Electrostatic chuck

Abstract

To provide an electrostatic chuck that can suppress the occurrence of dielectric breakdown while allowing the internal pressure of a lift pin hole, etc., to be adjusted through a gas flow path in a base plate.SOLUTION: An electrostatic chuck 10 includes a dielectric substrate 100 in which a first through hole 150 is formed, a base plate 200 which is a member for supporting the dielectric substrate 100 and in which a second through hole 250 connected to the first through hole 150 is formed, and an insulating member 400 which covers the inner surface of the second through hole 250 and is formed of an insulating material. A gas flow path FP which communicates with the inside of the second through hole 250 is formed in the base plate 200, and a plurality of flow paths 434 which are part of the gas flow path FP are formed so as to penetrate the insulating member 400.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an electrostatic chuck. [Background technology]

[0002] For example, in semiconductor manufacturing equipment such as an etching device, an electrostatic chuck is provided as a device for attracting and holding a substrate such as a silicon wafer to be processed. The electrostatic chuck includes a dielectric substrate provided with an attracting electrode and a base plate for supporting the dielectric substrate, which are joined together. When a voltage is applied to the attracting electrode, an electrostatic force is generated, and the substrate placed on the dielectric substrate is attracted and held.

[0003] As described in Patent Document 1 below, through holes are formed in the dielectric substrate and the base plate, penetrating both of them. Examples of such through holes include lift pin holes for passing lift pins when attaching and detaching the substrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-024328 Summary of the Invention [Problem to be solved by the invention]

[0005] The internal space of the lift pin hole is connected to the substrate side. Therefore, it is preferable to adjust the pressure in the space to an appropriate pressure. In order to enable such pressure adjustment, in recent years, studies have been conducted on forming a gas flow path inside the base plate and enabling the internal space of the lift pin hole to be pressurized or depressurized through the gas flow path.

[0006] However, the specific form of the gas flow path to be formed inside the base plate has not been sufficiently considered in the past. For example, if the opening that becomes the end of the above-mentioned gas flow path is formed on the inner surface of the lift pin hole, depending on the position and size of the opening, there is a possibility that insulation breakdown will occur in the path that passes through the opening.

[0007] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide an electrostatic chuck that can suppress the occurrence of dielectric breakdown while making it possible to adjust the internal pressure of a lift pin hole, etc., through a gas flow path in a base plate. [Means for solving the problem]

[0008] In order to solve the above problems, an electrostatic chuck according to one aspect of the present invention includes a dielectric substrate having a first through hole formed therein, a base plate that is a member for supporting the dielectric substrate and has a second through hole formed therein and connected to the first through hole, and an insulating part that covers an inner surface of the second through hole and is made of an insulating material. A gas flow passage that communicates with the inside of the second through hole is formed in the base plate, and a plurality of supply holes that are part of the gas flow passage are formed to penetrate the insulating part.

[0009] In an electrostatic chuck having such a configuration, for example, the pressure inside the second through hole, which is a part of the lift pin hole, can be adjusted through the gas flow path. As part of the gas flow path, not only one but multiple supply holes are formed through the insulating part. This makes it possible to reduce the cross-sectional area of ​​each supply hole and prevent the occurrence of dielectric breakdown, while still ensuring a sufficient flow rate of gas flowing through the gas flow path.

[0010] In order to solve the above problem, an electrostatic chuck according to another aspect of the present invention includes a dielectric substrate having a first through hole formed therein, a base plate that is a member for supporting the dielectric substrate and has a second through hole formed therein and connected to the first through hole, and an insulating part that covers an inner surface of the second through hole and is formed of an insulating material. A gas flow path is formed in the base plate and leads to the inside of the second through hole. The gas flow path includes a first flow path that extends in a direction perpendicular to the central axis of the second through hole, a second flow path that is connected to the first flow path and extends in a direction parallel to the central axis of the second through hole, and a supply hole that is connected to the second flow path and is formed to penetrate the insulating part.

[0011] In an electrostatic chuck having such a configuration, for example, the pressure inside the second through hole, which is a part of the lift pin hole, can be adjusted through the gas flow path. The gas flow path includes a second flow path extending in a direction parallel to the central axis of the second through hole. With such a configuration, a supply hole penetrating the insulating part can be formed at a different height position from the above while a part of the gas flow path (for example, the first flow path) is routed at a height position that avoids the coolant flow path. This makes it possible to form the supply hole at a position far enough from the dielectric substrate that the occurrence of dielectric breakdown through the supply hole can be prevented. Effect of the Invention

[0012] According to the present invention, it is possible to provide an electrostatic chuck that can suppress the occurrence of dielectric breakdown while making it possible to adjust the internal pressure of a lift pin hole, etc. through a gas flow path in a base plate. [Brief description of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view illustrating a schematic configuration of an electrostatic chuck according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged view of a portion of the configuration of FIG. [Diagram 3] FIG. 4 is a diagram illustrating a schematic diagram of a gas flow path inside the base plate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same components in each drawing are denoted by the same reference numerals as much as possible, and duplicated description will be omitted.

[0015] The electrostatic chuck 10 according to this embodiment is configured to electrostatically attract and hold a substrate W to be processed inside a semiconductor manufacturing apparatus (not shown), such as an etching apparatus. The substrate W is, for example, a silicon wafer. The electrostatic chuck 10 may be used in an apparatus other than a semiconductor manufacturing apparatus.

[0016] 1 shows, in a schematic cross-sectional view, the configuration of an electrostatic chuck 10 in a state in which the electrostatic chuck 10 attracts and holds a substrate W. The electrostatic chuck 10 includes a dielectric substrate 100 and a base plate 200.

[0017] The dielectric substrate 100 is a substantially disk-shaped member made of a sintered ceramic body. The dielectric substrate 100 contains, for example, high-purity aluminum oxide (Al2O3), but may contain other materials. The purity, type, and additives of the ceramics in the dielectric substrate 100 can be appropriately set in consideration of the plasma resistance and other properties required of the dielectric substrate 100 in semiconductor manufacturing equipment.

[0018] 1 of the dielectric substrate 100 is a "mounting surface" on which the substrate W is placed. Also, a lower surface 120 of the dielectric substrate 100 in FIG. 1 is a "bonded surface" that is bonded to a base plate 200 via a bonding layer 300 described below. The viewpoint when the electrostatic chuck 10 is viewed from the side of the surface 110 along a direction perpendicular to the surface 110 is hereinafter also referred to as a "top view".

[0019] An adsorption electrode 130 is embedded inside the dielectric substrate 100. The adsorption electrode 130 is a thin, flat layer made of a metal material such as tungsten, and is disposed so as to be parallel to the surface 110. The material of the adsorption electrode 130 may be molybdenum, platinum, palladium, or the like, in addition to tungsten. When a voltage is applied to the adsorption electrode 130 from the outside via a power supply path (not shown), an electrostatic force is generated between the surface 110 and the substrate W, thereby adsorbing and holding the substrate W. Only one adsorption electrode 130 may be provided as a so-called "monopolar" electrode as in this embodiment, or two may be provided as so-called "bipolar" electrodes.

[0020] As shown in Fig. 1, a space SP1 is formed between the dielectric substrate 100 and the substrate W. When a process such as etching is performed in the semiconductor manufacturing apparatus, an inert gas for temperature adjustment is supplied to the space SP1 from the outside through a gas hole (not shown). By providing the inert gas between the dielectric substrate 100 and the substrate W, the thermal resistance between them is adjusted, and the temperature of the substrate W is thereby maintained at an appropriate temperature. In this embodiment, helium gas is used as the inert gas for temperature adjustment supplied to the space SP1, but a gas other than helium gas may be used.

[0021] A seal ring 111 and dots 112 are provided on a surface 110 which is a mounting surface, and the above-mentioned space SP1 is formed around these.

[0022] The seal ring 111 is a wall that divides the space SP1 at the outermost position. The upper end of the seal ring 111 forms part of the surface 110 and abuts against the substrate W. Note that a plurality of seal rings 111 may be provided to divide the space SP1. With this configuration, it is possible to individually adjust the pressure of the helium gas in each space SP1 and make the surface temperature distribution of the substrate W during processing more uniform.

[0023] 1, the portion marked with the reference symbol "116" is the bottom surface of the space SP1. Hereinafter, this portion will also be referred to as the "bottom surface 116." The seal ring 111, together with the dots 112 described below, is formed as a result of digging down a part of the surface 110 to the position of the bottom surface 116. The bottom surface 116 is parallel to the surface 110.

[0024] The dots 112 are circular protrusions protruding from the bottom surface 116. A plurality of dots 112 are provided and are distributed approximately evenly on the mounting surface of the dielectric substrate 100. The upper end of each dot 112 forms part of the surface 110 and abuts against the substrate W. By providing a plurality of such dots 112, bending of the substrate W is suppressed.

[0025] A first through hole 150 is formed in the dielectric substrate 100. The first through hole 150 extends vertically from 120 toward the surface 110 side and penetrates the dielectric substrate 100. The first through hole 150, together with a second through hole 250 of the base plate 200 described later, is formed as a hole for inserting a lift pin (not shown) provided in a semiconductor manufacturing device. A total of three first through holes 150 are formed, and are arranged so as to be equally spaced at 120 degrees from the top view, but only one of them is shown in FIG. 1. The lift pin that moves up and down through the first through hole 150 attaches and detaches the substrate W to and from the surface 110 of the dielectric substrate 100.

[0026] A circular opening 131 is formed in the chucking electrode 130 at a position overlapping with the first through hole 150 in a top view. The center of the opening 131 in a top view coincides with the center of the first through hole 150. The diameter of the opening 131 is larger than the inner diameter of the first through hole 150. The formation of the opening 131 prevents the chucking electrode 130 from being exposed at the inner surface of the first through hole 150.

[0027] A seal ring 160 is provided around the first through hole 150. Similar to the seal ring 111 described above, the seal ring 160 is an annular protrusion formed on the surface 110 side of the dielectric substrate 100. The tip of the seal ring 160 forms part of the surface 110 and comes into contact with the substrate W.

[0028] In top view, the shape of the seal ring 160 is circular, and the centers of its inner and outer surfaces both coincide with the center of the first through hole 150. In other words, the seal ring 160 is a protrusion that extends in a circular shape in top view so as to surround the first through hole 150 from the outside, and its width is uniform around the entire circumference.

[0029] In a state in which the substrate W is adsorbed to the surface 110, the space SP1 and the space SP2 inside the first through hole 150 are separated by the seal ring 160. This makes it possible to adjust the pressure in the space SP2 to be different from the pressure in the space SP1.

[0030] For example, the pressure in the space SP2 can be set lower than the pressure in the space SP1 and maintained in a low pressure range that can prevent the occurrence of dielectric breakdown. Also, by setting the pressure in the space SP2 higher than the pressure in the space SP1, the portion of the substrate W directly above the first through hole 150 can be cooled to the same temperature as the surrounding area.

[0031] The pressure in the space SP2 is adjusted via a gas flow path FP formed in the base plate 200. A specific configuration of the gas flow path FP will be described later.

[0032] The base plate 200 is a substantially disk-shaped member that supports the dielectric substrate 100. The base plate 200 is formed of a metal material such as aluminum. The upper surface 210 of the base plate 200 in FIG. 1 is a "bonded surface" that is bonded to the dielectric substrate 100 via a bonding layer 300.

[0033] The bonding layer 300 is a layer provided between the dielectric substrate 100 and the base plate 200, and bonds the two together. The bonding layer 300 is formed by curing an adhesive made of an insulating material. In this embodiment, a silicone adhesive is used as the adhesive. However, the bonding layer 300 may be formed by curing another type of adhesive. In any case, it is preferable to use a material with as high a thermal conductivity as possible as the material for the bonding layer 300 so that the thermal resistance between the dielectric substrate 100 and the base plate 200 is small.

[0034] A coolant flow passage 240 for flowing a coolant is formed inside the base plate 200. When a process such as etching is performed in the semiconductor manufacturing apparatus, a coolant is supplied to the coolant flow passage 240 from the outside, thereby cooling the base plate 200. Heat generated in the substrate W during the process is transferred to the coolant via the helium gas in the space SP1, the dielectric substrate 100, and the base plate 200, and is discharged to the outside together with the coolant.

[0035] An insulating film may be formed on the surface of the base plate 200. The insulating film is preferably formed on the surface of the base plate 200 including at least the entire face 210, but may be formed only on the face exposed to the outside. As the insulating film, for example, an alumina film formed by thermal spraying can be used. By covering the surface of the base plate 200 with an insulating film, the dielectric strength voltage of the base plate 200 can be increased.

[0036] In the base plate 200, second through holes 250 are formed in each of the portions overlapping with the first through holes 150 in a top view. The second through holes 250 extend vertically from the surface 210 toward the surface 220 on the opposite side, and penetrate the base plate 200. The central axis of the second through hole 250 coincides with the central axis of the first through hole 150. Therefore, the second through hole 250 is connected to the first through hole 150. However, the inner diameter of the second through hole 250 is larger than the inner diameter of the first through hole 150. The portion of the second through hole 250 on the dielectric substrate 100 side is a reduced diameter portion 251 (see FIG. 2) having an inner diameter smaller than that of the other portions. For convenience of explanation, the position in the direction along the central axis of the second through hole 250 is also referred to as the "height position" below.

[0037] Inside the second through hole 250, an insulating member 400 and a fastening member 500 are disposed.

[0038] The insulating member 400 is a substantially cylindrical member, and is made of an insulating material such as ceramic, for example. The insulating member 400 is formed with a through hole 450 that passes linearly through the entire member.

[0039] The insulating member 400 is disposed inside the second through hole 250 with its central axis coinciding with the central axis of the second through hole 250. The outer diameter of the insulating member 400 is approximately equal to the inner diameter of the second through hole 250. The inner diameter of the insulating member 400 (i.e., the inner diameter of the through hole 450) is approximately equal to the inner diameter of the first through hole 150. The end of the insulating member 400 on the dielectric substrate 100 side abuts against the surface 120 of the dielectric substrate 100. Therefore, the through hole 450, which has the same diameter as the first through hole 150, is connected in a straight line to the first through hole 150.

[0040] The portion of insulating member 400 facing dielectric substrate 100 is reduced diameter section 401 (see FIG. 2) whose outer diameter is smaller than the remaining portion. The outer diameter of reduced diameter section 401 is approximately equal to the inner diameter of reduced diameter section 251. Reduced diameter section 401 is inserted inside reduced diameter section 251. With this configuration, the upper end of the range in which insulating member 400 can move toward dielectric substrate 100 is defined.

[0041] The fastening member 500 is a substantially cylindrical member, and is made of an insulating material such as resin, for example. The fastening member 500 is formed with a through hole 550 that passes linearly through the entire fastening member 500.

[0042] The fastening member 500 is disposed inside the second through hole 250 together with the insulating member 400 with its central axis aligned with the central axis of the second through hole 250. The fastening member 500 is disposed at a position closer to the surface 220 than the insulating member 400.

[0043] A female screw 260 is formed on a portion of the inner surface of the second through hole 250 that faces the fastening member 500. A male screw 560 is formed on the outer circumferential surface of the fastening member 500 and screws into the female screw 260. When the fastening member 500 is rotated around its central axis, the fastening member 500 moves in the upward direction in FIG. 1 accordingly. This allows the insulating member 400 to be sandwiched and fixed between the fastening member 500 and the base plate 200.

[0044] The inner diameter of the fastening member 500 (that is, the inner diameter of the through hole 550) is approximately equal to the inner diameters of the first through hole 150 and the through hole 450. Therefore, the through hole 550 is connected to the through hole 450 in a straight line.

[0045] The first through hole 150, the through hole 450, and the through hole 550 linearly pass through the entire electrostatic chuck 10. These holes as a whole function as holes for inserting the lift pins described above.

[0046] The internal spaces of the through hole 450 and the through hole 550 are part of the space SP2 described above, and are connected to the internal space of the first through hole 150. Hereinafter, the term "space SP2" will be used to represent the entire internal spaces of the first through hole 150, the through hole 450, and the through hole 550.

[0047] The insulating member 400 and the fastening member 500 are insulating members that cover the inner surface of the second through hole 250, and correspond to the "insulating portion" in this embodiment. By covering the inner surface of the second through hole 250 with the insulating portion, it is possible to prevent a situation in which a dielectric breakdown occurs between the base plate 200 and the substrate W through the space SP2.

[0048] As described above, the gas flow path FP for adjusting the pressure of the space SP2 is formed in the base plate 200. One end of the gas flow path FP opens on the surface 220 of the base plate 200, and the other end is connected to the space SP2. In other words, the gas flow path FP communicates with the inside of the second through-hole 250. The pressure of the space SP2 can be adjusted by supplying gas to the space SP2 or discharging gas from the space SP2 via the gas flow path FP.

[0049] A specific configuration of the gas flow path FP will be described with reference to Fig. 2. Fig. 2 shows an enlarged view of the configuration of the space SP2 and its neighboring parts in Fig. 1. The gas flow path FP includes a flow path 230, a flow path 231, a flow path 232, a flow path 433, and a flow path 434.

[0050] When gas is supplied to the space SP2 through the gas flow path FP, the flow path 230 is the most upstream part of the gas flow path FP. In the following description, the terms "upstream" and "downstream" are used assuming a case where gas is supplied to the space SP2.

[0051] Flow path 230 is a flow path formed to extend linearly from surface 220 along a direction (the vertical direction in FIG. 2) parallel to the central axis of second through hole 250. To an opening formed in surface 220 as an end portion of flow path 230, a pressure adjustment mechanism (not shown), such as a mass flow controller, is connected.

[0052] The flow path 230 is formed at a position where it does not interfere with the refrigerant flow path 240 in a top view. The flow path 230 extends from the surface 220 to a position further above the upper end of the refrigerant flow path 240 in FIG.

[0053] Flow path 231 is a flow path formed to extend from the downstream end (upper end in FIG. 2) of flow path 230 in a direction perpendicular to the central axis of second through hole 250. Therefore, flow path 231 is entirely located on the surface 210 side of refrigerant flow path 240. Flow path 231 corresponds to the "first flow path" in this embodiment.

[0054] Flow path 231 extends from the downstream end of flow path 230 toward second through hole 250, and its downstream end is connected to the outer surface of insulating member 400 located within second through hole 250. Flow path 231 may extend so as to be entirely linear when viewed from above, or may extend so as to be partially or entirely curved when viewed from above.

[0055] The flow path 232 is a flow path formed to extend from the downstream end (the left end in FIG. 2) of the flow path 231 along a direction parallel to the central axis of the second through hole 250. The flow path 232 corresponds to the "second flow path" in this embodiment. The flow path 232 may be directly connected to the flow path 231 as in this embodiment, or may be indirectly connected to the flow path 231 via another flow path.

[0056] Flow path 232 in this embodiment is a groove formed on the inner surface of second through hole 250, and extends from the end of flow path 231 toward the lower side in Fig. 2. In other words, it extends from the downstream end of flow path 231 toward the opposite side to dielectric substrate 100. The lower end of flow path 232 in Fig. 2 is located below the upper end of refrigerant flow path 240 and above the lower end of refrigerant flow path 240.

[0057] The flow passage 433 is a flow passage formed as an annular groove extending in the circumferential direction on the outer surface of the insulating member 400. The flow passage 433 is an annular flow passage that surrounds the insulating member 400, which is an insulating part, from the outer periphery, and corresponds to the "annular flow passage" in this embodiment. The height position at which the flow passage 433 is formed in the vertical direction in FIG. 2 is a position slightly higher than the lower end of the flow passage 232. Therefore, the flow passage 433 is connected to the downstream end of the flow passage 232. The flow passage 433 may be directly connected to the flow passage 232 as in this embodiment, or may be indirectly connected to the flow passage 232 via another flow passage. In addition, the flow passage 433 may be a groove formed on the outer surface of the insulating member 400 as in this embodiment, or may be a groove formed on the inner surface of the second through hole 250.

[0058] The flow path 434 is the most downstream portion of the gas flow path FP. The flow path 434 is a through hole formed so as to linearly penetrate the insulating member 400 from the bottom surface of the flow path 433, which is a groove, toward the space SP2 (i.e., along the radial direction). Such a flow path 434 is a flow path that leads to the space SP2 (i.e., the internal space of the second through hole 250) and corresponds to the "supply hole" in this embodiment.

[0059] A plurality of flow paths 434, specifically a total of four, are provided, which are connected to one flow path 433. Each flow path 434 is formed at a position at the same height as each other in a direction along the central axis of second through hole 250 (the up-down direction in FIG. 2).

[0060] 3 shows a schematic diagram of the gas flow through the gas flow path FP. Gas supplied from the outside toward the space SP2 first passes through the flow path 230 as indicated by the arrow AR0, then passes through the flow path 231 as indicated by the arrow AR1, and passes through the flow path 232 as indicated by the arrow AR2. The gas then passes through the annular flow path 433 as indicated by the arrow AR3, and is distributed to each of the flow paths 434. The gas passes through each of the flow paths 434 as indicated by the arrow AR4, and is supplied to the space SP2.

[0061] The reason why the gas flow path FP is configured as described above will be described. When the substrate W is being processed in the semiconductor manufacturing device, the potential difference between the substrate W and the base plate 200 becomes relatively large due to the influence of plasma, etc. For this reason, there is a concern that a dielectric breakdown may occur between the two.

[0062] In particular, a part of the space SP2 communicates with the substrate W, and another part communicates with a metal portion of the base plate 200 (specifically, the inner surface of the gas flow path FP). For this reason, dielectric breakdown is particularly likely to occur in the path via the space SP2 and the gas flow path FP.

[0063] Therefore, in this embodiment, not only one flow path 434 penetrating the insulating member 400 is provided as a part of the gas flow path FP, but multiple flow paths 434 are provided. By providing multiple flow paths 434, it is possible to ensure a sufficient flow rate of gas supplied to the space SP2 while reducing the cross-sectional area of ​​each flow path 434 and preventing the occurrence of dielectric breakdown. The cross-sectional area of ​​each flow path 434 may be appropriately set according to the required dielectric strength voltage. Moreover, the number of flow paths 434 may be appropriately set according to the required gas flow rate.

[0064] However, if both the flow rate of the gas passing through the flow path 434 and the dielectric strength voltage can be sufficiently satisfied, the number of the flow paths 434 may be only one.

[0065] The gas flow path FP needs to be provided at a position inside the base plate 200 where it does not interfere with the refrigerant flow path 240. For this reason, it is preferable to route the gas flow path FP at a different height position from the refrigerant flow path 240, for example, like the flow path 231 of this embodiment. In view of this, it seems better to provide the flow path 434 at the same height position as the flow path 231.

[0066] However, when the height position of the flow path 231 is brought closer to the surface 210 side, the distance from the substrate W becomes shorter, which increases the possibility of dielectric breakdown occurring through the flow path 231. Therefore, in this embodiment, the flow path 434 is disposed at a height position on the surface 220 side to suppress the occurrence of dielectric breakdown, while the flow path 231 is disposed at a height position on the surface 210 side to avoid interference with the coolant flow path 240. As a result, the flow path 434 and the flow path 231 are disposed at different height positions, and therefore the two are connected by the flow path 232.

[0067] In such a configuration, the flow path 231 (first flow path) is routed inside the base plate 200 at a height position that does not interfere with the coolant flow path 240, etc., while the flow path 434 (supply hole) connected to the flow path 231 can be formed at a position as far away as possible from the dielectric substrate 100 and the substrate W. This makes it possible to prevent the occurrence of dielectric breakdown through the gas flow path FP.

[0068] Depending on the shape and other configurations of the refrigerant flow path 240, the flow path 231 may be disposed at a position lower than the flow path 434 and the refrigerant flow path 240. In this case, the flow path 232 may be formed to extend from the downstream end of the flow path 231 toward the dielectric substrate 100.

[0069] In this embodiment, the plurality of flow paths 434 are formed at the same height position. With this configuration, gas can be easily distributed from one flow path 433 to each of the flow paths 434.

[0070] Instead of the configuration in which the insulating member 400 is disposed inside the second through hole 250, an insulating film may be formed so as to cover the inner surface of the second through hole 250. For example, an oxide film formed by anodizing can be used as such a film. In such a configuration, the film corresponds to the "insulating portion." In this case, the flow path 434 is formed so as to penetrate the film.

[0071] The flow paths FP are formed individually as flow paths independent of one another in correspondence with the three spaces SP2 in the electrostatic chuck 10. Instead of this embodiment, the three flow paths FP may share a part thereof (for example, the flow path 231).

[0072] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Any design modifications made by a person skilled in the art to these specific examples are also included within the scope of the present disclosure as long as they have the features of the present disclosure. The elements of each of the above-mentioned specific examples and their arrangements, conditions, shapes, etc. are not limited to those exemplified and can be changed as appropriate. The combination of each of the elements of each of the above-mentioned specific examples can be changed as appropriate as long as no technical contradiction occurs. [Explanation of symbols]

[0073] 10: Electrostatic chuck 100: Dielectric substrate 150: First through hole 200: Base plate 250: Second through hole 400: Insulating material 230, 231, 232, 433, 434: Flow path FP: Gas flow path

Claims

1. a dielectric substrate having a first through hole formed therein; a base plate that supports the dielectric substrate and has a second through hole formed therein and connected to the first through hole; an insulating portion covering an inner surface of the second through hole and formed of an insulating material; a gas flow passage is formed in the base plate, the gas flow passage being in communication with an inside of the second through hole; The electrostatic chuck is characterized in that a plurality of supply holes, which are part of the gas flow passage, are formed so as to penetrate the insulating portion.

2. 2 . The electrostatic chuck according to claim 1 , wherein the supply holes are formed at positions that are at the same height as each other in a direction along a central axis of the second through hole.

3. the gas flow passage includes an annular flow passage formed in an annular shape so as to surround the insulating portion from an outer circumferential side, 3. The electrostatic chuck of claim 2, wherein each of said feed holes is connected to one of said annular passages.

4. The gas flow path is A first flow path extending in a direction perpendicular to a central axis of the second through hole; a second flow passage connected to the first flow passage and extending in a direction parallel to a central axis of the second through hole, 4. The electrostatic chuck of claim 3, wherein the second flow passage is connected to the annular flow passage.

5. a dielectric substrate having a first through hole formed therein; a base plate that supports the dielectric substrate and has a second through hole formed therein and connected to the first through hole; an insulating portion covering an inner surface of the second through hole and formed of an insulating material; a gas flow passage is formed in the base plate, the gas flow passage being in communication with an inside of the second through hole; The gas flow path is A first flow path extending in a direction perpendicular to a central axis of the second through hole; a second flow passage connected to the first flow passage and extending in a direction parallel to a central axis of the second through hole; a supply hole connected to the second flow path and formed to penetrate the insulating portion.

6. The electrostatic chuck according to claim 5 , wherein the second flow passage extends from the first flow passage toward a side opposite to the dielectric substrate.

7. The electrostatic chuck according to claim 5 , wherein a plurality of the supply holes are formed in one of the insulating portions.

8. 8. The electrostatic chuck according to claim 7, wherein the supply holes are formed at positions that are at the same height as each other in a direction along the central axis of the second through hole.

9. the gas flow passage includes an annular flow passage formed in an annular shape so as to surround the insulating portion from an outer circumferential side, 9. The electrostatic chuck of claim 8, wherein each of said feed holes is connected to one of said annular channels.

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