JP7647782B2 - Electrostatic chuck and method of manufacturing same - Google Patents

Description

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

For example, in semiconductor manufacturing equipment such as CVD equipment, an electrostatic chuck is provided as a device for attracting and holding a substrate such as a silicon wafer to be processed. The electrostatic chuck comprises a dielectric substrate provided with an attraction electrode and a base plate supporting the dielectric substrate, which are joined together. The attraction electrode is generally built into the dielectric substrate, but as described in Patent Document 1 below, the metal base plate may also be used as the attraction 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.

In order to adjust the temperature of the substrate during processing, an inert gas such as helium is often supplied between the dielectric substrate and the substrate. Gas holes are formed in both the dielectric substrate and the base plate as supply paths for such gas.

JP 2005-203426 A

To suppress temperature unevenness in the substrate, it is preferable to supply gas as evenly as possible to each part between the dielectric substrate and the substrate. For this reason, it is common for the dielectric substrate to have a large number of gas holes so that the openings that serve as gas supply ports are distributed approximately evenly along the adsorption surface.

Because there are a large number of gas holes in the dielectric substrate, it is not practical to connect the same number of pipes to the base plate from the outside as there are gas holes. For this reason, in conventional electrostatic chucks, the flow path through which helium gas supplied from the outside passes is branched into multiple paths inside the base plate, and each of the branched paths is directed to each gas hole in the dielectric substrate. In other words, the flow paths connected to each of the multiple gas holes in the dielectric substrate are consolidated into a small number of flow paths inside the base plate, and gas pipes from the outside are connected to the consolidated flow paths.

To form branched flow paths inside the base plate, it is necessary to use a method such as dividing the base plate into multiple parts and forming grooves in some of the parts before welding the other parts. This makes the manufacturing process for the base plate complicated, resulting in high manufacturing costs.

As semiconductor manufacturing technology advances, the performance required of electrostatic chucks is increasing year by year, and the structure of electrostatic chucks is expected to become even more complex in the future. For example, heaters, RF electrodes, etc. are often built into dielectric substrates, and it is necessary to run electrical paths connecting these through the base plate. In addition, in order to ensure a uniform in-plane temperature distribution of the substrate during processing, the configuration of the coolant flow paths formed in the base plate is also becoming more complex. Under these circumstances, it is expected that it will become even more difficult in the future to form additional complex flow paths for passing gas inside the base plate from the standpoint of manufacturing costs, etc.

The present invention was made in consideration of these problems, and its purpose is to provide an electrostatic chuck that can reduce the manufacturing costs of the base plate, and a manufacturing method thereof.

In order to solve the above problems, the electrostatic chuck according to the present invention includes a dielectric substrate having a plurality of first gas holes formed therein, a base plate having a second gas hole formed therein, and a bonding layer formed of an insulating material and disposed between the dielectric substrate and the base plate. A plurality of first openings, which are ends of the first gas holes, are formed on the surface of the dielectric substrate facing the bonding layer. A second opening, which is an end of the second gas hole, is formed on the surface of the base plate facing the bonding layer. The second openings are connected to the plurality of first openings via communication grooves formed on the surface of the dielectric substrate facing the bonding layer.

In an electrostatic chuck having such a configuration, the second opening of the base plate is connected to the multiple first openings of the dielectric substrate via a communication groove provided in the dielectric substrate. Since there is no need to form a communication passage inside the base plate connecting the first gas hole and the second gas hole, the manufacturing cost of the base plate can be reduced.

In addition, in the above configuration, it is not necessary to provide the same number of second openings as first openings in the base plate. This allows the number of second openings to be reduced compared to the conventional case. Although metal is exposed inside the second openings, by reducing the number of second openings that can be the starting point of discharge, there is also the advantage that the possibility of discharge occurring is lower compared to the conventional case.

In addition, 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 facing the bonding layer. In such a configuration, the surface of the base plate is covered with both the bonding layer and the insulating film, which makes it possible to further suppress the occurrence of discharge.

In addition, 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 with high insulating properties and suppress the occurrence of discharge.

In the electrostatic chuck according to the present invention, it is also preferable that the bonding layer is a cured solid adhesive sheet. In this configuration, it is possible to reliably prevent uncured adhesive from entering the communicating groove or blocking the communicating groove during the process of curing the adhesive.

The 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; preparing a base plate in which a second gas hole and a second opening, which is an end of the second gas hole, are formed; preparing a solid adhesive sheet, which is an insulating member; placing the surface of the dielectric substrate in which the first opening, which is an end of the first gas hole, is formed and the surface of the base plate in which the second opening, which is an end of the second gas hole, is formed opposite each other so that the second opening and the multiple first openings are connected by the communication groove; sandwiching the adhesive sheet between the dielectric substrate and the base plate; and curing the adhesive sheet.

This method of manufacturing an electrostatic chuck makes it easy to manufacture an electrostatic chuck having the above-described configuration in which a communicating groove is formed in the base plate.

The present invention provides an electrostatic chuck that can reduce the manufacturing costs of the base plate, and a manufacturing method thereof.

1 is a cross-sectional view illustrating a schematic configuration of an electrostatic chuck according to an embodiment of the present invention. 2 is a diagram showing a configuration of a dielectric substrate provided in the electrostatic chuck of FIG. 1 . 2 is a diagram showing a configuration of a base plate included in the electrostatic chuck of FIG. 1 . 2 is a diagram showing a configuration of a bonding layer provided in the electrostatic chuck of FIG. 1 . 2 is a diagram showing a configuration of a dielectric substrate provided in the electrostatic chuck of FIG. 1 . 2 is a diagram for explaining a gas flow via a communication groove in the electrostatic chuck of FIG. 1 . FIG. 2A to 2C are diagrams for explaining a method for manufacturing the electrostatic chuck of FIG. 1 . 13A and 13B are diagrams for explaining a gas flow via a communication groove in an electrostatic chuck according to a modified example.

Hereinafter, this embodiment will be described with reference to the attached drawings. To facilitate understanding of the description, the same components in each drawing are denoted by the same reference numerals as much as possible, and duplicate descriptions will be omitted.

The electrostatic chuck 10 according to this embodiment is configured to attract and hold a substrate W to be processed by electrostatic force inside a semiconductor manufacturing apparatus (not shown), such as a CVD film forming apparatus. The substrate W is, for example, a silicon wafer. The electrostatic chuck 10 may also be used in apparatus other than semiconductor manufacturing apparatus.

Figure 1 shows a schematic cross-sectional view of the configuration of an electrostatic chuck 10 when it attracts and holds a substrate W. 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 sintered ceramic body. The dielectric substrate 100 contains, for example, high-purity aluminum oxide (Al ₂ O ₃ ), but may contain other materials. The purity, type, and additives of the ceramics in the dielectric substrate 100 can be appropriately set in consideration of the plasma resistance, etc. required for the dielectric substrate 100 in the semiconductor manufacturing equipment.

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

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 adsorption electrode 130 from the outside via the power supply line 13, an electrostatic force is generated between the surface 110 and the substrate W, thereby adsorbing and holding the substrate W. Two adsorption electrodes 130 may be provided as so-called "bipolar" electrodes, or only one may be provided as a so-called "monopolar" electrode.

In FIG. 1, the entire power supply path 13 is depicted in a simplified form. The portion of the power supply path 13 inside the dielectric substrate 100 is configured, for example, as a long and narrow via (hole) filled with a conductor, and an electrode terminal 103 (not shown in FIG. 1, see FIG. 5) is provided at its lower end. The portion of the power supply path 13 that penetrates the base plate 200 is a rod-shaped metal (bus bar) with one end connected to the electrode terminal 103. The base plate 200 is formed with a through hole 213 (not shown in FIG. 1, see FIG. 3) 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 providing helium gas between the dielectric substrate 100 and the substrate W, the thermal resistance between them is adjusted, thereby maintaining the temperature of the substrate W at an appropriate temperature. The temperature adjustment gas supplied to the space SP may be a type of gas other than helium.

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

The seal rings 111 are walls that divide the space SP, and multiple seal rings 111 are provided so as to be arranged concentrically when viewed from above. The upper end of each seal ring 111 forms part of the surface 110 and abuts against the substrate W. In this embodiment, a total of four seal rings 111 are provided, thereby dividing the space SP into four. With this configuration, it is 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.

The portion marked with the reference symbol "116" in FIG. 1 and other figures 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, together with the dots 112 described below, is formed as a result of digging down a portion of the surface 110 to the position of the bottom surface 116.

The dots 112 are circular protrusions that protrude from the bottom surface 116. As shown in FIG. 2, multiple 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 abuts against the substrate W. By providing multiple such dots 112, bending 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 formed so as to retreat further from the bottom surface 116 toward the surface 120. The groove 113 is formed for the purpose of quickly diffusing the helium gas supplied from the opening 141, which will be described below, into the space SP and making the pressure distribution in the space SP approximately uniform within a short period of 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 penetrate vertically from the surface 110 to the surface 120. A plurality of gas holes 140 are formed in each space SP, and one end of each gas hole 140 is the above-mentioned opening 141. 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. Of the gas holes 140, the opening 142 formed on the surface 120 corresponds to the "first opening" in this embodiment. The gas hole 140 has an enlarged diameter in the portion on the surface 120 side. Therefore, the inner diameter of the opening 142 is slightly larger than the inner diameter of the other portions of the gas hole 140.

As shown in FIG. 2, in this embodiment, all openings 141 are formed at positions that overlap grooves 113 in a top view. For convenience of illustration, the diameter of openings 141 is depicted in FIG. 2 as being larger than the width of grooves 113, but as shown in FIG. 1, the actual diameter of openings 141 is smaller than the width of grooves 113. The width of grooves 113 may be locally larger at the positions of openings 141 so that openings 141 fit inside grooves 113.

In FIG. 2, the reference numeral "115" denotes a hole through which a lift pin (not shown) provided in the semiconductor manufacturing apparatus is inserted. Hereinafter, this hole will also be referred to as "lift pin hole 115". A total of three lift pin holes 115 are formed, and they are arranged at equal intervals of 120 degrees. The lift pins that move up and down through the lift pin holes 115 are used to attach and detach the substrate W to and from the surface 110 of the dielectric substrate 100.

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

An insulating film 230 is formed on almost the entire surface of the base plate 200 except for the lower surface 220 in FIG. 1. The insulating film 230 is a film made of an insulating material such as alumina, and is formed by, for example, thermal spraying. The surface 210 described above is entirely on the insulating film 230. Therefore, on the surface 210, except for the portion where the opening 241 described below is formed, the metal constituting the base plate 200 is not exposed at all to the bonding layer 300 side. The range of the base plate 200 on which the insulating film 230 is formed may be a range different from the example in FIG. 1. For example, the insulating film 230 may be formed only on the surface 210, which is the surface to be bonded.

A coolant flow path 250 for flowing a coolant is formed inside the base plate 200. When a film formation process is performed in the semiconductor manufacturing device, a coolant is supplied to the coolant flow path 250 from the outside, thereby cooling the base plate 200. Heat generated in the substrate W during the film formation 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, the base plate 200 is formed with gas holes 240 that extend vertically from the surface 210 toward the surface 220. The gas holes 240 may be formed so that they extend linearly as a whole, as in this embodiment, but they may also be formed so that they bend on the way to 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 each gas hole 240 on the surface 220 side is an opening 242 formed in the surface 220. The gas holes 240 correspond to the "second gas hole" in this embodiment. Of the gas holes 240, the opening 241 formed in the surface 210 corresponds to the "second opening" in this embodiment.

Gas hole 240 is a hole that is connected to gas hole 140 described above, and is part of the path for supplying helium gas to space SP. However, gas hole 240 is provided at a different position from gas hole 140 when viewed from above. Also, the number of gas holes 240 is different from the number of gas holes 140.

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

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

As mentioned above, the through holes 213 are holes for passing the power supply paths 13. Two through holes 213 are formed, corresponding to the number of chucking electrodes 130. The lift pin holes 215 are holes through which lift pins are inserted, similar to the lift pin holes 115. There are three lift pin holes 215 in total, and they are formed at positions corresponding to the lift pin holes 115 when viewed from above.

Returning to FIG. 1, the explanation continues. The bonding layer 300 is a layer provided between the dielectric substrate 100 and the base plate 200, and bonds the two together. The bonding layer 300 is made by hardening an adhesive made of an insulating material. For example, a polyimide-based adhesive can be used as such an adhesive.

Figure 4 shows only the bonding layer 300 taken out of the electrostatic chuck 10, viewed from above in the same manner as Figures 2 and 3. As shown in Figure 4, the bonding layer 300 has a number of through holes formed therein. These through holes include an electrode hole 313, a lift pin hole 315, and a communication hole 340.

The electrode holes 313 are holes for passing the power supply path 13, similar to the through holes 213. There are two electrode holes 313 in total, and they are formed at positions corresponding to the through holes 213 when viewed from above.

The lift pin holes 315 are holes through which lift pins are inserted, similar to the lift pin holes 215. There are three lift pin holes 315 in total, and they are formed at positions corresponding to the lift pin holes 215 when viewed from above.

The communication holes 340 are holes formed to allow helium gas to pass through from the gas holes 240. There are four communication holes 340 in total, each formed at a position that overlaps with an opening 241 when viewed from above. The communication holes 340 are circular holes, and their inner diameter is slightly larger than the inner diameter of the opening 241.

Figure 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 on the surface 120. The communication groove 150 is a groove provided to communicate between the gas holes 140 and the gas holes 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 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 on the surface 210 of the base plate 200, and are provided at positions corresponding to the respective openings 241. In other words, the inlet portion 151 is provided at each position that overlaps with the openings 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. In the portion between the inlet portion 151 and the opening 241, the above-mentioned communication hole 340 is formed in the bonding layer 300.

The connection parts 152 and 153 are grooves formed as flow paths connecting the inlet part 151 and the opening 142. Of these, the connection part 153 is a groove that extends in an arc shape along the circumferential direction so as to connect the multiple openings 142. The connection part 152 is a groove that extends linearly from the inlet part 151 toward the connection part 153 on the outer periphery side.

In this embodiment, a total of four communication grooves 150 are formed, and are arranged so that they are lined up from the outer periphery toward the inner periphery when viewed from above. Each communication groove 150 corresponds to one of the four divided spaces SP, and is provided directly below each space SP.

Figure 6 shows a schematic diagram of the flow of helium gas through the innermost communication groove 150. The arrows AR1 in the figure represent the flow of helium gas through the gas holes 240 in the base plate 200. After flowing into the communication groove 150 from the inlet portion 151, the helium gas flows through the connection portion 152 and into the connection portion 153 (arrow AR2). The helium gas then flows along the connection portion 153 (arrow AR3) and into each opening 142 in the dielectric substrate 100, and is supplied to the space SP through the gas holes 140 (arrow AR4). Helium gas also flows in the other communication grooves 150 in the same manner as described above.

As described above, in the electrostatic chuck 10, the opening 241 (second opening) is connected to the multiple openings 142 (first openings) via the communication groove 150 formed in the surface 120 of the dielectric substrate 100 on the bonding layer 300 side. The helium gas that has passed through the gas hole 240 flows from the opening 241 into the communication groove 150, and is then distributed from the communication groove 150 to each of the multiple openings 142, and is supplied to each part of the space SP through the gas hole 140.

In this configuration, multiple gas holes 140 are provided in the dielectric substrate 100, making it possible to supply helium gas evenly to each part of the space SP, but there is no need to provide the same number of gas holes 240 in the base plate 200. In other words, the number of gas holes 240 provided in the base plate 200 can be kept to a minimum (specifically, four, the same as the number of spaces SP), while still allowing helium gas to be supplied evenly to each part of the space SP via the communicating grooves 150.

Incidentally, as a configuration for distributing helium gas toward each gas hole 140, instead of the communication groove 150 as in this embodiment, it is also possible to form a communication passage inside the base plate 200. However, in order to form a communication passage of a complex shape inside the base plate 200, it becomes necessary to use a method such as, for example, dividing the base plate 200 into multiple parts, forming grooves in some parts, and then welding the other parts. This makes the manufacturing process of the base plate complicated, and increases the manufacturing costs.

In contrast, in the electrostatic chuck of this embodiment, the communication groove 150 is formed on the surface 120 of the dielectric substrate 100, rather than inside the base plate 200. This makes it possible to reduce the manufacturing costs of the base plate 200, compared to when the communication passage is formed inside the base plate 200.

In addition, when the communication passages are formed inside the base plate 200, the surface 210 of the base plate 200 is formed with the same number of openings 241 as the openings 142. In contrast, in this embodiment, since it is not necessary to provide the same number of openings 241 as the openings 142, the number of openings 241 can be reduced compared to the conventional method. Although metal is exposed inside the openings 241, reducing the number of openings 241 that can be the starting point of discharge has the advantage of reducing the possibility of discharge occurring compared to the conventional method.

The number of inlets 151 provided in one communication groove 150 may be two or more. In any case, it is preferable that the number of inlets 151 in each communication groove 150 is less than the number of openings 142.

As described above, the insulating film 230 is provided on the surface 210 of the base plate 200 facing the bonding layer 300 so as to cover the entire surface. In this configuration, the surface of the base plate 200 is covered by both the bonding layer 300 and the insulating film 230, so that the occurrence of 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 made of another material. Note that if the insulating property can be sufficiently ensured by the bonding layer 300 alone, the insulating film 230 does not need to be formed on the base plate 200.

A method for manufacturing the electrostatic chuck 10 will be briefly described. First, as shown in FIG. 7, the dielectric substrate 100, the base plate 200, and the adhesive sheet 300A are prepared. Then, the adhesive sheet 300A is used to bond the dielectric substrate 100 and the base plate 200 together.

Before bonding, the dielectric substrate 100 is in a state in which the chucking electrode 130, gas hole 140, opening 142, seal ring 111, etc. are formed in advance. Various publicly known methods can be used to form these. In addition, the dielectric substrate 100 is also formed in advance with the communication groove 150 shown in FIG. 5 before bonding, and the communication groove 150 is in a state of being connected to the opening 142.

Before bonding, the base plate 200 is also in a state where the coolant flow path 250, gas hole 240, opening 241, insulating film 230, etc. are formed in advance. Various publicly known methods can be used to form these.

The adhesive sheet 300A is an insulating member that hardens during bonding to become the bonding layer 300. In other words, although the adhesive sheet 300A is an "adhesive," it is not liquid even before hardening, but is a flexible solid sheet-like member. For example, adhesive films such as polyimide-based, epoxy-based, silicone-based, and acrylic-based adhesive films can be used as the adhesive sheet 300A. Adhesive films with excellent thermal conductivity and high insulating properties are preferably used.

As described above, the adhesive sheet 300A is in the form of a solid sheet even before hardening. Therefore, for example, by performing a hole punching process using a mold, the communication holes 340, electrode holes 313, lift pin holes 315, etc. can be formed in advance before bonding.

After preparing the dielectric substrate 100, base plate 200, and adhesive sheet 300A as described above, as shown in FIG. 7, the adhesive sheet 300A is sandwiched between the dielectric substrate 100 and the base plate 200. Specifically, the surface 120 of the dielectric substrate 100 on which the openings 142 are formed and the surface 210 of the base plate 200 on which the openings 241 are formed are opposed to each other so that the openings 241 and the multiple openings 142 are connected by the communication grooves 150, and the adhesive sheet 300A is sandwiched between the dielectric substrate 100 and the base plate 200.

With the adhesive sheet 300A sandwiched as described above, the dielectric substrate 100, the base plate 200, and the entire adhesive sheet 300A are heated to a predetermined temperature. By heating, the adhesive sheet 300A hardens while being bonded to both the surface 120 and the surface 210, and becomes the bonding layer 300 of FIG. 1. Through holes such as the communication hole 340 that were formed in advance in the adhesive sheet 300A generally maintain their original shape even after the adhesive sheet 300A hardens. Therefore, no part of the adhesive sheet 300A enters the communication groove 150 formed in the dielectric substrate 100, and the communication groove 150 also maintains its original shape. By the above method, the electrostatic chuck 10 of the configuration shown in FIG. 1 is completed.

As described above, the bonding layer 300 of this embodiment is formed by hardening a solid adhesive sheet 300A in which the communication holes 340 and the like have been formed in advance. By using the adhesive sheet 300A, the communication holes 340 and the like can be easily formed in the part that will become the bonding layer 300 (the adhesive sheet 300A) before bonding. In addition, it is possible to reliably prevent the communication grooves 150 from being deformed or blocked during the process of hardening the adhesive.

If there is some way to prevent the adhesive from entering the communication groove 150, a liquid adhesive can 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 acts as a "bank" to prevent the liquid adhesive from entering is placed in advance along the outer periphery of the communication groove 150 and the communication hole 340, etc., and then bonding is performed, a bonding layer 300 similar to that of this embodiment can be formed.

The shape of the communication groove 150 formed in the dielectric substrate 100 can be modified as appropriate. In FIG. 8, the communication groove 150 of a modified electrostatic chuck 10 is depicted in the same manner as in FIG. 6.

In this modified example, the opening 241 in the base plate 200 is formed at a position that overlaps one of the multiple openings 142 in the electrostatic chuck 10 when viewed from above.

For ease of explanation, in FIG. 8, the three openings 142 are labeled "142A," "142B," and "142C," respectively. In the example of FIG. 8, a gas hole 240 and an opening 241 (not shown) are formed directly below opening 142A. In other words, opening 142A is both an inlet for helium gas to flow into communication groove 150 and an outlet for helium gas to flow out toward opening 142 directly above it. Due to this configuration, communication groove 150 of this modified example does not have an inlet portion 151 and a connection portion 152.

As shown by arrow AR1, a portion of the helium gas that has passed through gas hole 240 flows into opening 142A directly above it (arrow AR41) and is supplied to space SP through gas hole 140. Another portion of the helium gas that has passed through gas hole 240 as shown by arrow AR1 flows from opening 142A along connection portion 153 (arrow AR3) and flows from each of openings 142B and 142C into gas hole 140 in dielectric substrate 100 (arrow AR42) and is supplied to space SP through gas hole 140.

In this way, the multiple openings 142 through which helium gas is distributed from the opening 241 may be located in a position that partially overlaps with the opening 241 when viewed from above.

The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples made by a person skilled in the art are also included within the scope of the present disclosure as long as they have the features of the present disclosure. The elements of each of the above-mentioned specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of each of the above-mentioned specific examples can be combined in different ways as appropriate, as long as no technical contradictions arise.

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 (4)

a dielectric substrate having a plurality of first gas holes formed therein;
a base plate having a second gas hole formed therein;
a bonding layer provided between the dielectric substrate and the base plate and made of an insulating material;
a plurality of first openings, which are ends of the first gas holes, are formed on a surface of the dielectric substrate facing the bonding layer;
a second opening, which is an end of the second gas hole, is formed in a surface of the base plate facing the bonding layer;
the second opening is in communication with the first openings via a communication groove formed on a surface of the dielectric substrate facing the bonding layer ,
An electrostatic chuck, wherein an insulating film is provided on a surface of the base plate facing the bonding layer . 2. The electrostatic chuck according to claim 1 , wherein the insulating film is a film formed by thermal spraying. The electrostatic chuck of claim 1, characterized in that the bonding layer is a cured solid adhesive sheet. preparing a dielectric substrate having a first gas hole and a communication groove connected to a first opening which is an end of the first gas hole;
preparing a base plate in which a second gas hole, a second opening which is an end of the second gas hole, and an insulating film which covers a surface in which the second opening is formed are formed ;
A step of preparing a solid adhesive sheet that is an insulating member;
a step of placing a surface of the dielectric substrate, on which a first opening that is an end of the first gas hole is formed, and a surface of the base plate, on which a second opening that is an end of the second gas hole is formed, facing each other such that the second opening and the plurality of first openings are communicated with each other by the communication groove, and sandwiching the adhesive sheet between the dielectric substrate and the base plate;
and curing the adhesive sheet.

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