Retainer

Abstract

To provide a retainer capable of increasing an increase and dropping temperature speed of a surface holding an object in a first member while maintaining a bonding state of a first member holding the object and a second member bonded to the first member in a plate-part member.SOLUTION: In an embodiment of the present disclosure, a plate-like member bonding layer 60 includes a bonding layer center part 61, and a bonding layer outer periphery part 62 positioned to an outer peripheral side from the bonding layer center part 61 in an orthogonal direction orthogonal to a lamination direction of a first member 40 and a second member 50 in a plate-like member 10 of an electrostatic chuck 1. A thickness δ1 in the bonding layer center part 61 is formed so as to be smaller than a thickness δ2 in the bonding layer outer peripheral part 62.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a holding device for holding an object. [Background technology]

[0002] Patent Document 1 discloses a holding device in which a plate-like member for holding an object is formed by joining an upper portion (first member) and a lower portion (second member). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 213368 Summary of the Invention [Problem to be solved by the invention]

[0004] In the holding device disclosed in Patent Document 1, since a joint (joint layer) exists between the upper and lower parts of the plate-like member, the thermal resistance of this joint may reduce the rate at which the temperature is increased or decreased (i.e., the rate at which the temperature is increased and decreased) of the upper surface (holding surface) that holds the semiconductor wafer. On the other hand, if the joint is made thin to reduce the thermal resistance of the joint, the strength and adhesive force of the joint against the stress caused by the thermal expansion of the upper and lower parts may not be sufficient, and the bonded state between the upper and lower parts of the plate-like member may not be maintained.

[0005] Therefore, the present disclosure has been made to solve the above-mentioned problems, and aims to provide a holding device that can increase the rate of temperature rise and fall of the surface of a plate-shaped member that holds an object, while maintaining a bonded state between a first member that holds an object and a second member that is bonded to the first member. [Means for solving the problem]

[0006] In one embodiment of the present disclosure made to solve the above problem, in a holding device having a plate-shaped first member having a first surface for holding an object and a second surface provided on the opposite side of the first surface, a plate-shaped second member having a third surface and a fourth surface provided on the opposite side of the third surface, a plate-shaped member having a bonding layer disposed between the second surface of the first member and the third surface of the second member and bonding the first member to the second member, and a cooling member disposed on the fourth surface side of the plate-shaped member and thermally connected to the plate-shaped member, the bonding layer has a central portion and an outer periphery located on the outer periphery side of the central portion in an orthogonal direction perpendicular to a stacking direction of the first member and the second member, and the thickness of the central portion is formed to be smaller than the thickness of the outer periphery.

[0007] According to this aspect, by thinning the central portion of the bonding layer, the thermal resistance of the central portion of the bonding layer can be reduced, so that heat input to and heat removal from the first surface that holds the object through the bonding layer can be facilitated, and therefore the rate of temperature rise and fall of the first surface can be increased.

[0008] In addition, by not thinning the outer periphery of the bonding layer, the strength and adhesive force of the outer periphery of the bonding layer can be obtained, so that the outer periphery of the bonding layer can withstand the stress that is likely to occur in the outer periphery of the bonding layer due to thermal expansion of the first and second members, and therefore the bonded state between the first and second members can be maintained.

[0009] As a result of the above, in the plate-shaped member, it is possible to increase the rate of temperature increase / decrease of the first surface of the first member that holds the object, while maintaining the bonded state between the first member and the second member.

[0010] In the above aspect, it is preferable that the second surface of the first member and / or the third surface of the second member are formed so that the central portion of the surface bulges toward the bonding layer side.

[0011] According to this aspect, the thickness of the central portion of the bonding layer can be more reliably formed to be smaller than the thickness of the peripheral portion of the bonding layer, so that the rate of temperature rise and fall of the first surface of the first member that holds the object can be increased while maintaining the bonded state between the first and second members.

[0012] In the above aspect, it is preferable that the first surface is formed so that a central portion of the surface bulges toward the opposite side to the bonding layer side.

[0013] According to this aspect, the outer peripheral portion of the first member can be made thin, so that the thermal resistance of the outer peripheral portion of the first member can be reduced. Therefore, heat input to the first surface and heat removal from the first surface via the bonding layer can be more effectively performed. Therefore, the temperature rise and fall rate of the first surface can be more effectively increased. In addition, the strength of the first member can be ensured by making the center portion of the first member thicker.

[0014] In the above aspect, it is preferable that the first member includes a chuck electrode, and a portion of the first member between the first surface and the chuck electrode is formed so that the thickness at the outer periphery is smaller than the thickness at the center in a direction perpendicular to the stacking direction of the first member and the second member.

[0015] According to this aspect, the distance between the first surface and the chuck electrode can be reduced at the outer periphery of the first member. Therefore, the chucking force is increased at the outer periphery of the first member, improving the adhesion between the object and the first surface, and decreasing the interfacial thermal resistance (i.e., thermal resistance at the boundary surface) between the object and the first surface. Therefore, the balance of thermal resistance between the center of the first member and the outer periphery of the first member is improved, and the uniformity of the temperature distribution on the first surface is improved.

[0016] In the above aspect, it is preferable that the first member and the second member are formed from a material having the same main component.

[0017] According to this embodiment, the thermal expansion coefficients of the first and second members are the same or approximately the same, so that the stress caused by the thermal expansion of the first and second members can be alleviated, ensuring the durability of the bonding layer.

[0018] In the above aspect, it is preferable that the second member includes a heater electrode having a plurality of heater circuits, the plurality of heater circuits being arranged in a plurality of zones, and the bonding layer is formed to have the same or approximately the same thickness within the areas separated by each of the opposing zones.

[0019] According to this embodiment, by adjusting the thickness of each region of the bonding layer to a value suitable for each zone, the thermal resistance in each region of the bonding layer can be adjusted to a value suitable for each zone. Therefore, heat input to the first surface that holds the object through the bonding layer and heat extraction from the first surface can be more effectively performed. Therefore, the temperature rise and fall rate of the first surface is more effectively increased.

[0020] In the above aspect, it is preferable that the thickness of the first member within the region partitioned into each of the opposing zones is set in accordance with the amount of heat generated in the opposing zone.

[0021] According to this aspect, by setting the thickness of each region of the first member to a size suitable for the amount of heat generated in each zone, the uniformity of the temperature distribution in the first surface that holds the object is improved.

[0022] In the above aspect, it is preferable that the second member includes a heater electrode, and a portion of the second member between the third surface and the heater electrode is formed so that the thickness at the central portion is smaller than the thickness at the peripheral portion in a direction perpendicular to the stacking direction of the first member and the second member.

[0023] According to this aspect, since the heater electrode is brought close to the third surface at the center of the second member, the temperature rise rate at the first surface that holds the object can be increased. Also, since the heater electrode is not brought close to the third surface at the outer periphery of the second member, the temperature of the bonding layer can be kept low, thereby preventing a decrease in the tensile strength of the bonding layer and ensuring durability of the bonding layer. Effect of the Invention

[0024] According to the holding device of the present disclosure, in a plate-shaped member, the rate of temperature rise and fall of the surface of the first member that holds the object can be increased while maintaining a bonded state between the first member that holds the object and the second member that is bonded to the first member. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a schematic perspective view of an electrostatic chuck according to an embodiment of the present invention. [Diagram 2] 1 is a schematic configuration diagram of an XZ cross section of an electrostatic chuck according to a first embodiment. FIG. [Diagram 3] FIG. 2 is a schematic configuration diagram of an electrostatic chuck of a first modified example of the first embodiment, taken along an XZ cross section. [Figure 4] FIG. 11 is a schematic configuration diagram of an electrostatic chuck according to a second modified example of the first embodiment, taken along an XZ cross section. [Diagram 5] FIG. 11 is a schematic configuration diagram of an electrostatic chuck of a second embodiment in an XZ cross section. [Figure 6] FIG. 11 is a schematic configuration diagram of an electrostatic chuck of a third embodiment taken along an XZ cross section. [Figure 7] FIG. 13 is a diagram showing an example of zoning of a heater electrode in the fourth embodiment. [Figure 8] FIG. 13 is a diagram showing another example of zoning of the heater electrode in the fourth embodiment. [Figure 9] FIG. 13 is a schematic configuration diagram of an electrostatic chuck of a fourth embodiment in an XZ cross section. [Figure 10] FIG. 13 is a schematic configuration diagram of an electrostatic chuck of a fifth embodiment in an XZ cross section. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] An embodiment of a holding device according to the present disclosure will be described. In this embodiment, the holding device will be described by taking as an example an electrostatic chuck used in semiconductor manufacturing equipment such as a film forming apparatus (such as a CVD film forming apparatus or a sputtering film forming apparatus) or an etching apparatus (such as a plasma etching apparatus).

[0027] First Embodiment First, the first embodiment will be described.

[0028] (Overview of electrostatic chucks) The electrostatic chuck 1 of this embodiment will be described with reference to Figures 1 and 2. The electrostatic chuck 1 of this embodiment is a device that attracts and holds a semiconductor wafer W (i.e., an object) by electrostatic attraction using a chuck electrode 70 described below, and is used, for example, to fix the semiconductor wafer W in a vacuum chamber of a semiconductor manufacturing device.

[0029] As shown in FIG. 1, the electrostatic chuck 1 includes a plate-shaped member 10, a base member 20, and a bonding layer 30 that bonds the plate-shaped member 10 and the base member 20 together.

[0030] In the following description, for convenience of explanation, the X, Y and Z axes are defined as shown in Fig. 1. Here, the Z axis is an axis in the axial direction of the electrostatic chuck 1 (the vertical direction in Fig. 1), and the X and Y axes are axes in the radial directions of the electrostatic chuck 1.

[0031] 1, the plate-like member 10 is formed in a disk shape and is made of ceramics. Various ceramics are used as the ceramics, but from the viewpoints of strength, wear resistance, plasma resistance, etc., aluminum oxide (alumina, Al 2 O 3It is preferable to use ceramics mainly composed of aluminum nitride (AlN). The main component here means the component with the highest content (for example, a component with a volume content of 90 vol% or more). The diameter of the plate-like member 10 is, for example, about 150 mm to 350 mm, and the thickness of the plate-like member 10 is, for example, about 2 mm to 6 mm.

[0032] 1 and 2, the plate-shaped member 10 has a holding surface 11 for holding a semiconductor wafer W, and a lower surface 12 provided on the opposite side to the holding surface 11 in the thickness direction (a direction that coincides with the Z-axis direction, the up-down direction) of the plate-shaped member 10. The semiconductor wafer W is held on the holding surface 11.

[0033] In this embodiment, the plate-like member 10 is formed in a two-piece structure, and is formed by bonding a disk-shaped first member 40 and a disk-shaped second member 50 together via a plate-like member bonding layer 60.

[0034] 2, the first member 40 has an upper surface 41 which becomes the holding surface 11, and a lower surface 42 provided on the opposite side to the upper surface 41. Note that the upper surface 41 (i.e., the holding surface 11) is an example of a "first surface" in the present disclosure, and the lower surface 42 is an example of a "second surface" in the present disclosure.

[0035] The first member 40 also includes therein a chuck electrode 70. The chuck electrode 70 is connected to a power supply terminal 72 through a via 71.

[0036] The second member 50 has an upper surface 51 and a lower surface 52 (which becomes the lower surface 12) provided on the opposite side to the upper surface 51. The upper surface 51 is an example of a "third surface" in the present disclosure, and the lower surface 52 (i.e., the lower surface 12) is an example of a "fourth surface" in the present disclosure.

[0037] The second member 50 has therein a heater electrode 80. The heater electrode 80 has a plurality of heater circuits (not shown). The heater electrode 80 is connected to a power supply terminal 83 through a via 81 and a driver 82.

[0038] The plate-like member bonding layer 60 is a bonding layer that is disposed between the lower surface 42 of the first member 40 and the upper surface 51 of the second member 50, and bonds the first member 40 and the second member 50 together.

[0039] The plate-like member bonding layer 60 is made of a resin adhesive such as a silicone resin, an acrylic resin, or an epoxy resin.

[0040] As shown in FIG. 1, the base member 20 is disposed on the second member 50 side (i.e., the lower surface 12 side) of the plate-shaped member 10. The base member 20 is, for example, a cylindrical member. The base member 20 is formed of a metal (e.g., aluminum, an aluminum alloy, etc.). The base member 20 has a coolant flow path (not shown) for flowing a coolant (e.g., a fluorine-based inert liquid, water, etc.). The base member 20 is cooled by flowing a coolant in the coolant flow path, and thus the plate-shaped member 10 is cooled via the bonding layer 30, and heat is removed from the holding surface 11. The base member 20 is an example of a "cooling member" in the present disclosure.

[0041] 1 and 2, the base member 20 has an upper surface 21 and a lower surface 22 provided on the opposite side to the upper surface 21 in the Z-axis direction. The diameter of the base member 20 is, for example, about 150 mm to 350 mm. The thickness of the base member 20 (dimension in the Z-axis direction) is, for example, about 20 mm to 50 mm.

[0042] The bonding layer 30 is disposed between the lower surface 12 of the plate-shaped member 10 and the upper surface 21 of the base member 20, and bonds the plate-shaped member 10 to the base member 20. The lower surface 12 of the plate-shaped member 10 and the upper surface 21 of the base member 20 are thermally connected via the bonding layer 30. The thickness of the bonding layer 30 (the dimension in the Z-axis direction) is, for example, about 0.1 to 1.0 mm.

[0043] The bonding layer 30 is made of a resin adhesive such as a silicone resin, an acrylic resin, or an epoxy resin.

[0044] (Regarding plate-shaped members) In this embodiment, in the plate-shaped member 10, the plate-shaped member bonding layer 60 is present between the first member 40 and the second member 50. Therefore, due to the thermal resistance of the plate-shaped member bonding layer 60, it may be difficult for heat generated at the heater electrode 80 provided on the second member 50 to be transferred to the first member 40 through the plate-shaped member bonding layer 60, and the rate at which the temperature of the holding surface 11 increases may decrease. In addition, due to the thermal resistance of the plate-shaped member bonding layer 60, it may be difficult for heat to be transferred from the holding surface 11 to the base member 20, and the rate at which the temperature of the holding surface 11 decreases may decrease.

[0045] On the other hand, if the plate-shaped member bonding layer 60 is made thinner in order to reduce the thermal resistance of the plate-shaped member bonding layer 60, the strength and adhesive force of the plate-shaped member bonding layer 60 may not be sufficient to withstand the stress caused by the thermal expansion of the first member 40 and the second member 50, and the bonded state between the first member 40 and the second member 50 may not be maintained.

[0046] Therefore, in this embodiment, a technique is devised to increase the temperature rise and fall rate (i.e., temperature rise rate and temperature fall rate) of the holding surface 11 while maintaining the bonded state of the first member 40 and the second member 50. In the following description, the "central portion" refers to a portion located at the center in the orthogonal directions (X direction, Y direction) perpendicular to the stacking direction (Z direction) of the first member 40 and the second member 50. Also, the "periphery portion" refers to a portion located closer to the outer periphery than the central portion in the orthogonal directions perpendicular to the stacking direction of the first member 40 and the second member 50.

[0047] 2, the lower surface 42 of the first member 40 is formed such that a lower surface central portion 42a, which is the central portion of the surface, bulges (i.e., protrudes) toward the plate-shaped member bonding layer 60. As a result, a thickness δ1 at a bonding layer central portion 61, which is the central portion of the plate-shaped member bonding layer 60, is smaller than a thickness δ2 at a bonding layer peripheral portion 62, which is the peripheral portion of the plate-shaped member bonding layer 60. Note that the thicknesses δ1 and δ2 are thicknesses when viewed from an arbitrary cross section (including an XZ cross section) parallel to the Z-axis direction in the electrostatic chuck 1.

[0048] In this manner, in this embodiment, by thinning the bonding layer central portion 61, the thermal resistance of the bonding layer central portion 61 can be reduced, and heat input to and heat removal from the holding surface 11 via the plate-like member bonding layer 60 can be facilitated. This increases the temperature rise and fall rate of the holding surface 11. In detail, when the temperature rise and fall rate of the holding surface central portion 11a, which is the central portion of the holding surface 11, increases, the holding surface central portion 11a first reaches the target temperature quickly, and then the holding surface peripheral portion 11b, which is the peripheral portion of the holding surface 11, can reach the target temperature quickly by heat exchange with the holding surface central portion 11a.

[0049] In addition, "heat input to and heat dissipation from the holding surface 11 via the plate-shaped member joining layer 60" refers, in detail, to heat input from the heater electrode 80 to the holding surface 11 via the plate-shaped member joining layer 60, and heat dissipation from the holding surface 11 to the base member 20 via the plate-shaped member joining layer 60.

[0050] Furthermore, by maintaining the thickness δ2 without thinning the outer peripheral portion 62 of the bonding layer, the strength and adhesive force of the outer peripheral portion 62 of the bonding layer can be obtained, and the outer peripheral portion 62 of the bonding layer can withstand the stress that is likely to occur in the outer peripheral portion 62 of the bonding layer due to the thermal expansion of the first member 40 and the second member 50. Therefore, the bonded state between the first member 40 and the second member 50 can be maintained.

[0051] As described above, in this embodiment, the rate at which the temperature of the holding surface 11 of the plate-shaped member 10 increases can be increased while maintaining the bonded state between the first member 40 and the second member 50.

[0052] The height of the lower surface central portion 42a, which is formed by bulging toward the plate-like member bonding layer 60, is, for example, 5 to 50% of the average thickness of the plate-like member bonding layer 60. The top portion of the lower surface central portion 42a is not limited to being formed as a plane as shown in Fig. 2, and may be formed as a point. The average thickness of the plate-like member bonding layer 60 is, for example, 50 to 900 µm.

[0053] Furthermore, the central portion 42a of the lower surface of the first member 40 and the upper surface 51 of the second member 50 may be in contact with each other at the position of the central axis of the plate-like member 10.

[0054] As a first modified example, as shown in FIG. 3, the upper surface 51 of the second member 50 may be formed so that an upper surface central portion 51a, which is the central portion of the surface, bulges toward the plate-like member bonding layer 60 side.

[0055] Alternatively, as a second modified example, both the lower surface central portion 42a and the upper surface central portion 51a may be formed to bulge toward the plate-shaped member bonding layer 60 side, as shown in FIG.

[0056] With these first and second modified examples, the thickness δ1 of the central portion 61 of the bonding layer can be made smaller than the thickness δ2 of the peripheral portion 62 of the bonding layer, so that, similarly to the above, the rate at which the temperature of the holding surface 11 is increased while maintaining the bonded state between the first member 40 and the second member 50.

[0057] Furthermore, the first member 40 and the second member 50 may be made of a material whose main component is the same.

[0058] As a result, the thermal expansion coefficients of the first member 40 and the second member 50 become the same or almost the same, so that the stress generated in the plate-like member bonding layer 60 due to the thermal expansion of the first member 40 and the second member 50 can be alleviated, and the durability of the plate-like member bonding layer 60 can be ensured. Note that "materials with the same main component" refers to, for example, aluminum oxide (alumina, Al 2 O 3 ) or aluminum nitride (AlN) as its main component.

[0059] <Second embodiment> Next, the second embodiment will be described, with differences from the first embodiment being described, and descriptions of points in common with the first embodiment being omitted. For convenience of explanation, the chuck electrode 70, heater electrode 80, and the like are omitted from the schematic configuration diagrams of the XZ cross section of the electrostatic chuck in FIG. 5 and subsequent drawings, except when necessary.

[0060] In this embodiment, as shown in FIG. 5, the holding surface 11 is formed so that the central portion of the holding surface 11a, which is the central portion of the surface, bulges out toward the side opposite the plate-like member bonding layer 60, i.e., the side on which the semiconductor wafer W is held.

[0061] This allows the first member outer peripheral portion 44, which is the outer peripheral portion of the first member 40, to be thinned, so that the thermal resistance of the first member outer peripheral portion 44 can be reduced. Therefore, heat input to the holding surface 11 and heat removal from the holding surface 11 through the plate-shaped member bonding layer 60 can be more effectively performed. Therefore, the temperature rise and fall rate of the holding surface 11 can be more effectively increased. In addition, since the thickness of the first member central portion 43, which is the central portion of the first member 40, is maintained, the strength of the first member 40 can be ensured. For example, damage such as cracks occurring between the gas tunnel 90 and the holding surface 11 in the first member 40 can be prevented. The gas tunnel 90 is a passage that supplies an inert gas to the upper surface 41 (i.e., the holding surface 11) side, and is connected to the gas introduction passage 91 as shown in FIG. 5. In addition, the height of the holding surface central portion 11a (i.e., the height difference between the holding surface central portion 11a and the holding surface outermost peripheral portion 11c) is, for example, 50 μm or less.

[0062] <Third embodiment> Next, a third embodiment will be described. Differences from the first and second embodiments will be described, and descriptions of commonalities with the first and second embodiments will be omitted.

[0063] In this embodiment, as shown in FIG. 6 , the electrode upper portion 45, which is a portion between the holding surface 11 of the first member 40 and the chuck electrode 70, is formed so that the thickness δb at the position of its outer periphery, that is, the electrode upper portion outer periphery 45b, is smaller than the thickness δa at the position of the center portion 45a of the electrode upper portion 45, that is, the center portion of the electrode upper portion 45.

[0064] This makes it possible to reduce the distance between the holding surface 11 and the chuck electrode 70 at the first member outer circumferential portion 44. Therefore, the chucking force is increased at the first member outer circumferential portion 44, improving the adhesion between the semiconductor wafer W and the holding surface 11 and decreasing the interfacial thermal resistance (i.e., thermal resistance at the boundary surface) between the semiconductor wafer W and the holding surface 11. Therefore, the balance of the thermal resistance between the first member central portion 43 and the first member outer circumferential portion 44 is improved, and the uniformity of the temperature distribution on the holding surface 11 is improved.

[0065] <Fourth embodiment> Next, the fourth embodiment will be described. The differences from the first to third embodiments will be described, and a description of the points in common with the first to third embodiments will be omitted.

[0066] In this embodiment, a plurality of heater circuits (not shown) provided on the heater electrode 80 are arranged in a plurality of zones ZO, as shown in, for example, Figs. 7 and 8. In the example shown in Fig. 7, the zones ZO are divided into doughnut shapes, and in the example shown in Fig. 8, they are divided to include a sector-shaped zone ZO. The heater electrode 80 can be controlled independently for each zone ZO. At this time, as shown in Fig. 9, the plate-shaped member bonding layer 60 is formed so that the thicknesses are the same or approximately the same within the regions RE divided into each of the opposing zones ZO.

[0067] As a result, by making the thickness of each region RE of the plate-shaped member bonding layer 60 suitable for each zone, the thermal resistance in each region RE of the plate-shaped member bonding layer 60 can be made suitable for each zone ZO. Therefore, heat input to the holding surface 11 and heat removal from the holding surface 11 through the plate-shaped member bonding layer 60 can be more effectively performed. Therefore, the temperature rise and fall rate of the holding surface 11 is more effectively increased. Furthermore, by making the thickness of the plate-shaped member bonding layer 60 equal in each region RE, it is possible to prevent differences in thermal resistance from occurring at each location in one region RE. And, as a result, the temperature rise and fall rate of the holding surface 11 is increased while maintaining the uniformity of the temperature distribution in each region RE.

[0068] Also, the strength and adhesive force in each region RE of the plate-like member bonding layer 60 can be adjusted to a value suitable for each zone ZO. This makes it possible to more effectively withstand stress caused by thermal expansion of the first member 40 and the second member 50. This makes it possible to more effectively maintain the bonded state between the first member 40 and the second member 50.

[0069] Therefore, according to this embodiment, it is possible to more effectively increase the rate at which the temperature of the holding surface 11 that holds the semiconductor wafer W is increased and decreased while maintaining the bonded state between the first member 40 and the second member 50.

[0070] As a modified example, the thickness of the region RE in the first member 40 divided into opposing zones ZO may be set according to the amount of heat generated in the opposing zones ZO.

[0071] Thereby, by setting the thickness of each region RE of the first member 40 to a size suitable for the amount of heat generated in each zone ZO, the uniformity of the temperature distribution in the holding surface 11 is improved.

[0072] <Fifth embodiment> Next, the fifth embodiment will be described. The differences from the first to fourth embodiments will be described, and a description of the points in common with the first to fourth embodiments will be omitted.

[0073] In this embodiment, as shown in FIG. 10 , the electrode upper portion 53, which is the portion between the upper surface 51 of the second member 50 and the heater electrode 80, is formed so that the thickness δc of the electrode upper portion central portion 53a, which is the central portion of the electrode upper portion 53, is smaller than the thickness δd of the electrode upper portion peripheral portion 53b, which is the peripheral portion of the electrode upper portion 53.

[0074] In this way, the heater electrode 80 is brought closer to the upper surface 51 at the second member central portion 54, which is the central portion of the second member 50, so that the temperature rise rate at the holding surface 11 can be increased. In addition, the heater electrode 80 is not brought closer to the upper surface 51 at the second member outer peripheral portion 55, which is the outer peripheral portion of the second member 50, so that the temperature of the plate-shaped member bonding layer 60 is not raised at the second member outer peripheral portion 55, and the strength is not reduced. In this way, the second member central portion 54 may have a temperature rise and a strength reduction due to the heater electrode 80 approaching the upper surface 51, but since the generated stress tends to be smaller than that of the second member outer peripheral portion 55, the strength reduction is tolerated to some extent. On the other hand, since the generated stress tends to be larger than that of the second member central portion 54, the strength reduction is prevented.

[0075] It should be noted that the above-described embodiments are merely examples and do not limit the present disclosure in any way. Needless to say, various improvements and modifications are possible without departing from the spirit and scope of the present disclosure. [Explanation of symbols]

[0076] 1. Electrostatic chuck 10 Plate-shaped member 11 Holding surface 11a Center part of holding surface 12 Bottom side 20 Base material 21 Top side 22 Bottom side 30 Bonding layer 40 First member 41 Top side 42 Bottom surface 42a Bottom center part 43 Center of first component 44 First member outer periphery 45 Upper part of electrode 45a Upper center of electrode 45b Upper part of electrode outer periphery 50 Second member 51 Top side 51a Top center 52 Bottom surface 53 Upper part of electrode 53a Center part of the upper part of the electrode 53b Upper part of electrode outer periphery 54 Second component center 55 Second member outer periphery 60 Plate-like member bonding layer 61 Center of bonding layer 62 Bonding layer outer periphery 70 Chuck Electrode 80 Heater electrode W Semiconductor wafer δ1 Thickness (at the center of the bonding layer) δ2 (at the outer periphery of the bonding layer) Thickness δa (thickness at the center of the upper part of the electrode) δb (Electrode upper part outer periphery) Thickness δc (at the center of the upper part of the electrode) Thickness δd (thickness of the outer periphery of the upper part of the electrode) ZO Zone RE area

Claims

1. a plate-like first member having a first surface for holding an object and a second surface provided on the opposite side to the first surface; a plate-like second member having a third surface and a fourth surface provided on the opposite side to the third surface; and a bonding layer disposed between the second surface of the first member and the third surface of the second member, bonding the first member and the second member; a cooling member that is disposed on the fourth surface side of the plate-like member and is thermally connected to the plate-like member; In a holding device having the bonding layer has a central portion and an outer peripheral portion located on an outer periphery side of the central portion in an orthogonal direction orthogonal to a stacking direction of the first member and the second member, The thickness of the central portion is smaller than the thickness of the outer circumferential portion. A holding device comprising:

2. 2. The holding device of claim 1, the second surface of the first member and / or the third surface of the second member are formed so that a central portion of the surface bulges toward the bonding layer; A holding device comprising:

3. The holding device according to claim 1 or 2, the first surface is formed such that a central portion of the surface bulges toward an opposite side to the bonding layer side; A holding device comprising:

4. The holding device according to claim 1 or 2, the first member comprises a chuck electrode; a portion of the first member between the first surface and the chuck electrode is formed so that a thickness at an outer periphery is smaller than a thickness at a central portion in a direction perpendicular to a stacking direction of the first member and the second member; A holding device comprising:

5. The holding device according to claim 1 or 2, The first member and the second member are formed of the same material as a main component; A holding device comprising:

6. The holding device according to claim 1 or 2, the second member includes a heater electrode having a plurality of heater circuits; The heater circuits are arranged in a plurality of zones, The bonding layer is formed so that the thicknesses of the bonding layers are the same or approximately the same in the regions separated by the opposing zones; A holding device comprising:

7. 7. The holding device of claim 6, setting a thickness within an area divided into each of the opposing zones in the first member according to a heat generation amount of the opposing zone; A holding device comprising:

8. The holding device according to claim 1 or 2, the second member includes a heater electrode; a portion of the second member between the third surface and the heater electrode is formed so that a thickness at a central portion is smaller than a thickness at a peripheral portion in a direction perpendicular to a stacking direction of the first member and the second member; A holding device comprising:

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