing the risk of particle generation due to damage to the annular protrusions. On the other hand, if the width of the annular protrusions is uniformly increased in order to ensure strength, it directly leads to an increase in the contact rate, increasing the risk of foreign matter such as particles becoming trapped.

[0009] This invention has been made in view of these circumstances, and aims to provide a substrate holding member that reduces the contact rate between the substrate and the upper end surface of the annular projection while maintaining the strength of the annular projection. [Means for solving the problem]

[0010] (1) In order to achieve the above objective, the present invention First The substrate holding member comprises a flat base having one or more ventilation holes opening on its upper surface, a plurality of pin-shaped protrusions formed projecting upward from the upper surface of the base, and an annular protrusion formed in an annular shape along the outer circumference of the upper surface, wherein the annular protrusion has a bottom portion located closer to the upper surface of the base than the upper end surface of the annular protrusion. Furthermore, it is not connected to the inner region of the annular protrusion. The material has a recess, the radial length of the upper end surface of the annular projection varies depending on the position of the annular projection, and the distance H from the upper surface of the base to the upper end surface of the annular projection and the depth D from the upper end surface of the annular projection to the bottom satisfy the relationship 0.2H ≤ D ≤ 0.7H. The second substrate holding member of the present invention is a substrate holding member comprising: a flat plate-shaped base having one or more ventilation holes opening on its upper surface; a plurality of pin-shaped protrusions formed projecting upward from the upper surface of the base; and an annular protrusion formed in an annular shape along the outer circumference of the upper surface, wherein the annular protrusion has a recess with a bottom located closer to the upper surface of the base than the upper end surface of the annular protrusion, the recess formed in the annular protrusion does not connect the inner region and the outer region of the annular protrusion, the radial length of the upper end surface of the annular protrusion varies depending on the position of the annular protrusion, and the distance H from the upper surface of the base to the upper end surface of the annular protrusion and the depth D from the upper end surface to the bottom of the annular protrusion satisfy the relationship 0.2H ≤ D ≤ 0.7H.

[0011] Thus, the annular projection has a recess with a bottom located closer to the upper surface of the substrate than the upper end surface of the annular projection, and the radial length of the upper end surface of the annular projection varies depending on the position of the annular projection. This reduces the contact rate between the substrate and the upper end surface of the annular projection while maintaining the strength of the annular projection.

[0012] (2) Furthermore, the substrate holding member of the present invention is characterized in that the upper end of the pin-shaped projection and the upper end surface of the annular projection form the same plane.

[0013] Thus, 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 will always be in contact with the substrate. Therefore, the effect of reducing the contact rate between the substrate and the upper end surface of the annular protrusion due to the presence of a recess in the annular protrusion, and the effect of maintaining the strength of the annular protrusion, are more fully realized.

[0014] (3) Furthermore, the substrate holding member of the present invention is characterized in that at least a portion of the recess is connected to the inner region of the annular protrusion.

[0015] In this way, because the recess is connected to the inner region of the annular protrusion, an adhesive force can be generated even on the upper surface of the recess, allowing for stable adsorption of the substrate. Furthermore, when vacuum adsorption of the substrate, the atmosphere in the inner region and the recess can be kept at the same pressure, making it easier to ensure the flatness accuracy of the substrate.

[0016] (4) Furthermore, the substrate holding member of the present invention is characterized in that at least a portion of the recess is connected to the outer region of the annular protrusion.

[0017] In this way, because the recess is connected to the outer region of the annular protrusion, the atmosphere in the recess becomes like air, ensuring that the substrate can be easily removed during attachment and detachment. Furthermore, because the recess is not connected to the inner region, it is possible to prevent foreign matter remaining in the recess from entering the inner region. [Effects of the Invention]

[0018] According to the substrate holding member of the present invention, the contact rate between the substrate and the upper end surface of the annular projection is reduced, while the strength of the annular projection is maintained. [Brief explanation of the drawing]

[0019] [Figure 1] This is a schematic diagram showing an example of the upper surface of a substrate holding member according to an embodiment of the present invention. [Figure 2] (a) and (b) are partial cross-sectional views showing examples of substrate holding members according to embodiments of the present invention. [Figure 3] (a) to (c) are partial cross-sectional views showing examples of radial cross-sections of annular protrusions of substrate holding members according to embodiments of the present invention. [Figure 4](a) to (c) are partial cross-sectional views 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. [Figure 5] It is a partial schematic view showing a modification of the upper surface of a substrate holding member according to an embodiment of the present invention. [Figure 6] (a) and (b) are partial schematic views showing modifications of the upper surface of a substrate holding member according to an embodiment of the present invention. [Figure 7] (a) and (b) are partial schematic views showing modifications of the upper surface of a substrate holding member according to an embodiment of the present invention.

Embodiments for Carrying out the Invention

[0020] Next, embodiments of the present invention will be described with reference to the drawings. For ease of understanding of the description, the same reference numerals are given to the same components in each drawing, and overlapping descriptions are omitted. In the configuration diagrams, the sizes of the respective components are conceptually represented and do not necessarily represent actual dimensional ratios.

[0021] [Embodiment] The substrate holding member according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic view showing an example of the upper surface of a substrate holding member according to an embodiment of the present invention. Also, FIGS. 2(a) and (b) are partial cross-sectional views 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 base body 10 for adsorbing and holding a substrate (wafer) W. The base body 10 is formed in a substantially flat shape by a ceramic sintered body. In addition to being substantially disc-shaped, the base body 10 may have various shapes such as polygonal plate-shaped or elliptical plate-shaped.

[0022] The base body 10 has one or more ventilation holes 14 opening to the upper surface 12. If there are multiple ventilation holes 14, they may communicate with each other via a ventilation path that passes through the inside of the base body 10. The ventilation holes 14 are connected to a vacuum suction device (not shown). The position, shape, and size of the ventilation holes 14 vary depending on the design of the substrate holding member 100, including the shape of the suction surface area determined by the annular protrusions 24 (described later), the shape and type of the substrate W, and the suction force when vacuum suction is applied.

[0023] The base body 10 has an annular projection 24 that protrudes upward from the upper surface 12 and is formed in an annular shape along the outer circumference of the upper surface 12. For example, when the base body 10 is formed in a disc shape, it is preferable that the annular projection 24 is formed continuously in an annular shape when viewed from above, at a predetermined distance from the outer circumference of the upper surface 12 of the base body 10 toward the center.

[0024] The base body 10 has a plurality of pin-shaped protrusions 22 that project upward from the upper surface 12. The pin-shaped protrusions 22 are formed on the inside of the annular protrusion 24. The pin-shaped protrusions 22 may also be formed on the outside of the annular protrusion 24. The plurality of pin-shaped protrusions 22 support the substrate W. The upper ends 22a of the plurality of pin-shaped protrusions are formed substantially flush with the surface. 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 come into contact with the substrate W, and the substrate W is supported. It should be noted that some of the plurality of pin-shaped protrusions 22 may not have their upper ends in contact with the substrate W. This is because even if such pin-shaped protrusions 22 are present, the substrate W can still be supported depending on the arrangement of the surrounding pin-shaped protrusions 22.

[0025] The shape of the pin-shaped projection 22 may be cylindrical, prismatic, truncated cone, truncated pyramidal, etc., or it may have a stepped shape where the cross-sectional area of ​​the upper part is smaller than that of the lower part. The pin-shaped projection 22 may also be a steep truncated cone with a high aspect ratio. The upper end 22a of the pin-shaped projection is preferably a flat surface of a predetermined size. In that case, the maximum diameter of the flat surface of the upper end 22a of the pin-shaped projection is preferably 100 μm or more and 500 μm or less, and the surface roughness of the flat surface of the upper end 22a of the pin-shaped projection is preferably Ra 0.01 μm or more and 0.50 μm or less.

[0026] The arrangement of the pin-shaped protrusions 22 may be regular, such as in a triangular lattice, square lattice, or concentric circles, or it may be an irregular arrangement where localized density occurs. 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 protrusions 22 refers to the distance from the upper surface 12 of the base body 10 to the upper end 22a of the pin-shaped protrusion. Furthermore, the distance between the centers of adjacent pin-shaped protrusions 22 is preferably 1.5 mm or more and 8 mm or less.

[0027] It is preferable that the upper end 22a of the pin-shaped protrusion and the upper end surface 24a of the annular protrusion form the same plane. That is, it is preferable that the height of the annular protrusion 24 is the same as the height of the pin-shaped protrusion 22. In this way, 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 will always be in contact with the substrate W, thus further enhancing the effect of reducing the contact rate between the substrate W and the upper end surface 24a of the annular protrusion due to the annular protrusion 24 having a recess 26, and the effect of maintaining the strength of the annular protrusion 24.

[0028] The height of the annular projection 24 refers to the distance from the upper surface 12 of the base body 10 to the upper end surface 24a of the annular projection. The radial length (width) of the annular projection 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 projection 24 is preferably less than or equal to the distance between the centers of adjacent pin-shaped projections 22. Furthermore, the surface roughness of the upper end surface 24a of the annular projection is preferably Ra 0.01 μm or more and 0.50 μm or less.

[0029] The upper end surface 24a of the annular protrusion may be closer to the upper surface 12 of the base body 10 than the upper end 22a of the pin-shaped protrusion. That is, the height of the annular protrusion 24 may be lower than the height of the pin-shaped protrusion 22. In this case, during the adsorption operation of the substrate W, air will always flow in from outside the base body 10, and the Bernoulli effect will be exerted near the annular protrusion 24, suppressing the sinking of the edges of the substrate W. However, even with this configuration, the substrate W and the upper end surface 24a of the annular protrusion may come into contact depending on the shape and warping of the substrate W. Therefore, by applying the configuration of the present invention, the contact rate 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.

[0030] When the height of the annular protrusion 24 is lower than the height of the pin-shaped protrusion 22, it is preferable that the height of the annular protrusion 24 be 1 μm to 5 μm lower than the height of the pin-shaped protrusion 22. For example, when the height of the pin-shaped protrusion 22 is 100 μm, it is preferable that the height of the annular protrusion 24 be 95 μm to 99 μm.

[0031] Figure 2(a) is a partial cross-sectional view of the radial cross-section of the substrate holding member 100 including the annular protrusion 24 at a position where the recess 26 is not formed. Figure 2(b) is a partial cross-sectional view of the radial cross-section of the substrate holding member 100 including the annular protrusion 24 at a position where the recess 26 is formed. As shown in Figures 1 and 2(a) and (b), the annular protrusion 24 has a recess 26 with a bottom 26a at a position closer to the upper surface 12 of the base body 10 than the upper end surface 24a of the annular protrusion, and the radial length L of the upper end surface 24a 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. This reduces the contact rate between the substrate W and the upper end surface 24a of the annular protrusion, while maintaining the strength of the annular protrusion 24. The radial length L of the upper end surface 24a of the annular protrusion will be described later.

[0032] The recess 26 has a bottom portion 26a located closer to the upper surface 12 of the base 10 than the upper end surface 24a of the annular protrusion. As a result, the radial length L of the upper end surface 24a of the annular protrusion differs at least between the position where the recess 26 is not formed and the position where it is formed.

[0033] Figures 3(a) to 3(c) are partial cross-sectional views showing examples of radial cross-sections of annular protrusions 24 of a substrate holding member 100 according to an embodiment of the present invention. In the case of an annular protrusion 24 where no recess 26 is formed, as shown in Figure 3(a), or in the case of an annular protrusion 24 where a recess 26 is formed at the inner end (or outer end) of the annular protrusion 24, as shown in Figure 3(b), the radial length L of the upper end surface 24a of the annular protrusion is the length of a single line segment represented as the upper end surface 24a of the annular protrusion on the radial cross-section.

[0034] On the other hand, at the location of the annular projection 24 where the recess 26 is formed closer to the center of the annular projection 24, as shown in Figure 3(c), the radial length L of the upper end surface 24a of the annular projection is the sum of the lengths of two or more line segments that are represented as the upper end surface 24a of the annular projection on the radial cross-section. In the example of Figure 3(c), L = L1 + L2. The width of the upper end surface 24a of the annular projection at the location where the recess 26 is formed (the width of each if it is divided into two or more parts by the recess) is preferably 0.02 mm or more, and more preferably 0.05 mm or more from the viewpoint of further ensuring the strength of that part.

[0035] The width of the upper surface of the recess 26 (the difference between the radial length of the upper end surface 24a of the annular protrusion where the recess is not formed and the radial length of the upper end surface 24a of the annular protrusion where the recess 26 is formed) depends on the width of the annular protrusion 24, but in order to maintain the strength of the annular protrusion 24, it is preferable that it 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. The width of the upper surface of the recess 26 may differ at each position of the annular protrusion 24.

[0036] Figures 4(a) to 4(c) are partial cross-sectional views showing examples of radial cross-sections of the annular projection 24 of the substrate holding member 100 according to an embodiment of the present invention. The depth D of the recess 26 depends on the height of the annular projection 24, but is preferably 20% or more of the height H of the annular projection 24 so that it can perform its function even when the annular projection 24 is worn, or so that particles remaining in the recess 26 do not adhere to the substrate W. On the other hand, the depth D of the recess 26 is preferably 70% or less of the height H of the annular projection 24 in order to maintain the strength of the base body 10 and the annular projection 24.

[0037] The depth D of the recess 26 is the vertical distance from the upper end surface 24a of the annular protrusion to the bottom 26a of the recess 26. The bottom 26a of the recess 26 does not have to be a plane. If the bottom 26a of the recess 26 is not a plane, the depth D of the recess 26 is the largest value among the vertical distances from the upper end surface 24a of the annular protrusion to the bottom 26a of the recess 26. The depth D of the recess 26 may differ for each position of the annular protrusion 24.

[0038] Furthermore, as shown in Figure 4(c), if the recess 26 is located at the inner or outer end of the annular projection 24, and the depth D of the recess 26 is formed to be the same as the height H of the annular projection 24, then it is not possible to determine from that portion alone whether the annular projection 24 has a recess 26. However, if the radial length L of the upper end surface 24a of the annular projection at one position is different from the radial length L' of the upper end surface 24a of the annular projection at another position, that is, if the radial length of the upper end surface 24a of the annular projection differs depending on the position of the annular projection 24, then this falls within the scope of the present invention.

[0039] The corner connecting the upper end surface 24a of the annular protrusion and the side surface of the recess 26 may have a chamfered portion such as a C-face or R-face. This reduces friction with the substrate W when attaching and detaching the substrate W, thereby reducing the risk of particle generation. The inside of the recess 26 may also be mirror-finished. This suppresses the adhesion of foreign matter and the generation of particles within the recess 26.

[0040] The sides of the recess 26 and the sides of the annular projection 24 do not have to be flat, nor do they have to be perpendicular to the upper end surface 24a of the annular projection. However, it is preferable that they intersect the upper end surface 24a of the annular projection at an angle perpendicular or close to perpendicular, so that the contact ratio does not increase rapidly when the annular projection 24 is worn. For example, it is preferable that the angle between the upper end surface 24a of the annular projection and the side of the recess 26 or the side of the annular projection 24 is between 90° and 130°.

[0041] The circumferential length of a single recess 26 is not particularly limited, but it is preferable that the arrangement and length of the recesses 26 be symmetrical in order to hold the substrate W evenly and flatly overall. However, if the outer periphery shape of the substrate W to be supported (for example, a substrate W with partially different thicknesses, a substrate W with some warping, etc.) is unique, the arrangement and length of the recesses 26 may be designed to match the shape of the substrate W.

[0042] Figure 5 is a partially schematic diagram showing a modified example of the upper surface of a substrate holding member according to an embodiment of the present invention. Note that the pin-shaped protrusions 22 and ventilation holes 14 are omitted in Figures 5 to 7. As shown in Figure 5, adjacent recesses 26 may be connected by recesses 26 that are narrower than each other. Note that if the recesses 26 are formed so that the width of the annular protrusion 24 extending in the circumferential direction is constant, the overall width of the annular protrusion 24 will become uniformly smaller, which will lead to a decrease in the strength of the annular protrusion 24 and an increased risk of particle generation due to damage to the annular protrusion 24, so this is undesirable.

[0043] Figures 6(a) and 6(b) are partial schematic diagrams showing modified examples of the upper surface 12 of the substrate holding member 100 according to an embodiment of the present invention. As shown in Figures 6(a) and 6(b), it is preferable that at least some of the recesses 26 are connected to the inner region of the annular protrusion 24. By connecting the recesses 26 to the inner region of the annular protrusion 24 in this way, an adsorption force can be generated even on the upper surface of the recesses, thereby enabling stable adsorption of the substrate W. Furthermore, when vacuum adsorption of the substrate W, the atmosphere in the inner region and the recesses 26 can be kept at the same pressure, making it easier to ensure the flatness accuracy of the substrate W.

[0044] When the recess 26 is connected to the inner region of the annular projection 24, the entire recess 26 may be formed at the inner end of the annular projection 24, as shown in Figure 6(a), thereby connecting to the inner region, or, as shown in Figure 6(b), the recess 26 may be formed closer to the center of the annular projection 24, with a portion of the recess 26 that communicates with the inner region being formed, thereby connecting to the inner region.

[0045] Figures 7(a) and 7(b) are partial schematic diagrams showing modified examples of the upper surface 12 of the substrate holding member 100 according to an embodiment of the present invention. As shown in Figures 7(a) and 7(b), it is preferable that at least some of the recesses 26 are connected to the outer region of the annular protrusion 24. By connecting the recesses 26 to the outer region of the annular protrusion 24 in this way, the atmosphere in the recesses 26 becomes like air, thus ensuring that the substrate W can be easily removed when the substrate W is attached or detached. Furthermore, because the recesses 26 are not connected to the inner region, it is possible to prevent foreign matter from entering the inner region if foreign matter remains in the recesses 26.

[0046] When the recess 26 is connected to the outer region of the annular protrusion 24, the entire recess 26 may be formed at the outer end of the annular protrusion 24, as shown in Figure 7(a), thereby connecting to the outer region, or, as shown in Figure 7(b), the recess 26 may be formed closer to the center of the annular protrusion 24, with a portion of the recess 26 that communicates with the outer region being formed, thereby connecting to the outer region.

[0047] The substrate holding member 100 of the present invention may be constructed by combining the modified examples shown in Figures 5 to 7. However, the recess 26 is not configured to connect the inner and outer regions of the annular protrusion 24.

[0048] The substrate holding member of the present invention reduces the contact rate between the substrate and the upper end surface of the annular projection while maintaining the strength of the annular projection.

[0049] [Manufacturing method for substrate holding member] A flat molded body is produced from raw material powder using a well-known method, and a flat ceramic sintered body is obtained by firing this molded body. Although a disc-shaped substrate holder is shown in Figure 1, any shape is acceptable, such as polygonal or elliptical. Silicon carbide, aluminum oxide, and aluminum nitride are used as the ceramic sintered body.

[0050] Next, ventilation holes, pin-shaped protrusions, annular protrusions, etc., are formed on the upper surface of the ceramic sintered body. These can be formed by grinding, blasting, milling, laser processing, etc. Alternatively, the upper end surfaces of the pin-shaped protrusions and annular protrusions may be polished after they have been formed.

[0051] Multiple pin-shaped protrusions are formed. The arrangement, shape, and protrusion height of the pin-shaped protrusions are not particularly limited. They may be known forms or similar forms. For example, the arrangement may be regular, such as on a triangular grid, a square grid, or concentric circles, or it may be an irregular arrangement where density varies locally. The shape may be columnar or conical, and it may also be a stepped shape where the cross-sectional area of ​​the upper part is smaller than that of the lower part. The upper ends of the multiple pin-shaped protrusions are formed to be substantially flush. Preferably, the pin-shaped protrusions are designed according to the conditions of the substrate to be adsorbed, for example, with a protrusion amount of 50 μm to 200 μm, a diameter of the upper end surface of 100 μm to 500 μm if the upper end is formed as a plane, and a spacing between adjacent pin-shaped protrusions of 1.5 mm to 8 mm.

[0052] The annular protrusion is formed in an annular shape along the outer circumference of the upper surface of the base. Preferably, the amount of the annular protrusion protruding from the upper surface of the base is determined according to the amount of the pin-shaped protrusion protruding from the upper surface of the base. Depending on the design of the substrate holding member, the upper end surface of the annular protrusion and the upper ends of the multiple pin-shaped protrusions are formed to be substantially flush, or the upper end surface of the annular protrusion is formed to be closer to the upper surface of the base than the upper ends of the multiple pin-shaped protrusions. When the upper end surface of the annular protrusion is formed to be closer to the upper surface of the base than the upper ends of the multiple pin-shaped protrusions, for example, it is preferable that it be formed to be 1 μm to 5 μm lower than the height of the pin-shaped protrusions. Furthermore, it is preferable that the width of the annular protrusion is formed in the range of 0.05 mm to 4 mm.

[0053] The recess is preferably formed after the annular protrusion is formed, but it may also be formed at the same time as the annular protrusion. The recess can also be formed by the processing method described above, but laser processing is preferred because it makes it easier to form the recess on a narrow annular protrusion.

[0054] In this way, the substrate holding member of the present invention can be manufactured in which the contact rate between the substrate and the upper end surface of the annular protrusion is reduced while maintaining the strength of the annular protrusion.

[0055] The present invention is not limited to the embodiments described above, and it goes without saying that it extends to various modifications and equivalents that fall within the spirit and scope of the present invention. Furthermore, the structure, shape, number, position, size, etc., of the components shown in each drawing are for illustrative purposes only and may be modified as appropriate. [Explanation of symbols]

[0056] 10 Base 12 Top side 14 Ventilation holes 16 Center of the substrate 22 Pin-shaped protrusion 22a Upper end of pin-shaped protrusion 24 Annular protrusion 24a Upper end surface of the annular protrusion 26 recesses 26a bottom 30 Reference plane 100 Substrate holding member W board

Claims

1. A substrate holding member, A flat plate-shaped base having one or more ventilation holes opening on its upper surface, Multiple pin-shaped protrusions are formed projecting upward from the upper surface of the base, The base comprises an annular projection that protrudes upward from the upper surface and is formed in an annular shape along the outer circumference of the upper surface, The annular projection has a bottom portion located closer to the upper surface of the base than the upper end surface of the annular projection, and has a recess that is not connected to the inner region of the annular projection, and the radial length of the upper end surface of the annular projection varies depending on the position of the annular projection. The distance H from the upper surface of the base to the upper end surface of the annular projection, and the depth D from the upper end surface of the annular projection to the bottom are, 0.2H≦D≦0.7H A substrate holding member characterized by satisfying the following relationship.

2. A substrate holding member, A flat plate-shaped base having one or more ventilation holes opening on its upper surface, Multiple pin-shaped protrusions are formed projecting upward from the upper surface of the base, The base comprises an annular projection that protrudes upward from the upper surface and is formed in an annular shape along the outer circumference of the upper surface, The annular projection has a recess with a bottom located closer to the upper surface of the base than the upper end surface of the annular projection, and the recess formed in the annular projection does not connect the inner region and the outer region of the annular projection, and the radial length of the upper end surface of the annular projection varies depending on the position of the annular projection. The distance H from the upper surface of the base to the upper end surface of the annular projection, and the depth D from the upper end surface of the annular projection to the bottom are, 0.2H≦D≦0.7H A substrate holding member characterized by satisfying the following relationship.

3. The substrate holding member according to claim 1 or 2, characterized in that the upper end of the pin-shaped projection and the upper end surface of the annular projection form the same plane.

4. The substrate holding member according to claim 1 or 2, characterized in that at least a portion of the recess is connected to the outer region of the annular protrusion.

Images