electrostatic chuck

Abstract

The present invention provides an electrostatic chuck capable of suppressing variations in the in-plane temperature distribution of a substrate. [Solution] The electrostatic chuck 10 comprises a dielectric substrate 100 having a mounting surface 110, an RF electrode 140 provided inside the dielectric substrate 100, a base plate 200 made of metal and bonded to the dielectric substrate 100, and a conductive member 400 that electrically connects the RF electrode 140 and the base plate 200. A part of the conductive member 400 is housed in a first recess 160 formed on the surface 120 of the dielectric substrate 100 that faces the base plate 200. The end of the conductive member 400 that faces the base plate 200 is in contact with the surface 210 of the base plate 200 that faces the dielectric substrate 100, or is in contact with the bottom surface 262 of a second recess 260 formed on the surface 210, which is shallower than the first recess 160.

Description

Technical Field

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

Background Art

[0002] For example, in a semiconductor manufacturing apparatus such as an etching apparatus, an electrostatic chuck is provided as a device for adsorbing and holding a substrate such as a silicon wafer to be processed. The electrostatic chuck includes a dielectric substrate provided with an adsorption electrode and a base plate for supporting the dielectric substrate, and these have a configuration in which they are joined to each other. When a voltage is applied to the adsorption electrode, an electrostatic force is generated, and the substrate placed on the dielectric substrate is adsorbed and held.

[0003] As described in Patent Document 1 below, an RF electrode may be incorporated in the dielectric substrate. The RF electrode is an internal electrode provided inside the dielectric substrate as one of a pair of opposing electrodes for generating plasma in a semiconductor manufacturing apparatus. The RF electrode and the base plate are electrically connected via a conductive member. Thereby, the potential of the RF electrode during the processing of the substrate is maintained at the potential of the base plate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] To electrically connect a conductive member and an RF electrode, for example, a recess can be formed on the base plate side of the dielectric substrate, the RF electrode can be exposed at its bottom, and the conductive member can be housed inside the recess. Similarly, to electrically connect a conductive member and a base plate, for example, a recess can be formed on the dielectric substrate side of the base plate, and the conductive member can be housed inside the recess. In this case, a portion of the conductive member will be housed in the recess of the dielectric substrate, and another portion will be housed in the recess of the base plate.

[0006] Incidentally, the base plate is required to have the function of cooling the substrate during processing via the dielectric substrate and maintaining a uniform in-plane temperature distribution of the substrate. If the recess formed in the base plate is formed deeply, the cooling function of the base plate in that area will decrease, and the temperature of the substrate directly above it may rise locally. In other words, the part of the substrate directly above the recess may become a so-called "hot spot".

[0007] This invention has been made in view of these problems, and its objective is to provide an electrostatic chuck that can suppress variations in the in-plane temperature distribution of a substrate. [Means for solving the problem]

[0008] To solve the above problems, the electrostatic chuck according to the present invention comprises a dielectric substrate having a mounting surface on which an object to be adsorbed is placed, an internal electrode provided inside the dielectric substrate, a base plate made of metal and bonded to the dielectric substrate, and a conductive member that electrically connects the internal electrode and the base plate. A part of the conductive member is housed in a first recess formed on the base plate side of the dielectric substrate. The base plate side end of the conductive member is in contact with the dielectric substrate side of the base plate, or is in contact with the bottom surface of a second recess formed on that surface, which is shallower than the first recess.

[0009] In an electrostatic chuck with this configuration, the second recess, which could cause a hot spot, is formed relatively shallowly or not at all in the position of the conductive member on the base plate. As a result, localized temperature rise directly above the conductive member is suppressed, thereby reducing variations in the in-plane temperature distribution of the substrate during processing. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an electrostatic chuck that can suppress variations in the in-plane temperature distribution of a substrate. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic cross-sectional view showing the configuration of the electrostatic chuck according to the first embodiment. [Figure 2] This is a cross-sectional view showing in detail the configuration of the conductive member and its vicinity in the electrostatic chuck according to the first embodiment. [Figure 3] This is a perspective view showing the configuration of the conductive component. [Figure 4] This is a diagram illustrating a method for manufacturing an electrostatic chuck according to the first embodiment. [Figure 5] This is a cross-sectional view showing in detail the configuration of the conductive member and its vicinity in the electrostatic chuck according to the second embodiment. [Figure 6] This is a cross-sectional view showing in detail the configuration of the conductive member and its vicinity in the electrostatic chuck according to the third embodiment. [Modes for carrying out the invention]

[0012] This embodiment will be described below with reference to the attached drawings. To facilitate understanding of the explanation, the same reference numerals are used for identical components in each drawing whenever possible, and redundant explanations are omitted.

[0013] A first embodiment will be described. The electrostatic chuck 10 according to this embodiment is used to attract and hold a substrate W to be processed by electrostatic force inside a semiconductor manufacturing apparatus (not shown), such as an etching apparatus. The substrate W to be attracted is, for example, a silicon wafer. The electrostatic chuck 10 may also be used in apparatus other than semiconductor manufacturing apparatus.

[0014] Figure 1 shows a schematic cross-sectional view of the electrostatic chuck 10 in a state where the substrate W is adsorbed and held. The electrostatic chuck 10 comprises a dielectric substrate 100 and a base plate 200.

[0015] The dielectric substrate 100 is a substantially disc-shaped component made of a ceramic sintered body. The dielectric substrate 100 contains, for example, high-purity aluminum oxide (Al2O3), but may also contain other materials. The purity and type of ceramics in the dielectric substrate 100, as well as the additives, can be appropriately set considering the plasma resistance and other properties required of the dielectric substrate 100 in semiconductor manufacturing equipment.

[0016] The upper surface 110 of the dielectric substrate 100 in Figure 1 is the "mounting surface" on which the substrate W is placed. The lower surface 120 of the dielectric substrate 100 in Figure 1 is the "bonded surface" to which it is bonded to the base plate 200 via the bonding layer 300. The viewpoint from which the electrostatic chuck 10 is viewed from the surface 110 side, along a direction perpendicular to surface 110, will also be referred to as the "top view" below.

[0017] An adsorption electrode 130 is embedded inside the dielectric substrate 100. The adsorption electrode 130 is a thin flat plate-like layer formed of a metal material such as tungsten, for example, and is arranged to be parallel to the surface 110. As the material of the adsorption electrode 130, in addition to tungsten, molybdenum, platinum, palladium, etc. may also be used. 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, whereby the substrate W is adsorbed and held. As the configuration of the above power supply path, various known configurations can be adopted. The adsorption electrode 130 may be provided only one as a so-called "unipolar" electrode as in this embodiment, or may be provided two as a so-called "bipolar" electrode.

[0018] Inside the dielectric substrate 100, in addition to the above adsorption electrode 130, an RF electrode 140 is also embedded. The RF electrode 140 is provided as one of a pair of opposing electrodes for generating plasma in a semiconductor manufacturing apparatus. The other of the opposing electrodes is provided at a position above the electrostatic chuck 10 in the semiconductor manufacturing apparatus. When a high-frequency alternating voltage is applied between these opposing electrodes, plasma is generated above the substrate W and is used for processes such as film formation and etching on the substrate W. The RF electrode 140 corresponds to the "internal electrode" in this embodiment.

[0019] The RF electrode 140 is, like the adsorption electrode 130, a thin flat plate-like layer formed of a metal material such as tungsten, for example. As the material of the RF electrode 140, in addition to tungsten, molybdenum, platinum, palladium, etc. may also be used. The RF electrode 140 is embedded at a position closer to the surface 120 side than the adsorption electrode 130. The RF electrode 140 is arranged to be parallel to the surface 110, like the adsorption electrode 130. The RF electrode 140 is a single electrode that is substantially circular in a top view. The center of the RF electrode 140 in a top view coincides with the center of the dielectric substrate 100.

[0020] The electrostatic chuck 10 is provided with a conductive member 400. The conductive member 400 is a member for electrically connecting between the RF electrode 140 and a base plate 200 described later. Due to the conductive member 400, the potential of the RF electrode 140 during the processing of the substrate W becomes the same as the potential of the base plate 200. In FIG. 1, the conductive member 400 is schematically drawn as a simple straight line. The specific shape of the conductive member 400 will be described later.

[0021] As shown in FIG. 1, a space SP is formed between the dielectric substrate 100 and the substrate W. When processes such as etching are performed in the semiconductor manufacturing apparatus, helium gas for temperature adjustment is supplied from the outside into the space SP through a gas hole not shown. By interposing helium gas between the dielectric substrate 100 and the substrate W, the thermal resistance between the two is adjusted, and thereby the temperature of the substrate W is maintained at an appropriate temperature. Note that the gas for temperature adjustment supplied to the space SP may be a gas of a type different from helium.

[0022] A seal ring 111 and dots 112 are provided on the surface 110 which is the mounting surface, and the above-mentioned space SP is formed around these.

[0023] The seal ring 111 is a wall that partitions the space SP at the outermost peripheral position. The seal ring 111 is an annular protrusion formed on the surface 110 side. The tip (the upper end in FIG. 1) of the seal ring 111 is part of the surface 110 and abuts on the substrate W. The tip of the seal ring 111 can be said to be the outermost peripheral portion of the surface 110 which is the mounting surface.

[0024] Note that a plurality of seal rings 111 may be provided so as to divide the space SP. With such a configuration, it becomes possible to individually adjust the pressure of the helium gas in each space SP and make the surface temperature distribution of the substrate W during processing closer to uniform.

[0025] In Figure 1, the portion labeled "116" is the bottom surface of the space SP. Hereafter, this portion will also be referred to as "bottom surface 116". The seal ring 111, along with the dot 112 described below, is formed as a result of excavating a portion of the surface 110 down to the position of the bottom surface 116.

[0026] The dots 112 are circular protrusions that extend from the bottom surface 116. Multiple dots 112 are provided and are distributed approximately evenly on the mounting surface of the dielectric substrate 100. The tip of each dot 112 is part of the surface 110 and contacts the substrate W. By providing multiple such dots 112, the bending of the substrate W is suppressed.

[0027] The base plate 200 is a substantially disc-shaped member that supports the dielectric substrate 100. The base plate 200 is made of a metallic material such as aluminum. The base plate 200 is bonded to the surface 120 of the dielectric substrate 100 via a bonding layer 300. Of the base plate 200, the upper surface 210 in Figure 1 is the "bonded surface" that is bonded to the dielectric substrate 100.

[0028] The bonding layer 300 is a layer provided between the dielectric substrate 100 and the base plate 200, and it bonds the two together. The bonding layer 300 is made 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 made by curing another type of adhesive. In any case, it is preferable to use a material with the highest possible thermal conductivity for the bonding layer 300 so that the thermal resistance between the dielectric substrate 100 and the base plate 200 is reduced.

[0029] An insulating film may be formed on the surface of the base plate 200. 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 of the base plate 200 can be increased. The insulating film may be formed to cover the entire surface of the base plate 200, or it may be formed to cover only a part of the surface of the base plate 200, for example, only surface 210.

[0030] A refrigerant channel 250 is formed inside the base plate 200 for passing a refrigerant. When etching or other processes are performed in the semiconductor manufacturing equipment, a refrigerant is supplied from the outside to the refrigerant channel 250, thereby cooling the base plate 200. During processing, the heat generated in the substrate W is transferred to the refrigerant via the helium gas in the space SP, the dielectric substrate 100, and the base plate 200, and is discharged to the outside together with the refrigerant. The supply and discharge of refrigerant to and from the refrigerant channel 250 is performed through an opening (not shown) formed on the surface 220 of the base plate 200 opposite to the surface 210.

[0031] The specific configuration of the conductive member 400 and its vicinity will be described with reference to Figure 2. As shown in the figure, a first recess 160 is formed on the surface 120 of the dielectric substrate 100 on the base plate 200 side. The first recess 160 is a portion of the surface 120 that has been recessed toward the surface 110 in order to allow the conductive member 400 to be placed therein. In this embodiment, the first recess 160 is formed to a depth position that exposes the RF electrode 140. Therefore, the RF electrode 140, which is an internal electrode, is exposed at the bottom surface 162 of the first recess 160. In a top view, the shape of the first recess 160 is circular, and a substantially cylindrical space is formed inside it.

[0032] A second recess 260 is formed on the surface 210 of the base plate 200 that faces the dielectric substrate 100. The second recess 260 is formed on the surface 210 in the portion that overlaps with the first recess 160 when viewed from above. The second recess 260 is a portion of the surface 210 that has been recessed toward the surface 220 in order to allow the conductive member 400 to be placed therein. The metal portion of the base plate 200 is exposed throughout the inside of the second recess 260. The shape of the second recess 260 when viewed from above is circular, and a roughly cylindrical space is formed inside it. The central axis of the second recess 260 coincides with the central axis of the first recess 160. However, the diameter D2 of the inner circumferential surface 261 of the second recess 260 is larger than the diameter D1 of the inner circumferential surface 161 of the first recess 160.

[0033] A circular opening is formed in the joint layer 300 between the first recess 160 and the second recess 260. The first recess 160 and the second recess 260 are connected through this opening, and the entire area forms a single space.

[0034] In Figure 2, the component labeled "310" is a component positioned to prevent uncured adhesive from seeping into the inside of the first recess 160 and the second recess 260. This component will also be referred to as the "blocking portion 310" below. In a top view, the blocking portion 310 is an annular component positioned to surround the second recess 260 from the outside all around. The inner diameter of the blocking portion 310 is the same as the inner diameter of the second recess 260 (the diameter D2 mentioned above), but it may be a different size from the inner diameter of the second recess 260. For example, cured silicone adhesive can be used as the blocking portion 310.

[0035] The conductive member 400 is a substantially cylindrical member formed from a fibrous metal member and is housed inside the first recess 160 and the second recess 260. In other words, a portion of the conductive member 400 is housed in the first recess 160, and another portion of the conductive member 400 is housed in the second recess 260. In a top view, the diameter of the portion of the conductive member 400 housed in the first recess 160 is equal to the diameter of the portion of the conductive member 400 housed in the second recess 260.

[0036] The end of the conductive member 400 on the dielectric substrate 100 side (the upper end in Figure 2) is in contact with the RF electrode 140, which is exposed on the bottom surface 162 of the first recess 160. The end of the conductive member 400 on the base plate 200 side (the lower end in Figure 2) is in contact with the bottom surface 262 of the second recess 260. The conductive member 400, arranged in this manner, electrically connects the RF electrode 140 to the metal portion of the base plate 200.

[0037] As shown in Figure 3, the conductive member 400 has a substantially cylindrical main body portion 410 and a plurality of protrusions 420, and the entire body is integrally formed from a fibrous metal member. The protrusions 420 are substantially cylindrical projections formed so as to extend from the surface of the main body portion 410 facing the dielectric substrate 100, and further toward the dielectric substrate 100. In this embodiment, a total of four protrusions 420 are formed, but the number of protrusions 420 may be different.

[0038] The conductive member 400, which is made of fibrous metal material, has enough permeability to allow fluids such as air and adhesives to enter its interior. In other words, the fibrous metal material is not sufficiently dense, and there are gaps between the fibers. With this configuration, each part of the conductive member 400, including the protrusions 420, is an elastic body that can be easily deformed by external forces.

[0039] When no external force is being applied, the vertical dimension of the conductive member 400 (in the direction in which the protrusions 420 extend) is larger than the dimension in the same direction in the state shown in Figure 2. In other words, the conductive member 400 is compressed along the direction from the dielectric substrate 100 toward the base plate 200, housed inside the first recess 160 and the second recess 260, and sandwiched between the RF electrode 140 and the base plate 200. The tip of each protrusion 420 is elastically deformed so as to be crushed by being pressed against the bottom surface 162 of the first recess 160 (i.e., the RF electrode 140).

[0040] The conductive member 400 is pressed against the RF electrode 140 and the base plate 200 by its own restoring force. Therefore, even if thermal expansion or contraction occurs in various parts of the electrostatic chuck 10 during processing of the substrate W, the electrical connection between the RF electrode 140 and the base plate 200 is always maintained.

[0041] The number of conductive members 400 may be one or more. For example, spaces consisting of the first recess 160 and the second recess 260 may be formed in a manner that is arranged in a plurality along the circumferential direction, with one conductive member 400 housed in each space.

[0042] The conductive member 400 may have a different shape than that of this embodiment. For example, the conductive member 400 may be substantially cylindrical in shape and may not have a protruding portion 420.

[0043] Let's return to Figure 2 and continue the explanation. In the same figure, "L1" represents the depth of the first recess 160. In this embodiment, this depth is equal to the distance from surface 120 to bottom surface 162. L1 can also be defined as the dimension of the portion of the conductive member 400 housed in the first recess 160 in the state shown in Figure 2, along the direction perpendicular to the mounting surface.

[0044] In Figure 2, "L2" represents the depth of the second recess 260. In this embodiment, this depth is equal to the distance from the surface 220 to the bottom surface 262. L2 can also be defined as the dimension of the portion of the conductive member 400 housed in the second recess 260 in the state shown in Figure 2, along the direction perpendicular to the mounting surface.

[0045] In this embodiment, the depth (L2) of the second recess 260 is smaller than the depth (L1) of the first recess 160. In other words, the second recess 260 is formed as a shallower recess than the first recess 160.

[0046] Incidentally, the base plate 200 is required to have the function of cooling the substrate W during processing via the dielectric substrate 100 and maintaining a uniform in-plane temperature distribution of the substrate W. If the second recess 260 formed in the base plate 200 is formed deeply, the cooling function of the base plate 200 in that area will decrease, and the temperature of the substrate W directly above it may rise locally. In other words, the part of the substrate W directly above the second recess 260 may become a so-called "hot spot".

[0047] Therefore, in this embodiment, the second recess 260 is formed shallowly so that L2 is smaller than L1, as described above. Since the increase in thermal resistance due to the formation of the second recess 260 is kept to a minimum compared to the conventional method, local temperature rise directly above the conductive member 400 can be suppressed, and variations in the in-plane temperature distribution of the substrate W during processing can be suppressed.

[0048] "L3" shown in Figure 2 is the overall dimension of the conductive member 400 along the direction perpendicular to the mounting surface. Specifically, it is the overall dimension of the conductive member 400 along the direction perpendicular to the mounting surface when the conductive member 400 is housed and compressed inside the first recess 160 and the second recess 260. L3 is equal to the distance from the bottom surface 162 of the first recess 160 to the bottom surface 262 of the second recess 260.

[0049] In this embodiment, the shapes of the conductive member 400, the first recess 160, and the second recess 260 are adjusted such that the dimension of the portion of the conductive member 400 housed in the first recess 160 along the direction perpendicular to the mounting surface (i.e., L1) is at least half the overall dimension of the conductive member 400 along the same direction (i.e., L3).

[0050] To explain the advantages of this configuration, the method for joining the dielectric substrate 100 and the base plate 200 in the manufacturing method of the electrostatic chuck 10 will be described with reference to Figure 4. In Figure 4, the respective configurations of the dielectric substrate 100, the base plate 200, and the conductive member 400 are depicted in a simplified and schematic manner.

[0051] First, the dielectric substrate 100 is placed on a workbench (not shown) with its surface 120 facing upwards. A first recess 160 is pre-formed on surface 120. In addition, an adhesive that will become a bonding layer 300 after curing is pre-applied to substantially the entire surface 120. In Figure 4, the illustration of the adhesive is omitted. The adhesive may also be pre-applied to surface 220 of the base plate 200.

[0052] Next, the conductive members 400 are inserted into each of the first recesses 160. As shown in Figure 4, each conductive member 400 protrudes vertically from the surface 120 of the dielectric substrate 100.

[0053] Next, the base plate 200 is brought closer to the surface 120 from above, with the surface 210 facing downwards. A second recess 260 is pre-formed on the surface 210. The dielectric substrate 100 and the base plate 200 are aligned with each other so that each second recess 260 is directly above each first recess 160. The base plate 200 is moved along the arrows in Figure 4 and bonded to the dielectric substrate 100. Once the movement is complete, each conductive member 400 is housed inside the first recess 160 and the second recess 260. Then, the entire assembly is heated to cure the adhesive, completing the electrostatic chuck 10 shown in Figure 1.

[0054] When moving the base plate 200 along the arrow in Figure 4, if the first recess 160 formed in the surface 120 is too shallow, the conductive member 400 inserted in the first recess 160 will be prone to tipping over, significantly reducing work efficiency. Furthermore, if the diameter D1 of the inner circumferential surface 161 of the first recess 160 is too large, it becomes difficult to position the conductive member 400 so that it protrudes vertically from the surface 120, and the position of the conductive member 400 in that state may not be precisely determined.

[0055] Therefore, in this embodiment, the diameter D1 of the inner circumferential surface 161 of the first recess 160 is made to be approximately the same size as the diameter of the main body portion 410 of the conductive member 400, and the depth (L1) of the first recess 160 is made to be at least half the total length (L3) of the conductive member 400. With this configuration, it is possible to prevent the conductive member 400 from tipping over when joining the dielectric substrate 100 and the base plate 200.

[0056] If the diameter D2 of the inner circumferential surface 261 of the second recess 260 formed in the base plate 200 is smaller than the dimensions in this embodiment, for example, if it is about the same as the diameter D1 of the inner circumferential surface 161 of the first recess 160, then it becomes difficult to align the base plate 200 when bringing it closer to the dielectric substrate 100 below. In other words, it becomes difficult to get each conductive member 400 inside the second recess 260.

[0057] Therefore, in this embodiment, the shapes of the first recess 160 and the second recess 260 are designed so that the second recess 260 is larger than the first recess 160 when viewed from above. Specifically, the diameter D2 of the inner circumferential surface 261 is made larger than the diameter D1 of the inner circumferential surface 161. This makes it possible to easily insert each conductive member 400 into the inside of the second recess 260 while moving the base plate 200 downwards.

[0058] The second embodiment will now be described. The following will primarily focus on the differences from the first embodiment, while common points will be omitted as appropriate.

[0059] Figure 5 shows the configuration of the electrostatic chuck 10 according to this embodiment, from the same viewpoint as in Figure 2. As shown in Figure 5, the first recess 160 in this embodiment is not formed to a depth that exposes the RF electrode 140. The bottom surface 162 of the first recess 160 is located on the surface 120 side of the RF electrode 140.

[0060] The bottom surface 162 of the first recess 160 is covered by a metal plate 141. The metal plate 141 is a plate-shaped member made of, for example, molybdenum, and is in close contact with substantially the entire bottom surface 162. In this embodiment, the tip of the projection 420 is pressed against the metal plate 141.

[0061] The metal plate 141 and the RF electrode 140 are electrically connected by a plurality of via portions 142 provided in the dielectric substrate 100. Each via portion 142 is formed by filling the inside of a hole that extends along a direction perpendicular to the surface 120 with a conductive material such as tungsten. One end of each via portion 142 is connected to the metal plate 141, and the other end is connected to the RF electrode 140.

[0062] Thus, in this embodiment, the conductive member 400 and the RF electrode 140 are not directly connected, but are indirectly connected via the metal plate 141 and the via portion 142. This configuration also provides the same effects as those described in the first embodiment.

[0063] In this embodiment, "L1," that is, the depth of the first recess 160, is equal to the distance from the surface of the metal plate 141 facing the base plate 200 to surface 120. In this embodiment, as in the first embodiment, L2 is smaller than L1, and L1 is at least half the size of L3.

[0064] In this embodiment, since the electrical circuit in the via section 142 is relatively narrow, the electrical resistance of the via section 142 increases, potentially leading to significant Joule heating in the via section 142. To suppress the resulting localized temperature rise, it is preferable to increase the depth (L1) of the first recess 160 as much as possible and shorten the via section 142. In other words, in this embodiment, compared to the first embodiment, there is a particularly greater need to form the first recess 160, etc., such that L1 > L2.

[0065] A third embodiment will now be described. The following will primarily focus on the differences from the first embodiment, while commonalities will be omitted as appropriate.

[0066] Figure 6 shows the configuration of the electrostatic chuck 10 according to this embodiment, from the same viewpoint as in Figure 2. In this embodiment, the second recess 260 is not formed on the surface 210 of the base plate 200. The end of the conductive member 400 on the base plate 200 side is in contact with the surface 210 of the base plate 200 on the dielectric substrate 100 side. This configuration can also be described as a configuration in which the depth (L2) of the second recess 260 is 0. This configuration also produces the same effects as those described in the first embodiment.

[0067] As described in the first embodiment, an insulating film may be formed on the base plate 200 so as to cover the surface 210. In that case, the insulating film may not be formed on at least the portion of the surface 210 that the conductive member 400 contacts, leaving the metal portion of the base plate 200 exposed.

[0068] The embodiments have been described above with reference to specific examples. However, this disclosure is not limited to these specific examples. Modifications made to these specific examples by those skilled in the art are also included within the scope of this disclosure, as long as they retain the features of this disclosure. The elements, their arrangement, conditions, shapes, etc., of each of the aforementioned specific examples are not limited to those illustrated and can be modified as appropriate. The elements of each of the aforementioned specific examples can be combined in different ways as appropriate, as long as no technical inconsistencies arise. [Explanation of Symbols]

[0069] 10: Electrostatic Chuck 100: Dielectric substrate 110,120: face 160: First recess 140:RF electrode 200: Base plate 210: Face 260: Second recess 262: Bottom 400: Conductive material W: Circuit board

Claims

1. A dielectric substrate having a mounting surface on which an object to be adsorbed is placed, An internal electrode provided inside the dielectric substrate, A base plate formed of metal and bonded to the dielectric substrate, The system includes a conductive member that electrically connects the internal electrode and the base plate, A portion of the conductive member is housed in a first recess formed on the base plate side of the dielectric substrate. The end of the conductive member on the base plate side is, An electrostatic chuck characterized in that it is in contact with the surface of the base plate that is on the dielectric substrate side, or in contact with the bottom surface of a second recess formed on that surface, which is shallower than the first recess.

2. The electrostatic chuck according to claim 1, characterized in that the dimension of the portion of the conductive member housed in the first recess, along the direction perpendicular to the aforementioned mounting surface, is 1 / 2 or more of the total dimension of the conductive member along the same direction.

3. The base plate has the second recess formed therein. The electrostatic chuck according to claim 2, characterized in that the second recess is larger than the first recess when viewed from a direction perpendicular to the mounting surface.

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