Holding device

Abstract

To provide a holding device which prevents trouble caused by a circulation of gas or atmospheric air flowing in a through hole via a pore and the through hole in a spray layer which is formed on an electrostatic chuck surface and uses ceramic, etc., as a material.SOLUTION: An electrostatic chuck 10 which is a holding device for holding a subject comprises: a ceramic part 20 which is a tabular part formed in a tabular shape; a base part 30 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 35 is formed in a portion of one principal surface in the pair of principal surfaces; an adhesive layer 40 which contains an adhesive, is disposed between the tabular part and one principal surface of the base part and adheres the tabular part and the base part; and a seal projection 60 which is provided so as to enclose the opening in a region closer to the opening than a region, where the spray layer is formed, in one principal surface of the base part and protrudes from one principal surface to the adhesive layer and of which the top portion is in contact with the adhesive layer.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 an adhesive layer that bonds 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 of a component such as the base portion in order to improve plasma resistance, durability, and voltage resistance in a plasma environment (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] 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, and completely sealing these micropores is extremely difficult. Here, the base portion of an electrostatic chuck generally has various through-holes that penetrate the base portion in the thickness direction. These through-holes may include, for example, through-holes that are open to the atmosphere when the electrostatic chuck is in use, and through-holes that are not connected to the atmosphere when the electrostatic chuck is in use and serve as, for example, a gas flow path. Therefore, when the electrostatic chuck is in use, there is a possibility of inconvenience caused by the gas or atmosphere flowing through the through-holes passing through the micropores and through-holes within the thermal spray layer. This problem is not limited to electrostatic chucks, but is a common problem with holding devices that include a member having through-holes that penetrate the thickness direction and on which a thermal spray layer is formed. [Means for solving the problem]

[0005] 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 including: 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, and a thermal sprayed layer formed on a portion of one of the pair of main surfaces; an adhesive layer including an adhesive and 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; and a sealing protrusion provided in a region of the one main surface of the base portion closer to the opening than the region where the thermal sprayed layer is formed, the sealing protrusion protruding from the one main surface toward the adhesive layer and having a top portion in contact with the adhesive layer so as to surround the opening. According to this type of holding device, the sealing protrusion is provided to surround the opening of the through hole provided in the base portion, and the sealing protrusion prevents gas from flowing between the through hole and the thermal spray layer, thereby reducing inconveniences caused by undesirable gas flow within the holding device through the micropores and through holes in the thermal spray layer. (2) In the holding device of the above embodiment, the through-holes present in the region surrounded by the sealing protrusions may be through-holes that are open to the atmosphere when the holding device is in use. With this configuration, it is possible to prevent the atmosphere from flowing into the space in which the holding device is disposed or into other through-holes through the micropores and through-holes in the thermal spray layer. (3) In the holding device of the above embodiment, the through-hole present in the region surrounded by the sealing protrusion may be a through-hole that is not in communication with the atmosphere when the holding device is in use. With this configuration, it is possible to suppress inconveniences caused by communication between the through-hole and the space in which the holding device is disposed, or communication between the through-hole and other through-holes, via micropores in the sprayed layer. (4) In the holding device of the above aspect, the one main surface of the base portion may have a plurality of the openings, and the sealing protrusion may be formed to surround each of the plurality of openings. With this configuration, it is possible to suppress undesired gas flow through the micropores in the thermal spray layer in each of the through holes corresponding to the plurality of openings. (5) In the holding device of the above embodiment, the sealing protrusion may be a resin convex structure bonded to the base portion. With this configuration, by forming the sealing protrusion by bonding a resin convex structure to the base portion, it is possible to suppress undesired gas flow within the holding device through the micropores and through-holes in the thermal spray layer. Furthermore, using resin as the material for the sealing protrusion makes it easier to form the sealing protrusion compared to when, for example, a metal is used as the sealing protrusion, thereby facilitating the manufacturing process. Furthermore, when the sealing protrusion is a resin convex structure, the hardness is lower than when, for example, a metal convex structure. Therefore, even if there is some misalignment in the height of the sealing protrusion, the height is easily aligned due to the pressure applied when bonding the base portion and the plate-like portion. This eliminates the need for high-precision processing to align the height of the sealing protrusion, thereby preventing problems such as loss of adhesive adhesion due to misalignment in the height of the sealing protrusion. (6) In the holding device having the above configuration, the sealing protrusion may be a convex structure formed on one of the principal surfaces of the base portion as a surface structure of the base portion. With this configuration, by providing the sealing protrusion as a convex structure formed on one of the principal surfaces of the base portion as a surface structure of the base portion, it is possible to suppress the flow of undesired gas within the holding device through the micropores and through-holes in the thermal spray layer. Furthermore, by forming the sealing protrusion as part of the base portion, an adhesive layer or the like for bonding metal members is not required, compared to, for example, providing a separate metal sealing protrusion, and the bonding strength between the sealing protrusion and the base portion can be ensured. Furthermore, by forming the sealing protrusion as part of the base portion including metal, it is easier to ensure the bonding strength between the sealing protrusion and the plate-like portion compared to using a resin sealing protrusion. (7) In the holding device having the above configuration, the width of the top of the sealing protrusion may be 1 mm or more. With this configuration, the sealing protrusion can be more effectively prevented from blocking gas flow between the through hole and the thermal spray layer. (8) The holding device having the above-described configuration may be an electrostatic chuck having an electrostatic attraction electrode. With this configuration, it is possible to suppress undesirable gas flow within the holding device through the fine holes and through-holes in the thermal spray layer provided on 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]

[0006] [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. 1 is a cross-sectional view showing a schematic configuration of an electrostatic chuck of a comparative example. [Figure 5]FIG. 10 is a cross-sectional view showing a schematic configuration of an electrostatic chuck according to a second embodiment. [Figure 6] FIG. 11 is an explanatory diagram showing a state of a sealing convex portion formed on a base portion of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] 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 schematically showing the configuration of the electrostatic chuck 10. In FIG. 1, a portion of the electrostatic chuck 10 is cut away. In addition, in FIGS. 1 and 2 and FIGS. 3 to 6 described below, 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 indicates the vertical direction, and the X and Y axes indicate the horizontal direction. Note that each figure schematically shows the arrangement of each part constituting the electrostatic chuck 10 and does not accurately represent the dimensional ratios of the parts.

[0008] 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."

[0009] 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."

[0010] 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.

[0011] 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.

[0012] A plurality of coolant channels 32 are formed inside the base portion 30 along the XY plane. The base portion 30 is cooled by flowing a coolant, such as a fluorine-based inert liquid, water, or liquid nitrogen, through the coolant channels 32. 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 coolant channels 32 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.

[0013] As shown in FIG. 2, a sprayed layer 35 is formed on the base portion 30 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." In the base portion 30 of this embodiment, the sprayed layer 35 is also formed on a side surface parallel to the Z-axis direction. In addition, 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).

[0014] 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). Aluminum oxide and yttrium oxide are particularly desirable. The thickness of the sprayed layer 35 can be, for example, 200 μm to 1 mm.

[0015] The base portion 30 further has a plurality of through holes that form openings in each of the pair of main surfaces. On one main surface of the base portion 30, a sealing protrusion 60 is provided to surround each opening of the plurality of through holes. The sealing protrusion 60 protrudes from one main surface of the base portion 30 toward the adhesive layer 40 (in the +Z-axis direction) in an area of ​​the one main surface of the base portion 30 where the sprayed layer 35 is not formed, i.e., an area closer to the opening than the area where the sprayed layer 35 is formed, and is provided so that its top contacts the adhesive layer 40. The arrangement and configuration of the through holes and the sealing protrusion 60 will be described in detail later.

[0016] 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 protrusion 60 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.

[0017] (A-2) Arrangement and configuration of sealing protrusions: 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). 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, as through holes, gas flow path holes 50 and 51, a lift pin hole 53, a temperature sensor hole 54, and a chuck terminal hole 55. Note that 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 portion of which is constituted by the through holes in the base portion 30 will be referred to as gas flow path holes 50 and 51, lift pin hole 53, temperature sensor hole 54, and chuck terminal hole 55. Also, in FIG. 3, the position of the cross section shown in FIG. 2 is shown as cross section 2-2. The hole structure formed in the ceramic portion 20 so as to communicate with the through holes in the base portion 30 described above may have a shape different from that described above, and may have a shape other than a shape that penetrates the ceramic portion 20 straight in the vertical direction (Z-axis direction). For example, at least a portion of the hole structure may have a shape that extends in a direction other than the vertical direction within the ceramic portion 20.

[0018] The gas flow passage holes 50, 51 are provided so as to penetrate the base portion 30 as well as the thermal spray layer 35, the adhesive layer 40, and the ceramic portion 20 in the Z direction. 1 and 2. The gas flow passage holes 50 and 51 are 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 passage through which an inert gas is supplied, and the gas flow passage hole 51 is a 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 the wafer placed on the mounting surface 24. This improves the heat transfer between the ceramic part 20 and the wafer, further improving the controllability of the temperature distribution of the wafer.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] Of the above-described through holes, the gas flow passage holes 50 and 51 and the lift pin hole 53 communicate with the space inside a vacuum chamber during semiconductor manufacturing. The through holes that are not in communication with the atmosphere when the electrostatic chuck 10 is in use are also referred to as "vacuum system through holes." Furthermore, of the above-described through holes, the temperature sensor hole 54 and the chuck terminal hole 55 are open to the atmosphere when the electrostatic chuck 10 is in use. The through holes that communicate with the atmosphere in this manner are also referred to as "atmosphere system through holes."

[0023] The base portion 30 may further include other through holes. For example, if a heater electrode for heating a wafer is provided inside the ceramic portion 20, a heater terminal hole may be provided, which is a hole structure for arranging wiring electrically connected to the heater terminal of the heater electrode. Such a heater terminal hole is an "atmospheric through hole" that communicates with the atmosphere when the electrostatic chuck 10 is in use. 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.

[0024] The sealing protrusions 60 are provided on one main surface of the base portion 30 so as to surround the opening of each through hole without any gaps. As shown in FIG. 2, it is desirable that each sealing protrusion 60 is provided close to the outer periphery of the opening of the corresponding through hole. For example, each sealing protrusion 60 may be formed so as to be concentric with the opening of the corresponding through hole in a top view. It is desirable that the thermal spray layer 35 is formed on one main surface of the base portion 30 so as to cover the entire area where no sealing protrusions 60 are provided.

[0025] The sealing protrusion 60 of this embodiment is made of resin (for example, thermosetting resin) and has a base. The sealing protrusion 60 has a convex structure adhered onto the base portion 30. The resin that can be used to form the sealing protrusion 60 is, for example, a silicone resin, an acrylic resin, or an epoxy resin. In order to improve the adhesion between the sealing protrusion 60 and the adhesive layer 40, it is desirable that the resin that forms the sealing protrusion 60 and the adhesive that forms the adhesive layer 40 are the same type of resin.

[0026] When forming the sealing protrusion 60, for example, the above-described resin paste may be applied by screen printing to the position where the sealing protrusion 60 is to be formed on one main surface of the base portion 30. The above-described resin paste may also be applied to the position where the sealing protrusion 60 is to be formed using a dispenser or the like. Alternatively, the above-described resin may be formed into a sheet, cut out in the shape of the sealing protrusion 60, and attached to the position where the sealing protrusion 60 is to be formed. The sealing protrusion 60 can then be formed by thermally curing the resin paste or resin sheet applied to the base portion 30. When forming the thermal spray layer 35 on the surface of the base portion 30 prior to forming the sealing protrusion 60, for example, formation of the thermal spray layer 35 in the region where the sealing protrusion 60 is to be formed may be suppressed by, for example, placing a hard mask of a specific shape on one main surface of the base portion 30. Alternatively, after forming the thermal spray layer on one main surface of the base portion 30, the region where the sealing protrusion 60 is to be formed may be subjected to a blasting treatment to partially remove the thermal spray layer.

[0027] When manufacturing the electrostatic chuck 10, for example, the sealing protrusion 60 may be prepared in a semi-cured state at a desired position on one main surface of the base portion 30, and the adhesive layer 40 may be prepared in a semi-cured state on the surface of the ceramic portion 20 opposite the mounting surface 24. Then, the base portion 30 and the ceramic portion 20 are overlapped so that the sealing protrusion 60 and the adhesive layer 40 are in contact with each other, and the resin constituting the sealing protrusion 60 and the adhesive layer 40 is completely cured by heating. This allows high adhesion to be achieved between the sealing protrusion 60 and the adhesive layer 40, and between the sealing protrusion 60 and the base portion 30.

[0028] The thickness of the sealing protrusion 60 (height in the Z-axis direction before being bonded to the adhesive layer 40) is preferably 200 μm or more, more preferably 300 μm or more, and even more preferably 500 μm or more, from the viewpoint of suppressing gas flow between the through hole and the thermal spray layer 35. Furthermore, from the viewpoint of suppressing an increase in the size of the electrostatic chuck 10, the thickness is preferably 1 mm or less, more preferably 800 μm or less, and even more preferably 600 μm or less.

[0029] The width of the top of the sealing protrusion 60 is preferably 1 mm or more from the viewpoints of ensuring adhesion between the sealing protrusion 60 and the base portion 30 and the adhesive layer 40, suppressing gas flow between the through hole and the thermal spray layer 35, and forming the sealing protrusion 60 with high precision. Here, the "top width" of the sealing protrusion 60 does not refer to the overall size of the sealing protrusion 60 that is provided to surround the opening of the through hole, but refers to the width of the sealing protrusion 60 in a direction perpendicular to the direction in which the sealing protrusion 60 extends while surrounding the opening of the through hole, and is shown as length "a" in FIG. 2. In other words, the "top width" of the sealing protrusion 60 refers to the width of the linear portion of the sealing protrusion 60 that extends linearly on one main surface of the base portion 30 when viewed from above.

[0030] Furthermore, on one main surface of the base portion 30, the distance between the outer periphery of the base portion 30 and the sealing protrusion 60 is preferably 1 mm or more. The "distance between the outer periphery of the base portion 30 and the sealing protrusion 60" is the shortest distance between the outer periphery of the base portion 30 and the sealing protrusion 60, and is shown as length "b" in FIG. 2. Furthermore, on one main surface of the base portion 30, the distance between the sealing protrusions 60 provided to surround each of the openings of adjacent through holes is preferably 1 mm or more. The "distance between the sealing protrusions 60 provided to surround each of the openings of adjacent through holes" is the shortest distance between the sealing protrusions 60 provided to surround each of the openings of adjacent through holes, and is shown as length "c" in FIG. 2.

[0031] It is desirable that the thicknesses of the sealing protrusions 60 and the sprayed layer 35 (their heights in the Z-axis direction before bonding to the adhesive layer 40) are the same. The sealing protrusions 60 have the function of suppressing the flow of gas between the through holes and the sprayed layer 35, but if the sealing protrusions 60 are thinner (have a lower height in the Z-axis direction) than the sprayed layer 35, this function may be reduced. Furthermore, if the sprayed layer 35 is thinner (have a lower height in the Z-axis direction) than the sealing protrusions 60, the adhesion between the sprayed layer 35 and the adhesive layer 40 may be reduced. However, it is acceptable as long as the degree of the above-mentioned inconvenience caused by the sealing protrusions 60 being thinner than the sprayed layer 35 or the sprayed layer 35 being thinner than the sealing protrusions 60 is within an acceptable range, and a difference of about 100 μm is permitted between the thicknesses of the sealing protrusions 60 and the sprayed layer 35 (their heights in the Z-axis direction before bonding to the adhesive layer 40). For example, by ensuring that the thickness of adhesive layer 40, which is formed from a relatively flexible resin, is approximately 150 μm to 1 mm, adhesive layer 40 can absorb the difference in thickness between sprayed layer 35 and sealing protrusion 60, thereby making it possible to reduce inconveniences caused by the difference in thickness between the two. In order to make the thicknesses of sealing protrusion 60 and sprayed layer 35 the same (height in the Z-axis direction before bonding to adhesive layer 40), for example, it is desirable to form sprayed layer 35 and sealing protrusion 60 on one main surface of base portion 30, and then perform flush processing to grind the surface so that the heights of sprayed layer 35 and sealing protrusion 60 are the same.

[0032] According to the electrostatic chuck 10 of the present embodiment configured as described above, the base portion 30 has, on one main surface facing the ceramic portion 20, a sealing protrusion 60 that is provided in a region closer to the opening than the region where the thermal sprayed layer 35 is formed, so as to surround the opening, protrudes from the one main surface toward the adhesive layer 40, and has a top portion that contacts the adhesive layer 40. Therefore, the sealing protrusion 60 can suppress the flow of gas between the through hole and the thermal sprayed layer 35, thereby preventing problems caused by such gas flow. Below, a description will be given of problems caused by the flow of gas between the through hole and the thermal sprayed layer 35.

[0033] 4 is a cross-sectional view similar to that of FIG. 2, showing a schematic configuration of an electrostatic chuck 110 as a comparative example that does not have a sealing protrusion 60. The electrostatic chuck 110 has a configuration similar to that of the electrostatic chuck 10 except that it does not have the sealing protrusion 60, and the same reference numerals are used to designate common parts.

[0034] When the electrostatic chuck 110 is in use, i.e., when the electrostatic chuck 110 is placed in a vacuum chamber to manufacture wafers, the temperature sensor hole 54, which is open to the atmosphere, is connected to the micropores in the thermal spray layer 35, allowing atmospheric air to flow into the vacuum chamber through the temperature sensor hole 54 and the micropores in the thermal spray layer 35. This phenomenon is also called "atmospheric air leakage." The arrow α in FIG. 4 indicates the flow of atmospheric air from the temperature sensor hole 54 into the thermal spray layer 35, causing an atmospheric leak. This type of atmospheric leakage can occur not only through the temperature sensor hole 54, but also through other atmospheric through-holes, such as the chuck terminal hole 55.

[0035] Furthermore, when the electrostatic chuck 110 is in use, the gas flow path 50 communicates with the micropores in the thermal spray layer 35, which can allow an excess amount of inert gas to flow into the vacuum chamber through the gas flow path 50 and the micropores in the thermal spray layer 35. This phenomenon is also referred to as a "gas leak." The arrow γ in FIG. 4 indicates the flow of inert gas from the gas flow path 50 toward the outer periphery of the thermal spray layer 35, causing a gas leak. This type of gas leak can occur not only through the gas flow path 50, but also through other through-holes through which gas flows, such as the gas flow path 51.

[0036] Furthermore, when the electrostatic chuck 110 is in use, the temperature sensor hole 54 and the gas flow path hole 50 are connected via the micropores in the thermal spray layer 35, so that air can flow from the temperature sensor hole 54 to the gas flow path hole 50. This phenomenon is also called "air inflow between through-holes." Air flows from the temperature sensor hole 54 to the gas flow path hole 50, causing air inflow between through-holes. This state is indicated by arrow β in Figure 4. This type of air inflow between the through-holes can occur in various combinations of atmosphere system through-holes and vacuum system through-holes, not just between the temperature sensor hole 54 and the gas flow path hole 50.

[0037] In the electrostatic chuck 10 of this embodiment, the sealing protrusions 60 are provided on one main surface of the base portion 30 so as to surround each of the openings of the plurality of through holes. This makes it possible to suppress problems caused by gas flow between the through holes and the thermal spray layer 35, specifically, the above-mentioned air leak, gas leak, and air inflow between the through holes. In particular, in this embodiment, the sealing protrusions 60 are made of resin, which makes it easy to uniform the thicknesses of the plurality of sealing protrusions 60 (heights in the Z-axis direction before bonding to the adhesive layer 40) and to form sealing protrusions 60 having the same thickness as the thermal spray layer 35. Furthermore, by making the sealing protrusions 60 of resin, which is a relatively soft material, even if there is a difference in thickness between the sealing protrusions 60 and the thermal spray layer 35, the influence of such a difference in thickness is suppressed, making it easy to improve the adhesion between the sealing protrusions 60 and the thermal spray layer 35 and the adhesive layer 40.

[0038] B. Second embodiment: Fig. 5 is a cross-sectional view showing a schematic configuration of an electrostatic chuck 210 of the second embodiment, similar to Fig. 2. The electrostatic chuck 210 has a configuration similar to that of the electrostatic chuck 10, except that the electrostatic chuck 210 includes a base portion 230 having a sealing protrusion 260 instead of the base portion 30 and the sealing protrusion 60, and the same reference numerals are used to designate common parts.

[0039] The base portion 230 of the electrostatic chuck 210 has a sealing protrusion 260, which is a convex structure formed on one main surface of the base portion 230, as a surface structure of the base portion 230. The sealing protrusion 260 is provided on one main surface of the base portion 230 at the same position as the sealing protrusion 60 of the first embodiment so as to surround the opening of each through-hole, and has its top portion adhered to the adhesive layer 40.

[0040] To form the sealing protrusions 260 as a surface structure of the base portion 230, a convex structure that will become the sealing protrusions 260 may be formed on one main surface of the member that will become the base portion 230 by cutting or the like. After forming the sealing protrusions 260, which are such convex structures, a thermal spray layer 35 may be formed on the surface of the base portion 230. The thermal spray layer 35 may be formed, for example, by thermal spraying the entire main surface of the base portion 230 on which the sealing protrusions 260 are formed, and then removing only the portion of the layer formed by thermal spraying that is formed on the sealing protrusions 260 by polishing or blasting. Alternatively, the thermal spray layer 35 may be formed by placing a hard mask only on the sealing protrusions 260 on one main surface of the base portion 230 on which the sealing protrusions 260 are formed, performing thermal spraying, and then polishing. After forming the thermal spray layer 35 in this manner, if necessary, further flush processing may be performed to align the heights of the thermal spray layer 35 and the sealing protrusions 260.

[0041] The parameters relating to the size of the sealing protrusion 260 may be set in the same manner as for the sealing protrusion 60 of the first embodiment. The thickness of the sealing protrusion 260 (the height in the Z-axis direction before bonding to the adhesive layer 40) is, for example, preferably 200 μm or more, more preferably 300 μm or more, and even more preferably 500 μm or more, from the viewpoint of suppressing the flow of gas between the through hole and the thermal spray layer 35. Furthermore, from the viewpoint of suppressing an increase in the size of the electrostatic chuck 210, the thickness is preferably 1 mm or less, more preferably 800 μm or less, and even more preferably 600 μm or less.

[0042] The width of the top of the sealing protrusion 260 (length "a" in FIG. 5) is set to 1 mm or more from the viewpoint of ensuring adhesion between the sealing protrusion 260 and the base portion 30 and the adhesive layer 40, suppressing the flow of gas between the through hole and the sprayed layer 35, and from the viewpoint of forming the sealing protrusion 60 with high precision. It is desirable that the distance between the outer periphery of the base portion 230 and the sealing protrusion 260 on one main surface of the base portion 230 (length "b" in FIG. 5) is 1 mm or more. It is also desirable that the distance between the sealing protrusions 260 provided so as to surround the openings of adjacent through holes on one main surface of the base portion 230 (length "c" in FIG. 5) is 1 mm or more.

[0043] With this configuration, the provision of the sealing protrusion 260 can suppress the flow of gas between the through hole and the sprayed layer 35, thereby achieving the same effect as in the first embodiment, that is, suppressing the inconvenience caused by such gas flow. Furthermore, in the second embodiment, the sealing protrusion 260 is formed as a surface structure of the base portion 230, and therefore, compared to the first embodiment in which the sealing protrusion 60, which is a separate resin member, is used, it is possible to improve the adhesion between the sealing protrusion and the adhesive layer 40 and increase reliability regarding gas leakage between the sealing protrusion and the adhesive layer 40.

[0044] C. Third embodiment: In the first and second embodiments, a sealing protrusion is provided for each opening of the plurality of through holes on one main surface of the base, but a different configuration may be used. Below, a configuration in which a single sealing protrusion is provided for the openings of the plurality of through holes will be described as a third embodiment.

[0045] 6 is an explanatory diagram showing the state of the sealing protrusions formed on one main surface of the base portion 30 of the electrostatic chuck of the third embodiment. The electrostatic chuck of the third embodiment has the same configuration as the electrostatic chuck 10 of the first embodiment except for the arrangement of the sealing protrusions, and the same reference numerals are used for the common parts.

[0046] 6, in the third embodiment, a sealing protrusion 360a is formed on the base portion 30 so as to surround the openings of the two lift pin holes 53, and a sealing protrusion 360b is formed so as to surround the openings of the two temperature sensor holes 54. Note that, for the openings of the through holes other than the two lift pin holes 53 and the two temperature sensor holes 54, a sealing protrusion 60 similar to that of the first embodiment is provided (not shown). Furthermore, parameters related to the size of the sealing protrusions 360a and 360b, specifically, the thickness of the sealing protrusions 360a and 360b (the height in the Z-axis direction before bonding to the adhesive layer 40), the width of the tops of the sealing protrusions 360a and 360b, and the distance between the outer periphery of the base portion 30 and the sealing protrusions 360a and 360b, may be set similarly to the sealing protrusion 60 of the first embodiment.

[0047] As shown in Fig. 6, even when multiple lift pin holes 53 are surrounded by a single sealing protrusion 360a, it is possible to obtain the effect of suppressing atmospheric inflow between these lift pin holes 53 and other atmospheric system through-holes. Also, as shown in Fig. 6, even when multiple temperature sensor holes 54 are surrounded by a single sealing protrusion 360b, it is possible to obtain the effect of suppressing atmospheric leakage through these temperature sensor holes 54 and the effect of suppressing atmospheric inflow between these temperature sensor holes 54 and other vacuum system through-holes. When providing a sealing protrusion to surround the openings of multiple through-holes, it is also possible to provide a sealing protrusion to surround the openings of, for example, three or more through-holes of the same type.

[0048] Furthermore, when the openings of multiple through holes are surrounded by a single sealing protrusion, the through holes corresponding to the multiple openings surrounded by the single sealing protrusion may be of the same type or different types. Specifically, the openings of different types of through holes (e.g., gas flow path hole 50 and lift pin hole 53) belonging to the vacuum system through holes may be surrounded by a single sealing protrusion. Even in such a case, by providing a sealing protrusion, it is possible to obtain the effect of suppressing gas leakage through the gas flow path hole 50 and the effect of suppressing atmospheric inflow between these gas flow path hole 50 and lift pin hole 53 and other atmospheric system through holes. Furthermore, the openings of different types of through holes (e.g., temperature sensor hole 54 and chuck terminal hole 55) belonging to the atmospheric system through holes may be surrounded by a single sealing protrusion. Even in such a case, the provision of the sealing protrusion can provide the effect of suppressing air leakage through the temperature sensor hole 54 and the chuck terminal hole 55, and the effect of suppressing air inflow between the temperature sensor hole 54 and the chuck terminal hole 55 and other vacuum system through-holes.

[0049] Alternatively, a sealing protrusion may be provided for each opening of either the vacuum system through-hole or the atmosphere system through-hole, or for a group of openings of a plurality of through-holes, which makes it possible to at least suppress the inflow of atmosphere between the through-holes, and furthermore, for through-holes having openings surrounded by a sealing protrusion, it is possible to obtain the effect of suppressing air leakage or gas leakage depending on the type of through-hole.

[0050] This variation in the arrangement of the sealing convex portion can be applied not only when the sealing convex portion is formed using resin as in the first embodiment, but also when the sealing convex portion is formed by a convex structure provided as a surface structure of the base portion as in the second embodiment.

[0051] D. Other Embodiments: In the first embodiment described above, the sealing protrusion 60 is a resin convex structure bonded to the base portion 30, but it is also possible to configure the sealing protrusion with a resin member that is not bonded to the base portion 30. For example, a resin O-ring may be used as the sealing protrusion, and the sealing protrusion and the adhesive layer 40 may be bonded with an adhesive, while the sealing protrusion and the base portion 30 may be tightly sealed without using an adhesive. The sealing protrusion may be formed so as to protrude from one main surface of the base portion toward the adhesive layer, with the top of the sealing protrusion being in contact with the adhesive layer.

[0052] The present disclosure may be applied to holding devices other than electrostatic chucks that hold wafers using electrostatic attraction. That is, the present disclosure may be similarly applied to other holding devices that include a plate-shaped member such as a ceramic member and a base member 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 suitable for use in devices used in plasma environments where a thermal spray coating is desired to ensure corrosion resistance and voltage resistance.

[0053] 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]

[0054] 10, 110, 210...Electrostatic chuck 20...Ceramic section 22...Chuck electrode 24...Placement surface 30,230...Base 32... Refrigerant flow path 35...sprayed layer 40...adhesive layer 50, 51...Gas flow passage holes 52...Gas outlet 53...Lift pin hole 54...Temperature sensor hole 55...Chuck terminal hole 60,260,360a,360b...Sealing convex part

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, the base portion having a through hole forming an opening in each of the pair of main surfaces, and a thermal spray layer formed on a part of one of the pair of main surfaces; an adhesive layer including an adhesive and 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; a sealing protrusion provided in a region of the one main surface of the base portion closer to the opening than the region where the sprayed layer is formed, the sealing protrusion protruding from the one main surface toward the adhesive layer and having a top portion in contact with the adhesive layer; Equipped with The sealing protrusion is a resin-made protruding structure formed on the one main surface of the base. holding device.

2. 2. The holding device of claim 1, The through-hole present in the region surrounded by the sealing protrusion is a through-hole that is open to the atmosphere when the holding device is in use. holding device.

3. 2. The holding device of claim 1, The through-holes present in the region surrounded by the sealing protrusions are through-holes that are not in communication with the atmosphere when the holding device is in use. holding device.

4. A holding device according to any one of claims 1 to 3, the one main surface of the base portion has a plurality of the openings, The sealing protrusion is formed so as to surround each of the plurality of openings. holding device.

5. A holding device according to any one of claims 1 to 4, The sealing protrusion and the thermal spray layer are at the same height from the one main surface of the base portion and are in contact with the surface of the adhesive layer on the side of the base portion. holding device.

6. A holding device according to any one of claims 1 to 5, The width of the top of the sealing protrusion is 1 mm or more. holding device.

7. A holding device according to any one of claims 1 to 6, The electrostatic chuck is characterized by being equipped with an electrode for electrostatic attraction. holding device.

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