Holding device

Abstract

The holding device equalizes the temperature distribution of the workpiece it holds. [Solution] The holding device 1 includes a plate-shaped member 10 having a first surface S1 and a second surface S2 for holding a wafer W. The plate-shaped member 10 has a groove 50 that is recessed from the first surface S1 toward the second surface S2, and a gas channel 11 that penetrates the bottom 50B of the groove 50 and the second surface S2, through which a thermally conductive gas can pass. An outlet hole 112, which is the outlet for the thermally conductive gas in the gas channel 11, is formed at the bottom 50B of the groove 50. When the first surface S1 is viewed in plan view, the center position P2 of the outlet hole 112 and the center position P1 of the groove 50 are located at different positions.

Description

Technical Field

[0001] The present disclosure relates to a holding device.

Background Art

[0002] As an example of a holding device for holding a wafer when manufacturing a semiconductor, an electrostatic chuck is known. The electrostatic chuck generally includes a ceramic substrate and a base member for cooling the ceramic substrate, and is configured to hold a wafer on the surface of the ceramic substrate by electrostatic attraction. The ceramic substrate and the base member are joined to each other by a bonding layer interposed therebetween. The ceramic substrate is cooled by heat transfer (heat removal) between the base member and the ceramic substrate through the bonding layer.

[0003] In this type of electrostatic chuck, in plasma processing such as plasma etching, a heat-conductive gas such as helium gas is supplied between the ceramic substrate and the wafer to remove heat from the wafer. Therefore, inside the ceramic substrate of the electrostatic chuck, a pipe for flowing the heat-conductive gas supplied from the outside toward the wafer is formed so as to extend from the back surface of the ceramic substrate to the surface on which the wafer is placed.

[0004] Patent Document 1 discloses an electrostatic chuck in which grooves are formed so as to retreat from the surface of the ceramic substrate toward the opposite surface on the opposite side thereof, and gas holes extending from the back surface of the ceramic substrate toward the surface are formed in the grooves. Such grooves are formed to quickly diffuse the gas supplied from the gas holes into the space formed between the surface of the ceramic substrate and the wafer. In this electrostatic chuck, in a plan view, the position of the center of the groove and the position where the central axis of the gas outlet portion of the gas holes are arranged are arranged at the same position.

[0005] Furthermore, Patent Document 2 discloses an electrostatic chuck comprising a recessed groove corresponding to the groove described above, and a plug placement hole that penetrates the ceramic substrate in the thickness direction and opens to the bottom surface of the recessed groove, wherein a porous plug that allows gas flow is placed in the plug placement hole. Such a porous plug is provided to suppress dielectric breakdown occurring during plasma processing inside the linearly extending gas hole. In this electrostatic chuck, in a plan view, the position of the center of the recessed groove and the position of the center of the porous plug exposed to the bottom surface of the recessed groove are located at the same position. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 7494973 [Patent Document 2] Patent No. 7546160 [Overview of the project] [Problems that the invention aims to solve]

[0007] In ceramic substrates, areas with grooves, gas holes, and porous plugs experience less heat transfer due to the ceramics compared to other parts of the substrate. Therefore, a temperature difference is likely to occur between the areas with grooves, gas holes, and porous plugs and the areas without them. Furthermore, if the gas pressure of the thermal conductive gas passing through the gas holes and porous plugs (which are outlets for the thermal conductive gas at the bottom of the grooves) is relatively high, the thermal conductive gas may forcefully strike the areas of the wafer facing the grooves, gas holes, and porous plugs, making those areas more susceptible to the temperature influence of the thermal conductive gas than other parts of the wafer. In other words, areas of a ceramic substrate with grooves, gas holes, and porous plugs tend to become temperature-specific areas with temperatures different from other parts of the substrate. To achieve uniform processing accuracy, such as etching, it is preferable that the temperature of the entire wafer be uniform during processing.

[0008] This disclosure aims to equalize the temperature distribution of a workpiece held by a holding device. [Means for solving the problem]

[0009] The holding device according to this disclosure comprises a plate-shaped member having a first surface for holding a workpiece and a second surface located on the opposite side of the first surface, wherein the plate-shaped member has a groove that is recessed from the first surface toward the second surface, and a gas passage that penetrates the bottom of the groove and the second surface, through which gas can pass, and an outlet hole is formed at the bottom of the groove, which is the outlet of the gas in the gas passage that penetrates the bottom and the second surface, through which gas can pass from the second surface toward the bottom, and when the first surface is viewed in plan view, the position of the center of the outlet hole and the position of the center of the groove are located at different positions. [Effects of the Invention]

[0010] According to this disclosure, the temperature distribution of the workpiece held by the holding device can be made uniform. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a schematic diagram illustrating the general configuration of the holding device according to the first embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view showing the internal structure of the holding device according to the first embodiment. [Figure 3] Figure 3 is a schematic cross-sectional view showing an enlarged view of the second circumferential groove and the area around the outlet hole of the gas flow path formed at its bottom. [Figure 4] Figure 4 is a schematic plan view showing an enlarged view of the circular groove and the area around the outlet hole of the gas flow path formed at its bottom. [Figure 5] Figure 5 is a schematic plan view showing an enlarged view of the second circumferential groove and the area around the outlet hole of the gas flow path formed at its bottom. [Figure 6]Figure 6 is a schematic cross-sectional view showing an enlarged view of the second circumferential groove portion and the area around the outlet hole of the gas flow path formed at its bottom according to the second embodiment. [Figure 7] Figure 7 is a schematic cross-sectional view showing an enlarged view of the second circumferential groove and the area around the outlet hole of the gas flow path formed at its bottom according to the third embodiment. [Figure 8] Figure 8 is a schematic cross-sectional view showing an enlarged view of the second circumferential groove and the area around the outlet hole of the gas flow path formed at its bottom according to the fourth embodiment. [Figure 9] Figure 9 is a schematic cross-sectional view showing an enlarged view of the second circumferential groove and the area around the outlet hole of the gas flow path formed at its bottom according to the fifth embodiment. [Figure 10] Figure 10 is a schematic cross-sectional view showing an enlarged view of the second circumferential groove and the area around the outlet hole of the gas flow path formed at its bottom according to the sixth embodiment. [Figure 11] Figure 11 is a schematic plan view showing an enlarged view of the circular groove portion and the area around the outlet hole of the gas flow path formed at its bottom according to the seventh embodiment. [Figure 12] Figure 12 is a schematic cross-sectional view showing an enlarged view of the second circumferential groove and the area around the outlet hole of the gas flow path formed at its bottom according to the eighth embodiment. [Modes for carrying out the invention]

[0012] First, embodiments of this disclosure will be listed and described. (1) The holding device according to the present disclosure comprises a plate-shaped member having a first surface for holding a workpiece and a second surface located on the opposite side of the first surface, wherein the plate-shaped member has a groove that is recessed from the first surface toward the second surface, and a gas passage that penetrates the bottom of the groove and the second surface and through which gas can pass, and an outlet hole is formed at the bottom of the groove, which is the outlet of the gas in the gas passage that penetrates the bottom and the second surface and through which gas can pass from the second surface toward the bottom, and when the first surface is viewed in plan view, the position of the center of the outlet hole and the position of the center of the groove are located at different positions.

[0013] In the plate-shaped member, since the inner region of the groove portion and the inner region of the gas flow path are spaces where the material constituting the plate-shaped member is not arranged, heat drawing (heat transfer) by the material constituting the plate-shaped member is likely to be difficult to occur. The holding device according to the present disclosure can provide the space related to the inner region of the gas flow path at a position shifted from the center position of the space related to the inner region of the groove portion by arranging the center position of the groove portion and the center position of the outlet hole at different positions when the first surface is viewed in a plane. In this case, the position where the space related to the inner region of the gas flow path is provided is deviated with respect to the space related to the inner region of the groove portion, as compared with the case where the center position of the groove portion and the center position of the outlet hole are arranged aligned at the same position when the first surface is viewed in a plane. Although a minute temperature gradient is likely to occur in the peripheral portion of the outlet hole at the bottom of the groove portion, heat transfer is performed in the peripheral portion of the outlet hole so that the temperature gradient becomes gentle. As a result, the temperature distribution of the peripheral portion of the outlet hole and the entire inner region of the groove portion is likely to become uniform. In this way, the holding device according to the present disclosure can uniformize the temperature distribution of the workpiece held by the holding device by uniformizing the temperature distribution of the peripheral portion of the outlet hole and the inner region of the groove portion.

[0014] (2) In the holding device according to (1), when the first surface is viewed in a plane, it is preferable that the width of the groove portion is made larger than the diameter of the outlet hole.

[0015] In this case, since the gas flowing out from the outlet hole can sufficiently spread in the inner region of the groove portion having a width larger than the diameter of the outlet hole, the gas flowing out from the outlet hole is suppressed from directly heading toward the workpiece. Therefore, the temperature distribution of the workpiece is made uniform.

[0016] (3) In the holding device according to (1) or (2), it is preferable that the length of the groove depth in which the groove portion is recessed from the first surface toward the second surface side to the bottom is shorter than the length of the gas flow path extending from the second surface to the outlet hole.

[0017] The groove is formed so that its opening is exposed on the first surface, and it becomes a spatial region facing the workpiece. Therefore, the longer the groove depth, the more difficult it becomes to ensure the heat transfer effect of the material constituting the plate-like member in the groove. On the other hand, the gas flow path is formed inside the plate-like member, and the material constituting the plate-like member is arranged around it. For this reason, increasing the length of the gas flow path has less impact on the heat transfer effect of the material constituting the plate-like member than increasing the groove depth. By making the groove depth shorter than the length of the gas flow path, the portion of the plate-like member where the groove and gas flow path are formed is suppressed from becoming a temperature-specific portion relative to other parts of the plate-like member.

[0018] (4) In the holding device described in any of (1) to (3), a porous plug made of a porous material may be placed inside a part or all of the gas flow path.

[0019] In this case, the flow velocity of the gas as it flows out of the outlet hole is suppressed, preventing the gas from forcefully hitting the grooves, outlet holes, and parts of the workpiece facing the porous plug. Therefore, the temperature distribution of the workpiece is made more uniform.

[0020] In the holding device described in (5)(4), if the porous plug is arranged in the region of the gas flow path that includes the outlet hole, it is preferable that the position of the center of the porous plug and the position of the center of the groove are at different locations when the first surface is viewed in a planar view.

[0021] In this case, the porous plug is positioned at a location offset from the center of the space within the groove. Compared to the case where the center of the groove and the center of the porous plug are aligned at the same position when the first surface is viewed in a plane, the location of the gas-permeable area provided by the porous plug is biased relative to the space within the groove. As a result, a small temperature gradient is more likely to occur around the porous plug at the bottom of the groove. However, heat transfer occurs around the porous plug to balance this temperature gradient, and as a result, the temperature distribution around the porous plug and the entire space within the groove becomes more uniform.

[0022] (6) In the holding device described in any of (1) to (5), the outlet hole may be formed by a plurality of holes.

[0023] When an outlet hole is formed by multiple holes, the amount of gas flowing out from each of the multiple holes is less than the amount of gas flowing out from a single outlet hole. This suppresses the forceful impact of the gas on the part of the workpiece facing the outlet hole. Consequently, the temperature distribution of the workpiece becomes more uniform.

[0024] (7) In the holding device described in any of (1) to (6), it is preferable that a plurality of outlet holes corresponding to each of the plurality of gas passages are formed in one groove, and when the first surface is viewed in plan view, the positions of the centers of each of the plurality of outlet holes are arranged to be in a different positional relationship with respect to the center of the groove.

[0025] In this case, when multiple outlet holes are formed in the groove, the temperature distribution across the entire inner region of the groove tends to become more uniform.

[0026] <Details of the first embodiment of this disclosure> A schematic configuration of the first embodiment of this disclosure will be described with reference to Figures 1 to 5. This disclosure is not limited to these examples, but is intended to include all modifications within the meaning and scope of the claims as indicated by the claims. In the following description, for multiple identical components, only some components may be reference-labeled, while the reference numerals for others may be omitted. In this specification, the configuration of the holding device 1 is described with the positive Z-axis direction as the upward direction, the negative Z-axis direction as the downward direction, and the XY plane direction as the horizontal direction, but the actual usage embodiment of the holding device 1 may have a different configuration. In this specification, "horizontal" and "parallel" also include configurations that are substantially perceived as horizontal and parallel.

[0027] The holding device 1 of the first embodiment is an electrostatic chuck capable of adsorbing and holding a workpiece (hereinafter referred to as "wafer W"). The workpiece is a semiconductor wafer, a glass substrate, etc. The electrostatic chuck is installed, for example, inside the processing chamber of a semiconductor manufacturing apparatus (not shown) and used to perform various processes on the wafer W, such as film deposition and etching, using plasma.

[0028] The holding device 1 of the first embodiment comprises a plate-shaped member 10 and a base member 20, as shown in Figure 1. The plate-shaped member 10 and the base member 20 are bonded to each other by an adhesive layer 30 disposed between the plate-shaped member 10 and the base member 20. The adhesive layer 30 is made of an adhesive such as a silicone resin, acrylic resin, or epoxy resin.

[0029] The plate-shaped member 10 is a plate-shaped member that is substantially circular when viewed in the Z-axis direction and has insulating properties. In the first embodiment, the plate-shaped member 10 has a shape having, for example, a diameter of about 300 mm and a thickness of about 3 mm. The plate-shaped member 10 is formed of a ceramic whose main component is, for example, alumina (Al2O3) or aluminum nitride (AlN). In this specification, "main component" means that the component present in the largest proportion.

[0030] The plate-shaped member 10 has a first surface S1 for holding the wafer W and a second surface S2, shown in Figure 2, located on the opposite side of the first surface S1. The first surface S1 and the second surface S2 are substantially circular surfaces extending in a direction perpendicular to the Z-axis direction (XY plane direction, horizontal direction). The first surface S1 is located on the upper side of the plate-shaped member 10, and the second surface S2 is located on the lower side of the plate-shaped member 10.

[0031] A chuck electrode 55, made of a conductive material including tungsten and molybdenum, is arranged inside the plate-shaped member 10. The chuck electrode 55 is, for example, planar and substantially parallel to the first surface S1. The chuck electrode 55 is provided with a power supply terminal (not shown), and an electrostatic attraction force is generated when power is supplied to the chuck electrode 55 from an external power source via the power supply terminal. This electrostatic attraction force causes the wafer W to be attracted and held on the first surface S1.

[0032] As shown in Figure 1, the base member 20 is a roughly disc-shaped member. The base member 20 is a disc with a larger diameter than the plate-shaped member 10, and is shaped for example with a diameter of about 340 mm and a thickness of about 20 mm. The base member 20 is formed from a metal such as aluminum or an aluminum alloy, a ceramic mainly composed of silicon carbide (SiC), alumina, aluminum nitride, etc., or a composite material of metal and ceramic.

[0033] As shown in Figure 2, the base member 20 has a third surface S3 located on the side of the plate-shaped member 10 and a fourth surface S4 located on the opposite side of the third surface S3. The third surface S3 and the fourth surface S4 are both substantially circular surfaces extending in directions perpendicular to the Z-axis direction (XY plane direction, horizontal direction). The third surface S3 is located on the upper side of the base member 20, and the fourth surface S4 is located on the lower side of the base member 20. The third surface S3 is bonded to the second surface S2 of the plate-shaped member 10 by an adhesive layer 30.

[0034] A flow channel 28 is formed inside the base member 20. The flow channel 28 is formed inside the base member 20, for example, in a helical shape in a plan view. A portion of the flow channel 28 has an end portion 28B that extends from the helical portion toward the fourth surface S4 of the base member 20, and this end portion 28B is connected to a refrigerant circulation device (not shown). The refrigerant circulation device is configured to circulate a refrigerant through the flow channel 28. The refrigerant can be a fluorine-based inert liquid, water, or the like. When the refrigerant flows through the flow channel 28, the base member 20 is cooled. The plate-shaped member 10 is cooled by heat transfer between the base member 20 and the plate-shaped member 10 via the adhesive layer 30. This controls the temperature of the wafer W held on the first surface S1 of the plate-shaped member 10. Note that the flow channel 28 may contain not only a refrigerant, but also various heat transfer media, such as a heating medium for transferring heat to the base member 20 to warm it. Although the channel 28 is formed to be rectangular in the XZ plane cross-sectional view as shown in Figure 2, the channel 28 may also be formed to have other shapes such as circular or elliptical.

[0035] The adhesive layer 30 is disposed between the second surface S2 of the plate-shaped member 10 and the third surface S3 of the base member 20. The thickness of the adhesive layer 30 is, for example, about 0.1 mm to 1 mm. The adhesive layer 30 is composed of an adhesive having a predetermined thermal conductivity and thermal expansion properties. As the adhesive constituting the adhesive layer 30, an organic resin material, a metal adhesive material, or an inorganic adhesive material can be used. Organic resin materials include, for example, silicone resins, fluororesins, acrylic resins, and epoxy resins. Metal adhesive materials include, for example, metals such as aluminum and aluminum alloys. Inorganic adhesive materials include, for example, those mainly composed of ceramics and inorganic polymers.

[0036] With the plate-shaped member 10 facing the base member 20, the second surface S2 of the plate-shaped member 10 and the third surface S3 of the base member 20 are bonded together by the adhesive layer 30.

[0037] As shown in Figure 1, the first surface S1 of the plate-shaped member 10 has various grooves 50 formed therein that are recessed in the Z-axis direction from the first surface S1 toward the second surface S2. The grooves 50 include radial grooves 51 and circumferential grooves 52. The radial grooves 51 extend linearly in the radial direction of the first surface S1 and include three grooves formed at approximately equal intervals in the circumferential direction of the first surface S1. The circumferential grooves 52 extend in an annular shape in the circumferential direction of the first surface S1 and include two grooves, a first circumferential groove 521 and a second circumferential groove 522.

[0038] The first circumferential groove 521 is a single groove formed as an annular depression on the first surface S1 in a plan view. The second circumferential groove 522 is positioned radially outward from the first circumferential groove 521 and is a single groove formed as an annular depression on the first surface S1 in a plan view. This is just an example; for example, the circumferential groove 52 may include only one annular groove or may include three or more annular grooves. The inner radial ends of each of the three radial grooves 51 are positioned to overlap with the first circumferential groove 521. The outer radial ends of each of the three radial grooves 51 are positioned to overlap with the second circumferential groove 522. In this embodiment, each of the three radial grooves 51 is formed at approximately equal intervals in the circumferential direction of the first surface S1 so as to connect the first circumferential groove 521 and the second circumferential groove 522. This is just an example, and the ends of each of the three radial grooves 51 do not necessarily have to be connected to either or both of the first circumferential groove 521 and the second circumferential groove 522. Also, the three radial grooves 51 on the first surface S1 may be formed randomly rather than at equal intervals. Furthermore, the number of radial grooves 51 is just an example, and there may be four or more radial grooves 51 on the first surface S1. Also, there may be two or fewer radial grooves 51 on the first surface S1, or there may be no radial grooves 51 at all on the first surface S1. In this embodiment, the portion where each of the three radial grooves 51 connects to the second circumferential groove 522 is formed to spread out in a circular shape in plan view. This portion is designated as a circular groove 53. However, a circular groove 53 does not necessarily have to be formed in the portion where the radial groove 51 and the second circumferential groove 522 connect.

[0039] Multiple outlet holes 112, which are the outlets for gas in the gas flow path 11, are formed at the bottom 50B of these grooves 50. As shown in Figures 2 and 3, an inlet hole 111, which is the entrance for gas in the gas flow path 11, is formed on the second surface S2. The inlet hole 111 and the outlet hole 112 are positioned to overlap in a plan view, and by connecting the inlet hole 111 and the outlet hole 112, a gas flow path 11 is formed that penetrates the plate-shaped member 10 in the vertical direction (Z-axis direction). That is, the gas flow path 11 penetrates the bottom 50B of the grooves 50 and the second surface S2 in the thickness direction of the plate-shaped member 10, and is formed so that gas can pass from the second surface S2 towards the first surface S1.

[0040] As shown in Figure 2, in the base member 20, a gas inlet hole 21 is formed at a position that overlaps with the gas flow path 11 in a plan view, so as to penetrate the base member 20 vertically. In the adhesive layer 30, a gas flow hole 31 is formed at a position that overlaps with the gas flow path 11 and the gas inlet hole 21 in a plan view, so as to penetrate the adhesive layer 30 vertically. The gas inlet hole 21, the gas flow hole 31, and the gas flow path 11 are provided in the holding device 1 to supply a thermally conductive gas from the fourth surface S4 side of the base member 20 toward the first surface S1 side of the plate-shaped member 10.

[0041] The thermally conductive gas that flows in through the gas inlet hole 21, passes through the gas flow hole 31 and the gas channel 11, flows out through the outlet hole 112 and mainly flows along the radial groove 51, the circumferential groove 52 and the circular groove 53. This makes it easier for the thermally conductive gas to spread uniformly to both the central and outer parts of the first surface S1. The thermally conductive gas that has spread on the first surface S1 in this way fills the space formed between the lower surface of the wafer W and the first surface S1, thereby improving the thermal conductivity between the lower surface of the wafer W and the first surface S1. In this embodiment, helium gas is used as the thermally conductive gas, but a different type of gas may be used as the thermally conductive gas.

[0042] The detailed structure of the plate-like member 10 will now be described. As shown in Figure 3, a flat portion 12, a plurality of dots 13, and a sealing band 14 are formed on the upper surface of the plate-like member 10, and these constitute the first surface S1. The flat portion 12 is a surface that extends substantially parallel to the second surface S2 of the plate-like member 10. The plurality of dots 13 are, for example, cylindrical in shape and protrude from the flat portion 12 in the direction opposite to the second surface S2. Since the plurality of dots 13 are minute protrusions, in Figure 3, for the sake of illustration, the plurality of dots 13 are shown larger than their actual size. In this embodiment, each of the plurality of dots 13 is arranged in a grid pattern with respect to the flat portion 12. Each of the plurality of dots 13 may be arranged at predetermined intervals in a concentric circle pattern centered on the center of the circle formed by the first surface S1.

[0043] The sealing band 14 is formed on the outer peripheral edge of the first surface S1 as an outer wall that demarcates the space formed between the lower surface of the wafer W and the first surface S1. The sealing band 14 protrudes from the flat portion 12 in the direction opposite to the second surface S2. The wafer W is held by the tips of the multiple dots 13 and the tips of the sealing band 14. By appropriately selecting the height, number, shape, etc. of the multiple dots 13 relative to the flat portion 12, and the height, shape, etc. of the sealing band 14, for example, the adhesion of particles to the wafer W is suppressed.

[0044] Each of the grooves 50, consisting of a radial groove 51, a circumferential groove 52, and a circular groove 53, is positioned radially inward from the seal band 14 on the first surface S1. Figure 3 shows the detailed configuration of the grooves 50 and the gas flow path 11 formed in the grooves 50, using the second circumferential groove 522 as an example. As shown in Figure 3, the grooves 50 are formed such that their bottom portion 50B is positioned closer to the second surface S2 than to the flat portion 12 of the first surface S1. In other words, on the first surface S1, the grooves 50 are formed in a shape that is deeper than the flat portion 12. The bottom portion 50B of the grooves 50 extends substantially parallel to the flat portion 12. The bottom portion 50B may have a portion that does not extend parallel to the flat portion 12, for example, by being formed to have a rounded shape in an XZ planar cross-sectional view. As described above, an outlet hole 112 for the gas flow path 11 is formed at the bottom 50B of the groove 50. The thermal conductive gas supplied to the gas flow path 11 via the gas inlet hole 21 and the gas flow hole 31, and which flows out from the outlet hole 112, flows along the groove 50 and overflows onto the flat portion 12 of the first surface S1. The thermal conductive gas that overflows onto the flat portion 12 can pass between the multiple dots 13 and spread throughout the entire space formed between the lower surface of the wafer W and the first surface S1.

[0045] As shown in Figure 3, the width of the second circumferential groove 522 is defined as width M1. Width M1 corresponds to the radial length of the second circumferential groove 522 when the first surface S1 is viewed in a plane. The position of the center in the direction of width M1 is defined as position P1. Position P1 is the position indicating the center of the second circumferential groove 522. In this specification, "center of the groove" refers to the position of the center of the groove itself formed on the first surface S1. The axis extending through position P1 in the thickness direction (Z-axis direction) of the plate-like member 10 is defined as axis L1. The diameter of the outlet hole 112 of the gas flow path 11 formed at the bottom 50B of the second circumferential groove 522 is defined as diameter M2. The position of the center of the outlet hole 112 when the first surface S1 is viewed in a plane is defined as position P2. The axis extending through position P2 in the thickness direction (Z-axis direction) of the plate-like member 10 corresponds to the central axis of the gas flow path 11. The central axis of the gas flow path 11 is defined as axis L2. The position where axis L2 intersects the bottom 50B of the second circumferential groove 522 corresponds to the center position P2 of the outlet hole 112. The second circumferential groove 522 and the gas flow path 11 are formed such that, when the first surface S1 is viewed in plane, axis L1 and axis L2 are positioned at different locations from each other. That is, when the first surface S1 is viewed in plane, the center position P2 of the outlet hole 112 and the center position P1 of the second circumferential groove 522 are positioned at different locations.

[0046] In the plate-shaped member 10, the inner region of the second circumferential groove 522 and the inner region of the gas flow path 11 are spaces where no material constituting the plate-shaped member 10 is placed, making it less likely for heat to be drawn (heat transferred) by the material constituting the plate-shaped member 10 to occur. Because positions P1 and P2 are located at different positions when the first surface S1 is viewed in a plane, axes L1 and L2 extend to different positions. That is, when the first surface S1 is viewed in a plane, the space related to the inner region of the gas flow path 11 (the space formed extending in the Z-axis direction with axis L2 as the center) is located at a position offset from the center position P1 of the space related to the inner region of the second circumferential groove 522 (the space formed extending in the Z-axis direction with axis L1 as the center). As a result, the position in which the space related to the inner region of the gas flow path 11 is provided is biased relative to the space related to the inner region of the second circumferential groove 522, compared to when positions P1 and P2 are located in the same position when the first surface S1 is viewed in a planar view. The portion of the bottom 50B of the second circumferential groove 522 around the outlet hole 112 tends to have a different temperature than the rest of the bottom 50B. Even in this situation, heat dissipation (heat transfer) occurs by the material constituting the portion of the plate-like member 10 including the side wall in the bottom 50B. For this reason, heat dissipation (heat transfer) occurs more easily by the material constituting the plate-like member 10 in the portion of the second circumferential groove 522 closer to the side wall than in the portion further away from the side wall. Therefore, the position of the space related to the inner region of the gas flow path 11 is biased relative to the space related to the inner region of the second circumferential groove 522, which makes it easier for heat to be transferred in such a way that the temperature gradient around the outlet hole 112 of the bottom 50B becomes gentler. Consequently, the temperature distribution around the outlet hole 112 and the entire inner region of the second circumferential groove 522 becomes more uniform.

[0047] Although not shown in Figure 3, as shown in Figure 1, the center position of the exit hole 112 formed at the bottom 50B of the first circumferential groove 521 and the center position of the width of the first circumferential groove 521 are positioned at different locations when the first surface S1 is viewed in a planar orientation. Similarly, as shown in Figure 1, the center position of the exit hole 112 formed at the bottom 50B of the radial groove 51 and the center position of the width of the radial groove 51 are positioned at different locations when the first surface S1 is viewed in a planar orientation. The width of the radial groove 51 corresponds to the circumferential length of the radial groove 51 when the first surface S1 is viewed in a planar orientation. In this embodiment, the width of the first circumferential groove 521 and the width of the radial groove 51 are the same as the width M1. However, the width of the first circumferential groove 521, the width of the second circumferential groove 522, and the width of the radial groove 51 may each be of different lengths.

[0048] In the circular groove 53, the groove is formed to spread out in a circular shape when the first surface S1 is viewed in a planar orientation. The center of the circular groove 53 is the position P3 of the center of the circle, as shown in Figure 4. In the first embodiment, when the first surface S1 is viewed in a planar orientation, the center P2 of the outlet hole 112 formed at the bottom 50B of the circular groove 53 and the center P3 of the circular groove 53 are located at different positions. This makes it easier to achieve a uniform temperature distribution in the area surrounding the outlet hole 112 and the entire inner region of the circular groove 53.

[0049] In this embodiment, as shown in Figure 3, the width M1 of the second circumferential groove 522 is larger than the diameter M2 of the outlet hole 112. Therefore, the thermally conductive gas flowing out from the outlet hole 112 can spread sufficiently into the inner region of the second circumferential groove 522, which has a width M1 larger than the diameter M2 of the outlet hole 112. In this case, the thermally conductive gas flowing out from the outlet hole 112 is prevented from directly heading toward the lower surface of the wafer W, thereby achieving a more uniform temperature distribution on the wafer W.

[0050] As shown in Figure 3, the length of the groove depth of the second circumferential groove 522 is defined as length D1. The length D1 of the groove depth is the length by which the second circumferential groove 522 is recessed from the first surface S1 toward the second surface, and is the length in the thickness direction (Z-axis direction) of the plate-like member 10 from the flat portion 12 of the first surface S1 to the bottom portion 50B of the second circumferential groove 522. The length of the gas passage 11 through which the outlet hole 112 is formed at the bottom portion 50B of the second circumferential groove 522 is defined as length D2. The length D2 is the length in the thickness direction (Z-axis direction) of the plate-like member 10 from the second surface S2 to the outlet hole 112. In this embodiment, the length D1 of the groove depth of the second circumferential groove 522 is shorter than the length D2 of the gas passage 11.

[0051] The inner region of the groove 50 is a space region facing the lower surface of the wafer W. Therefore, the longer the groove depth D1, the more difficult it becomes to ensure the heat dissipation (heat transfer) effect by the material constituting the plate-shaped member 10 in the groove 50. On the other hand, the gas flow path 11 is formed inside the plate-shaped member 10, and the material constituting the plate-shaped member 10 is arranged around it. Furthermore, since the diameter M2 of the outlet hole 112, which corresponds to the diameter of the gas flow path 11, is smaller than the width M1 of the second circumferential groove 522, increasing the length D2 of the gas flow path 11 is less likely to reduce the heat dissipation (heat transfer) effect by the material constituting the plate-shaped member 10 than increasing the groove depth D1. Therefore, by making the groove depth D1 shorter than the length D2 of the gas flow path 11, the portion of the plate-shaped member 10 in which the second circumferential groove 522 and the gas flow path 11 are formed is suppressed from becoming a temperature-specific portion relative to other parts of the plate-shaped member 10.

[0052] Although not shown in Figure 3, the length of the groove depth of the first circumferential groove 521 is also shorter than the length of the gas passage 11 in which the outlet hole 112 is formed at the bottom 50B of the first circumferential groove 521. The length of the groove depth of the radial groove 51 is also shorter than the length of the gas passage 11 in which the outlet hole 112 is formed at the bottom 50B of the radial groove 51. As a result, even if grooves 50 and gas passages 11 are formed, it is suppressed that these parts become temperature-sensitive areas relative to other parts of the plate-shaped member 10.

[0053] Furthermore, in this embodiment, as shown in Figure 1, a plurality of outlet holes 112 corresponding to a plurality of gas flow paths 11 are formed in the bottom 50B of the second circumferential groove 522. As shown in Figure 5, the center position P1 in the width M1 direction of the second circumferential groove 522 is defined as the center line L3, which is the arc connecting the center position P1 in the direction in which the second circumferential groove 522 extends. The center positions P2 of the plurality of outlet holes 112 formed in the bottom 50B of the second circumferential groove 522 are, from left to right, P2A, P2B, and P2C. In this embodiment, when the first surface S1 is viewed in a planar view, the positions P2A, P2B, and P2C are arranged to have different positional relationships with respect to the center position P1 in the width M1 direction of the second circumferential groove 522. Specifically, position P2A is located outside the center line L3. Position P2B is located inside the center line L3. Position P2C is located inside the center line L3. Also, position P2C is located closer to the center line L3 than position P2B. By making the position P2 of each center of the outlet hole 112 different relative to the center line L3 in this way, the temperature distribution throughout the inner region of the second circumferential groove 522 becomes more uniform.

[0054] Although not shown in Figure 5, as shown in Figure 1, multiple outlet holes 112 corresponding to multiple gas flow paths 11 are also formed at the bottom 50B of the first circumferential groove 521. When the first surface S1 is viewed in plan view, the positions of the centers of the multiple outlet holes 112 formed in the first circumferential groove 521 are arranged to be in different positions relative to the center of the first circumferential groove 521. This makes it easier to achieve a uniform temperature distribution throughout the inner region of the first circumferential groove 521.

[0055] Furthermore, one outlet hole 112 is formed at the bottom 50B of each of the three radial grooves 51. These outlet holes 112 are arranged in three ways: one is formed between the first circumferential groove 521 and the second circumferential groove 522, one is formed closer to the first circumferential groove 521, and one is formed closer to the second circumferential groove 522. In addition, one outlet hole 112 is formed in each of the three circular grooves 53, and these are arranged in three ways: one is formed at the 11 o'clock position, one at the 4 o'clock position, and one at the 8 o'clock position from the center of each circular groove 53. As a result, the temperature distribution in the entire inner region of each of the three radial grooves 51 and each of the three circular grooves 53 tends to become more uniform. In other words, the temperature distribution in the entire inner region of the grooves 50 tends to become more uniform. In this embodiment, the circular groove 53 is formed on the first surface S1 at the point where the circumferential groove 52 and the radial groove 51 connect. However, it is not limited to this, and the circular groove 53 may not be connected to the circumferential groove 52 and the radial groove 51, and may be provided on the first surface S1 as a circular, elliptical, or polygonal groove independent of the circumferential groove 52 and the radial groove 51.

[0056] As described above, the holding device 1 includes a plate-shaped member 10 having a first surface S1 for holding the wafer W and a second surface S2 located on the opposite side of the first surface S1. The plate-shaped member 10 has a groove 50 that is recessed from the first surface S1 toward the second surface S2, and a gas channel 11 that penetrates the bottom 50B of the groove 50 and the second surface S2, through which a thermally conductive gas can pass. An outlet hole 112, which is the outlet for the thermally conductive gas in the gas channel 11, is formed at the bottom 50B of the groove 50. When the first surface S1 is viewed in plan view, the center position P2 of the outlet hole 112 and the center position P1 of the groove 50 are located at different positions.

[0057] In the plate-shaped member 10, the inner region of the groove 50 and the inner region of the gas flow path 11 are spaces where no material constituting the plate-shaped member 10 is placed, making it less likely for heat to be drawn (heat transferred) by the material constituting the plate-shaped member 10 to occur. The holding device 1 can provide the space related to the inner region of the gas flow path 11 at a position offset from the center position P1 of the space related to the inner region of the groove 50 by arranging the center position P1 of the groove 50 and the center position P2 of the outlet hole 112 at different positions when the first surface S1 is viewed in plane. In this case, the position where the space related to the inner region of the gas flow path 11 is provided is more biased relative to the space related to the inner region of the groove 50 than when the center position P1 of the groove 50 and the center position P2 of the outlet hole 112 are aligned at the same position when the first surface is viewed in plane. A small temperature gradient is likely to occur around the exit hole 112 at the bottom 50B of the groove 50. However, by performing heat transfer around the exit hole 112 in such a way that the temperature gradient becomes gentler, the temperature distribution around the exit hole 112 and the entire inner region of the groove 50 becomes more uniform. In this way, the holding device 1 can equalize the temperature distribution of the wafer W held by the holding device 1 by equalizing the temperature distribution around the exit hole 112 and the inner region of the groove 50.

[0058] When the first surface S1 is viewed in a planar manner, the width M1 of the groove 50 is made larger than the diameter M2 of the exit hole 112.

[0059] In this case, the gas flowing out from the outlet hole 112 can spread sufficiently into the inner region of the groove 50, which has a width M1 larger than the diameter M2 of the outlet hole 112. This suppresses the direct flow of the thermally conductive gas flowing out from the outlet hole 112 towards the wafer W. Therefore, the temperature distribution of the wafer W is made more uniform.

[0060] The length D1 of the groove depth, which extends from the first surface S1 towards the second surface S2 and down to the bottom 50B, is shorter than the length D2 of the gas flow path 11 extending from the second surface S2 to the outlet hole 112.

[0061] The groove 50 is formed so that its opening is exposed on the first surface S1, and it becomes a spatial region facing the wafer W. Therefore, the longer the groove depth D1, the more difficult it becomes to ensure the heat dissipation (heat transfer) effect by the material constituting the plate-shaped member 10 in the groove 50. On the other hand, the gas flow path 11 is formed inside the plate-shaped member 10, and the material constituting the plate-shaped member 10 is arranged around it. For this reason, increasing the length D2 of the gas flow path 11 has less impact on the heat dissipation (heat transfer) effect by the material constituting the plate-shaped member 10 than increasing the groove depth D1. By making the groove depth D1 shorter than the length D2 of the gas flow path 11, the portion of the plate-shaped member 10 in which the groove 50 and gas flow path 11 are formed is suppressed from becoming a temperature-specific portion relative to the other parts of the plate-shaped member 10.

[0062] In the second circumferential groove 522, which is one of the grooves 50, multiple outlet holes 112 corresponding to each of the multiple gas flow paths 11 are formed, and when the first surface S1 is viewed in a planar view, the positions P2 of the centers of each of the multiple outlet holes 112 are arranged to be in different positions relative to the center position P1 of the groove 50. The same applies to the first circumferential groove 521, which is one of the grooves 50.

[0063] In this case, when multiple outlet holes 112 are formed in a single groove such as the first circumferential groove 521 and the second circumferential groove 522, the temperature distribution across the entire inner region of the first circumferential groove 521 and the second circumferential groove 522 tends to become more uniform.

[0064] <Details of the second embodiment of this disclosure> Next, a holding device 100 according to the second embodiment of this disclosure will be described with reference to Figure 6. In the second embodiment, the same reference numerals are used for the same parts as in the first embodiment, and redundant explanations of the structure, operation, and effect will be omitted.

[0065] The holding device 100 according to the second embodiment includes a plate-shaped member 10A. The plate-shaped member 10A has a groove 50 formed therein, including a second circumferential groove 522. An outlet hole 612 for a gas flow path 61 is formed at the bottom 50B of the second circumferential groove 522. The inlet hole 611 of the gas flow path 61 is positioned to overlap with the outlet hole 612 in a plan view, and the gas flow path 61 penetrates the plate-shaped member 10 in the vertical direction (Z-axis direction). A porous plug 58 is arranged throughout the inner region of this gas flow path 61. The porous plug 58 is a member formed of a gas-permeable porous body mainly composed of insulating ceramics and containing a large number of pores. The porous body constituting the porous plug 58 may be made of the same material as the material constituting the plate-shaped member 10, or it may be made of a different material from the material constituting the plate-shaped member 10. When porous plugs 58 are arranged throughout the entire inner region of the gas flow path 61, the diameter M2 of the outlet hole 612 and the diameter of the porous plugs 58 are approximately the same.

[0066] Since the porous material constituting the porous plug 58 is formed to contain many pores, the density of the material constituting the porous material is lower than the density of the material constituting the plate-shaped member 10A, and heat dissipation (heat transfer) by the material constituting the porous material is less likely to occur. For this reason, when the porous plug 58 is placed in the inner region of the gas flow path 61, the inner region of the gas flow path 61 tends to become a temperature-specific region with respect to the part of the plate-shaped member 10A where the gas flow path 61 is not formed, similar to the case when the porous plug 58 is not placed in the inner region of the gas flow path 61. In the second embodiment, the position P2 of the center of the outlet hole 612 and the position P1 of the center of the second circumferential groove 522 having a width M1 larger than the diameter M2 of the outlet hole 612 are arranged to be at different positions when the first surface S1 is viewed in a plane. That is, the position of the center of the porous plug 58 is the same as position P2, and the porous plug 58 is placed at a position biased relative to the inner region of the second circumferential groove 522. Therefore, the temperature distribution across the entire inner region of the second circumferential groove 522 tends to become more uniform.

[0067] Furthermore, when the porous plug 58 is placed in the inner region of the gas channel 61, the flow velocity of the thermal conductive gas flowing out from the outlet hole 612 is suppressed compared to when the porous plug 58 is not placed in the inner region of the gas channel 61. Therefore, when the porous plug 58 is placed in the inner region of the gas channel 61, the thermal conductive gas flowing out from the outlet hole 612 does not forcefully strike the lower surface of the wafer W. Consequently, the temperature distribution of the wafer W is made more uniform.

[0068] <Details of the third embodiment of this disclosure> Next, a holding device 200 according to the third embodiment of this disclosure will be described with reference to Figure 7. In the third embodiment, the same reference numerals are used for the same parts as in the first and second embodiments, and redundant explanations of the structure, operation, and effect will be omitted.

[0069] The holding device 200 according to the third embodiment includes a plate-shaped member 10B. The plate-shaped member 10B has a groove 50 formed therein, including a second circumferential groove 522. An outlet hole 622 for the gas flow path 62 is formed at the bottom 50B of the second circumferential groove 522. The diameter M2 of the outlet hole 622 of the gas flow path 62 is larger than the diameter of the inlet hole 621, and the inlet hole 621 and the outlet hole 622 are positioned to overlap in a plan view. The upper region of the gas flow path 62, including the outlet hole 622, has a diameter M2 and extends in the thickness direction (Z-axis direction) of the plate-shaped member 10, while the region below it has a diameter smaller than M2 and extends in the thickness direction (Z-axis direction) of the plate-shaped member 10. A porous plug 58 is placed in the upper part of the inner region of the gas flow path 62, but no porous plug 58 is placed in the lower part of the inner region of the gas flow path 62.

[0070] In the third embodiment, the center position P2 of the outlet hole 622 and the center position P1 of the second circumferential groove 522, which has a width M1 larger than the diameter M2 of the outlet hole 622, are positioned at different locations when the first surface S1 is viewed in a planar view. That is, the center position of the porous plug 58 is at the same position as position P2, and the porous plug 58 is positioned at an off-center location relative to the inner region of the second circumferential groove 522. Therefore, the temperature distribution across the entire inner region of the second circumferential groove 522 tends to become more uniform.

[0071] When the porous plug 58 is positioned at the top of the inner region of the gas channel 62, the flow velocity of the thermal conductive gas flowing out of the outlet hole 622 is suppressed compared to when the porous plug 58 is not positioned at all in the inner region of the gas channel 62. Therefore, when the porous plug 58 is positioned in the inner region of the gas channel 62, the thermal conductive gas flowing out of the outlet hole 622 does not forcefully strike the lower surface of the wafer W. Consequently, the temperature distribution of the wafer W is made more uniform.

[0072] <Details of the fourth embodiment of this disclosure> Next, a holding device 300 according to the fourth embodiment of this disclosure will be described with reference to Figure 8. In the fourth embodiment, the same reference numerals are used for the same parts as in the first, second, and third embodiments, and redundant explanations of the structure, operation, and effect will be omitted.

[0073] The holding device 300 according to the fourth embodiment includes a plate-shaped member 10C. The plate-shaped member 10C has grooves 50 formed therein, including a second circumferential groove 522. An outlet hole 632 for a gas flow path 63 is formed at the bottom 50B of the second circumferential groove 522. The diameter M2 of the outlet hole 632 for the gas flow path 63 is smaller than the diameter of the inlet hole 631, and the inlet hole 631 and the outlet hole 632 are positioned to overlap in a plan view. The upper region of the gas flow path 63, including the outlet hole 632, has a diameter M2 and extends in the thickness direction (Z-axis direction) of the plate-shaped member 10, while the region below it has a diameter larger than M2 and extends in the thickness direction (Z-axis direction) of the plate-shaped member 10. A porous plug 58 is disposed in the lower part of the inner region of the gas flow path 62, but no porous plug 58 is disposed in the upper part of the inner region of the gas flow path 62.

[0074] In the fourth embodiment, the center position P2 of the outlet hole 632 and the center position P1 of the second circumferential groove 522, which has a width M1 larger than the diameter M2 of the outlet hole 632, are positioned at different locations when the first surface S1 is viewed in a planar orientation. That is, the center position of the porous plug 58 is at the same position as position P2, and the porous plug 58 is positioned at an offset relative to the inner region of the second circumferential groove 522. Therefore, the temperature distribution across the entire inner region of the second circumferential groove 522 tends to become more uniform. Note that the center position of the porous plug 58 may be positioned at a different location from position P2 when the first surface S1 is viewed in a planar orientation. That is, the inlet hole 631 and the outlet hole 632 may be positioned at different locations when the first surface S1 is viewed in a planar orientation.

[0075] When the porous plug 58 is positioned at the bottom of the inner region of the gas channel 63, the flow velocity of the thermal conductive gas flowing out of the outlet hole 632 is suppressed compared to when the porous plug 58 is not positioned at all in the inner region of the gas channel 63. Therefore, when the porous plug 58 is positioned in the inner region of the gas channel 63, the thermal conductive gas flowing out of the outlet hole 632 does not forcefully strike the lower surface of the wafer W. Consequently, the temperature distribution of the wafer W is made more uniform.

[0076] As described above, a porous plug 58, formed from a porous material, is placed inside part or all of the gas passages 61, 62, and 63.

[0077] As in the second, third, and fourth embodiments, by arranging porous plugs 58 in part or all of the internal region of the gas flow paths 61, 62, and 63, the flow velocity of the thermally conductive gas when it flows out from the outlet holes 612, 622, and 632 is suppressed. This prevents the thermally conductive gas from forcefully hitting the portion of the wafer W facing the grooves 50, the outlet holes 612, 622, and 632, and the porous plugs 58. Therefore, the temperature distribution of the wafer W is made more uniform.

[0078] When the porous plug 58 is placed in the region of the gas flow paths 61 and 62 that includes the outlet holes 612 and 622, the position P2 corresponding to the center of the porous plug 58 and the position P1 corresponding to the center of the groove 50 are located at different positions when the first surface S1 is viewed in a plane.

[0079] The porous plug 58 is positioned at a location offset from the center P1 of the space within the inner region of the groove 50. In this case, the porous plug 58 is positioned at a more off-center location relative to the space within the inner region of the groove 50 than if the center P2 of the groove 50 and the center P2 of the porous plug 58 were aligned at the same location when the first surface S1 is viewed in a plane. As a result, a small temperature gradient is likely to occur around the porous plug 58 at the bottom 50B of the groove 50, but heat transfer occurs around the porous plug 58 so that this temperature gradient is balanced. As a result, the temperature distribution around the porous plug 58 and the entire inner region of the groove 50 tends to become more uniform.

[0080] Furthermore, the configuration in which the porous plug 58 is placed in a part of the gas flow path is not limited to that of gas flow paths 62 and 63. For example, the porous plug 58 may be placed in a region that does not include the inlet hole and outlet hole, such as the approximate center in the vertical direction of the inner region of the gas flow path.

[0081] <Details of the fifth embodiment of this disclosure> Next, a holding device 400 according to the fifth embodiment of this disclosure will be described with reference to Figure 9. In the fifth embodiment, the same reference numerals are used for the same parts as in the first embodiment, and redundant explanations of the structure, operation, and effect are omitted.

[0082] The holding device 400 according to the fifth embodiment includes a plate-shaped member 10D. The plate-shaped member 10D has grooves 50 formed therein, including a second circumferential groove 522.

[0083] The bottom 50B of the second circumferential groove 522 has outlet holes 712 for gas passage 71, 722 for gas passage 72, and 732 for gas passage 73. The second surface S2 has inlet holes 711 for gas passage 71, 721 for gas passage 72, and 731 for gas passage 73. The inlet holes 711, 721, and 731 and the outlet holes 712, 722, and 732 are arranged at equal intervals at different positions on a virtual line extending in the X-axis direction in a plan view. By connecting the inlet holes 711, 721, and 731 with the outlet holes 712, 722, and 732, gas passages 71, 72, and 73 are formed that penetrate the plate-shaped member 10 in the vertical direction (Z-axis direction).

[0084] Each of the inlet holes 711, 721, and 731 is positioned to overlap with the gas inlet hole 21 and the gas flow hole 31 in a plan view. In other words, in the first embodiment, the gas flow path 11 is formed as a single through-hole penetrating the plate-shaped member 10, but in the fifth embodiment, the through-hole penetrating the plate-shaped member 10 is formed as three through-holes consisting of gas flow paths 71, 72, and 73. That is, in the first embodiment, the outlet hole 112, which is formed as a single hole at the bottom 50B of the second circumferential groove 522, is divided into three holes, outlet holes 712, 722, and 732, in the fifth embodiment. The central axes of the gas flow paths 71, 72, and 73 are denoted as axes L21, L22, and L23, respectively. The positions where axes L21, L22, and L23 intersect with the bottom 50B of the second circumferential groove 522 correspond to the central positions P21, P22, and P23 of the outlet holes 712, 722, and 732, respectively. Here, when the first surface S1 is viewed in plane form, the central position where positions P21, P22, and P23 of the three outlet holes 712, 722, and 732 are distributed can be called position P22. Since this position P22 is located at a different position from the central position P1 of the second circumferential groove 522, the temperature distribution of the peripheral parts of the outlet holes 712, 722, and 732 and the entire inner region of the circular groove 53 tends to become uniform.

[0085] Furthermore, if the amount of thermally conductive gas supplied to the gas flow paths 71, 72, and 73 via the gas inlet hole 21 and the gas flow hole 31 is the same as in the first embodiment, the amount of thermally conductive gas flowing out from each of the outlet holes 712, 722, and 732 will be approximately one-third of the amount of thermally conductive gas flowing out from the outlet hole 112 in the first embodiment. This suppresses the forceful impact of the thermally conductive gas on the portion of the wafer W facing each of the outlet holes 712, 722, and 732.

[0086] As described above, in the first embodiment, the outlet hole 112 is formed as a single hole in the bottom 50B of the second circumferential groove 522, while in the fifth embodiment, it is formed as multiple holes, namely outlet holes 712, 722, and 732.

[0087] When the gas flow path is formed by multiple outlet holes, such as outlet holes 712, 722, and 732, the amount of gas flowing out from each of the multiple holes is less than the amount of gas flowing out from a single outlet hole if there were only one. This suppresses the forceful impact of the thermally conductive gas on the portions of the wafer W facing each of the outlet holes 712, 722, and 732. Therefore, the temperature distribution of the wafer W is made more uniform.

[0088] <Details of the sixth embodiment of this disclosure> Next, a holding device 500 according to the sixth embodiment of this disclosure will be described with reference to Figure 10. In the sixth embodiment, the same reference numerals are used for the same parts as in the first embodiment, and redundant explanations of the structure, operation, and effect are omitted.

[0089] The holding device 500 according to the sixth embodiment includes a plate-shaped member 10E. The plate-shaped member 10E has grooves 50 formed therein, including a second circumferential groove 522.

[0090] The bottom 50B of the second circumferential groove 522 has outlet holes 762 for gas passage 76, 772 for gas passage 77, and 782 for gas passage 78. The second surface S2 has an inlet hole 751 for gas passage 75. The diameters of the outlet holes 762, 772, and 782 are smaller than the inlet hole 751 for gas passage 75, and the upper end of gas passage 75 is in communication with the lower ends of gas passages 76, 77, and 78. The width M1 of the second circumferential groove 522 is larger than the diameter of the inlet hole 751 for gas passage 75. The diameter of the inlet hole 751 for gas passage 75 is approximately the same size as the gas inlet hole 21 and the gas flow hole 31.

[0091] The outlet holes 762, 772, and 782 are each equally spaced at different positions on a virtual line extending in the X-axis direction in a plan view. The central axes of the gas flow paths 76, 77, and 78 are denoted as axes L21, L22, and L23, respectively. The positions where axes L21, L22, and L23 intersect with the bottom 50B of the second circumferential groove 522 correspond to the central positions P21, P22, and P23 of the outlet holes 762, 772, and 782, respectively. Here, the central position where the central positions P21, P22, and P23 of the outlet holes 762, 772, and 782 are distributed when the first surface S1 is viewed in a plan view can be called position P22. Since this position P22 is located at a different position from the center position P1 of the second circumferential groove 522, the temperature distribution around the outlet holes 762, 772, and 782 and the entire inner region of the circular groove 53 tends to become more uniform.

[0092] The gas channel 75 is formed extending in the vertical direction, and a porous plug 58 is placed in its inner region. That is, the gas channel 75, which is formed as a single gas channel, branches into three gas channels 76, 77, and 78 inside the plate-shaped member 10E. The flow velocity of the thermally conductive gas supplied from the gas inlet hole 21 and the gas flow hole 31 is suppressed by the porous plug 58 inside the gas channel 75. The thermally conductive gas that flows out from the upper end of the gas channel 75, i.e., the upper end of the porous plug 58, with its flow velocity suppressed, branches into each of the gas channels 76, 77, and 78. In this way, the gas channel may be formed so that the thermally conductive gas supplied from the gas inlet hole 21 and the gas flow hole 31 branches into each of the multiple gas channels 76, 77, and 78 via a single gas channel 75.

[0093] In this case, the flow velocity of the thermal conductive gas flowing out from each of the three outlet holes 762, 772, and 782 is more easily suppressed than the flow velocity of the thermal conductive gas flowing out from each of the three outlet holes 712, 722, and 732 in the fifth embodiment. Therefore, the forceful impact of the thermal conductive gas on the portion of the wafer W facing the groove 50 and the outlet holes 762, 772, and 782 is further suppressed, and the uniformity of the temperature distribution of the wafer W is further improved.

[0094] <Details of the seventh embodiment of this disclosure> Next, a holding device 600 according to the seventh embodiment of this disclosure will be described with reference to Figure 11. In the seventh embodiment, the same reference numerals are used for the same parts as in the first embodiment, and redundant explanations of the structure, operation, and effect are omitted.

[0095] In the seventh embodiment, similar to the fifth and sixth embodiments, the gas flow paths 81, 82, and 83 are formed such that the thermally conductive gas supplied from the gas inlet hole 21 and the gas flow hole 31 branches into three gas flow paths 81, 82, and 83 and is supplied onto the first surface S1. At the bottom 50B of the circular groove 53, the outlet holes 812, 822, and 832 of the gas flow paths 81, 82, and 83 are formed. As shown in Figure 11, the outlet holes 812, 822, and 832 are arranged at the bottom 50B of the circular groove 53 such that a triangle is formed when the positions P21, P22, and P23 of the centers of the outlet holes 812, 822, and 832 are connected. The position of the geometric center (centroid) of this triangle can be said to be the center of the distribution of positions P21, P22, and P23. Let this center of the distribution of positions P21, P22, and P23 be position P2.

[0096] In the seventh embodiment, when the first surface S1 is viewed in a planar view, the position P2, which is the center of the distribution of the central positions P21, P22, and P23 of the multiple outlet holes 812, 822, and 832, is located at a different position from the central position P3 of the circular groove 53. This makes it easier for the temperature distribution to become uniform throughout the periphery of the outlet holes 812, 822, and 832 and the inner region of the circular groove 53.

[0097] Furthermore, when an outlet hole is composed of multiple holes, and the figure formed by connecting the centers of these multiple holes does not form a polygon, specifically when an outlet hole is also formed inside the triangle formed by the positions P21, P22, and P23 of the centers of the outlet holes 812, 822, and 832, the position where all the centers of the multiple outlet holes are distributed may be designated as position P2. When the first surface S1 is viewed in plane form, position P2, which is the position where all the centers of the multiple outlet holes are distributed, may be placed at a position different from the center position P3 of the circular groove 53 or the center position P1 in the width direction of the radial groove 51 and the circumferential groove 52. In these cases as well, the temperature distribution of the surrounding areas of the multiple outlet holes and the entire inner region of the groove 50 tends to become more uniform.

[0098] <Details of the eighth embodiment of this disclosure> Next, a holding device 700 according to the eighth embodiment of this disclosure will be described with reference to Figure 12. In the eighth embodiment, the same reference numerals are used for the same parts as in the first embodiment, and redundant explanations of the structure, operation, and effect are omitted.

[0099] The holding device 700 according to the eighth embodiment includes a plate-shaped member 10G. The plate-shaped member 10G has a groove portion 50 formed therein, including a second circumferential groove portion 522. An outlet hole 902 for a gas flow path 90 is formed at the bottom portion 50B of the second circumferential groove portion 522. The gas flow path 90 is formed by a first portion 91, a second portion 92, and a third portion 93. The first portion 91 is the portion of the gas flow path 90 that forms a vertical hole extending from the outlet hole 902 toward the second surface S2. The third portion 93 is the portion that forms a vertical hole extending toward the first surface S1 from an inlet hole 901 formed at a different position from the outlet hole 902 in a plan view on the second surface S2 of the plate-shaped member 10G. The second portion 92 is the portion that extends substantially horizontally inside the plate-shaped member 10G and forms a transverse hole connecting the lower end of the first portion 91 and the upper end of the third portion 93. In other words, the gas flow path 90 penetrates the plate-shaped member 10G in its thickness direction (Z-axis direction) through the interconnection of the first portion 91, the second portion 92, and the third portion 93.

[0100] In this gas flow path 90, the position of the center of the outlet hole 902, that is, the position where the central axis of the first portion 91 extends in the Z-axis direction, is defined as position P2. In the eighth embodiment, the position P1 of the center of the groove 50 including the second circumferential groove 522 and the position P2 of the center of the outlet hole 902 are located at different positions when the first surface S1 is viewed in a plane. In this case, the space relating to the inner region of the gas flow path 90, particularly the position where the inner region of the first portion 91 is provided, is biased relative to the space relating to the inner region of the groove 50, compared to the case where the position P1 of the center of the groove 50 and the position P2 of the center of the outlet hole 902 are aligned at the same position when the first surface is viewed in a plane. As a result, the temperature distribution of the area around the outlet hole 902 and the entire inner region of the groove 50 tends to become more uniform. In this way, even when the holding device 700 is formed with a gas flow path 90 having a first portion 91 and a third portion 93 which are vertical holes and a second portion 92 which is a horizontal hole, the temperature distribution of the area around the outlet hole 902 and the inner region of the groove 50 can be made uniform. Therefore, the temperature distribution of the wafer W held by the holding device 700 can be made uniform.

[0101] <Other Embodiments> This disclosure is not limited to the embodiments described above and in the drawings. For example, the following embodiments are also included in the technical scope of this disclosure, and various modifications can be made without departing from the spirit of the disclosure.

[0102] (1) The exit holes 112, 612, 622, 632, 712, 722, 732, 762, 772, 782, 812, 822, 832, and 902 are not limited to being circular in plan view, but may be elliptical or polygonal in shape. If the exit holes 112, 612, 622, 632, 712, 722, 732, 762, 772, 782, 812, 822, 832, and 902 are elliptical in shape, the position P2 of their center may be the position of the center of the ellipse. If the shape of the outlet holes 112, 612, 622, 632, 712, 722, 732, 762, 772, 782, 812, 822, 832, and 902 is polygonal, the position P2 of its center may be the position of the geometric center of the polygon formed by the outlet holes 112, 612, 622, 632, 712, 722, 732, 762, 772, 782, 812, 822, 832, and 902.

[0103] (2) The first surface S1 of the plate-shaped members 10, 10A, 10B, 10C, 10D, 10E, 10F, 10G may not include at least one of the plurality of dots 13 and the sealing band 14, and may, for example, only have a flat portion 12.

[0104] (3) Other electrodes besides the chuck electrode 55, such as heater electrodes, may be provided inside the plate-shaped members 10, 10A, 10B, 10C, 10D, 10E, 10F, and 10G. Also, the plate-shaped member 10 does not need to contain electrodes such as the chuck electrode 55 inside it.

[0105] (4) The porous plug 58 may be placed in part or all of the inner regions of the gas flow path 11 and the gas inlet hole 21. Even in this case, the flow velocity of the thermally conductive gas flowing out from the outlet holes 112, 612, 622, 632, 712, 722, 732, 762, 772, 782, 812, 822, 832, 902 is suppressed. This prevents the gas from forcefully hitting the portion of the wafer W facing the grooves 50 and the outlet holes 112, 612, 622, 632, 712, 722, 732, 762, 772, 782, 812, 822, 832, 902, thereby achieving a more uniform temperature distribution on the wafer W. [Explanation of symbols]

[0106] 1,100,200,300,400,500,600,700: Holding device 10,10A,10B,10C,10D,10E,10F,10G: Plate-shaped member 11,61,62,63,71,72,73,76,77,78,81,82,83,90: Gas flow path 12: Flat section 13: Dot 14: Seal band 20: Base member 30: Adhesive layer 50: Groove section 50B: Bottom section 51: Radial groove section 53: Circumferential groove section 112,612,622,632,712,722,732,762,772,782,812,822,832,902: Outlet hole 521: First circumferential groove section 522: Second circumferential groove L3: Center line M1: Width M2: Diameter D1, D2: Length P1, P2, P2A, P2B, P2C, P3, P21, P22, P23: Position S1: First surface S2: Second surface S3: Third surface S4: Fourth surface W: Wafer

Claims

1. The plate-shaped member comprises a first surface for holding the workpiece and a second surface located on the opposite side of the first surface, The first surface is composed of a flat portion extending parallel to the second surface and a sealing band protruding from the flat portion in the direction opposite to the second surface. The plate-shaped member includes, A groove that is recessed from the first surface toward the second surface, A gas passage is provided that penetrates the bottom of the groove and the second surface, allowing gas to pass through. A structure has been formed, The bottom portion of the groove is formed to be located closer to the second surface than the flat portion of the first surface. An outlet hole, which is the outlet for the gas in the gas passage, is formed at the bottom of the groove. When the first surface is viewed in a planar manner, the position of the center of the exit hole and the position of the center of the groove in the width direction are located at different positions. holding device.

2. The holding device according to claim 1, wherein, when the first surface is viewed in a planar manner, the width of the groove is greater than the diameter of the outlet hole.

3. The holding device according to claim 1, wherein the length of the groove depth in which the groove portion is recessed from the first surface toward the second surface to the bottom is shorter than the length of the gas flow path extending from the second surface to the outlet hole.

4. The holding device according to claim 1, wherein a porous plug formed of a porous material is disposed in part or all of the inside of the gas flow path.

5. The holding device according to claim 4, wherein when the porous plug is disposed in a region of the gas flow path that includes the outlet hole, the position of the center of the porous plug and the position of the center of the groove in the width direction are at different positions when the first surface is viewed in a planar view.

6. The holding device according to claim 1 or 4, wherein the outlet hole is formed by a plurality of holes.

7. Multiple outlet holes corresponding to each of the multiple gas flow paths are formed in one of the grooves. The holding device according to claim 1, wherein, when the first surface is viewed in a planar manner, the positions of the centers of the plurality of exit holes are arranged in a different positional relationship with respect to the center position in the width direction of the groove.

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