Holding device

Abstract

To provide a holding device that increases the thermal conductivity of the holding device while suppressing the occurrence of warping or cracking of the holding device due to a difference in thermal expansion between a plate member and a base member.SOLUTION: An electrostatic chuck is a holding device that can hold an object (wafer W) such as a semiconductor wafer and a glass substrate by suction includes an insulating plate member 10 having a first surface for holding the object and a second surface 10B on the opposite side, a base member 20 adhered to the second surface 10B, and a metal heat conductive member 30 joined to the second surface 10B of the plate member 10. A plurality of recesses 22 are formed in the base member 20 to accommodate at least a portion of the heat conductive member 30, respectively. The recesses 22 each have a shape that prevents the heat conductive member 30 from coming out.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a retention device. [Background technology]

[0002] For example, an electrostatic chuck is used as a holding device for holding a wafer in a processing chamber of a semiconductor manufacturing device. The electrostatic chuck includes a plate-shaped member made of a material containing ceramics, a base member made of a metal, a joint that joins the plate-shaped member and the base member, and a chuck electrode provided inside the plate-shaped member. The electrostatic chuck attracts and holds a wafer on the surface of the plate-shaped member by utilizing electrostatic attraction generated by applying a voltage to the chuck electrode. The joint that joins the plate-shaped member and the base member is made of a material containing resin, as described in Patent Document 1, for example. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-143796 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration of the conventional electrostatic chuck described above, the joint portion joining the plate-shaped member and the base member is formed of a material containing resin, so there is room for improvement in the thermal conductivity of the joint portion. To improve the thermal conductivity of the electrostatic chuck, it is also possible to form the joint portion from an inorganic material (an inorganic adhesive such as a metal or ceramic) that has a higher thermal conductivity than resin. However, when the joint portion is formed from an inorganic material, the inorganic material is harder than resin, so it is unable to effectively relieve stress caused by the difference in thermal expansion between the plate-shaped member and the base member, which may result in warping or cracking of the electrostatic chuck due to the difference in thermal expansion.

[0005] The present disclosure was completed based on the above circumstances, and aims to increase the thermal conductivity of the holding device while suppressing the occurrence of warping or cracking of the holding device due to the difference in thermal expansion between the plate-shaped member and the base member. [Means for solving the problem]

[0006] The holding device of the present disclosure comprises an insulating plate-shaped member having a first surface for holding an object and a second surface opposite the first surface, a base member having a third surface arranged opposite the second surface, and a plurality of metal heat-conducting members joined to the second surface of the plate-shaped member, wherein the base member has a plurality of recesses formed therein that are recessed from the third surface and each accommodate at least a portion of the heat-conducting member, the recesses having a narrow portion and a wide portion that is wider than the narrow portion in a direction parallel to the first surface, the narrow portion being connected to the wide portion and being arranged closer to the third surface than the wide portion, the heat-conducting member having a shaft portion extending from the second surface toward the base member and a return portion formed at the tip of the shaft portion, the shaft portion being inserted into the narrow portion, and the return portion being in contact with the inner wall of the wide portion, preventing the heat-conducting member from slipping out of the recess. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to increase the thermal conductivity of the holding device while suppressing the occurrence of warping or cracking of the holding device due to the difference in thermal expansion between the plate-like member and the base member. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view schematically illustrating the external configuration of an electrostatic chuck according to a first embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view of an electrostatic chuck. [Figure 3] FIG. 3 is an enlarged view of the portion surrounded by the dashed line in FIG. [Figure 4]FIG. 4 is a schematic plan view of the electrostatic chuck, showing an enlarged view of the periphery of the heat conducting member, with the plate-like member not shown. [Figure 5] FIG. 5 is a diagram illustrating a heat conduction member according to a first example. [Figure 6] FIG. 6 is a schematic cross-sectional view of an electrostatic chuck showing a protruding portion of a recess according to a first example. [Figure 7] FIG. 7 is a diagram illustrating a heat conducting member according to a second example. [Figure 8] FIG. 8 is an explanatory diagram showing how the heat conducting member according to the second example is inserted into the recess. [Figure 9] FIG. 9 is a schematic cross-sectional view of an electrostatic chuck showing an enlarged view of the periphery of a heat conduction member according to the second embodiment. [Figure 10] FIG. 10 is a schematic cross-sectional view of an electrostatic chuck showing an enlarged view of the periphery of a heat conduction member according to the third embodiment. [Figure 11] FIG. 11 is a schematic cross-sectional view of an electrostatic chuck showing an enlarged view of the periphery of a heat conduction member according to the fourth embodiment. [Figure 12] FIG. 12 is an explanatory view showing how the heat conducting member according to the fifth embodiment is inserted into the recess. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described. (1) The holding device of the present disclosure comprises an insulating plate-shaped member having a first surface for holding an object and a second surface opposite the first surface, a base member having a third surface arranged opposite the second surface, and a plurality of metal heat-conducting members joined to the second surface of the plate-shaped member, wherein the base member has a plurality of recesses formed therein that are recessed from the third surface and each accommodate at least a portion of the heat-conducting member, and the recesses have a narrow portion and a wide portion that is wider than the narrow portion in a direction parallel to the first surface, and the narrow portion is connected to the wide portion and is arranged closer to the third surface than the wide portion, and the heat-conducting member has a shaft portion extending from the second surface toward the base member and a return portion formed at the tip of the shaft portion, and the shaft portion is inserted into the narrow portion, and the return portion contacts an inner wall of the wide portion to prevent the heat-conducting member from slipping out of the recess.

[0010] The metal heat-conducting member is arranged so as to contact the inner wall of the wide portion of the recess in the base member, thereby improving heat conduction between the base member and the plate-like member. In addition, the return portion prevents the heat-conducting member from slipping out of the recess, improving the bond between the base member and the plate-like member.

[0011] (2) In the holding device of (1) above, it is preferable that the heat conduction member has an expanding diameter portion that expands in diameter from the shaft portion in a direction parallel to the first surface, and the expanding diameter portion is in contact with the third surface.

[0012] Since the expanded diameter portion contacts the third surface of the base member, the heat conduction between the base member and the plate-like member can be further improved.

[0013] (3) In the holding device of (1) or (2) above, when the thermal expansion coefficient of the material that mainly constitutes the plate-shaped member is different from the thermal expansion coefficient of the material that mainly constitutes the base member, it is preferable that a gap be provided between the inner wall of the narrow portion and the shaft portion.

[0014] When there is a difference in thermal expansion between the plate-shaped member and the base member, the plate-shaped member and the base member are misaligned relative to each other in the direction parallel to the first surface due to thermal expansion. In the above configuration, because a gap is provided between the inner wall of the narrow portion and the shaft portion, damage to the heat conduction member can be suppressed even when the plate-shaped member and the base member are misaligned relative to each other in the direction parallel to the first surface due to thermal expansion.

[0015] (4) In the holding device of (1), (2), or (3) above, it is preferable that a resin joint be interposed between the second surface and the third surface.

[0016] By providing a resin joint between the second and third surfaces, it is possible to ensure heat dissipation and a vacuum in the areas where the heat conduction member is not located, and it is also possible to further improve the bonding between the base member and the plate-like member.

[0017] [Details of the First Embodiment of the Present Disclosure] A first embodiment of the present disclosure will be described with reference to Figures 1 to 8. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. In the following description, when multiple identical components are used, only some of the components may be designated by reference numerals, and the reference numerals for other components may be omitted.

[0018] <Electrostatic chuck> The holding device of the present disclosure is an electrostatic chuck 100 that can attract and hold an object such as a semiconductor wafer or a glass substrate (hereinafter referred to as a "wafer W"). The electrostatic chuck 100 is attached to, for example, a processing chamber of a semiconductor manufacturing apparatus (not shown), and is used to perform various processes (film formation, etching, etc.) on the wafer W using plasma.

[0019] 1, the electrostatic chuck 100 includes a plate-like member 10, a base member 20, and a heat conductive member 30 (see FIG. 2). The electrostatic chuck 100 is capable of attracting and holding the wafer W by electrostatic attraction.

[0020] <Base material> The base member 20 is a disk-shaped member and can be formed into a shape with, for example, a diameter of approximately 340 mm and a thickness of approximately 35 mm. The base member 20 is mainly composed of a conductive material such as aluminum or an aluminum alloy. Here, the term "main component" refers to the component with the largest content (weight percentage). As shown in FIG. 2, the base member 20 has a third surface 20A disposed on the plate-like member 10 side and a fourth surface 20B disposed on the opposite side to the third surface 20A. The third surface 20A is disposed on the upper side of the base member 20, and the fourth surface 20B is disposed on the lower side of the base member 20.

[0021] A coolant flow path 21 is provided inside the base member 20. The coolant flow path 21 is connected to a coolant circulation device (not shown). The coolant circulation device is configured to circulate a coolant such as a fluorine-based inert liquid or water through the coolant flow path 21. When the coolant flows through the coolant flow path 21, the base member 20 is cooled, and heat transfer (heat dissipation) between the base member 20 and the plate-shaped member 10 via the thermal conduction member 30 (described later) cools the plate-shaped member 10, and the wafer W held on the first surface 10A of the plate-shaped member 10 is cooled. This allows the temperature of the wafer W to be controlled.

[0022] <Concave, narrow, wide> As shown in FIG. 3, the base member 20 has a plurality of recesses 22 recessed downward (toward the fourth surface 20B) from the third surface 20A. Each recess 22 has a narrow portion 23 and a wide portion 24 that is wider than the narrow portion 23 in the horizontal direction (a direction parallel to the first surface 10A). The narrow portion 23 communicates with the wide portion 24 and is disposed closer to the third surface 20A than the wide portion 24. As shown in FIG. 4, the narrow portion 23 and the wide portion 24 may be formed in a substantially circular shape when viewed from above. Alternatively, the narrow portion 23 and the wide portion 24 may be formed in a substantially polygonal shape when viewed from above.

[0023] <Plate-shaped components> The plate-shaped member 10 has an overall disk shape and can be formed into a shape with, for example, a diameter of approximately 300 mm and a thickness of approximately 5 mm. The plate-shaped member 10 is an insulating substrate formed of, for example, ceramics containing aluminum nitride (AlN) or alumina (Al2O3) as its main component. The plate-shaped member 10 has a first surface 10A (see FIG. 1) that holds the wafer W, and a second surface 10B (see FIG. 2) that is disposed on the opposite side of the first surface 10A. As shown in FIG. 2, the first surface 10A is disposed on the upper side of the plate-shaped member 10, and the second surface 10B is disposed on the lower side of the plate-shaped member 10. The second surface 10B is disposed opposite a third surface 20A of the base member 20.

[0024] A chuck electrode 40 made of a conductive material (e.g., tungsten, molybdenum, platinum, etc.) is disposed on the first surface 10A side of the interior of the plate-shaped member 10. When a voltage is applied to the chuck electrode 40 from a chuck power supply (not shown) via a chuck electrode terminal (not shown), an electrostatic attraction force is generated, and the wafer W is attracted and fixed to the first surface 10A of the plate-shaped member 10 by this electrostatic attraction force.

[0025] Furthermore, a heater electrode 50 made of a resistance heating element containing a conductive material (for example, tungsten, molybdenum, platinum, etc.) is disposed inside the plate-shaped member 10. When a voltage is applied to the heater electrode 50 from a heater power supply (not shown) via a heater electrode terminal (not shown), the heater electrode 50 generates heat, thereby heating the plate-shaped member 10 and the wafer W held on the first surface 10A of the plate-shaped member 10. This allows control of the temperature distribution of the wafer W to be achieved.

[0026] <Thermal conductive material> A plurality of heat conducting members 30 are joined to the second surface 10B of the plate-shaped member 10. The heat conducting members 30 are made of metal such as aluminum, copper, or stainless steel. The plate-shaped member 10 and the heat conducting members 30 are joined by brazing, for example. The dimension (outer diameter) of the heat conducting members 30 as viewed from the top and bottom is, for example, about 5 to 10 mm.

[0027] <Shaft, return part> As shown in Fig. 3, the heat conduction member 30 includes a shaft portion 31 and a return portion 32 formed at the tip of the shaft portion 31. The shaft portion 31 is connected to the second surface 10B and extends toward (downward from) the base member 20. The return portion 32 is disposed at the lower end of the shaft portion 31. The return portion 32 has a shape that protrudes horizontally from the shaft portion 31. As shown in Fig. 4, the heat conduction member 30 of this embodiment is provided with four return portions 32, which are shaped to radiate out from the shaft portion 31 when viewed in the vertical direction.

[0028] 3, in the electrostatic chuck 100, the heat conduction member 30 is accommodated in the recess 22 of the base member 20. The shaft portion 31 is inserted into the narrow width portion 23, and the return portion 32 is disposed in the wide width portion 24. The return portion 32 extends horizontally outward beyond the narrow width portion 23. This prevents the heat conduction member 30 from slipping out of the recess 22. The return portion 32 is in contact with the inner wall of the wide width portion 24. Therefore, heat is easily conducted between the base member 20 and the plate-like member 10 via the heat conduction member 30.

[0029] In this embodiment, the thermal expansion coefficient of the ceramic material that is the main component of the plate-shaped member 10 is different from the thermal expansion coefficient of the conductive material that is the main component of the base member 20. In detail, the thermal expansion coefficient of the ceramic material that is the main component of the plate-shaped member 10 is smaller than the thermal expansion coefficient of the conductive material that is the main component of the base member 20. Therefore, when the temperature of the electrostatic chuck 100 changes, a difference occurs in the magnitude of dimensional change due to thermal expansion between the plate-shaped member 10 and the base member 20.

[0030] For example, when the temperature of the electrostatic chuck 100 changes, the base member 20 expands or contracts more than the plate-like member 10 in the horizontal direction, which may cause the inner wall of the narrow portion 23 to come into pressure contact with the shank 31, resulting in damage to the recess 22 and the heat conduction member 30. However, in this embodiment, the horizontal dimension of the narrow portion 23 is set to be larger than the horizontal dimension of the shank 31, and a gap CL is provided between the inner wall of the narrow portion 23 and the shank 31. As a result, even when the temperature of the electrostatic chuck 100 changes, the inner wall of the narrow portion 23 is less likely to come into contact with the shank 31 due to dimensional changes caused by thermal expansion, thereby preventing damage to the recess 22 and the heat conduction member 30.

[0031] Hereinafter, the shape of the heat conduction member 30 and the insertion of the heat conduction member 30 into the recess 22 will be described using a heat conduction member 30A (first specific example) and a heat conduction member 30B (second specific example) as examples. Note that the shape of the heat conduction member 30 of the present disclosure and the method of inserting the heat conduction member 30 into the recess 22 are not limited to these specific examples.

[0032] <First specific example> 5 before being inserted into the recess 22, the heat conductive member 30A according to the first specific example has a shape as shown in FIG. 5, and the return portion 32 is not expanded relative to the shaft portion 31. The return portion 32 in the state before the heat conductive member 30A is inserted into the recess 22 is referred to as a leg portion 33. The leg portion 33 can be formed, for example, by making a slit in the lower end portion of the circular shaft portion 31.

[0033] When the heat conduction member 30A is inserted into the recess 22 with the legs 33 spread outward relative to the shaft 31 so as not to be wider than the narrow portion 23, the legs 33 come into sliding contact with the bottom surface of the recess 22, thereby forcing the legs 33 to spread outward relative to the shaft 31. This allows the return portion 32 to be in contact with the inner wall of the wide portion 24 of the recess 22 (see FIG. 6).

[0034] 6, recess 22 into which heat conduction member 30A is inserted may be provided with protrusions 25 that protrude from the bottom surface of recess 22 toward third surface 20A. This makes it easier for leg portions 33 to spread outward relative to shaft portion 31 when heat conduction member 30A is inserted into recess 22.

[0035] <Second specific example> 7, unlike heat conduction member 30A, heat conduction member 30B according to the second specific example has substantially the same shape before and after insertion into recess 22. Return portion 32 of heat conduction member 30B is formed as an elastic piece 34 that is elastically deformable with shaft portion 31 as its base end. Elastic piece 34 can be formed, for example, by press-working the tip end of cylindrical shaft portion 31.

[0036] 8, when heat conduction member 30B is inserted into recess 22, elastic pieces 34 come into sliding contact with the inner wall of narrow portion 23 and are elastically deformed. When heat conduction member 30B is further pushed into recess 22, elastic pieces 34 reach inside wide portion 24. Elastic pieces 34 return to their natural state or come into contact with the inner wall of wide portion 24 in a slightly elastically deformed state.

[0037] <Effects of the First Embodiment> As described above, the holding device (electrostatic chuck 100) of the first embodiment includes an insulating plate-like member 10 having a first surface 10A for holding an object (wafer W) and a second surface 10B located opposite to the first surface 10A, a base member 20 having a third surface 20A disposed opposite to the second surface 10B, and a plurality of metal heat conduction members 30 joined to the second surface 10B of the plate-like member 10, and the base member 20 has a plurality of recesses recessed from the third surface 20A and each accommodating at least a portion of the heat conduction members 30. 22 is formed, and the recess 22 has a narrow portion 23 and a wide portion 24 that is formed wider than the narrow portion 23 in a direction parallel to the first surface 10A, and the narrow portion 23 is connected to the wide portion 24 and is arranged closer to the third surface 20A than the wide portion 24, and the heat conduction member 30 has a shaft portion 31 extending from the second surface 10B toward the base member 20 and a return portion 32 formed at the tip of the shaft portion 31, and the shaft portion 31 is inserted into the narrow portion 23, and the return portion 32 contacts the inner wall of the wide portion 24 to prevent the heat conduction member 30 from slipping out of the recess 22.

[0038] The metallic heat conducting member 30 is disposed so as to contact the inner wall of the wide portion 24 of the recess 22 of the base member 20, thereby improving heat conduction between the base member 20 and the plate-shaped member 10. Furthermore, the return portion 32 prevents the heat conducting member 30 from slipping out of the recess 22, thereby improving the bonding between the base member 20 and the plate-shaped member 10.

[0039] In embodiment 1, when the thermal expansion coefficient of the material that mainly constitutes the plate-shaped member 10 is different from the thermal expansion coefficient of the material that mainly constitutes the base member 20, a gap CL is provided between the inner wall of the narrow portion 23 and the shaft portion 31.

[0040] When there is a difference in thermal expansion between the plate-shaped member 10 and the base member 20, the plate-shaped member 10 and the base member 20 are arranged so as to be misaligned with each other in the direction parallel to the first surface 10A due to thermal expansion. In the above configuration, because the gap CL is provided between the inner wall of the narrow width portion 23 and the shaft portion 31, damage to the heat conduction member 30 can be suppressed even when the plate-shaped member 10 and the base member 20 are arranged so as to be misaligned with each other in the direction parallel to the first surface 10A due to thermal expansion.

[0041] [Details of the Second Embodiment of the Present Disclosure] A second embodiment of the present disclosure will be described with reference to Fig. 9. An electrostatic chuck 200 of the second embodiment includes a plate-shaped member 10, a base member 20, and a heat conduction member 130. The heat conduction member 130 differs from the heat conduction member 30 of the first embodiment in that it includes an expanded diameter portion 135. The other configurations of the second embodiment are the same as those of the first embodiment, and therefore the same members as those of the first embodiment are denoted by the same reference numerals and will not be described again.

[0042] The heat conduction member 130 includes a shaft portion 31, a return portion 32, and an expanded diameter portion 135 disposed on the second surface 10B side (upper side) of the shaft portion 31. The expanded diameter portion 135 expands outward in a horizontal direction (a direction parallel to the first surface 10A) relative to the shaft portion 31. When viewed in the vertical direction, the expanded diameter portion 135 has, for example, a polygonal or circular shape. An end face of the expanded diameter portion 135 on the second surface 10B side (upper side) is joined to the second surface 10B. The expanded diameter portion 135 has an opposing surface 136 disposed opposite the third surface 20A of the base member 20. The vertical and horizontal dimensions of the expanded diameter portion 135 are set so that at least a portion of the opposing surface 136 contacts the third surface 20A.

[0043] <Effects of the Second Embodiment> In the second embodiment, the heat conducting member 130 includes an expanded diameter portion 135 that expands in diameter from the shaft portion 31 in a direction parallel to the first surface 10A, and the expanded diameter portion 135 is in contact with the third surface 20A.

[0044] Since the expanded diameter portion 135 contacts the third surface 20A of the base member 20, the heat conduction between the base member 20 and the plate-like member 10 can be further improved.

[0045] [Details of the Third Embodiment of the Present Disclosure] A third embodiment of the present disclosure will be described with reference to Fig. 10. An electrostatic chuck 300 of the third embodiment differs from the electrostatic chuck 100 of the first embodiment in that it includes a joint 260 that joins the plate-shaped member 10 and the base member 20. The other configurations of the third embodiment are the same as those of the first embodiment, and therefore the same members as those of the first embodiment are denoted by the same reference numerals and will not be described again.

[0046] The bonding portion 260 is made of an adhesive such as a silicone resin, an acrylic resin, or an epoxy resin. The bonding portion 260 is disposed between the second surface 10B of the plate-shaped member 10 and the third surface 20A of the base member 20. The bonding portion 260 is disposed so as to surround at least the recessed portion 22 and the heat conductive member 30. When the bonding portion 260 occupies almost the entire space between the second surface 10B and the third surface 20A, the bonding portion 260 is formed with through holes 261 at positions corresponding to the recessed portion 22 and the heat conductive member 30.

[0047] <Effects of the Third Embodiment> In the third embodiment, a resin joint 260 is interposed between the second surface 10B and the third surface 20A.

[0048] By providing the resin joint 260 between the second surface 10B and the third surface 20A, it is possible to ensure heat removal and a vacuum in the portion where the heat conduction member 30 is not disposed. In addition, it is possible to further improve the bonding between the base member 20 and the plate-like member 10.

[0049] [Details of the Fourth Embodiment of the Present Disclosure] A fourth embodiment of the present disclosure will be described with reference to Fig. 11. An electrostatic chuck 400 of the fourth embodiment includes the heat conduction member 130 of the second embodiment and the bonding portion 260 of the third embodiment. The configuration and effects of the fourth embodiment are similar to those described in the first to third embodiments, and therefore will not be described again.

[0050] [Details of the Fifth Embodiment of the Present Disclosure] A fifth embodiment of the present disclosure will be described with reference to Fig. 12. An electrostatic chuck 500 of the fifth embodiment differs from that of the first embodiment in the shape of a return portion 432 of a heat conduction member 430. The other configurations of the fifth embodiment are the same as those of the first embodiment, and therefore the same members as those of the first embodiment are denoted by the same reference numerals and description thereof will be omitted.

[0051] The return portion 432 of the fifth embodiment has a pair of deformation portions 433 and a slit portion 434 that is surrounded by the pair of deformation portions 433. Before the heat conduction member 430 is inserted into the recess 22, the pair of deformation portions 433 extend in the vertical direction, and the across dimension of the pair of deformation portions 433 is approximately the same as that of the shaft portion 31. The slit portion 434 has an elongated hole shape that is long in the vertical direction.

[0052] When the heat conduction member 430 is inserted into the recess 22, the tip of the heat conduction member 430 abuts against the bottom surface of the recess 22, and the pair of deformation portions 433 deform so as to spread outward relative to the shaft portion 31. When the heat conduction member 430 is inserted deep into the recess 22, the pair of deformation portions 433 come into contact with the inner wall of the wide portion 24. In this state, the slit portion 434 has a long hole shape that is long in the horizontal direction.

[0053] The effects of the fifth embodiment are the same as those of the first embodiment, and therefore a description thereof will be omitted.

[0054] <Other embodiments> The shapes, sizes, etc. of the recess 22 and the heat conduction members 30, 130, 430 in the above-described embodiment are merely examples, and can be appropriately changed, for example, as described below. (1) The return portion does not have to be in a shape that spreads radially from the shaft portion. (2) The number of return portions provided on one heat conducting member may be set arbitrarily. [Explanation of symbols]

[0055] 10... Plate-shaped member 10A... First surface 10B... Second surface 20... Base member 20A... Third surface 20B... Fourth surface 21... Coolant flow path 22... Recess 23... Narrow portion 24... Wide portion 25... Protrusion 30, 130, 430...Heat conductive member 30A...Heat conductive member 30B...Heat conductive member 31...Shaft portion 32, 432...Burnt portion 33...Leg portion 34...Elastic piece 135...Expanded diameter portion 136...Opposite surface 433...Pair of deformation portions 434...Slit portion 40...Chuck electrode 50...Heater electrode 100, 200, 300, 400, 500...Electrostatic chuck 260...Joint part 261...Through hole CL...gap W...wafer

Claims

1. an insulating plate-like member having a first surface for holding an object and a second surface located opposite to the first surface; a base member having a third surface disposed opposite the second surface; a plurality of metal heat conduction members joined to the second surface of the plate-like member, the base member has a plurality of recesses formed therein that are recessed from the third surface and each of which accommodates at least a portion of the heat conduction member; the recess has a narrow portion and a wide portion that is wider than the narrow portion in a direction parallel to the first surface, the narrow portion communicates with the wide portion and is disposed closer to the third surface than the wide portion; the heat conduction member includes a shaft portion extending from the second surface toward the base member, and a return portion formed at a tip end of the shaft portion, The shaft portion is inserted through the narrow portion, The retaining device, wherein the return portion contacts an inner wall of the wide portion and prevents the heat conduction member from slipping out of the recess.

2. the heat conduction member includes an expanding portion that expands in diameter from the shaft portion in a direction parallel to the first surface, The retaining device of claim 1 , wherein the enlarged diameter portion contacts the third surface.

3. The thermal expansion coefficient of the material that mainly constitutes the plate-shaped member and the material that mainly constitutes the base member When the thermal expansion coefficient of the The holding device according to claim 1 or 2, wherein a gap is provided between an inner wall of the narrow portion and the shaft portion.

4. The holding device according to claim 1 or 2, wherein a resin joint is interposed between the second surface and the third surface.

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