JP7409536B1 - Electrostatic chuck and its manufacturing method - Google Patents

Abstract

The present invention provides an electrostatic chuck that can suppress the occurrence of discharge through gas holes, and a method for manufacturing the same. An electrostatic chuck 10 is provided between a dielectric substrate 100 in which a gas hole 140 is formed, a base plate 200 in which a gas hole 240 is formed, and between the dielectric substrate 100 and the base plate 200, and is provided with an insulating material. A bonding layer 300 formed of a material. An opening 142, which is an end of a gas hole 140, is formed in a surface 120 of the dielectric substrate 100 on the bonding layer 300 side. An opening 241 , which is an end of a gas hole 240 , is formed in a surface 210 of the base plate 200 on the bonding layer 300 side at a position different from the opening 142 . A communication groove 150 that communicates between the opening 142 and the opening 241 is formed in the surface 120 of the dielectric substrate 100 on the bonding layer 300 side. [Selection diagram] Figure 1

Description

The present invention relates to an electrostatic chuck and a method for manufacturing the same.

For example, semiconductor manufacturing equipment such as a CVD equipment is provided with an electrostatic chuck as a device for attracting and holding a substrate such as a silicon wafer to be processed. An electrostatic chuck includes a dielectric substrate provided with a suction electrode and a base plate supporting the dielectric substrate, and has a configuration in which these are joined to each other. The suction electrode is generally built into a dielectric substrate, but as described in Patent Document 1 listed below, a metal base plate is sometimes used as the suction electrode. When a voltage is applied to the attraction electrode, an electrostatic force is generated, and the substrate placed on the dielectric substrate is attracted and held.

An inert gas such as helium is often supplied between the dielectric substrate and the substrate for the purpose of adjusting the temperature of the substrate during processing. As such gas supply paths, gas holes are formed in each of the dielectric substrate and the base plate.

Japanese Patent Application Publication No. 2005-203426

In the configuration described in Patent Document 1, the gas hole is formed so as to linearly penetrate the joint portion between the dielectric substrate and the base plate along a direction perpendicular to the surface to be joined. Metal is exposed on the inner surface of the gas hole provided in the base plate, and this exposed metal faces the substrate through the linear gas hole. Therefore, in the electrostatic chuck having the above configuration, discharge between the substrate and the base plate is relatively likely to occur along the linear gas hole.

The present invention has been made in view of such problems, and an object thereof is to provide an electrostatic chuck that can suppress the occurrence of discharge through the gas holes, and a method for manufacturing the same.

In order to solve the above problems, an electrostatic chuck according to the present invention includes a dielectric substrate in which a first gas hole is formed, a base plate in which a second gas hole is formed, and a gap between the dielectric substrate and the base plate. and a bonding layer formed of an insulating material. A first opening, which is an end of the first gas hole, is formed on the surface of the dielectric substrate on the bonding layer side. A second opening, which is an end of the second gas hole, is formed on the surface of the base plate on the bonding layer side at a position different from the first opening. A communication groove that communicates between the first opening and the second opening is formed in the surface of the dielectric substrate on the bonding layer side.

In an electrostatic chuck having such a configuration, the first opening, which is the end of the first gas hole, and the second opening, which is the end of the second gas hole, are located at different positions, and there is a space between them. They are communicated by a communication groove provided in the dielectric substrate. The above-mentioned "position" refers to, for example, the position of the first opening and the second opening when viewed from a direction perpendicular to the surface to be joined.

In such a configuration, the inner surface of the second gas hole is not exposed toward the substrate directly below the first gas hole. The creepage distance of the path from the metal exposed on the inner surface of the second gas hole to the substrate through the first gas hole is ensured longer than in the conventional configuration, so the generation of electric discharge along the path is suppressed. be able to.

Further, in the electrostatic chuck according to the present invention, it is also preferable that the second opening communicates with the plurality of first openings via communication grooves. In such a configuration, the number of second openings can be made smaller than the number of first openings. By reducing the number of second openings that can serve as starting points for discharge, it is possible to further suppress the occurrence of discharge.

Further, in the electrostatic chuck according to the present invention, it is also preferable that an insulating film is provided on the surface of the base plate on the bonding layer side. In such a configuration, the surface of the base plate is covered with both the bonding layer and the insulating film, making it possible to further suppress the occurrence of discharge.

Further, in the electrostatic chuck according to the present invention, it is also preferable that the insulating film is a film formed by thermal spraying. In such a configuration, it is possible to easily form a film having high insulating properties and suppress the occurrence of discharge.

Further, in the electrostatic chuck according to the present invention, it is also preferable that the bonding layer is formed by curing a solid adhesive sheet. In such a configuration, in the process of curing the adhesive, it is possible to reliably prevent uncured adhesive from entering the communication groove or blocking the communication groove.

A method for manufacturing an electrostatic chuck according to the present invention includes the steps of preparing a dielectric substrate in which a first gas hole and a communication groove connected to a first opening, which is an end of the first gas hole, are formed; A step of preparing a base plate in which a second gas hole and a second opening, which is an end of the second gas hole, is formed; a step of preparing a solid adhesive sheet that is an insulating member; The surface of the dielectric substrate where the first opening is formed and the second opening of the base plate are formed so that the first opening and the second opening located at different positions communicate with each other through a communication groove. and sandwiching an adhesive sheet between the dielectric substrate and the base plate, and curing the adhesive sheet.

According to such a method of manufacturing an electrostatic chuck, it is possible to easily manufacture an electrostatic chuck that can suppress the generation of discharge through the gas holes as described above.

According to the present invention, it is possible to provide an electrostatic chuck that can suppress the occurrence of discharge through gas holes, and a method for manufacturing the same.

FIG. 1 is a cross-sectional view schematically showing the configuration of an electrostatic chuck according to the present embodiment. 2 is a diagram showing the configuration of a dielectric substrate included in the electrostatic chuck of FIG. 1. FIG. 2 is a diagram showing the configuration of a base plate included in the electrostatic chuck of FIG. 1. FIG. FIG. 2 is a diagram showing the structure of a bonding layer included in the electrostatic chuck of FIG. 1. FIG. 2 is a diagram showing the configuration of a dielectric substrate included in the electrostatic chuck of FIG. 1. FIG. FIG. 2 is a diagram for explaining the flow of gas through a communication groove in the electrostatic chuck of FIG. 1. FIG. FIG. 3 is a diagram for explaining a discharge path via a gas hole. 2 is a diagram for explaining a method of manufacturing the electrostatic chuck of FIG. 1. FIG. FIG. 7 is a diagram for explaining the flow of gas through a communication groove in an electrostatic chuck according to a modification.

This embodiment will be described below 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 redundant description will be omitted.

The electrostatic chuck 10 according to the present embodiment attracts and holds a substrate W to be processed using electrostatic force inside a semiconductor manufacturing apparatus (not shown) such as a CVD film forming apparatus, for example. The substrate W is, for example, a silicon wafer. The electrostatic chuck 10 may be used in equipment other than semiconductor manufacturing equipment.

FIG. 1 shows a schematic cross-sectional view of the structure of an electrostatic chuck 10 that holds a substrate W by suction. The electrostatic chuck 10 includes a dielectric substrate 100, a base plate 200, and a bonding layer 300.

The dielectric substrate 100 is a substantially disk-shaped member made of a ceramic sintered body. Dielectric substrate 100 includes, for example, high-purity aluminum oxide (Al ₂ O ₃ ), but may also include other materials. The purity, type, additives, etc. of the ceramics in the dielectric substrate 100 can be appropriately set in consideration of the plasma resistance required of the dielectric substrate 100 in semiconductor manufacturing equipment.

The upper surface 110 of the dielectric substrate 100 in FIG. 1 is a "suction surface" on which the substrate W is placed. Further, a lower surface 120 of the dielectric substrate 100 in FIG. 1 serves as a "surface to be bonded" to be bonded to the base plate 200 via a bonding layer 300, which will be described later. The viewpoint when looking at the electrostatic chuck 10 from the surface 110 side along the direction perpendicular to the surface 110 will also be referred to as "top view" below.

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. When a voltage is applied to the attraction electrode 130 from the outside via the power supply path 13, an electrostatic force is generated between the surface 110 and the substrate W, thereby attracting and holding the substrate W. Two adsorption electrodes 130 may be provided as a so-called "bipolar" electrode, but only one adsorption electrode 130 may be provided as a so-called "monopolar" electrode.

In FIG. 1, the entire power supply path 13 is depicted in a simplified manner. A portion of the power supply path 13 inside the dielectric substrate 100 is configured as, for example, a long and narrow via (hole) filled with a conductor, and an electrode terminal 103 (not shown in FIG. 1, FIG. 5 ) is provided. A portion of the power supply path 13 that penetrates the base plate 200 is a rod-shaped metal (bus bar) whose one end is connected to the electrode terminal 103 described above. A through hole 213 (not shown in FIG. 1, see FIG. 3) is formed in the base plate 200 for inserting the metal.

As shown in FIG. 1, a space SP is formed between the dielectric substrate 100 and the substrate W. When a film formation process is performed in the semiconductor manufacturing apparatus, helium gas for temperature adjustment is supplied to the space SP from the outside through a gas hole 140, which will be described later. By interposing helium gas between the dielectric substrate 100 and the substrate W, the thermal resistance between the two is adjusted, thereby maintaining the temperature of the substrate W at an appropriate temperature. Note that the temperature adjustment gas supplied to the space SP may be a different type of gas than helium.

FIG. 2 is a top view of the dielectric substrate 100. As shown in FIG. 2, a seal ring 111 and dots 112 are provided on the surface 110, which is the suction surface, and the above-mentioned space SP is formed around these.

The seal rings 111 are walls that partition the space SP, and a plurality of seal rings 111 are arranged concentrically in a top view. The upper end of each seal ring 111 forms part of the surface 110 and comes into contact with the substrate W. In this embodiment, a total of four seal rings 111 are provided, thereby dividing the space SP into four parts. With such a configuration, it is possible to individually adjust the pressure of helium gas in each space SP and make the surface temperature distribution of the substrate W during processing close to uniform.

In FIG. 1 and the like, the part marked with the symbol "116" is the bottom surface of the space SP. Hereinafter, this portion will also be referred to as the "bottom surface 116." The seal ring 111 is formed as a result of digging down a part of the surface 110 to the position of the bottom surface 116, together with the dots 112 described below.

The dots 112 are circular protrusions that protrude from the bottom surface 116. As shown in FIG. 2, a plurality of dots 112 are provided and are distributed approximately evenly on the attraction surface of the dielectric substrate 100. The upper end of each dot 112 forms part of the surface 110 and comes into contact with the substrate W. By providing a plurality of such dots 112, deflection of the substrate W is suppressed.

A groove 113 and an opening 141 are formed in the bottom surface 116 of each space SP. The groove 113 is a groove formed to recede further from the bottom surface 116 toward the surface 120 side. The groove 113 is formed for the purpose of quickly diffusing helium gas supplied from the opening 141 described below into the space SP and making the pressure distribution within the space SP substantially uniform within a short time.

The opening 141 is an opening provided as an outlet for helium gas supplied into the space SP. As shown in FIG. 1, gas holes 140 are formed in the dielectric substrate 100 so as to perpendicularly penetrate from the surface 110 toward the surface 120. A plurality of gas holes 140 are formed in each space SP, and one end of each gas hole 140 serves as the opening 141 described above. The other end of each gas hole 140 is an opening 142 formed in the surface 120 of the dielectric substrate 100. Each opening 141 may be formed as a single opening as in this embodiment, or may be formed as a collection of multiple small openings.

The gas hole 140 corresponds to the "first gas hole" in this embodiment. Among the gas holes 140, the opening 142 formed in the surface 120 corresponds to the "first opening" in this embodiment. The gas hole 140 is enlarged in diameter at a portion on the surface 120 side. Therefore, the inner diameter of the opening 142 is slightly larger than the inner diameter of the other portion of the gas hole 140.

As shown in FIG. 2, in this embodiment, all the openings 141 are formed at positions overlapping the grooves 113 when viewed from above. For convenience of illustration, the diameter of the opening 141 is depicted as being larger than the width of the groove 113 in FIG. 2, but as shown in FIG. It is smaller than the width of 113. The width of the groove 113 may be locally increased at the position of the opening 141 so that the opening 141 is accommodated inside the groove 113.

In FIG. 2, the reference numeral "115" indicates a hole into which a lift pin (not shown) provided in the semiconductor manufacturing apparatus is inserted. This hole will also be referred to as a "lift pin hole 115" below. A total of three lift pin holes 115 are formed, and these are arranged at equal intervals of 120 degrees. The substrate W is attached to and detached from the surface 110 of the dielectric substrate 100 by a lift pin that moves up and down through the lift pin hole 115.

Returning to FIG. 1, the explanation will be continued. The base plate 200 is a substantially disk-shaped member that supports the dielectric substrate 100. The base plate 200 is made of metal such as aluminum, for example. The upper surface 210 of the base plate 200 in FIG. 1 is a "joined surface" that is joined to the dielectric substrate 100 via the joining layer 300.

An insulating film 230 is formed on substantially the entire surface of the base plate 200 except for the lower surface 220 in FIG. The insulating film 230 is a film made of an insulating material such as alumina, and is formed by, for example, thermal spraying. The entire surface 210 mentioned above is a surface on the insulating film 230. Therefore, on the surface 210, no metal constituting the base plate 200 is exposed to the bonding layer 300 side, except for a portion where an opening 241 (described later) and the like are formed. Note that the range in which the insulating film 230 is formed on the base plate 200 may be different from the example shown in FIG. 1 . For example, the insulating film 230 may be formed only within the range of the surface 210 that is the surface to be bonded.

A refrigerant flow path 250 for flowing refrigerant is formed inside the base plate 200. When a film forming process is performed in a semiconductor manufacturing apparatus, a coolant is supplied from the outside to the coolant flow path 250, thereby cooling the base plate 200. Heat generated in the substrate W during the film forming process is transferred to the coolant 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 coolant.

As shown in FIG. 1, a gas hole 240 is formed in the base plate 200 and extends vertically from the surface 210 toward the surface 220 side. Note that the gas hole 240 may be formed so as to extend linearly as a whole as in this embodiment, but may be formed so as to be bent on the way toward the surface 220.

A plurality of gas holes 240 are formed in the base plate 200. The end of each gas hole 240 on the surface 210 side is an opening 241 formed in the surface 210. The end of the gas hole 240 on the surface 220 side is an opening 242 formed in the surface 220. The gas hole 240 corresponds to a "second gas hole" in this embodiment. Among the gas holes 240, the opening 241 formed in the surface 210 corresponds to the "second opening" in this embodiment.

The gas hole 240 is a hole that communicates with the gas hole 140 described above, and is part of a path for supplying helium gas toward the space SP. However, the gas hole 240 is provided at a different position from the gas hole 140 when viewed from above. Further, the number of gas holes 240 is different from the number of gas holes 140.

FIG. 3 is a top view of only the surface 210 of the base plate 200, similar to FIG. 2. As shown in FIG. 3, in this embodiment, a total of four gas holes 240 are formed, and four openings 241, which are the ends of each gas hole, are formed in the surface 210. As is clear from comparing FIGS. 2 and 3, the position where the opening 241 is formed in the top view is different from the position where the opening 141 and the opening 142 of the dielectric substrate 100 are formed. As will be explained later, the gas holes 140 and 240 located at different positions are communicated with each other by a communication groove 150 provided in the dielectric substrate 100.

As shown in FIG. 3, the base plate 200 is formed with a through hole 213 and a lift pin hole 215, the ends of which are open at the surface 210.

The through hole 213 is a hole through which the power supply path 13 passes, as described above. Two through holes 213 are formed corresponding to the number of adsorption electrodes 130. The lift pin hole 215 is a hole into which a lift pin is inserted, similar to the lift pin hole 115. A total of three lift pin holes 215 are provided, and they are formed at positions corresponding to each of the lift pin holes 115 when viewed from above.

Returning to FIG. 1, the explanation will be continued. Bonding layer 300 is a layer provided between dielectric substrate 100 and base plate 200, and bonds them together. The bonding layer 300 is a hardened adhesive made of an insulating material. As such an adhesive, for example, a polyimide adhesive can be used.

FIG. 4 is a top view of only the bonding layer 300 taken out from the electrostatic chuck 10, similar to FIGS. 2 and 3. As shown in FIG. 4, a plurality of through holes are formed in the bonding layer 300. These through holes include an electrode hole 313, a lift pin hole 315, and a communication hole 340.

The electrode hole 313 is a hole for passing the power supply path 13 similarly to the through hole 213. A total of two electrode holes 313 are provided, and they are formed at positions corresponding to each of the through holes 213 when viewed from above.

The lift pin hole 315 is a hole into which a lift pin is inserted, similar to the lift pin hole 215. A total of three lift pin holes 315 are provided, and they are formed at positions corresponding to each of the lift pin holes 215 when viewed from above.

The communication hole 340 is a hole formed to allow the gas from the gas hole 240 to pass through. A total of four communication holes 340 are provided, and they are formed at positions that overlap with the openings 241 when viewed from above. The communication hole 340 is a circular hole, and its inner diameter is slightly larger than the inner diameter of the opening 241.

FIG. 5 is a diagram of the dielectric substrate 100 viewed from the surface 120 side. As shown in the figure, a communication groove 150 is formed in the surface 120. The communication groove 150 is a groove provided to communicate between the gas hole 140 and the gas hole 240 located at different positions. Each communication groove 150 includes an inlet portion 151 and connection portions 152 and 153.

The inlet portion 151 is a portion that serves as an inlet when the helium gas that has passed through the gas hole 240 of the base plate 200 flows into the communication groove 150 . The inlet portions 151 are formed in the same number as the openings 241 formed in the surface 210 of the base plate 200, and are provided at positions corresponding to the respective openings 241. That is, the entrance portion 151 is provided at each position overlapping the opening 241 when viewed from above. The inlet portion 151 is a substantially circular recess, and its inner diameter is slightly larger than the inner diameter of the opening 241. The above-described communication hole 340 is formed in the bonding layer 300 in a portion between the inlet portion 151 and the opening 241.

The connecting portions 152 and 153 are grooves formed as flow paths that connect the inlet portion 151 and the opening 142. Among these, the connecting portion 153 is a groove extending in an arc shape along the circumferential direction so as to connect the plurality of openings 142. The connecting portion 152 is a groove extending linearly from the inlet portion 151 toward a connecting portion 153 on the outer circumferential side thereof.

In this embodiment, a total of four communication grooves 150 are formed, and these are arranged so as to line up from the outer circumferential side toward the inner circumferential side when viewed from above. Each communication groove 150 corresponds to each of the four divided spaces SP, and is provided directly below each space SP.

FIG. 6 schematically depicts the flow of helium gas passing through the communication groove 150 located on the innermost side. Arrow AR1 in the figure represents the flow of helium gas through the gas hole 240 of the base plate 200. Helium gas flows into the communication groove 150 from the inlet portion 151, and then flows into the connection portion 153 through the connection portion 152 (arrow AR2). Thereafter, the helium gas flows along the connection portion 153 (arrow AR3), flows into each opening 142 of the dielectric substrate 100, and is supplied to the space SP through the gas hole 140 (arrow AR4). Helium gas flows in the other communication grooves 150 in the same manner as described above.

As described above, in the electrostatic chuck 10, the position of the opening 142 (first opening) and the position of the opening 241 (second opening) are made different from each other, and the communication groove 150 that communicates between them is It is formed on the surface 120 of the dielectric substrate 100.

The advantages of such a configuration will be explained with reference to FIG. 7. FIG. 7A shows the configuration of an electrostatic chuck according to a comparative example. In this comparative example, the opening 142 and the opening 241 are formed at the same position, that is, at positions overlapping each other when viewed from above. A through hole connecting the opening 142 and the opening 241 is formed in the bonding layer 300, and the gas hole 140 and the gas hole 240 are communicated with each other through the through hole. In other words, in this comparative example, the entire helium gas flow path consisting of the gas holes 140 and the gas holes 240 is formed to penetrate the bonding layer 300 vertically and immediately before it.

Metal is exposed on the inner surface of the gas hole 240 provided in the base plate 200. A point P1 shown in FIG. 7A represents the uppermost portion of the metal surface exposed on the inner surface of the gas hole 240. In the configuration of this comparative example, point P1 is in a state facing substrate W through a linear space. In such a configuration, since the so-called "creepage distance" is short, discharge is relatively likely to occur along a substantially linear path as shown by arrow AR11.

In contrast, in this embodiment, as described above, the positions of the openings 142 and 241 are made different from each other, and the communication grooves 150 that communicate between the two are formed in the surface 120 of the dielectric substrate 100. is forming. In such a configuration, the inner surface of the gas hole 240 is not exposed toward the substrate W directly below the gas hole 140, as shown in FIG. 7(B). The path from the metal exposed on the inner surface of the gas hole 240 to the substrate W through the gas hole 140 and the like is a curved path as shown by an arrow AR12. Since the creepage distance is ensured longer than in the comparative example, it is possible to sufficiently suppress the occurrence of discharge along the path.

As shown in FIGS. 5 and 6, each communication groove 150 is formed such that one entrance portion 151 is connected to a plurality of openings 142 via connecting portions 152 and 153. As a result, in this embodiment, one opening 241 communicates with the plurality of openings 142 via the communication groove 150. In such a configuration, the number of openings 241 can be smaller than the number of openings 142. By reducing the number of openings 241 that can serve as starting points for discharge, it is possible to further suppress the occurrence of discharge.

Note that the number of inlet portions 151 provided in one communication groove 150 may be two or more. In any case, it is preferable that the number of inlets 151 provided in one communication groove 150 is smaller than the number of openings 142 connected to one communication groove 150.

As described above, the insulating film 230 is provided on the surface 210 of the base plate 200 on the bonding layer 300 side so as to cover the entire surface. In such a configuration, the surface of the base plate 200 is covered with both the bonding layer 300 and the insulating film 230, so that generation of electric discharge can be sufficiently suppressed. As the insulating film 230, an alumina film formed by thermal spraying as in this embodiment is preferable, but it may be a film formed by another manufacturing method or a film made of another material. Note that if sufficient insulation can be ensured only by the bonding layer 300, the insulating film 230 may not be formed on the base plate 200.

A method for manufacturing the electrostatic chuck 10 will be briefly described. First, as shown in FIG. 8, the dielectric substrate 100, the base plate 200, and the adhesive sheet 300A are each prepared. Thereafter, the dielectric substrate 100 and the base plate 200 are bonded using the adhesive sheet 300A.

The dielectric substrate 100 is in a state in which an adsorption electrode 130, a gas hole 140, an opening 142, a seal ring 111, etc. are formed in advance before bonding. Various known methods can be used to form these. Further, the communication groove 150 shown in FIG. 5 is also formed in advance in the dielectric substrate 100 before bonding, and the communication groove 150 is connected to the opening 142.

The base plate 200 is also in a state in which a refrigerant flow path 250, a gas hole 240, an opening 241, an insulating film 230, etc. are formed in advance before bonding. Various known methods can be used to form these.

The adhesive sheet 300A is an insulating member that hardens to become the bonding layer 300 during bonding. That is, although the adhesive sheet 300A is an "adhesive", it is not in a liquid state even before curing, but is a solid sheet-like member having flexibility. As such an adhesive sheet 300A, for example, a polyimide adhesive film, an epoxy adhesive film, a silicone adhesive film, an acrylic adhesive film, or the like can be used. As the adhesive film, one having excellent thermal conductivity or one having high insulation properties can be suitably used.

As described above, the adhesive sheet 300A is in a solid sheet shape even before curing, so for example, by punching holes using a mold, the communication holes 340 and the electrode holes 313 can be formed before bonding. , lift pin hole 315, etc. can be formed in advance.

After preparing the dielectric substrate 100, base plate 200, and adhesive sheet 300A as described above, the adhesive sheet 300A is sandwiched between the dielectric substrate 100 and the base plate 200, as shown in FIG. Specifically, the surface 120 of the dielectric substrate 100 where the opening 142 is formed and the surface 120 of the base plate 200 so that the communication groove 150 communicates between the opening 142 and the opening 241 located at different positions. Adhesive sheet 300A is sandwiched between dielectric substrate 100 and base plate 200, with surfaces 210 on which openings 241 are formed facing each other.

With the adhesive sheet 300A sandwiched therebetween as described above, the entire dielectric substrate 100, base plate 200, and adhesive sheet 300A are heated to a predetermined temperature. By heating, adhesive sheet 300A is cured while being bonded to both surface 120 and surface 210, forming bonding layer 300 in FIG. 1. The through holes, such as the communication holes 340, formed in advance in the adhesive sheet 300A generally maintain their original shape even after the adhesive sheet 300A is cured. Therefore, a portion of the adhesive sheet 300A does not enter the communication groove 150 formed in the dielectric substrate 100, and the communication groove 150 also maintains its original shape. By the method described above, the electrostatic chuck 10 having the configuration shown in FIG. 1 is completed.

As described above, the bonding layer 300 of this embodiment is obtained by curing the solid adhesive sheet 300A in which communication holes 340 and the like are formed in advance. By using the adhesive sheet 300A, communication holes 340 and the like can be easily formed in the portion that will become the bonding layer 300 (adhesive sheet 300A) before bonding. Further, in the process of curing the adhesive, it is possible to reliably prevent the communication groove 150 from being deformed or blocked.

Note that if the adhesive can be prevented from entering the communication groove 150 by some method, a liquid adhesive may be used instead of the adhesive sheet 300A as the adhesive for the bonding layer 300. For example, if a string-like solid material that serves as an "embankment" that prevents liquid adhesive from entering is placed in advance along the outer periphery of the communication groove 150, the communication hole 340, etc., and then bonded, this embodiment can be applied. A bonding layer 300 similar to the above can be formed.

The shape of the communication groove 150 formed in the dielectric substrate 100 can be changed as appropriate. In FIG. 9, the communication groove 150 of the electrostatic chuck 10 according to the modified example is drawn in the same manner as in FIG. 6. In this modification, the number of gas holes 140 formed in dielectric substrate 100 and the number of gas holes 240 formed in base plate 200 are the same number. Therefore, each communication groove 150 provided on the surface 120 of the dielectric substrate 100 has one inlet portion 151 and one connecting portion 152, and the distance between the inlet portion 151 and the opening 142 is one. They are directly connected through a connecting portion 152 of the book. In this way, each of the openings 241 may be configured to communicate with only one opening 142 via the communication groove 150.

The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design changes made by those skilled in the art as appropriate to these specific examples are also included within the scope of the present disclosure as long as they have the characteristics of the present disclosure. The elements included in each of the specific examples described above, their arrangement, conditions, shapes, etc. are not limited to those illustrated, and can be changed as appropriate. The elements included in each of the specific examples described above can be appropriately combined as long as no technical contradiction occurs.

10: Electrostatic chuck 100: Dielectric substrate 140: Gas hole 142: Opening 150: Communication groove 200: Base plate 230: Insulating film 240: Gas hole 241: Opening 300: Bonding layer

Claims (5)

a dielectric substrate in which a first gas hole is formed;
a base plate in which a second gas hole is formed;
a bonding layer provided between the dielectric substrate and the base plate and formed of an insulating material,
A first opening, which is an end of the first gas hole, is formed on the surface of the dielectric substrate on the bonding layer side;
A second opening, which is an end of the second gas hole, is formed on the surface of the base plate on the bonding layer side at a position different from the first opening;
A communication groove is formed on the surface of the dielectric substrate on the bonding layer side, and the communication groove allows communication between the first opening and the second opening.
An electrostatic chuck, characterized in that an insulating film is provided on a surface of the base plate on the bonding layer side . The electrostatic chuck according to claim 1, wherein the second opening communicates with the plurality of first openings via the communication groove. The electrostatic chuck according to claim 1 , wherein the insulating film is a film formed by thermal spraying. The electrostatic chuck according to claim 1, wherein the bonding layer is a hardened solid adhesive sheet. preparing a dielectric substrate in which a first gas hole and a communication groove connected to a first opening that is an end of the first gas hole are formed;
preparing a base plate on which a second gas hole, a second opening that is an end of the second gas hole, and an insulating film covering a surface where the second opening is formed ;
a step of preparing a solid adhesive sheet that is an insulating member;
The surface of the dielectric substrate where the first opening is formed and the surface of the base plate so that the first opening and the second opening, which are located at different positions from each other, communicate with each other through the communication groove. sandwiching the adhesive sheet between the dielectric substrate and the base plate, with the surfaces on which the second openings are formed facing each other;
A method for manufacturing an electrostatic chuck, comprising the step of curing the adhesive sheet.

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