Electrostatic chuck

Abstract

The invention provides an electrostatic chuck capable of easily realizing electric connection between an internal electrode and a power supply terminal. Specifically, the electrostatic chuck (10) is provided with: a dielectric substrate (100); an RF electrode (140) provided inside the dielectric substrate (100); a power supply terminal (170) disposed on the inner side of a recess (160) formed on a surface (120) of the dielectric substrate (100), the surface (120) being on the opposite side from the placement surface; and a connection unit (190) that electrically connects the RF electrode (140) and the power supply terminal (170). The connection part (190) extends from the bottom surface (161) of the recess (160) toward the placement surface side, and extends to a position closer to the placement surface side than the RF electrode (140).

Description

Technical Field

[0001] This invention relates to electrostatic chucks. Background Technology

[0002] For example, in semiconductor manufacturing apparatuses such as etching machines, electrostatic chucks are provided as devices for adsorbing and holding substrates such as silicon wafers that are being processed. An electrostatic chuck has a dielectric substrate with adsorption electrodes and a base supporting the dielectric substrate, and is configured to connect them together. When a voltage is applied to the adsorption electrodes, an electrostatic force is generated to adsorb and hold the substrate placed on the dielectric substrate.

[0003] An internal electrode is provided inside the dielectric substrate. An "internal electrode" refers, for example, to the adsorption electrode described above. In addition, as an "internal electrode," one of a pair of opposing electrodes, namely an RF electrode, for generating plasma in a semiconductor manufacturing apparatus, is sometimes provided inside the dielectric substrate.

[0004] A power supply terminal is also provided on the dielectric substrate. The power supply terminal is a conductive component for receiving electricity supplied from the outside to the internal electrodes. As described in Patent Document 1 below, the power supply terminal is usually disposed inside a recess formed on a surface of the dielectric substrate opposite to the mounting surface.

[0005] Patent documents Patent Document 1: Japanese Patent No. 7184034 Summary of the Invention

[0006] As a specific configuration for electrically connecting the internal electrode and the power supply terminal, for example, the aforementioned recess could be formed such that the internal electrode is exposed on the bottom surface, and the power supply terminal disposed inside the recess is directly connected to the exposed internal electrode. However, with this configuration, the depth of the recess needs to be precisely adjusted, thus presenting a problem where the processing of the recess is extremely difficult.

[0007] The present invention was made in view of the following problem: the technical problem to be solved is to provide an electrostatic chuck that can easily realize the electrical connection between the internal electrodes and the power supply terminal.

[0008] To address the aforementioned issues, the electrostatic chuck of the present invention comprises: a dielectric substrate having a placement surface for holding an object to be adsorbed; an internal electrode disposed inside the dielectric substrate; a power supply terminal disposed inside a recess formed on a surface of the dielectric substrate opposite to the placement surface; and a connecting portion electrically connecting the internal electrode and the power supply terminal. The connecting portion extends from the bottom surface of the recess toward the placement surface and extends to a position closer to the placement surface than the internal electrode.

[0009] When manufacturing the electrostatic chuck with the above configuration, simply form the first recess on the dielectric substrate to a depth further forward than the internal electrode, then form the second recess from the bottom surface of the first recess to a position exceeding the internal electrode, and finally place the conductor, which serves as a connecting portion, inside the second recess. Strict depth adjustment is not required when processing either the first or second recess. Therefore, electrical connection between the internal electrode and the power supply terminal can be easily achieved.

[0010] According to the present invention, an electrostatic chuck is provided that enables easy electrical connection between internal electrodes and power supply terminals. Attached Figure Description

[0011] Figure 1 This is a cross-sectional view showing the configuration of the electrostatic chuck according to the first embodiment. Figure 2 This is an enlarged view of the configuration of the power supply terminal and its surrounding area in the electrostatic chuck according to the first embodiment. Figure 3 It is a diagram that depicts the power supply terminals and connections, viewed from a direction perpendicular to the mounting surface. Figure 4 This is a diagram used to explain the manufacturing method of the electrostatic chuck according to the first embodiment. Figure 5 This is a diagram used to explain the manufacturing method of the electrostatic chuck according to the first embodiment. Figure 6 This is a diagram used to explain the manufacturing method of the electrostatic chuck according to the first embodiment. Figure 7 It is a diagram that enlarges the structure of the top part of the connector and its surrounding parts. Figure 8 This is a cross-sectional view showing the configuration of the electrostatic chuck according to the second embodiment. Figure 9 This is a perspective view showing the configuration of the connecting components of the electrostatic chuck according to the second embodiment. Figure 10 This is a diagram showing the configuration of the electrostatic chuck involved in the comparative example. Symbol Explanation 10 - Electrostatic chuck; 110, 120 - Surface; 140 - RF electrode; 160 - Recess; 161 - Bottom surface; 170 - Power supply terminal; 180 - Solder; 190 - Connector; W - Substrate. Detailed Implementation

[0012] The present embodiment will now be described with reference to the accompanying drawings. To facilitate understanding, the same symbols are used as much as possible to represent the same constituent elements in each drawing, and repeated descriptions are omitted.

[0013] The first embodiment will be described. The electrostatic chuck 10 described in this embodiment is, for example, a device used inside a semiconductor manufacturing apparatus (not shown) such as an etching apparatus to hold a substrate W, which is the object to be processed, by using electrostatic force. The object to be held, i.e., the substrate W, is, for example, a silicon wafer. The electrostatic chuck 10 can also be used in devices other than semiconductor manufacturing apparatuses.

[0014] exist Figure 1 The diagram shows a schematic cross-sectional view of an electrostatic chuck 10 in which a substrate W is held in place by adsorption. The electrostatic chuck 10 includes a dielectric substrate 100 and a base 200.

[0015] The dielectric substrate 100 is a generally disk-shaped component made of sintered ceramic body. The dielectric substrate 100 may contain, for example, high-purity alumina (Al2O3), but may also contain other materials. The purity and type of ceramic, additives, etc., in the dielectric substrate 100 can be appropriately set considering requirements such as plasma resistance required for the dielectric substrate 100 in the manufacture of semiconductor manufacturing equipment.

[0016] dielectric substrate 100 Figure 1 The upper side surface 110 of the dielectric substrate 100 is the "placement surface" for placing the substrate W. Furthermore, in the dielectric substrate 100... Figure 1 The lower side surface 120 is the "joined surface" that is joined to the chassis 200 through the joining layer 300. Hereinafter, the viewpoint when observing the electrostatic chuck 10 from the side of surface 110 along the direction perpendicular to surface 110 will also be described as "top view".

[0017] An adsorption electrode 130 is embedded inside the dielectric substrate 100. The adsorption electrode 130 is, for example, a thin, flat layer formed of a metal material such as tungsten, and is arranged parallel to the surface 110. Besides tungsten, molybdenum, platinum, palladium, etc., can also be used as the material for the adsorption electrode 130. When a voltage is applied to the adsorption electrode 130 from the outside via a power supply circuit (not shown), an electrostatic force is generated between the surface 110 and the substrate W, thereby adsorbing and holding the substrate W. Various known configurations can be used for the aforementioned power supply circuit. The adsorption electrode 130 can be provided as a single "monopolar" electrode as in this embodiment, or it can be provided as two "bipolar" electrodes.

[0018] Inside the dielectric substrate 100, in addition to the aforementioned adsorption electrode 130, an RF electrode 140 is also embedded. The RF electrode 140 is provided in the semiconductor manufacturing apparatus as one of a pair of opposing electrodes used to generate plasma. The other opposing electrode is positioned 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 supplied to processes such as film deposition or etching of the substrate W.

[0019] Similar to the adsorption electrode 130, the RF electrode 140 is, for example, a thin, flat layer formed of a metallic material such as tungsten. Besides tungsten, molybdenum, platinum, palladium, etc., can also be used as the material for the RF electrode 140. The RF electrode 140 is embedded in a position closer to surface 120 than the adsorption electrode 130. Like the adsorption electrode 130, the RF electrode 140 is configured parallel to surface 110. Viewed from above, the RF electrode 140 is a generally circular, single electrode. The RF electrode 140 is referred to as the "internal electrode" in this embodiment.

[0020] Power is supplied to the RF electrode 140 from an external power source via a power supply component 14 and a power supply terminal 170. The power supply component 14 is a rod-shaped conductive component electrically connected to an external power source (not shown). The power supply component 14 is held by a holding mechanism (not shown) so that its tip abuts against the power supply terminal 170. Alternatively, the power supply component 14 can be configured to extend or retract elastically. There can be one or more power supply components 14 connected to the electrostatic chuck 10.

[0021] The power supply terminal 170 is a terminal provided on the dielectric substrate 100 as a portion for receiving electricity supplied to the RF electrode 140. The power supply terminal 170 is a generally circular plate-shaped component formed of a conductive material such as metal. As a material for the power supply terminal 170, a material containing molybdenum can be used, for example.

[0022] A recess 160 is formed on the surface 120 of the dielectric substrate 100 opposite to the placement surface. A power supply terminal 170 is disposed inside the recess 160 and is electrically connected to the RF electrode 140 via a connection portion 190 described later. The specific configuration of the power supply terminal 170 and its surrounding portion will be described later.

[0023] A space SP is formed between the dielectric substrate 100 and the substrate W. During etching and other processes in a semiconductor manufacturing apparatus, helium gas for temperature regulation is supplied from the outside into the space SP through a vent (not shown). By introducing helium gas between the dielectric substrate 100 and the substrate W, the thermal resistance between them can be adjusted, thereby maintaining the temperature of the substrate W at an appropriate temperature. Alternatively, the gas supplied to the space SP for temperature regulation can be a different type of gas than helium.

[0024] A sealing ring 111 and a dot 112 are provided on the placement surface, i.e., surface 110, and the aforementioned space SP is formed around them.

[0025] The sealing ring 111 is the wall that divides the space SP at the outermost periphery. The upper end of the sealing ring 111 becomes part of the surface 110 and abuts against the substrate W. Alternatively, multiple sealing rings 111 can be provided to divide the space SP. By adopting this configuration, the pressure of helium gas in each space SP can be adjusted individually, and the surface temperature distribution of the substrate W during processing can be made nearly uniform.

[0026] Figure 1 The portion marked with the symbol "116" is the bottom surface of space SP. Hereinafter, this portion will also be referred to as "bottom surface 116". As a result of cutting a portion of surface 110 down to the position of bottom surface 116, sealing ring 111 and the dot 112 described below are formed together.

[0027] The dot 112 is a circular protrusion extending 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 becomes part of the surface 110 and abuts against the substrate W. By pre-setting a plurality of such dots 112, the deflection of the substrate W can be suppressed.

[0028] In this embodiment, a flange 150 is provided on the dielectric substrate 100. The flange 150 is a portion that protrudes further outward from the mounting surface, i.e., surface 110. Viewed from above, the flange 150 surrounds the entire surface 110 from the outside. The surface of the substrate W side in the flange 150 ( Figure 1 The upper side of the middle) is located further to the chassis 200 side than surface 110. Figure 1 The ring-shaped component (not shown) is located on the lower side of the substrate W. When processing the substrate W, a ring-shaped component, such as a "focusing ring", is placed on the edge 150. Alternatively, the edge 150 may not be provided on the dielectric substrate 100, and the aforementioned ring-shaped component may be placed directly on the chassis 200.

[0029] The chassis 200 is a generally disk-shaped component that supports the dielectric substrate 100. The chassis 200 is formed of a metal material, such as aluminum. The chassis 200 is bonded to the surface 120 of the dielectric substrate 100 via a bonding layer 300. In the chassis 200, Figure 1 The upper side surface 210 is the "joined surface" that is joined with the dielectric substrate 100.

[0030] The bonding layer 300 is a layer disposed between the dielectric substrate 100 and the chassis 200, bonding the two together. The bonding layer 300 is formed by curing an adhesive material made of an insulating material. In this embodiment, a silicone adhesive is used as the adhesive. However, the bonding layer 300 may also be formed by curing other types of adhesives. In any case, it is preferable to use a material with the highest possible thermal conductivity as the material for the bonding layer 300, in order to reduce the thermal resistance between the dielectric substrate 100 and the chassis 200.

[0031] An insulating film can also be formed on the surface of the chassis 200. For example, an aluminum oxide film formed by spraying can be used as the insulating film. By pre-covering the surface of the chassis 200 with an insulating film, the insulation withstand voltage of the chassis 200 can be improved.

[0032] Inside the chassis 200, a refrigerant channel 250 is formed for the flow of refrigerant. During processes such as etching in the semiconductor manufacturing apparatus, refrigerant is supplied from the outside to the refrigerant channel 250, thereby cooling the chassis 200. During the process, heat generated by the substrate W is conducted to the refrigerant through the helium gas in the space SP, the dielectric substrate 100, and the chassis 200, and is discharged to the outside along with the refrigerant. The supply and discharge of refrigerant to the refrigerant channel 250 are carried out through an opening (not shown) formed on the surface 220 of the chassis 200 opposite to the surface 210.

[0033] A through hole 260 is formed on the chassis 200. The through hole 260 is a hole provided for passing through the aforementioned power supply component 14, and is formed from surface 210 to surface 220 in a manner that perpendicularly penetrates the chassis 200. A cylindrical component for preventing discharge between the two may also be disposed between the inner surface of the through hole 260 and the power supply component 14.

[0034] exist Figure 2 In the middle, it is shown that Figure 1 The specific configuration of the power supply terminal 170 and its surrounding area in the electrostatic chuck 10 shown. Additionally, in Figure 2 The diagram of power supply component 14 is omitted.

[0035] As previously described, a recess 160 is formed on surface 120 of dielectric substrate 100. The recess 160 is circular in shape when viewed from above. The recess 160 is a bottomed hole formed by receding from surface 120 toward surface 110. The diameter of the recess 160 (or the inner diameter of the recess 160) when viewed from above is slightly larger than the outer diameter of the power supply terminal 170 when viewed from above.

[0036] Hereinafter, the bottom surface of the recess 160, i.e., the surface of the recess 160 located on the side closest to the surface 110, will also be referred to as the "bottom surface 161". The power supply terminal 170 is joined to the bottom surface 161 of the recess 160 by solder 180. The solder 180 is, for example, a silver solder with added titanium, which can be directly soldered to the surface of the ceramic, i.e., dielectric substrate 100. In addition to silver and titanium, the solder 180 may also contain copper or the like.

[0037] The position of the bottom surface 161, where the power supply terminal 170 is joined, is located further towards the surface 120 than the RF electrode 140. The RF electrode 140 and the power supply terminal 170 are electrically connected via a connecting portion 190. The connecting portion 190 is formed such that it extends from the bottom surface 161 of the recess 160 towards the surface 110 (in... Figure 2 The connecting portion 190 extends from the upper side (in the middle) and further extends to a position closer to the surface 110 than the RF electrode 140. That is, the connecting portion 190 passes through the RF electrode 140 and is electrically connected to the RF electrode 140. In the connecting portion 190, Figure 2 The lower end of the connector 190 is connected to the solder 180. In this embodiment, the material of the connector 190 is the same as the material of the solder 180, and the two are integrally connected. With the above configuration, the RF electrode 140 and the power supply terminal 170 are electrically connected through the solder 180 and the connector 190.

[0038] exist Figure 3 The figure depicts a view of the portion of the dielectric substrate 100 with the recessed portion 160 from the side of surface 120. In this figure, the connecting portion 190, located further inward than the power supply terminal 170, is depicted with dashed lines. In this embodiment, multiple connecting portions 190 are connected to one power supply terminal 170. Each connecting portion 190 is circular in shape when viewed from above.

[0039] From a top view, multiple connecting portions 190 are arranged in a circular pattern inside the recess 160. Figure 3 The dotted line DL shown represents an imaginary circle passing through the center of each connecting portion 190 when viewed from above. That is, the multiple connecting portions 190 are arranged along the circle of the dotted line DL. The center of this circle when viewed from above coincides with the center of the recess 160.

[0040] In this embodiment, the plurality of connecting portions 190 are further configured to be arranged at equal intervals along the dotted line DL. Here, "interval" refers to the length along the dotted line DL between adjacent pairs of connecting portions 190. The equal intervals along the dotted line DL can be all of the plurality of connecting portions 190, or it can be only a portion of the plurality of connecting portions 190.

[0041] Alternatively, other connecting portions 190 may be provided at locations different from those described above. For example, in a top view, another connecting portion 190 may be provided at the center of the circle of the dashed line DL.

[0042] The method for manufacturing the electrostatic chuck 10, particularly the method for forming the connecting portion 190, will be described. First, a dielectric substrate 100 with the adsorption electrode 130 and the RF electrode 140 built in it is manufactured. As a manufacturing method, various existing known methods such as sheet lamination can be used.

[0043] After the dielectric substrate 100 is calcined, a recess 160 is formed on the surface 120. Figure 4 The image shows a cross-section of the dielectric substrate 100 at a point in time after the formation of the recess 160 is completed. The recess 160 is not formed to a depth reaching the RF electrode 140. As previously mentioned, the bottom surface 161 of the recess 160 is located closer to the surface 120 than the RF electrode 140. Therefore, the RF electrode 140 is not exposed on the inner surface of the recess 160.

[0044] Next, a plurality of recesses 162 are formed such that they extend further toward the surface 110 from the bottom surface 161 of the recess 160. Figure 5 The image shows the state after the recesses 162 have been formed. Recesses 162 are the part that later becomes the connecting portion 190. The shape of each recess 162 is circular when viewed from above.

[0045] Hereinafter, the bottom surface of the recess 162, i.e., the surface in the recess 162 located closest to the surface 110, will also be referred to as the "bottom surface 163". At the point in time after the processing of the recess 162 is completed, the bottom surface 163 is located closer to the surface 110 than the RF electrode 140. That is, each recess 162 is formed to extend to a depth penetrating the RF electrode 140. Therefore, the RF electrode 140 is exposed on the inner surface of the recess 162.

[0046] Next, as Figure 6As shown, firstly, the solder 180 is placed onto the bottom surface 161 of the recess 160, and then the power supply terminal 170 is placed. The solder 180 is made by processing a plate-shaped solder 180 before melting into a round shape. Alternatively, a paste-like solder 180 can be applied to the bottom surface 161. At this point, since the solder 180 does not enter the recess 162, a space is formed inside the recess 162.

[0047] from Figure 6 The dielectric substrate 100 is heated entirely, for example, using a vacuum furnace. As a result, the bottom surface 161 and power supply terminals 170 are wetted by molten solder 180. A portion of the molten solder 180 enters the interior of the recess 162. The interior of the recess 162 is filled with solder 180, and the RF electrode 140 exposed on the inner surface of the recess 162 and the solder 180 are connected to each other.

[0048] When the heating in the vacuum furnace ends, the brazing filler metal 180 inside the recess 162 solidifies to form the connecting part 190. This completes the process. Figure 2 The electrostatic chuck 10 shown is configured as follows.

[0049] exist Figure 7 The diagram shows an enlarged view of the portion of the connector 190 that penetrates the RF electrode 140. The "L" shown in the diagram indicates the amount of protrusion of the connector 190 from the RF electrode 140. Hereinafter, this amount of protrusion will also be referred to as "protrusion amount L". The protrusion amount L is from the surface 110 side of the connector 190 (in... Figure 7 The distance from the end of the RF electrode 140 (the upper side) to the surface of the RF electrode 110 along a direction perpendicular to the surface 110.

[0050] like Figure 7 As shown, the outer periphery of the top end of the connecting portion 190 is R-shaped. Therefore, the diameter of the connecting portion 190 is slightly smaller at the top end compared to other parts. This shape of the connecting portion 190 is derived from the shape of the tool used when machining the recess 162.

[0051] If the protrusion amount L is too small, there is a possibility that the diameter of the portion of the connector 190 penetrating the RF electrode 140 may become smaller. Since this configuration would result in a lower resistance between the connector 190 and the RF electrode 140 than designed, it is not preferable. To achieve the designed resistance, the protrusion amount L only needs to be large enough. Specifically, the protrusion amount L only needs to be increased to the point that the diameter D1 of the portion of the connector 190 closer to surface 120 than the RF electrode 140 and the diameter D2 of the portion of the connector 190 closer to surface 110 than the RF electrode 140 are approximately equal to each other. For example, it is preferable to ensure that the protrusion amount L is at least 50 μm beforehand.

[0052] When there are no particular issues with the resistance between the connector 190 and the RF electrode 140, the diameter D2 can be less than or equal to the diameter D1.

[0053] To explain the advantages of the configuration of this embodiment as described above, firstly, refer to... Figure 10 The configuration involved in the comparative example will be described. As shown in the figure, in this comparative example, the recess 160 is formed such that the RF electrode 140 is exposed on the bottom surface 161. Furthermore, the power supply terminal 170 is directly connected to the exposed RF electrode 140 via solder 180.

[0054] In this comparative configuration, an electrical connection can also be made between the RF electrode 140 and the power supply terminal 170. However, when forming the recess 160 on the dielectric substrate 100, the depth of the recess 160 needs to be precisely adjusted so that the thinner RF electrode 140 is exposed on the entire bottom surface 161. Therefore, there is a problem that the processing of the recess 160 is extremely difficult.

[0055] Therefore, in the electrostatic chuck 10 according to this embodiment, by adopting Figure 2 The configuration shown eliminates the need for precise adjustment of the depth of the recess 160.

[0056] For reference Figure 4 In this embodiment, the recess 160 is not formed to a depth reaching the RF electrode 140. Since it is not necessary to precisely adjust the position of the bottom surface 161 of the recess 160 to the position where the RF electrode 140 is exposed, the recess 160 can be formed relatively easily.

[0057] In formation Figure 5 The same applies to the recess 162 shown. Since it is not necessary to precisely adjust the position of the bottom surface 163 of the recess 162 to the position where the RF electrode 140 is exposed, the recess 162 can be formed relatively easily.

[0058] Therefore, when manufacturing the electrostatic chuck 10 according to this embodiment, it is not necessary to strictly adjust the depth of either the recess 160 or the recess 162 during machining. Consequently, it is easy to realize the electrical connection between the RF electrode 140 and the power supply terminal 170.

[0059] In this embodiment, by providing multiple connection portions 190 to a single power supply terminal 170, the resistance between the power supply terminal 170 and the RF electrode 140 can be minimized. Furthermore, since the multiple connection portions 190 are arranged at equal intervals along a circle when viewed from above, the current will not be biased relative to a portion of the connection portions 190. Because the current can flow substantially uniformly through the multiple connection portions 190, localized heating can be prevented.

[0060] In this embodiment, when the bottom surface 161 and the power supply terminal 170 are joined by the solder 180, a portion of the solder 180 enters the recess 162 to become the connecting portion 190. Therefore, it is easy to form the connecting portion 190.

[0061] The material of the connecting part 190 and the material of the brazing filler 180 can be the same as in this embodiment, or they can be different materials.

[0062] Typically, the materials for the internal electrodes, namely the RF electrode 140 and the adsorption electrode 130, need to be selected considering the shrinkage during the calcination of the dielectric substrate 100, thus presenting limitations such as difficulty in sufficiently reducing resistivity. Furthermore, in the case of air calcination, there is also a limitation that only materials that are not easily oxidized can be used as materials for the RF electrode 140, etc.

[0063] On the other hand, since the connecting portion 190 is formed after calcination, the material of the connecting portion 190 can be freely selected without considering the limitations described above. Therefore, in this embodiment, a material different from the material of the RF electrode 140 is used as the material of the connecting portion 190. Specifically, a material with a lower resistivity (e.g., silver) compared to the material of the RF electrode 140 (e.g., tungsten) is used as the material of the connecting portion 190. Furthermore, since a material with a melting point lower than the calcination temperature of ceramic can be used as the material of the connecting portion 190, it also has the advantage of reducing residual stress when returning to room temperature.

[0064] The configuration described above for supplying power to the RF electrode 140, which is the same as the configuration including the recess 160, the power supply terminal 170, and the connecting portion 190, can also be applied to the configuration for supplying power to the adsorption electrode 130.

[0065] The second embodiment will be described below. Hereinafter, the differences from the first embodiment will be mainly described, while the commonalities with the first embodiment will be omitted as appropriate.

[0066] exist Figure 8 In China, utilizing and Figure 1 The same cross-sectional view schematically depicts the configuration of the electrostatic chuck 10 according to this embodiment. In this embodiment, the power supply to the RF electrode 140 is not provided by the power supply component 14, but by the chassis 200 and the connecting component 400.

[0067] The connecting component 400 is used to electrically connect the RF electrode 140 and the chassis 200. Through the connecting component 400, the potential of the RF electrode 140 during processing of the substrate W is the same as the potential of the chassis 200. The potential of the chassis 200 can be adjusted, for example, by an external power supply.

[0068] In this embodiment, no through hole 260 is formed on the chassis 200. Therefore, the inside of the recess 160 is a sealed space. The connecting member 400 is disposed within this sealed space.

[0069] The connecting member 400 is a generally cylindrical component formed from a fibrous metal part and is housed inside the recess 160. One end of the connecting member 400 abuts against the power supply terminal 170 disposed in the recess 160. The other end of the connecting member 400 abuts against the surface 210 of the chassis 200. Through this configuration of the connecting member 400, an electrical connection is established between the power supply terminal 170 and the chassis 200. Alternatively, a recess (i.e., a bottomed hole) may be formed directly below the recess 160 in the surface 210 of the chassis 200, and a portion of the connecting member 400 may be housed within this recess.

[0070] like Figure 9 As shown, the connecting member 400 has a generally cylindrical body portion 410 and a plurality of protrusions 420, and is integrally formed from a fibrous metal component. Each protrusion 420 is a generally cylindrical projection formed from the dielectric substrate 100 side of the body portion 410, extending further toward the dielectric substrate 100 side. In this embodiment, a total of four protrusions 420 are formed, but the number of protrusions 420 may vary.

[0071] The connecting member 400, made of fibrous metal components, has a degree of permeability that allows fluids such as air or adhesives to penetrate its interior. That is, the fibrous metal components are not dense enough, with gaps between the fibers. By adopting such a configuration, the connecting member 400 becomes an elastic body in which each part, including the protrusions 420, can be easily deformed by external force.

[0072] The vertical dimension (direction of the protrusion 420) of the connecting member 400 when not subjected to external force Figure 1 The dimensions in the same direction are larger in the current state. That is, the connecting member 400 is housed inside the recess 160 and sandwiched between the power supply terminal 170 and the surface 210 in a compressed state along the direction from the dielectric substrate 100 toward the chassis 200. The tips of each protrusion 420 are elastically deformed by being pressed against the power supply terminal 170 in a flattened manner.

[0073] The connecting component 400 is pressed against the power supply terminal 170 and the surface 210 by its own restoring force. Therefore, even if thermal expansion or contraction occurs at various parts of the electrostatic chuck 10 during the processing of the substrate W, the electrical connection between the power supply terminal 170 and the surface 210 will always be maintained.

[0074] The shape of the connecting member 400 may also be different from that of this embodiment. For example, the connecting member 400 may be formed as a generally cylindrical shape and may not have a protrusion 420.

[0075] Even in this embodiment, where the power supply terminal 170 and the chassis 200 are electrically connected via the connecting member 400, the same effect as described in the first embodiment can be achieved.

[0076] The above description of this embodiment refers to specific examples. However, this disclosure is not limited to these specific examples. As long as the features of this disclosure are present, products with appropriate design modifications to these specific examples by those skilled in the art are also included within the scope of this disclosure. The elements, configurations, conditions, shapes, etc., of the aforementioned specific examples are not limited to the illustrated contents and can be appropriately modified. As long as no technical contradiction arises, the elements of the aforementioned specific examples can be appropriately changed and combined.

Claims

1. An electrostatic chuck characterized by comprising: a dielectric substrate having a mounting surface on which an object to be attracted is mounted; an internal electrode provided inside the dielectric substrate; a power supply terminal disposed on the inner side of a recess formed on the surface of the dielectric substrate opposite to the mounting surface; and a connecting portion electrically connecting between the internal electrode and the power supply terminal, wherein the connecting portion extends from the bottom surface of the recess toward the mounting surface side and extends to a position closer to the mounting surface side than the internal electrode.

2. The electrostatic chuck according to claim 1, characterized in that a plurality of the connecting portions are connected to one of the power supply terminals.

3. The electrostatic chuck according to claim 2, characterized in that when viewed in a direction perpendicular to the mounting surface, the recess has a circular shape, and the plurality of connecting portions are arranged along the circle.

4. The electrostatic chuck according to claim 3, characterized in that when viewed in a direction perpendicular to the mounting surface, the plurality of connecting portions are arranged along the circle at equal intervals.

5. The electrostatic chuck according to claim 1, characterized in that the bottom surface of the recess and the power supply terminal are joined by a solder.

6. The electrostatic chuck according to claim 5, characterized in that the material of the connecting portion and the material of the solder are the same as each other.

7. The electrostatic chuck according to claim 6, characterized in that the material of the connecting portion is a material different from the material of the internal electrode.

8. The electrostatic chuck according to claim 7, characterized in that the material of the connecting portion has a lower resistivity than the material of the internal electrode.

9. The electrostatic chuck according to claim 8, characterized in that both the material of the connecting portion and the material of the solder contain silver.

10. The electrostatic chuck according to claim 1, characterized in that the connecting portion has a projection amount of 50 μm or more from the internal electrode. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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