Holding device

Abstract

To suppress influences exerted upon a function of a through hole by intruding a hole sealing agent into a through hole of a base part when hole sealing processing is applied to a spray layer of a surface of the base part.SOLUTION: A holding device for holding a subject comprises: a tabular part which is formed in a tabular shape; a base part which contains a metal, is formed in a tabular shape including a pair of principal surfaces and includes a through hole forming openings on the pair of principal surfaces and in which a spray layer is formed by sealing pores on one principal surface in the pair of principal surfaces; and an adhesive layer which contains an adhesive, is disposed between the tabular part and the one principal surface of the base part and adheres the tabular part and the base part. The through hole of the base part includes a step of which the inner width is changed in such a manner that an inner width in an end part of the through hole including the opening provided on one principal surface is larger than an inner width in the other portion of the through hole.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Conventionally, electrostatic chucks have been known as holding devices for holding objects, such as wafers during semiconductor manufacturing. An electrostatic chuck generally includes a ceramic portion on which the object is placed, a base portion in which a flow path such as a coolant flow path is formed, and a joining portion that joins the ceramic portion to the base portion. In such electrostatic chucks, a thermally sprayed layer made of a ceramic or other material is provided on the surface or side of a component such as the base portion in order to improve plasma resistance and voltage resistance in a plasma environment, for example (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-243139 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-185391 Summary of the Invention [Problem to be solved by the invention]

[0004] However, thermal spray layers generally have micropores that extend three-dimensionally within the thermal spray layer, which can allow gas to flow through the thermal spray layer. Specifically, the base of an electrostatic chuck generally has various through-holes that penetrate the base in the thickness direction, such as through-holes through which gas flows and through-holes that communicate with the atmosphere. Therefore, when gas flows through the thermal spray layer, the thermal spray layer formed at the openings of these through-holes can cause problems such as the gas flowing through the micropores in the thermal spray layer leaking to the outside of the electrostatic chuck, or air flowing into a chamber in which the electrostatic chuck is placed through the micropores and through-holes in the thermal spray layer. Furthermore, air can flow into the through-holes through which gas flows via the micropores in the thermal spray layer and other through-holes.

[0005] To solve the problem of gas flowing through the thermal spray layer, a technique of performing a sealing treatment on the thermal spray layer using a resin or the like is known, as described in Patent Document 2, for example. However, when performing a sealing treatment to block the micropores in the thermal spray layer, a new problem may arise in that the resin solution used in the sealing treatment may enter the through-holes in the base portion and affect the function of the through-holes. This problem is not limited to electrostatic chucks, but is common to holding devices that have through-holes that penetrate through the thickness direction and have a member on the surface of which a thermal spray layer is formed. [Means for solving the problem]

[0006] The present disclosure can be realized in the following forms. (1) According to one aspect of the present disclosure, there is provided a holding device for holding an object, the holding device comprising: a plate-shaped portion formed in a plate shape; a plate-shaped base portion including a metal and having a pair of main surfaces, the base portion including a through hole forming an opening in each of the pair of main surfaces, the base portion having a sprayed layer with sealed pores formed on one of the pair of main surfaces; and an adhesive layer including an adhesive, disposed between the plate-shaped portion and the one main surface of the base portion, and adhering the plate-shaped portion and the base portion together, the through hole in the base portion having an inner width at an end portion including the opening provided in the one main surface being larger than the inner width of the other portion of the through hole. The inner width of the step portion changes so that the According to this type of holding device, the through hole in the base portion is provided with a step portion, so that even if the sealing agent flows into the through hole when the sealing agent is applied to the thermal spray layer to seal the pores in the thermal spray layer, the sealing agent remains within the step portion, thereby preventing the sealing agent from flowing over the step portion into the through hole, thereby preventing the function of the through hole from being affected by the sealing agent flowing into the through hole. (2) In the holding device of the above embodiment, the opening in the one main surface of the base may include a resin layer formed so as to extend from the surface of the sprayed layer, beyond a side surface in a thickness direction of the sprayed layer, toward the step portion. With this configuration, the side surface in the thickness direction of the sprayed layer at the opening is sealed by the resin layer, thereby preventing gas from flowing through the sprayed layer via the side surface. (3) In the holding device having the above configuration, the resin layer may be formed so as to extend from the entire outer periphery of the opening in the one main surface of the base portion toward the stepped portion. With this configuration, it is possible to enhance the effect of suppressing gas flow within the sprayed layer via the side portion in the thickness direction of the sprayed layer. (4) In the holding device having the above configuration, the sprayed layer may have a chamfered portion at a portion covering the outer periphery of the opening in the one main surface of the base. With this configuration, damage to the sprayed layer due to stress concentration at the corners of the sprayed layer can be suppressed, and even if the chamfered portion makes it easier for the sealant to flow into the through hole, the sealant can be prevented from flowing over a step into the through hole. (5) In the holding device having the above configuration, the difference between the inner width of the end of the through hole including the opening provided in the one main surface and the inner width of the remaining portion of the through hole may be 2 mm or more and 8 mm or less. This configuration can enhance the function of retaining the sealant that has flowed into the through hole at the step portion, and can prevent a decrease in heat transfer between the plate-shaped portion and the base portion due to the through hole opening in one main surface of the base portion. (6) The holding device having the above configuration may be an electrostatic chuck including an electrostatic attraction electrode. This configuration can prevent the function of the through hole from being affected by a sealing agent for sealing pores in a thermal spray layer provided on the base portion flowing into the through hole in the base portion of the electrostatic chuck. The present disclosure can be realized in various forms other than those described above, for example, in the form of a semiconductor manufacturing apparatus including a holding device, a manufacturing method for a holding device, and the like. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view illustrating a schematic appearance of an electrostatic chuck according to a first embodiment. [Figure 2] FIG. 1 is a cross-sectional view schematically illustrating a configuration of an electrostatic chuck. [Figure 3] FIG. 4 is an explanatory diagram showing an example of the arrangement of through holes formed in the base portion. [Figure 4] FIG. 4 is a schematic cross-sectional view illustrating the configuration of a step portion. [Figure 5] 5 is an enlarged schematic cross-sectional view showing a portion indicated as region A in FIG. 4. [Figure 6] FIG. 10 is an explanatory diagram showing how a jig is used during a sealing treatment. [Figure 7] FIG. 10 is a schematic cross-sectional view illustrating a base portion of a comparative example that does not have a step portion. [Figure 8] FIG. 10 is a cross-sectional view showing the configuration of a base portion according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. First embodiment: (A-1) Structure of electrostatic chuck: FIG. 1 is a perspective view showing an outline of the appearance of an electrostatic chuck 10 according to a first embodiment. FIG. 2 is a cross-sectional view showing a schematic configuration of the electrostatic chuck 10. In FIG. 1, a part of the electrostatic chuck 10 is cut away. In addition, in FIG. 1, FIG. 2, and FIG. 3, FIG. 4, and FIG. 6 to FIG. 8 described later, mutually orthogonal X, Y, and Z axes are shown to identify directions. The X, Y, and Z axes shown in each figure each indicate the same direction. In this specification, the Z axis is a vertical axis. The X-axis and Y-axis indicate the horizontal direction. Note that each figure shows the arrangement of each part constituting the electrostatic chuck 10 in a schematic manner, and does not accurately represent the dimensional ratio of each part.

[0009] The electrostatic chuck 10 is a device that attracts and holds an object by electrostatic attraction, and is used, for example, to fix a wafer as the object in a vacuum chamber of a semiconductor manufacturing device. The electrostatic chuck 10 includes a ceramic portion 20, a base portion 30, and an adhesive layer 40. These are stacked in the order of the ceramic portion 20, the adhesive layer 40, and the base portion 30 in the -Z axis direction (vertically downward). The electrostatic chuck 10 in this embodiment is also referred to as a "holding device."

[0010] The ceramic portion 20 is a substantially circular plate-like member, and is formed mainly from ceramic (for example, aluminum oxide or aluminum nitride). The diameter of the ceramic portion 20 may be, for example, about 50 mm to 500 mm, and is usually about 200 mm to 350 mm. The thickness of the ceramic portion 20 may be, for example, about 1 mm to 10 mm. The ceramic portion 20 is also called a "plate-like portion."

[0011] As shown in FIG. 2, a chuck electrode 22 (electrode for electrostatic attraction) is disposed inside the ceramic portion 20. The chuck electrode 22 is formed of a conductive material such as tungsten or molybdenum. When a voltage is applied to the chuck electrode 22 from a power supply (not shown), an electrostatic force is generated, and the wafer is attracted and fixed to the mounting surface 24 of the ceramic portion 20 by this electrostatic force. The chuck electrode 22 may be of either a bipolar or unipolar type. In addition, a heater electrode (not shown) may be provided inside the ceramic portion 20. The heater electrode is a resistance heating element formed of a conductive material (such as tungsten or molybdenum) and is used to heat the wafer attracted and fixed to the mounting surface 24.

[0012] The base portion 30 is a plate-like member containing metal and formed into a substantially circular shape. The base portion 30 of this embodiment is formed using a metal containing aluminum (aluminum or an aluminum alloy). From the viewpoint of increasing the cooling efficiency of the base portion 30 while reducing manufacturing costs, it is desirable that the base portion 30 contain a high metal content, and it is desirable that the base portion 30 be mainly composed of metal. For example, it is desirable that the base portion 30 contain 90 mass % or more of aluminum, which is highly versatile (for example, aluminum alloy such as A6061 or A5052). However, the base portion 30 may also contain components other than metal, such as ceramic. The diameter of the base portion 30 may be, for example, approximately 220 mm to 550 mm, and is typically 220 mm to 350 mm. The thickness of the base portion 30 may be, for example, approximately 20 mm to 40 mm.

[0013] A plurality of refrigerant flow paths 31 are formed inside the base portion 30 along the XY plane. The base portion 30 is cooled by flowing a refrigerant, such as a fluorine-based inert liquid, water, or liquid nitrogen, through the refrigerant flow paths 31. The ceramic portion 20 is cooled by heat transfer between the base portion 30 and the ceramic portion 20 via the adhesive layer 40, and the wafer held on the mounting surface 24 of the ceramic portion 20 is cooled. This allows for wafer temperature control. In addition to the configuration in which the refrigerant flow paths 31 are formed inside the base portion 30, the base portion 30 may be provided with a cooling function by cooling the base portion 30 from the outside of the base portion 30.

[0014] As shown in Fig. 2, the base portion 30 has a sprayed layer 35 formed on it so as to cover the surface of the base portion 30. Specifically, the base portion 30, which is a plate-shaped member, has a pair of main surfaces, and the sprayed layer 35 is formed on a portion of one of the pair of main surfaces. In Fig. 2, the "surface facing the ceramic portion 20" of the surfaces of the base portion 30 corresponds to the above-mentioned "one of the main surfaces." The base portion 30 of this embodiment further has a sprayed layer 35 on a side surface parallel to the Z-axis direction. The sprayed layer 35 may also be formed on the other of the pair of main surfaces of the base portion 30 (the back surface of the base portion 30 in the −Z-axis direction).

[0015] The sprayed layer 35 can be formed by, for example, plasma spraying. Examples of materials that can be used to form the sprayed layer 35 include yttrium oxide (yttria: Y2O3), aluminum oxide (alumina: Al2O3), aluminum nitride, zirconium oxide (zirconia: ZrO2), alumina-zirconia, spinel, aluminum yttrium garnet (YAG), yttrium fluoride (YF3), and yttrium oxyfluoride (YOF). Yttria is particularly desirable. The thickness of the sprayed layer 35 can be, for example, 200 μm to 1 mm.

[0016] A sealant layer 37 is formed on a surface portion, including the surface, of the thermal spray layer 35. The thermal spray layer 35 has micropores extending three-dimensionally within it. By subjecting the thermal spray layer 35 to a sealing treatment using a sealant, the pores are sealed with the sealant to form a sealant layer 37 in the surface portion, including the surface, of the thermal spray layer 35. Examples of the sealant used in the sealing treatment include resin materials such as silicone resin, epoxy resin, polyester resin, polytetrafluoroethylene, and polyimide. To perform the sealing treatment, a liquid sealant containing one of these materials may be applied to the thermal spray layer 35 by a method such as screen printing, and the sealant may then be infiltrated into the pores of the thermal spray layer 35 by vacuum degassing or the like. The sealant may then be heated at a temperature and for a time set according to the sealant, drying and curing the sealant to form the sealant layer 37. As the sealing agent, in addition to a resin material, a ceramic material such as yttrium oxide (yttria: Y2O3) may be used to form sealing agent layer 37 by a sol-gel method. If the penetration of the sealing agent into thermal spray layer 35 causes unevenness to form on the surface of sealing agent layer 37, the surface of sealing agent layer 37 may be flattened by polishing or the like.

[0017] The base portion 30 further has a plurality of through holes that form openings in each of the pair of main surfaces. Each through hole has a step portion 32 at an end of the through hole, including the opening of the through hole provided in one of the main surfaces of the base portion 30. In FIG. 2, a temperature sensor hole 54 and a gas flow path hole 50 are shown as examples of through holes. The configurations of the through holes provided in the base portion 30 and the step portions 32 provided in the through holes will be described in detail later.

[0018] The adhesive layer 40 is disposed between one main surface of the base portion 30, on which the thermal spray layer 35 and the sealing agent layer 37 are formed, and the ceramic portion 20, to bond the base portion 30 and the ceramic portion 20. The adhesive layer 40 contains an adhesive such as a silicone resin, an acrylic resin, or an epoxy resin. The adhesive layer 40 may contain an inorganic filler such as ceramic powder. The thickness of the adhesive layer 40 can be, for example, about 100 μm to 1 mm.

[0019] (A-2) Configuration relating to the step portion of the through hole: FIG. 3 is an explanatory diagram showing an example of the arrangement of through holes formed in the base portion 30, and shows the electrostatic chuck 10 as viewed from above (as viewed in the −Z-axis direction). First, the through holes formed in the base portion 30 will be described below. The multiple through holes formed in the base portion 30 are formed in a region that overlaps with the ceramic portion 20 when viewed from above, and in FIG. 3, each through hole is represented by its position relative to the ceramic portion 20. As shown in FIG. 3, the base portion 30 of this embodiment includes gas flow path holes 50 and 51, a lift pin hole 53, a temperature sensor hole 54, and a chuck terminal hole 55 as through holes. In FIG. 3, holes that penetrate to the surface (mounting surface 24) of the ceramic portion 20 are represented by solid lines, and holes that do not penetrate to the surface of the ceramic portion 20 are represented by dotted lines. Hereinafter, both the through-holes provided in the base portion 30 and the hole structure formed in the electrostatic chuck 10 and at least a part of which is constituted by the through-holes provided in the base portion 30 will be referred to as the gas flow passage holes 50, 51, and the lift pipe 12. These are called a chuck hole 53, a temperature sensor hole 54, and a chuck terminal hole 55. In addition, in Fig. 3, the position of the cross section shown in Fig. 2 is shown as the 2-2 cross section.

[0020] The gas flow passage holes 50 and 51 are provided penetrating the base portion 30, the thermal spray layer 35, the adhesive layer 40, and the ceramic portion 20 in the Z direction, and open to a gas discharge port 52 formed in the mounting surface 24 (see FIGS. 1 and 2). The gas flow passage holes 50 and 51 are flow passages through which an inert gas, such as helium gas, supplied from a gas supply device (not shown) flows. The gas flow passage hole 50 is a flow passage through which the inert gas flows, and the gas flow passage hole 51 is a flow passage through which an inert gas is supplied from a separate system. The inert gas supplied from the gas supply device is discharged from the gas discharge port 52 into the space between the mounting surface 24 and a wafer placed on the mounting surface 24. This improves heat transfer between the ceramic portion 20 and the wafer, further improving controllability of the temperature distribution of the wafer.

[0021] Like the gas flow path holes 50 and 51, the lift pin hole 53 is provided so as to penetrate not only the base portion 30 but also the thermal spray layer 35, the adhesive layer 40, and the ceramic portion 20 in the Z direction. The lift pin hole 53 has a hole structure into which a lift pin is inserted for raising and lowering a wafer placed on the mounting surface 24 of the electrostatic chuck 10. The lift pin is provided as an attachment to a vacuum chamber of a semiconductor manufacturing device in which the electrostatic chuck 10 is housed.

[0022] The temperature sensor hole 54 is provided so as to penetrate the base portion 30 as well as the thermal spray layer 35 and the adhesive layer 40 in the Z direction, but does not penetrate the ceramic portion 20 (see FIG. 2). The temperature sensor hole 54 is a hole structure for inserting a temperature sensor probe such as a thermocouple and positioning the temperature sensor probe in close proximity to the ceramic portion 20 to detect the temperature of the ceramic portion 20.

[0023] The chuck terminal hole 55 is provided so as to penetrate not only the base portion 30 but also the sprayed layer 35 and the adhesive layer 40 in the Z direction and extend into the ceramic portion 20. The chuck terminal hole 55 has a hole structure for arranging wiring that is electrically connected to an electrode terminal of the chuck electrode 22 (electrostatic attraction electrode) provided inside the ceramic portion 20.

[0024] The base portion 30 may further have other through holes. For example, if a heater electrode for heating the wafer is provided inside the ceramic portion 20, heater terminal holes may be provided, which are hole structures for arranging wiring electrically connected to the heater terminals of the heater electrode. The arrangement of each through hole may be different from that shown in FIG. 3. Each through hole may have a shape other than one that penetrates the base portion 30 straight in the vertical direction (Z-axis direction). For example, at least a portion of each through hole may have a shape that extends in a direction different from the vertical direction. Each through hole may have an opening in each of the pair of main surfaces of the base portion 30 and communicate between the pair of main surfaces.

[0025] FIG. 4 is a schematic cross-sectional view illustrating the configuration of the stepped portion 32, using the temperature sensor hole 54 as an example of one of the multiple through holes. FIG. 4 illustrates only a portion of the electrostatic chuck 10 near the outer periphery of the base portion 30, which has the thermal spray layer 35 and the sealing agent layer 37. Hereinafter, the temperature sensor hole 54 will be described as an example of a through hole, but the other through holes also have stepped portions 32 with a similar configuration. However, some of the through holes provided in the base portion 30 may not have stepped portions 32. The stepped portion 32 is a portion where the inner width of the through hole at the end including the opening of the through hole provided in one main surface of the base portion 30 changes so that it is larger than the inner width of the remaining portion of the through hole. The stepped portion 32 is designed to retain the liquid sealing agent flowing in from the opening when sealing is performed by applying a sealing agent to the thermal spray layer 35, thereby preventing the sealing agent from penetrating beyond the stepped portion 32 and into the through hole.

[0026] In this embodiment, the step portion 32 is formed so that, when the base portion 30 is viewed from above (when viewed in the −Z-axis direction), the outer periphery of the step portion 32 is concentric with the outer periphery of the other portion of the through hole other than the step portion 32. This provides the same effect of suppressing the intrusion of the sealing agent regardless of the position of the opening of the through hole from which the sealing agent flows into the through hole. However, when the base portion 30 is viewed from above (when viewed in the −Z-axis direction), the center of the outer periphery of the step portion 32 does not have to coincide with the center of the outer periphery of the other portion of the through hole other than the step portion 32. Furthermore, the step portion 32 has, as its inner wall surface, a step portion bottom surface 32a that is parallel to the horizontal direction (XY plane) and a step portion side surface 32b that extends upward in the vertical direction (Z-axis direction) from the outer periphery of the step portion bottom surface 32a. The bottom surface 32a of the step portion does not need to be a flat surface parallel to the horizontal direction, but may be, for example, a curved surface, and the side surface 32b of the step portion may have a shape extending in a direction different from the vertical direction. The step portion 32 only needs to have the function of retaining the sealing agent that has flowed in.

[0027] In FIG. 4 , the inner width of the temperature sensor hole 54 at a portion other than the stepped portion 32 is indicated as “φX,” and the inner width of the stepped portion 32 (the inner width at the end of the temperature sensor hole 54 including the opening) is indicated as “φX + α.” The magnitude of the difference in inner width, α, is desirably, for example, 2 mm or more from the viewpoint of ensuring the function of retaining the flowing sealing agent at the stepped portion 32. Furthermore, the magnitude of the difference in inner width, α, is desirably, for example, 8 mm or less from the viewpoint of suppressing uneven temperature distribution on the mounting surface 24 of the ceramic portion 20. This is because the larger the opening provided in one main surface of the base portion 30, the larger the area of ​​the portion of the ceramic portion 20 that is not in contact with the base portion 30, and the heat transfer from the ceramic portion 20 to the base portion 30 at the portion where the opening is formed may be insufficient.

[0028] 4, the depth of the step portion 32 (the size in the Z-axis direction) is indicated as "γ." The depth γ of the step portion 32 is desirably set to, for example, 0.5 mm or more in order to ensure the function of retaining the flowing sealing agent in the step portion 32. The depth γ of the step portion 32 is desirably set to, for example, 4 mm or less in order to prevent uneven temperature distribution on the mounting surface 2 side 4 of the ceramic portion 20. This is because making the step portion 32 deeper may also result in locally insufficient heat transfer from the ceramic portion 20 side to the base portion 30 side.

[0029] 4, the distance between the outer periphery of the opening of the stepped portion 32 and the outer periphery of the base portion 30 is indicated as "β." The distance β from the outer periphery of the base portion 30 is desirably 1 mm or more. This is to form the sprayed layer 35 with high precision and to prevent gas from passing between the through hole and the outside of the electrostatic chuck 10 via the sprayed layer 35. Note that the "distance between the outer periphery of the opening of the stepped portion 32 and the outer periphery of the base portion 30" is the shortest distance between the outer periphery of the opening of the stepped portion 32 and the outer periphery of the base portion 30.

[0030] In FIG. 4 , the portion of the sealing agent flowing into the step portion 32 from the opening of the step portion 32 in one main surface of the base portion 30 is shown as a drip portion 38. The drip portion 38 is formed in the opening in the one main surface of the base portion 30 so as to extend from the surface of the sprayed layer 35, over the side portion in the thickness direction of the sprayed layer 35, toward the step portion 32. This drip portion 38 is also referred to as a "resin layer." In FIG. 4 , the side portion in the thickness direction of the sprayed layer 35 at the opening of the step portion 32 is shown as a "side portion 39." In this embodiment, by applying the sealing agent to form the sealing agent layer 37 so as to form the drip portion 38, the side portion 39 of the sprayed layer 35 is sealed, thereby preventing gas from passing through the sprayed layer 35 via the side portion 39. Even if sealing agent layer 37 is formed by applying a sufficient amount of sealing agent so as to form dripping portions 38 that cover side surface portions 39, provision of step portions 32 can prevent the sealing agent from flowing over step portions 32 into the through holes. It is desirable that the opening be formed so as to extend from the entire periphery of the opening in one of the main surfaces of the insulating film 30 toward the stepped portion 32.

[0031] FIG. 5 is an enlarged cross-sectional view of the area surrounded by a dashed line as region A in FIG. 4 . That is, FIG. 5 illustrates the vicinity of the outer periphery of the opening of the stepped portion 32 in one main surface of the base portion 30. As shown in FIG. 5 , the thermal spray layer 35 preferably has a chamfered portion 36, which rounds off the corners, in a portion covering the outer periphery of the opening in one main surface of the base portion 30. When the thermal spray layer 35 is made of ceramic or the like, stress may concentrate at the corners of the thermal spray layer 35 when the electrostatic chuck 10 is subjected to vibration, which may damage the corners. By forming the chamfered portion 36 in the thermal spray layer 35 as shown in FIG. 5 , damage such as cracking caused by stress concentration at the corners can be suppressed. However, providing the chamfered portion 36 in the thermal spray layer 35 makes it easier for the sealant to flow (drip) into the through holes during the sealing process. By providing the step portion 32 as in this embodiment, problems caused by the inflow of sealing agent into the through hole can be effectively suppressed, even when the chamfered portion 36 is formed in the thermal spray layer 35. The chamfered portion 36 can be formed, for example, by polishing using a machining center. The "chamfered portion 36" may be formed by cutting off the corners, or may have a convex curved shape as shown in FIG. 5 . Alternatively, the height of the thermal spray layer 35 may gradually decrease toward the opening of the through hole. Any shape that can suppress stress concentration at the corners may be used. Furthermore, the chamfered portion 36 is not essential, and the thermal spray layer 35 may not necessarily have the chamfered portion 36.

[0032] FIG. 6 is an explanatory diagram showing how a jig is used during a hole sealing process. The jig 60 shown in FIG. 6(A) is generally cylindrical and has an outer diameter approximately equal to the inner diameter of the through hole (temperature sensor hole 54 in FIG. 6) for which the jig 60 is to be used. During a hole sealing process, the jig 60 is inserted into the through hole. That is, the jig 60 is inserted from the other main surface of the base portion 30 to the other main surface thereof so that its tip exceeds the stepped portion 32, or at least the bottom surface 32a of the stepped portion 32. With the jig 60 inserted in the through hole, a sealing agent is applied to the thermal spray layer 35, and the hole sealing process is performed. By using such a jig 60, even if an excessive amount of sealing agent flows into the stepped portion 32 relative to the size of the stepped portion 32, the sealing agent can be prevented from passing over the stepped portion 32 and entering the through hole. After the sealing agent is applied to the thermal spray layer 35, an appropriate process depending on the sealing agent, such as vacuum degassing or heating, may be performed, and then the jig 60 may be removed from the through hole. Figure 6(B) shows the use of another example of a jig, a jig 62 having a head structure for aligning the jig when inserting it into the through hole.

[0033] 6 shows the temperature sensor hole 54 among the through holes formed in the base portion 30, but a similar jig can be used for sealing the other through holes as well. Furthermore, instead of preparing a separate jig for each through hole, a jig integrally formed with multiple insertion portions for insertion into each of the multiple through holes may be used. The use of a jig such as that shown in FIG. 6 is not essential, and a jig may not be used if, for example, the amount of sealing agent applied can be adjusted to prevent the sealing agent from penetrating beyond the stepped portion 32 and into the through hole.

[0034] According to the electrostatic chuck 10 of the present embodiment configured as described above, the stepped portion 32 is provided in the through hole of the base portion 30, and therefore, when a sealing agent is applied to the thermal spray layer 35 to form the sealing agent layer 37, it is possible to prevent the sealing agent from flowing into the through hole and affecting the function of the through hole. Even if the sealing agent flows into the stepped portion 32, the sealing agent remains within the stepped portion 32, and therefore, the sealing agent is prevented from flowing beyond the stepped portion 32 into the through hole.

[0035] FIG. 7 shows a comparative example in which the surface of the base portion 130 does not have the step portion 32 and the thermal spray layer 35 and the sealing layer are formed on the surface of the base portion 130. 7A and 7B are cross-sectional schematic diagrams illustrating a state in which a sealing agent layer 37 is formed. FIG. 7 illustrates a temperature sensor hole 54 as an example of a through hole. If a sealing agent flows into a through hole that does not have a step portion 32, the following problems may occur. For example, as shown in FIG. 7 , when the through hole is a temperature sensor hole 54, a sensor probe 65 of a temperature sensor such as a thermocouple is inserted into the temperature sensor hole 54 to detect the temperature of the ceramic portion 20. FIG. 7A illustrates the flow of sealing agent into the temperature sensor hole 54 of the base portion 130, similar to FIG. 4 . FIG. 7B illustrates the insertion of the sensor probe 65 into the temperature sensor hole 54 in an electrostatic chuck 110 of a comparative example that includes such a base portion 130. As shown in FIG. 7B, the diameter of the temperature sensor hole 54 is reduced by the dripping portion 38, making it impossible to insert the sensor probe 65 into a position sufficiently close to the ceramic portion 20. As a result, the accuracy of detecting the temperature of the ceramic portion 20 may be reduced.

[0036] Similarly, if the through-holes are lift pin holes 53, the dripping portions 38 may reduce the diameter of the lift pin holes 53, hindering the insertion of lift pins into the lift pin holes 53 and potentially causing problems with the lifting and lowering of the wafer. Furthermore, if the through-holes are gas flow path holes 50, 51, the dripping portions 38 may reduce the diameter of the gas flow path holes 50, 51, changing the flow rate of the inert gas flowing through the gas flow path holes 50, 51, potentially reducing the effect of the inert gas in enhancing heat transfer between the ceramic portion 20 and the wafer. Furthermore, if the through-holes are chuck terminal holes 55 or heater terminal holes, the dripping portions 38 may reduce the diameter of the chuck terminal holes 55 or heater terminal holes, potentially causing insufficient conduction between the electrodes via wiring. According to this embodiment, a step portion 32 is provided in the through hole, which prevents the sealing agent from flowing beyond the step portion 32 into the through hole. This prevents the above-mentioned inconvenience caused by the sealing agent reducing the diameter of the through hole, and ensures the functionality of the through hole.

[0037] B. Second embodiment: 8 is a cross-sectional view similar to FIG. 4, showing the configuration of a base portion 30 included in an electrostatic chuck according to a second embodiment. The base portion 30 according to the second embodiment is used in an electrostatic chuck similar to the electrostatic chuck 10 according to the first embodiment, and includes a sealing agent layer 237 and a resin layer 238 instead of the sealing agent layer 37. In the second embodiment, parts common to those in the first embodiment are denoted by the same reference numerals.

[0038] The sealant layer 237 of the second embodiment is formed of a sealant similar to that of the sealant layer 37 of the first embodiment, and the resin layer 238 is formed of a resin material. The resin material constituting the resin layer 238 can be the same resin as that constituting the sealant layer 37, and preferably an adhesive. Examples of suitable resin materials include a silicone adhesive, an epoxy adhesive, and a polyimide adhesive. When manufacturing an electrostatic chuck, a sealant is applied to the surface of the thermal spray layer 35 to form the sealant layer 237. Then, a resin material for forming the resin layer 238 is applied along the periphery of the opening of the stepped portion 32 on one main surface of the base portion 30 using, for example, a dispenser. The resin material is then heated at a temperature and for a time appropriate for the resin material, drying and curing the resin material to form the resin layer 238.

[0039] Even with this configuration, by providing the step portion 32 in the through hole, it is possible to obtain the same effect as in the first embodiment. Also, in the second embodiment, the shape and arrangement of the step portion 32 can be the same as in the first embodiment. That is, when the inner width of the other portion of the through hole different from the step portion 32 is "φX" and the inner width of the step portion 32 is "φX+α", it is desirable that the size of the difference in the inner width, α, is, for example, 2 mm or more from the viewpoint of ensuring the function of retaining the resin that has flowed in at the step portion 32. Also, the size of the difference in the inner width, α, is determined to be, for example, 2 mm or more, in order to prevent unevenness in the temperature distribution on the mounting surface 24 of the ceramic portion 20. From the viewpoint of suppressing non-uniformity of the temperature distribution on the mounting surface 24 of the ceramic part 20, the depth γ of the step part 32 is preferably set to, for example, 8 mm or less. From the viewpoint of ensuring the function of retaining the resin that flows in at the step part 32, the depth γ of the step part 32 is preferably set to, for example, 0.5 mm or more. Furthermore, from the viewpoint of suppressing non-uniformity of the temperature distribution on the mounting surface 24 of the ceramic part 20, the depth γ of the step part 32 is preferably set to, for example, 4 mm or less. Furthermore, the distance β between the outer periphery of the base part 30 and the outer periphery of the opening of the step part 32 is preferably set to 1 mm or more.

[0040] Furthermore, by providing resin layer 238 separately from sealing agent layer 237 formed by applying a sealing agent to thermal spray layer 35, it is possible to easily form a resin layer formed so as to extend from the surface of thermal spray layer 35 toward stepped portion 32, beyond side portion 39 in the thickness direction of thermal spray layer 35. Furthermore, since a resin material is disposed along the outer periphery of the opening of stepped portion 32 separately from the operation of applying a sealing agent to thermal spray layer 35, it is possible to more uniformly distribute the resin on side portion 39 of thermal spray layer 35, thereby improving the accuracy of sealing side portion 39 of thermal spray layer 35. Furthermore, because it is easy to form resin layer 238 so as to extend from the entire outer periphery of the opening in one main surface of base portion 30 toward stepped portion 32, it is possible to improve the reliability of sealing side portion 39 even when chamfered portion 36 is provided in thermal spray layer 35, for example, as shown in FIG. 5.

[0041] When the sealing agent layer 237 is made of a resin, the sealing agent constituting the sealing agent layer 37 and the resin constituting the resin layer 238 may be the same or different. For example, when the sealing agent layer 237 is formed using a silicone resin and the resin layer 238 is formed using a silicone-based resin, using the same resins improves the compatibility between the sealing agent layer 237 and the resin layer 238, thereby improving the reliability of the sealing. Furthermore, when the sealing agent layer 237 and the resin layer 238 are formed using different types of resins, selecting resins that allow each layer to perform more appropriately can improve the overall performance of the electrostatic chuck. For example, when a resin having a higher thermal conductivity than the resin constituting the sealing agent layer 237 is used as the resin constituting the resin layer 238, heat transfer from the ceramic portion 20 side at the opening of the step portion 32 where the resin layer 238 is provided can be improved. As a result, by providing a step portion 32 having an opening where the ceramic portion 20 and the base portion 30 do not come into contact, localized insufficient heat transfer between the ceramic portion 20 and the base portion 30 can be prevented, and the temperature distribution within the surface can be made uniform.

[0042] The present disclosure may be applied to holding devices other than electrostatic chucks that use electrostatic attraction to hold a wafer W. That is, the present disclosure is similarly applicable to other holding devices that include a plate-shaped member such as a ceramic member and a base portion as a coated structure bonded to the plate-shaped member and coated with a thermal spray layer, and that hold an object on the surface of the plate-shaped member, such as a heater device for a vacuum device for CVD, PVD, PLD, etc., or a vacuum chuck. In particular, the present disclosure is preferably applicable to devices used in a plasma environment where a thermal spray layer is desired to ensure corrosion resistance and voltage resistance.

[0043] The present disclosure is not limited to the above-described embodiments, and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0044] 10,110...Electrostatic chuck 20...Ceramic section 22...Chuck electrode 24...Placement surface 30,130...Base 31... Refrigerant flow path 32...Step 32a...bottom of step part 32b…Side surface of step part 35...Thermal spray layer 36...Beveled part 37,237...Sealing agent layer 38...Drip part 39...Side part 40...adhesive layer 50, 51...Gas flow passage holes 52...Gas outlet 53...Lift pin hole 54...Temperature sensor hole 55...Chuck terminal hole 60,62...Jig 65...Sensor probe 238...Resin layer

Claims

1. A holding device for holding an object, a plate-shaped portion formed in a plate shape; a plate-shaped base portion including a metal and having a pair of main surfaces, each of the pair of main surfaces having a through hole forming an opening, and one of the pair of main surfaces having a sprayed layer with sealed pores formed thereon; an adhesive layer including an adhesive, the adhesive layer being disposed between the plate-shaped portion and the one main surface of the base portion to bond the plate-shaped portion and the base portion; the through hole of the base portion includes a stepped portion whose inner width changes so that an end portion of the through hole including the opening provided in the one main surface is larger than an inner width of another portion of the through hole; a space surrounded by an inner wall of the step portion is formed within the holding device, The holding device further comprises: The opening in the one main surface of the base portion is provided with a resin layer formed so as to extend from the surface of the sprayed layer, beyond the side surface in the thickness direction of the sprayed layer, toward the step portion. holding device.

2. 2. The holding device of claim 1, The resin layer is formed so as to extend from the entire periphery of the opening in the one main surface of the base portion to the step portion side. holding device.

3. 3. The holding device according to claim 1 or 2, The thermal spray layer has a chamfered portion at a portion covering the outer periphery of the opening in the one main surface of the base portion. holding device.

4. A holding device according to any one of claims 1 to 3, The difference between the inner width of the end of the through hole including the opening provided in the one main surface and the inner width of the other part of the through hole is 2 mm or more and 8 mm or less. holding device.

5. A holding device according to any one of claims 1 to 4, The electrostatic chuck is characterized by being equipped with an electrode for electrostatic attraction. holding device.

6. A holding device for holding an object, a plate-shaped portion formed in a plate shape; a plate-shaped base portion including a metal and having a pair of main surfaces, each of the pair of main surfaces having a through hole forming an opening, and one of the pair of main surfaces having a sprayed layer with sealed pores formed thereon; an adhesive layer including an adhesive, the adhesive layer being disposed between the plate-shaped portion and the one main surface of the base portion to bond the plate-shaped portion and the base portion; the through hole of the base portion includes a stepped portion whose inner width changes so that an end portion of the through hole including the opening provided in the one main surface is larger than an inner width of another portion of the through hole; The holding device further comprises: the opening in the one main surface of the base portion includes a resin layer formed so as to extend from the surface of the sprayed layer beyond the side surface in the thickness direction of the sprayed layer toward the step portion and in direct contact with the base portion. holding device.

7. A holding device for holding an object, a plate-shaped portion formed in a plate shape; a plate-shaped base portion including a metal and having a pair of main surfaces, each of the pair of main surfaces having a through hole forming an opening, and one of the pair of main surfaces having a sprayed layer with sealed pores formed thereon; an adhesive layer including an adhesive, the adhesive layer being disposed between the plate-shaped portion and the one main surface of the base portion to bond the plate-shaped portion and the base portion; the through hole of the base portion includes a stepped portion whose inner width changes so that an end portion of the through hole including the opening provided in the one main surface is larger than an inner width of another portion of the through hole; a space surrounded by an inner wall of the step portion is formed within the holding device, The thermal spray layer has a chamfered portion at a portion covering the outer periphery of the opening in the one main surface of the base portion. holding device.

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