Holding device

Abstract

To provide a retaining device capable of preventing a lift pin from coming into contact with a seal member protecting a junction layer.SOLUTION: A ceramic member 10 of an electrostatic chuck 1 has a first through hole 15, into which a lift pin 60 pushing up a semiconductor wafer W from a suction surface 11 is inserted, formed, a base member 20 has a second through hole 25, which communicates with the first through hole 15 and into which the lift pin 60 is inserted, formed, and also has at least one annular seal member 50 which is sandwiched between the ceramic member 10 and base member 20, and arranged surrounding the first through hole 15 and second through hole 25 in plan view, and the junction layer 40 is arranged outside the seal member 50, the seal member arranged most closely to the first through hole 15 and second through hole 25 among the seal members 50 is so arranged that an inner peripheral edge 51 thereof is located outside respective peripheral surfaces 15b, 25b of the first through hole 15 and second through hole 25.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a holding device for holding an object. [Background technology]

[0002] As a holding device, for example, Patent Document 1 discloses a holding device having a first member (electrostatic chuck) having a first surface and a second surface provided on the opposite side to the first surface, and a second member (base) having a third surface and a fourth surface provided on the opposite side to the third surface, and holding an object on the first surface of the first member. The first member and the second member are stacked vertically so that the second surface and the third surface face each other. The first member is formed with a first through hole that penetrates between the first surface and the second surface and through which a lift pin that pushes up the object from above the first surface is inserted. The second member is formed with a second through hole that penetrates between the third surface and the fourth surface and through which the lift pin is inserted.

[0003] The holding device further includes a third member (base) having a fifth surface and a sixth surface provided on the opposite side to the fifth surface. The third member is stacked vertically together with the first and second members such that the fifth surface faces the fourth surface of the second member. A gas flow path is provided between the fourth surface of the second member and the fifth surface of the third member. The third member is also formed with a third through hole through which the lift pin is inserted. The first through hole, the second through hole, and the third through hole are arranged in series in the first direction (vertical direction) in which the lift pin moves.

[0004] Between the gas flow path and the third through hole, two annular O-rings are arranged side by side (double) in the radial direction to prevent gas from leaking into the third through hole. Of the two O-rings, the O-ring arranged near (inside) the third through hole is arranged so that its inner peripheral edge is located inside the peripheral surface of the third through hole (so that it is exposed to the third through hole). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-135737 A Summary of the Invention [Problem to be solved by the invention]

[0006] Here, the first member and the second member are bonded by a bonding layer disposed between the second surface of the first member and the third surface of the second member, for example. The bonding layer is formed with an intermediate through hole located between the first through hole and the second through hole, through which the lift pin is inserted. Therefore, in the above-mentioned holding device, when plasma or the like flows into the holding device through the first through hole and the plasma or the like comes into contact with the bonding layer, the bonding layer may be corroded. In order to prevent such corrosion of the bonding layer, an annular seal member (such as an O-ring) is sandwiched and disposed between the second surface of the first member and the third surface of the second member so as to surround the through hole.

[0007] However, as with the O-ring, if the inner peripheral edge of the seal member (referred to as the innermost seal member) that is disposed closest to the first through hole and the second through hole among the at least one (one or more) seal members is disposed inside the respective peripheral surfaces of the first through hole and the second through hole, the lift pin moving up and down may come into contact with the innermost seal member. If the innermost seal member is damaged, it becomes impossible to adequately prevent corrosion of the bonding layer.

[0008] Therefore, the present disclosure has been made to solve the above-mentioned problems, and aims to provide a holding device that can prevent the lift pins from coming into contact with the sealing member that protects the bonding layer. [Means for solving the problem]

[0009] In order to solve the above problems, one aspect of the present disclosure is to A first member having a first surface and a second surface provided on an opposite side to the first surface; a second member having a third surface and a fourth surface provided on an opposite side to the third surface; a bonding layer disposed between the second surface of the first member and the third surface of the second member, bonding the first member and the second member; A holding device for holding an object on the first surface of the first member, a first through hole through which a lift pin that pushes up the object from above the first surface is inserted is formed in the first member; the second member has a second through hole formed therein, the second through hole communicating with the first through hole and through which the lift pin is inserted; at least one annular seal member is sandwiched between the first member and the second member and arranged to surround the first through hole and the second through hole in a plan view; The bonding layer is disposed on the outer side of the seal member. And, Among the sealing members, one that is disposed closest to the first through hole and the second through hole is disposed such that an inner peripheral edge thereof is positioned outside the respective peripheral surfaces of the first through hole and the second through hole, a space communicating with the first through hole and the second through hole is provided between the first member and the second member and on the inner side of the seal member; The entire inner peripheral edge of the seal member is exposed to the space. It is characterized by the fact that and, the second member is a base member having a refrigerant flow path, and the second through hole is provided in the base member itself; The seal member may be disposed between the first member and the base member.

[0010] In this holding device, at least one annular seal member (e.g., an O-ring) is disposed between the first member and the second member so as to surround the first through hole and the second through hole in a plan view (i.e., when the holding device is viewed in a plan view). Among the seal members disposed for one through hole, the seal member disposed closest to the first through hole and the second through hole (hereinafter also referred to as the "innermost seal member") is disposed so that its inner peripheral edge is located outside the respective peripheral surfaces of the first through hole and the second through hole. That is, in a plan view, the inner peripheral edge of the innermost seal member is not located inside the first through hole and the second through hole, but is located outside the first through hole and the second through hole (farther from the center). Therefore, it is possible to prevent the lift pin from contacting the seal member.

[0011] By placing and sandwiching the entire innermost seal member between the second surface of the first member and the third surface of the second member, a large contact surface (seal surface) between the seal member and the second and third surfaces can be ensured, thereby improving the sealing performance of the seal member.

[0012] Here, if the inner peripheral edge of the innermost seal member is located inside the inner peripheral edges of the first through hole and the second through hole, a part of the innermost seal member may be pressed against the corner between the circumferential surface of the first through hole in the first member and the second surface, or against the corner between the circumferential surface of the second through hole in the second member and the third surface, which may cause stress to concentrate in that portion of the innermost seal member, resulting in cracks, etc.

[0013] In contrast, in this holding device, the innermost seal member is arranged so that its inner peripheral edge is not positioned inside the respective peripheral surfaces of the first through hole and the second through hole, but is positioned outside the respective inner peripheral edges of the first through hole and the second through hole. Therefore, it is possible to prevent the innermost seal member from being deformed by contacting the corner between the peripheral surface of the first through hole and the second surface of the first member, or the corner between the peripheral surface of the second through hole and the third surface of the second member. This allows the innermost seal member to be uniformly elastically deformed, and it is possible to prevent the occurrence of cracks or the like in the innermost seal member, thereby improving the durability of the innermost seal member. Therefore, according to this holding device, the seal member can reliably prevent leakage of gas or plasma that corrodes the bonding layer from the through hole to the bonding layer.

[0014] In the above-mentioned holding device, The second member is an inner member in which the second through hole is formed; an outer member disposed outside the inner member and joined to the first member by the joining layer; It is preferable that the seal member is disposed between the inner member and the first member. Alternatively, as another aspect of the present disclosure, A first member having a first surface and a second surface provided on an opposite side to the first surface; a second member having a third surface and a fourth surface provided on an opposite side to the third surface; a bonding layer disposed between the second surface of the first member and the third surface of the second member, bonding the first member and the second member; A holding device for holding an object on the first surface of the first member, a first through hole through which a lift pin that pushes up the object from above the first surface is inserted is formed in the first member; The second member is an inner member having a second through hole communicating with the first through hole and through which the lift pin is inserted; an outer member disposed outside the inner member and joined to the first member by the joining layer; Equipped with at least one annular seal member is sandwiched between the first member and a leading end of the inner member on the first member side and is arranged to surround the first through hole and the second through hole in a plan view; the bonding layer is disposed on an outer side of the seal member, Among the sealing members, the one arranged closest to the first through hole and the second through hole may be characterized in that its inner peripheral edge is arranged to be positioned outside the respective peripheral surfaces of the first through hole and the second through hole.

[0015] In this way, after the first member and the outer member of the second member are joined by the joining layer, the seal member can be sandwiched between the first member and the inner member of the second member, and the seal member can be disposed between the first member and the second member. Therefore, the seal member can be sandwiched between the first member and the inner member of the second member without misalignment, and the seal member can be elastically deformed firmly. Since the misalignment of the seal member is suppressed in this way, the sealability of the seal member is improved, and leakage of gas or plasma from the through hole to the joining layer can be reliably prevented.

[0016] In the above-mentioned holding device, It is preferable that both the first member and the second member are ceramic members.

[0017] Even when the ceramic members are bonded together by the bonding layer in this manner, the seal member (innermost seal member) that is disposed closest to the first and second through holes among the seal members disposed in one through hole is disposed so that its inner peripheral edge is positioned outside the respective peripheral surfaces of the first and second through holes, thereby making it possible to prevent the lift pin from coming into contact with the seal member.

[0018] In addition, since the seal member is firmly sandwiched and fixed between the first ceramic member and the second ceramic member, the sealing performance between the first ceramic member and the second ceramic member can be improved, and therefore it is possible to reliably prevent gas or plasma that corrodes the bonding layer from leaking from the through holes to the bonding layer.

[0019] In this case, it is preferable that the heating resistor is disposed on the third surface of the second member. For example, when a ceramic member having a heating resistor therein is manufactured by pressing and firing a plurality of green sheets as the first member, a heating resistor of a predetermined pattern is formed in advance on the surface of one green sheet, and the green sheets are pressed and fired together with the other green sheets. Therefore, when the temperature distribution of the first surface (holding surface for holding an object) of the first member caused by the heat generated by the heating resistor is not the desired temperature distribution, the heating resistor is embedded inside the ceramic member, and therefore the heating resistor itself cannot be processed (trimmed) to adjust the temperature distribution.

[0020] In contrast, by doing as described above, the heating resistor itself can be easily processed (trimmed) so that the first surface (the holding surface that holds the object) has a desired temperature distribution. Specifically, first, a heating resistor of a predetermined pattern is provided on the third surface of the second member (for example, the heating resistor is printed). Then, while checking the temperature distribution on the third surface of the second member when the heating resistor is heated, the heating resistor itself is trimmed (shaved) so that the third surface has a desired temperature distribution (for example, a uniform temperature distribution over the entire third surface). In this way, after the third surface of the second member when the heating resistor is heated is adjusted to a desired temperature distribution, the first member and the second member may be joined by a joining layer to manufacture the holding device. According to the holding device manufactured in this way, the first surface (the holding surface that holds the object) can be precisely made to have a desired temperature distribution by applying electricity to the heating resistor.

[0021] Here, in the area where the sealing member is disposed, the sealing member is interposed between the first member and the second member, and therefore no bonding layer is interposed between the first member and the second member. Since the sealing member has a lower thermal conductivity than the bonding layer, the more sealing members are disposed for one through hole, the worse the thermal conduction between the first member and the second member becomes, and the temperature around the through hole on the first surface becomes higher than other areas.

[0022] Therefore, in the above-mentioned holding device, It is preferable that one seal member is disposed for each of the first through hole and the second through hole.

[0023] In this way, the number of sealing members interposed between the first member and the second member is reduced compared to the case where multiple sealing members are arranged for one through hole, and the bonding layer can be arranged up to the periphery of the through hole, so that the thermal conduction between the first member and the second member in the periphery of the through hole can be increased, thereby improving the thermal uniformity on the first surface of the first member. Effect of the Invention

[0024] According to the present disclosure, it is possible to provide a holding device capable of preventing the lift pins from coming into contact with a seal member that protects a bonding layer. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a perspective view showing electrostatic chucks according to a first embodiment, a second embodiment, and a fourth embodiment. [Diagram 2] 1 is a cross-sectional view showing an electrostatic chuck according to a first embodiment. [Diagram 3] 2 is a partially enlarged plan view of the electrostatic chuck according to the first embodiment, viewed in a first direction. FIG. [Figure 4] FIG. 4 is a cross-sectional view showing an electrostatic chuck according to a second embodiment. [Diagram 5] FIG. 11 is a partially enlarged plan view of an electrostatic chuck according to a second embodiment, viewed in a first direction. [Figure 6] FIG. 11 is a perspective view showing an electrostatic chuck according to a third embodiment. [Figure 7] FIG. 11 is a cross-sectional view showing an electrostatic chuck according to a third embodiment. [Figure 8] FIG. 8 is a partially enlarged view of FIG. [Figure 9] FIG. 11 is a partially enlarged plan view of the electrostatic chuck according to the third embodiment, viewed in a first direction. [Figure 10] FIG. 11 is a cross-sectional view showing an electrostatic chuck according to a fourth embodiment. [Figure 11] FIG. 11 is an enlarged view of an electrostatic chuck according to a fourth embodiment when viewed in a plan view in a first direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] [First embodiment] A holding device according to an embodiment of the present disclosure will be described in detail with reference to the drawings. In this embodiment, an electrostatic chuck 1 that holds a semiconductor wafer W as an object will be described as an example. The electrostatic chuck 1 of this embodiment will be described with reference to Figs. 1 to 3.

[0027] The electrostatic chuck 1 of the present embodiment is a device that attracts and holds a semiconductor wafer W (object) by electrostatic attraction, and is used, for example, to fix the semiconductor wafer W in a vacuum chamber of a semiconductor manufacturing device. As shown in Fig. 1, the electrostatic chuck 1 has a ceramic member 10, a base member 20, and a bonding layer 40 that bonds the ceramic member 10 and the base member 20. The ceramic member 10 is an example of a "first member" in the present disclosure, and the base member is an example of a "second member" in the present disclosure.

[0028] The ceramic member 10 is a disk-shaped member made of ceramics, as shown in Fig. 1. Various ceramics can be used as the ceramic, but from the viewpoints of strength, wear resistance, plasma resistance, etc., it is preferable to use ceramics whose main component is, for example, aluminum oxide (alumina, Al2O3) or aluminum nitride (AlN). Note that the main component here means the component with the highest content (for example, a component with a volume content of 90 vol% or more).

[0029] As shown in Figs. 1 and 2, the ceramic member 10 has an adsorption surface 11 (upper surface) that adsorbs and holds the semiconductor wafer W, and a lower surface 12 that is provided on the opposite side to the adsorption surface 11 in the thickness direction of the ceramic member 10 (a direction that coincides with the first direction D1, the vertical direction in the figure). The ceramic member 10 has a cylindrical first through hole 15 that penetrates between the adsorption surface 11 and the lower surface 12 in the first direction D1 (the vertical direction in Fig. 2, the direction that coincides with the thickness direction of the electrostatic chuck 1). The adsorption surface 11 is an example of the "first surface" in the present disclosure, and the lower surface 12 is an example of the "second surface" in the present disclosure. The first direction is the direction in which a lift pin 60, which will be described later, moves.

[0030] The ceramic member 10 has a thermal conductivity of, for example, 20 W / mK. The ceramic member 10 has a diameter of, for example, about 150 to 300 mm, and a thickness of, for example, about 2 to 6 mm. The thermal conductivity of the ceramic member 10 is desirably within a range of 10 to 50 W / mK (more preferably, 18 to 30 W / mK).

[0031] The base member 20 is a cylindrical member as shown in Fig. 1. Specifically, the base member 20 has a stepped cylindrical shape in which two cylinders of different diameters are overlapped with a common central axis (more specifically, a cylindrical upper stage portion having a smaller diameter is overlapped on a cylindrical lower stage portion having a larger diameter). The base member 20 is preferably made of a metal (e.g., aluminum or an aluminum alloy), but may be made of a material other than metal.

[0032] 1 and 2, the base member 20 has an upper surface 21 and a lower surface 22 provided on the opposite side to the upper surface 21 in the thickness direction of the base member 20 (a direction that coincides with the first direction D1, the up-down direction in the figure). The base member 20 is formed with a cylindrical second through hole 25 that penetrates between the upper surface 21 and the lower surface 22 in the first direction D1. The second through hole 25 is coaxial with the first through hole 15 and has the same inner diameter. The upper surface 21 is an example of a "third surface" in the present disclosure, and the lower surface 22 is an example of a "fourth surface" in the present disclosure.

[0033] The diameter of the base member 20 is, for example, about 150 to 300 mm at the upper portion and about 180 to 350 mm at the lower portion. The thickness of the base member 20 (dimension in the first direction D1) is, for example, about 20 to 50 mm. The thermal conductivity of the base member 20 (assumed to be aluminum) is desirably within a range of 180 to 250 W / mK (preferably, about 230 W / mK).

[0034] The base member 20 is formed with a refrigerant flow path (not shown) for flowing a refrigerant (e.g., a fluorine-based inert liquid, water, etc.). The refrigerant flow path is connected to a supply port and a discharge port (not shown) provided on the lower surface 22 of the base member 20, and the refrigerant supplied to the base member 20 from the supply port flows through the refrigerant flow path and is discharged from the discharge port to the outside of the base member 20. In this way, by flowing the refrigerant through the refrigerant flow path of the base member 20, the base member 20 is cooled, and thereby the ceramic member 10 is cooled via the bonding layer 40.

[0035] The bonding layer 40 is disposed between the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20, and bonds the ceramic member 10 and the base member 20. The lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20 are thermally connected via the bonding layer 40. The bonding layer 40 is made of an adhesive material such as a silicone resin, an acrylic resin, or an epoxy resin. The bonding layer 40 has a cylindrical intermediate through hole 45 located between the first through hole 15 and the second through hole 25. The intermediate through hole 45 is coaxial with the first through hole 15 and the second through hole 25, and has a larger inner diameter than the first through hole 15 and the second through hole 25.

[0036] The thickness (dimension in the first direction D1) of the bonding layer 40 is, for example, about 0.1 to 1.0 mm. The thermal conductivity of the bonding layer 40 is, for example, 1.0 W / mK. The thermal conductivity of the bonding layer 40 (assumed to be a silicone-based resin) is preferably within a range of 0.1 to 2.0 W / mK (preferably, 0.5 to 1.5 W / mK).

[0037] Here, the first through hole 15, the intermediate through hole 45, and the second through hole 25 are arranged in a line in the first direction D1 to form a lift pin insertion hole 35 penetrating the electrostatic chuck 1 in the first direction D1 (thickness direction). A lift pin 60 for pushing up the semiconductor wafer W from the chucking surface 11 is inserted into the lift pin insertion hole 35 (the first through hole 15, the intermediate through hole 45, and the second through hole 25) from the lower surface 22 side of the base member 20. The lift pin 60 has a cylindrical shape (round bar shape) and moves in the lift pin insertion hole 35 in the first direction D1. When the lift pin 60 moves to one side in the first direction D1 (the upper side in FIG. 2), the tip portion (upper end portion) of the lift pin 60 protrudes to the outside from the chucking surface 11 of the ceramic member 10, so that the semiconductor wafer W placed on the chucking surface 11 is separated from the chucking surface 11 (the semiconductor wafer W is lifted by the lift pin 60).

[0038] In the electrostatic chuck 1 of the present embodiment, three lift pin insertion holes 35 (i.e., three first through holes 15, three intermediate through holes 45, and three second through holes 25) are formed, and a lift pin 60 is inserted into each lift pin insertion hole 35. The three lift pin insertion holes 35 are formed at equal intervals in the circumferential direction of the electrostatic chuck 1 (see FIG. 1).

[0039] In the electrostatic chuck 1, an annular seal member 50 (e.g., an O-ring) is disposed in each intermediate through-hole 45 (through-hole of the bonding layer 40) so as to surround the first through-hole 15 and the second through-hole 25 in a plan view in the first direction D1, in a manner sandwiched between the ceramic member 10 and the base member 20 (more specifically, sandwiched between the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20) (see FIGS. 2 and 3). The seal member 50 is intended to protect the bonding layer 40 and prevent corrosion of the bonding layer 40.

[0040] That is, when the electrostatic chuck 1 is used to fix a semiconductor wafer W in a vacuum chamber of a semiconductor manufacturing device, a process gas, plasma, etc. used in forming a circuit pattern on the semiconductor wafer W flow into the electrostatic chuck 1 through the first through hole 15. If the plasma, etc., penetrates and contacts the bonding layer 40, the bonding layer 40 will corrode, so the seal member 50 is provided. By providing the seal member 50, the gap between the lower surface 12 of the ceramic member 10 exposed in the intermediate through hole 45 and the upper surface 21 of the base member 20 is airtightly sealed, and the plasma, etc., that flows into the electrostatic chuck 1 through the first through hole 15 can be prevented from penetrating into the bonding layer 40 through the intermediate through hole 45 and contacting the bonding layer 40.

[0041] In this embodiment, one seal member 50 is disposed in one intermediate through hole 45. Note that "when viewed in a plan view in the first direction D1" means "when the electrostatic chuck 1 is viewed in a plan view in the first direction D1," and more specifically, means "when the electrostatic chuck 1 is viewed in a plan view along the first direction D1 from the adsorption surface 11 side of the ceramic member 10."

[0042] Here, when the seal member 50 is disposed so that its inner peripheral edge 51 is located inside (toward the center line CL) of the peripheral surface 15b of the first through hole 15 and the peripheral surface 25b of the second through hole 25, the lift pin 60 moving (moving up and down) in the first direction D1 may come into contact with the seal member 50. In particular, in the electrostatic chuck 1 of this embodiment, the peripheral surface 15b of the first through hole 15 and the peripheral surface 25b of the second through hole 25 are close to the outer peripheral surface of the lift pin 60, respectively. Therefore, when the inner peripheral edge 51 of the seal member 50 is located inside the peripheral surface 15b of the first through hole 15 and the peripheral surface 25b of the second through hole 25, the lift pin 60 moving in the first direction D1 is highly likely to come into contact with the seal member 50. When the lift pin 60 comes into contact with the seal member 50 and the seal member 50 is damaged, it may not be possible to appropriately prevent corrosion of the bonding layer 40 and particles may be generated.

[0043] Therefore, in this embodiment, each seal member 50 is arranged so that its inner peripheral edge 51 is located outside (radially outside) the peripheral surface 15b of the first through hole 15 and the peripheral surface 25b of the second through hole 25 (see Figs. 2 and 3). That is, as shown in Fig. 3, in a plan view in the first direction D1, the inner peripheral edge 51 of the seal member 50 is not located inside the first through hole 15 and the second through hole 25, but is located outside (farther from the center line CL) the first through hole 15 and the second through hole 25. This can reliably prevent the lift pin 60 from contacting the seal member 50 arranged in the intermediate through hole 45 of the bonding layer 40.

[0044] Each of the seal members 50 thus arranged is disposed entirely between the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20. This allows the seal member 50 to be firmly sandwiched between the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20 and uniformly elastically deformed to be fixed, and also ensures a large contact surface (sealing surface) of the seal member 50 with the lower surface 12 and the upper surface 21. This makes it possible to improve the sealing property (airtightness) between the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20, and reliably prevent leakage of plasma or the like, which corrodes the bonding layer 40, into the bonding layer.

[0045] Here, if the inner peripheral edge 51 of the sealing member 50 is positioned inward (radially inward) than the peripheral surface 15b of the first through hole 15 and the peripheral surface 25b of the second through hole 25, a part of the sealing member 50 will be pressed against the corner 17 between the peripheral surface 15b of the first through hole 15 (hole surface 15c that constitutes the first through hole 15) of the ceramic member 10 and the lower surface 12, or against the corner 27 between the peripheral surface 25b of the second through hole 25 (hole surface 25c that constitutes the second through hole 25) of the base member 20 and the upper surface 21, which may cause stress to concentrate at that portion of the sealing member 50, resulting in the occurrence of cracks, etc.

[0046] Therefore, in the electrostatic chuck 1 of the present embodiment, as described above, the seal member 50 is disposed so that its inner peripheral edge 51 is not positioned inside (inside in the radial direction) the peripheral surfaces 15b, 25b of the first through hole 15 and the second through hole 25, but is positioned outside the peripheral surfaces 15b, 25b of the first through hole 15 and the second through hole 25. This can prevent the seal member 50 from contacting the corner 17 between the peripheral surface 15b (hole forming surface 15c constituting the first through hole 15) of the first through hole 15 of the ceramic member 10 and the lower surface 12, or the corner 27 between the peripheral surface 25b (hole forming surface 25c constituting the second through hole 25) of the second through hole 25 of the base member 20 and the upper surface 21. This can prevent the above-mentioned cracks and the like from occurring in the seal member 50. In the electrostatic chuck 1 of the present embodiment, only one seal member 50 is disposed in one intermediate through-hole 45, and therefore each seal member 50 serves as an “innermost seal member.” In addition, the durability of the innermost seal member can be improved.

[0047] Incidentally, the bonding layer 40 is not present at the location between the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20 where the sealing member 50 is disposed. In addition, in the electrostatic chuck 1 of the present embodiment, the sealing member 50 (its material) has a lower thermal conductivity than the bonding layer 40 (its material). For this reason, the more the number of sealing members 50 disposed in one intermediate through-hole 45 is increased, the more the thermal conductivity between the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20 decreases.

[0048] Therefore, in the electrostatic chuck 1 of the present embodiment, only one seal member 50 is disposed in one intermediate through hole 45. As a result, the number of seal members 50 interposed between the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20 is reduced compared to the case where a plurality of seal members 50 are disposed in one intermediate through hole 45, and the bonding layer 40 can be disposed up to the periphery of the through hole, so that the area of ​​the bonding layer 40 in contact with the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20 can be increased. Therefore, in the periphery of the lift pin insertion hole 35, the thermal conduction between the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20 can be increased, and the thermal uniformity in the adsorption surface 11 can be improved.

[0049] As described above, according to the electrostatic chuck 1 of the present embodiment, one annular seal member 50 is disposed so as to surround one first through hole 15 and one second through hole 25, and in a plan view, the inner peripheral edge 51 of the seal member 50 is disposed outside (farther from the center) the first through hole 15 and the second through hole 25, rather than being positioned inside the first through hole 15 and the second through hole 25. This reliably prevents the lift pins 60 from contacting the seal member 50, and enhances thermal conduction around the lift pin insertion holes 35, thereby improving the thermal uniformity on the adsorption surface 11.

[0050] Moreover, the seal member 50 can be uniformly elastically deformed and the occurrence of cracks or the like in the seal member 50 can be prevented, thereby improving the durability of the seal member 50. Therefore, the seal member 50 can reliably prevent leakage of plasma or the like, which corrodes the bonding layer 40, into the bonding layer 40.

[0051] [Second embodiment] Next, a second embodiment will be described with reference to Figures 4 and 5. The second embodiment has the same basic configuration as the first embodiment, but the configuration of the base member is different from that of the first embodiment. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals and their description is omitted as appropriate, and the differences from the first embodiment will be mainly described.

[0052] 4, the electrostatic chuck 101 of the present embodiment has a ceramic member 10 similar to that of the first embodiment, a bonding layer 40 similar to that of the first embodiment, and a base member 120 different from that of the first embodiment. The base member 120 includes a cylindrical inner member 120A having a second through hole 125 formed therein, and an outer member 120B disposed outside (radially outside) the inner member 120A.

[0053] Moreover, the bonding layer 40 is disposed between the outer member 120B and the ceramic member 10. That is, the bonding layer 40 is disposed between the ceramic member 10 and the outer member 120B, not between the ceramic member 10 and the inner member 120A. Therefore, the outer member 120B of the base member 120 is bonded to the ceramic member 10 by the bonding layer 40.

[0054] Here, the inner member 120A is fixed to the outer member 120B. In this embodiment, for example, the outer member 120B is formed with a female screw hole 123 penetrating in the first direction D1. In this embodiment, three female screw holes 123 are formed in the outer member 120B so as to be coaxial with the first through hole 15 of the ceramic member 10. Meanwhile, a male screw 126 that screws into the female screw of the female screw hole 123 is formed on the outer peripheral surface of the inner member 120A. Therefore, the inner member 120A is fixed to the outer member 120B by inserting the inner member 120A into the female screw hole 123 of the outer member 120B while screwing the male screw 126 of the inner member 120A into the female screw of the female screw hole 123 of the outer member 120B. In this embodiment, the inner member 120A is disposed in each of the three female screw holes 123. Therefore, the base member 120 of this embodiment is composed of one outer member 120B and three inner members 120A.

[0055] In such a base member 120, the second through hole 125 of the inner member 120A penetrates between the upper surface 121 and the lower surface 122 of the base member 120 in the first direction D1. The second through hole 125 is coaxial with the first through hole 15 of the ceramic member 10 and has the same inner diameter as the first through hole 15 of the ceramic member 10. The first through hole 15 of the ceramic member 10, the intermediate through hole 45 of the bonding layer 40, and the second through hole 125 of the base member 120 are arranged in series in the first direction D1 to form a lift pin insertion hole 135 that penetrates the electrostatic chuck 101 in the first direction D1.

[0056] In the electrostatic chuck 101 of the present embodiment, an annular seal member 50 is disposed in each intermediate through hole 45 so as to surround the first through hole 15 and the second through hole 125 in a plan view in the first direction D1 in a manner sandwiched between the lower surface 12 of the ceramic member 10 and the upper surface 121 of the base member 120 (specifically, the upper surface 127 of the inner member 120A) (see FIGS. 4 and 5). As a result, the seal member 50 hermetically seals the gap between the lower surface 12 of the ceramic member 10 exposed in the intermediate through hole 45 and the upper surface 121 of the base member 120. Therefore, it is possible to prevent the plasma or the like that has flowed into the electrostatic chuck 101 through the first through hole 15 from penetrating into the bonding layer 40 and coming into contact with the bonding layer 40.

[0057] Also, in the electrostatic chuck 101 of this embodiment, each seal member 50 is disposed such that its inner peripheral edge 51 is located outside (radially outside) the peripheral surface 15b of the first through hole 15 and the peripheral surface 125b of the second through hole 125 (see FIGS. 4 and 5). That is, as shown in FIG. 5, in a plan view in the first direction D1, the inner peripheral edge 51 of the seal member 50 is not located inside the first through hole 15 and the second through hole 125, but is located outside (farther from the center line CL) the first through hole 15 and the second through hole 125. This can reliably prevent the lift pin 60 from contacting the seal member 50.

[0058] Here, such an electrostatic chuck 101 is manufactured as follows. That is, first, the ceramic member 10 and the outer member 120B of the base member 120 are joined by the joining layer 40, and the position of the outer member 120B relative to the ceramic member 10 is fixed. Then, the inner member 120A is fixed to the outer member 120B so that the seal member 50 is sandwiched between the ceramic member 10 and the inner member 120A of the base member 120. Specifically, the inner member 120A is inserted into the female thread hole 123 of the outer member 120B while the male thread 126 of the inner member 120A is screwed into the female thread of the female thread hole 123 of the outer member 120B. Then, the base member 120 is formed by fixing the inner member 120A to the outer member 120B, and the seal member 50 can be disposed between the ceramic member 10 and the base member 120 (the inner member 120A).

[0059] Therefore, it becomes easier to arrange the seal member 50 at a predetermined position, and it is possible to suppress misalignment of the seal member 50. Since misalignment of the seal member 50 is suppressed in this manner, the seal member 50 can be elastically deformed reliably, improving the sealing performance between the lower surface 12 of the ceramic member 10 and the upper surface 121 of the base member 120, and more reliably preventing leakage of plasma or the like to the bonding layer 40.

[0060] As described above, according to the electrostatic chuck 101 of the present embodiment, the lift pins 60 can be reliably prevented from coming into contact with the sealing member 50, and the sealing property of the sealing member 50 is improved, so that leakage of plasma and the like to the bonding layer 40 can be more reliably prevented.

[0061] [Third embodiment] Next, a third embodiment will be described with reference to Fig. 6 to Fig. 9. The third embodiment has the same basic configuration as the second embodiment, but the configuration of the ceramic member is different from that of the second embodiment. Therefore, the same reference numerals are used for the same configuration as the second embodiment, and the description is omitted as appropriate, and the differences from the second embodiment will be mainly described.

[0062] 6 and 7, the electrostatic chuck 201 of the present embodiment includes a first ceramic member 210, a second ceramic member 220, and a bonding layer 240 that bonds the first ceramic member 210 and the second ceramic member 220. The first ceramic member 210 is an example of a "first member" in the present disclosure, and the second ceramic member 220 is an example of a "second member" in the present disclosure.

[0063] The electrostatic chuck 201 also includes a base member 120 similar to that of the second embodiment, and a bonding layer 40 that bonds the base member 120 and a second ceramic member 220. Furthermore, the electrostatic chuck 201 includes an annular seal member 50 disposed in each intermediate through-hole 45 in a manner that the seal member 50 is sandwiched between a lower surface 222 of the second ceramic member 220 and an upper surface 121 of the base member 120 (more specifically, an upper surface 127 of the inner member 120A) in the same manner as in the second embodiment.

[0064] The first ceramic member 210 has a cylindrical first through hole 215 penetrating between the adsorption surface 211 and the lower surface 212 in the first direction D1 (see Figs. 7 and 8). The adsorption surface 211 is an example of the "first surface" of the present disclosure, and the lower surface 212 is an example of the "second surface" of the present disclosure. The second ceramic member 220 has a cylindrical second through hole 225 penetrating between the upper surface 221 and the lower surface 222 in the first direction D1. The upper surface 221 is an example of the "third surface" of the present disclosure, and the lower surface 222 is an example of the "fourth surface" of the present disclosure. The second through hole 225 is coaxial with the first through hole 215 and has the same inner diameter.

[0065] A cylindrical intermediate through hole 245 is formed in the bonding layer 240 and is located between the first through hole 215 and the second through hole 225. The intermediate through hole 245 is coaxial with the first through hole 215 and the second through hole 225, and has a larger inner diameter than the first through hole 215 and the second through hole 225.

[0066] The first through hole 215, the intermediate through hole 245, and the second through hole 225 are arranged in series in the first direction D1 and form a part of a lift pin insertion hole 235 that penetrates the electrostatic chuck 201 in the first direction D1 (thickness direction). A lift pin 60 that pushes up the semiconductor wafer W from above the adsorption surface 211 is inserted into the lift pin insertion hole 235 from the lower surface 122 side of the base member 120.

[0067] In each intermediate through-hole 245, a ring-shaped seal member 250 (e.g., an O-ring) is disposed so as to surround the first through-hole 215 and the second through-hole 225 in a plan view in the first direction D1 in a manner sandwiched between the lower surface 212 of the first ceramic member 210 and the upper surface 221 of the second ceramic member 220 (see FIGS. 7 and 8). As a result, the seal member 250 hermetically seals the gap between the lower surface 212 of the first ceramic member 210 and the upper surface 221 of the second ceramic member 220 exposed in the intermediate through-hole 245, and the plasma or the like that has flowed into the electrostatic chuck 201 through the first through-hole 215 can be prevented from penetrating into the bonding layer 240 and coming into contact with the bonding layer 240.

[0068] Also, in the electrostatic chuck 201 of this embodiment, each seal member 250 is disposed such that its inner peripheral edge 251 is located outside (radially outside) the outer peripheral surface 215b of the first through hole 215 and the outer peripheral surface 225b of the second through hole 225 (see FIG. 8). That is, as shown in FIG. 9, in a plan view in the first direction D1, the inner peripheral edge 251 of the seal member 250 is not located inside the first through hole 215 and the second through hole 225, but is located outside (farther from the center line CL) the first through hole 215 and the second through hole 225. This can reliably prevent the lift pin 60 from contacting the seal member 250 disposed in the intermediate through hole 245 of the bonding layer 240.

[0069] Furthermore, the seal member 250 can be firmly sandwiched and fixed between the lower surface 212 of the first ceramic member 210 and the upper surface 221 of the second ceramic member 220, and a large contact surface (sealing surface) of the seal member 250 with the lower surface 212 of the first ceramic member 210 and the upper surface 221 of the second ceramic member 220 can be ensured. Therefore, the sealing property between the lower surface 212 of the first ceramic member 210 and the upper surface 221 of the second ceramic member 220 can be improved. Therefore, the seal member 250 arranged in the intermediate through-hole 245 can reliably prevent plasma or the like from entering the bonding layer 240 and coming into contact with the bonding layer 240.

[0070] 8, the electrostatic chuck 201 of this embodiment is provided with a heating resistor 270 on the upper surface 221 of the second ceramic member 220. The heating resistor 270 is arranged in a spiral shape over the entire upper surface 221 of the second ceramic member 220. When a voltage is applied to the heating resistor 270 from a power source (not shown), the heating resistor 270 generates heat, whereby the attracting surface 211 of the first ceramic member 210 is heated, and the semiconductor wafer W held on the attracting surface 211 is heated.

[0071] Incidentally, when manufacturing a ceramic member having a heating resistor therein by, for example, pressing and firing a plurality of green sheets, a heating resistor of a predetermined pattern is formed in advance on the surface of a green sheet pressing body, and another green sheet pressing body is superimposed and pressed, and then fired. Therefore, if the temperature distribution on the adsorption surface (first surface) of the ceramic member due to the heat generated by the heating resistor is not the desired temperature distribution, the heating resistor itself cannot be processed (trimmed) because it is embedded inside the ceramic member.

[0072] In contrast, in the electrostatic chuck 201 of the present embodiment, during manufacturing, the temperature distribution can be adjusted while processing the heating resistor 270 so that the attracting surface 211 has a desired temperature distribution. That is, the heating resistor 270 provided in a predetermined pattern on the upper surface 221 of the second ceramic member 220 is caused to generate heat, the temperature distribution on the upper surface 221 of the second ceramic member 220 is confirmed, and the heating resistor 270 can be trimmed (shaved) so that the upper surface 221 has a desired temperature distribution (for example, a substantially uniform temperature distribution over the entire upper surface 221).

[0073] Then, after trimming and adjusting the heating resistor 270, the first ceramic member 210 and the second ceramic member 220 are joined by the joining layer 240, so that the upper surface 221 of the second ceramic member 220 can be precisely adjusted to a desired temperature distribution. As a result, the attraction surface 211 of the first ceramic member 210 joined to the second ceramic member 220 via the joining layer 240 can also be precisely adjusted to a desired temperature distribution. Therefore, according to the electrostatic chuck 201 of this embodiment, the temperature controllability of the attraction surface 211 can be improved. Note that the seal member 250 is sandwiched between the lower surface 212 of the first ceramic member 210 and the upper surface 221 of the second ceramic member 220 when the first ceramic member 210 and the second ceramic member 220 are joined together, and is disposed in each intermediate through hole 245.

[0074] As described above, according to the electrostatic chuck 201 of the present embodiment, it is possible to reliably prevent the lift pins 60 from coming into contact with the seal member 250, and the seal member 250 can reliably prevent leakage of plasma or the like to the bonding layer 40. Furthermore, during manufacturing, the heating resistor 270 can be trimmed (shaved) so that the attraction surface 211 has a desired temperature distribution, and therefore the temperature controllability on the attraction surface 211 can be improved.

[0075] [Fourth embodiment] Finally, the fourth embodiment will be described with reference to FIGS. 10 and 11. The fourth embodiment has the same basic configuration as the first embodiment, but is different from the first embodiment in that a plurality of seal members are provided for one through hole. That is, the present disclosure is not limited to application to an electrostatic chuck in which one seal member is disposed for one through hole, but can also be applied to an electrostatic chuck in which at least one seal member (i.e., one or more seal members) is disposed for one through hole. Therefore, the same reference numerals are used to designate the same configuration as the first embodiment, and the description is omitted as appropriate, and the differences from the first embodiment will be mainly described.

[0076] In the electrostatic chuck 301 of the present embodiment, as shown in Figs. 10 and 11, two seal members (seal member 50 and seal member 350) are disposed in one intermediate through hole 245. Specifically, as shown in Fig. 10, the electrostatic chuck 301 has a ceramic member 10 similar to that of the first embodiment, a bonding layer 240 different from that of the first embodiment, and a base member 20 similar to that of the first embodiment. The bonding layer 240 of the present embodiment differs from the bonding layer 40 of the first embodiment only in the diameter of the intermediate through hole. Specifically, the intermediate through hole 245 of the bonding layer 240 of the present embodiment has a larger diameter than the intermediate through hole 45 of the bonding layer 40 of the first embodiment in order to dispose two seal members therein.

[0077] The sealing member 50 and the annular sealing member 350 are disposed adjacent to each other in the radial direction so as to surround the first through hole 15 and the second through hole 25 in a plan view in the first direction D1, in a manner sandwiched between the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20 in each intermediate through hole 245 (see FIG. 11). The sealing member 350 has an inner diameter and an outer diameter larger than those of the sealing member 50, and is disposed so as to surround the sealing member 50.

[0078] In this manner, two seal members (seal member 50 and seal member 350) are disposed in one intermediate through hole 245, and therefore, compared to the electrostatic chucks of the other embodiments, it is possible to improve the airtightness between the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20. This makes it possible to more reliably prevent plasma or the like that has flowed into the electrostatic chuck 301 through the first through hole 15 from entering the intermediate through hole 245 and coming into contact with the bonding layer 240.

[0079] Among the seal members 50, 350 arranged in one intermediate through hole 245, the seal member 50 (innermost seal member) arranged closest to the first through hole 15 and the second through hole 25 is arranged so that its inner peripheral edge 51 is located outside the respective peripheral surfaces 15b, 25b of the first through hole 15 and the second through hole 25 (see FIG. 10). That is, as shown in FIG. 11, in a plan view in the first direction D1, the inner peripheral edge 51 of the seal member 50, which is the innermost seal member, is not located inside the first through hole 15 and the second through hole 25, but is located outside the first through hole 15 and the second through hole 25 (the side farther from the center line CL). Therefore, it is possible to reliably prevent the lift pin 60 from contacting the seal member 50.

[0080] As described above, according to the electrostatic chuck 301 of the present embodiment, it is possible to reliably prevent the lift pin 60 from coming into contact with the seal member 50, which is the innermost seal member, and the doubly arranged seal members 50, 350 can increase the airtightness between the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20, thereby more reliably preventing leakage of plasma and the like to the bonding layer 40.

[0081] It should be noted that the above-described embodiment is merely an example, does not limit the present disclosure in any way, and various improvements and modifications are possible without departing from the spirit and scope of the present disclosure. For example, in the above-described embodiment, the present disclosure is applied to an electrostatic chuck, but the present disclosure is not limited to electrostatic chucks and can be applied to any holding device that holds an object on its surface.

[0082] In addition, in the above embodiment, an electrostatic chuck in which a sealing member 50 is placed in the intermediate through hole 45 of the bonding layer 40 is exemplified, but the present disclosure can also be applied to an electrostatic chuck in which a countersunk hole is provided in the underside of the ceramic member 10 and a sealing member 50 is placed in the countersunk hole.

[0083] In the above-described second embodiment, the female screw hole 123 is formed in the outer member 120B, and the male screw 126 is formed in the inner member 120A, and the male screw 126 is screwed into the female screw of the female screw hole 123, thereby fixing the inner member 120A to the outer member 120B. However, the method of fixing the inner member 120A to the outer member 120B is not limited to this, and for example, a flange with a through hole may be formed at the lower end of the inner member 120A, and a bolt hole (threaded hole) may be formed in the lower surface of the outer member 120B, and the inner member 120A may be fixed to the outer member 120B by a bolt. Alternatively, the inner member 120A may be fixed to the outer member 120B by using an adhesive.

[0084] In the above third embodiment, the base member 120 including the inner member 120A and the outer member 120B is exemplified as the base member, but the base member 20 similar to that in the first embodiment can also be used. [Explanation of symbols]

[0085] 1. Electrostatic chuck 10 Ceramic materials 11 Adsorption surface 12 Bottom side 15 First through hole 15b Circumferential surface 17 Corner 20 Base material 21 Top side 22 Bottom side 25 Second through hole 25b Circumferential surface 27 Corner 40 Bonding layer 50 Sealing material 51 Inner edge 60 Lift Pin 101 Electrostatic Chuck 120 Base material 120A Inner member 120B Outer member 125 Second Through Hole 125b Circumferential surface 201 Electrostatic Chuck 210 First ceramic member 215 First Through Hole 215b Peripheral surface 220 Second ceramic member 225 Second Through Hole 225b Peripheral surface 240 Bonding layer 250 Sealing material 251 Inner edge 301 Electrostatic Chuck 350 Sealing material W Semiconductor wafer

Claims

1. A first member having a first surface and a second surface provided on an opposite side to the first surface; a second member having a third surface and a fourth surface provided on the opposite side to the third surface; and a bonding layer disposed between the second surface of the first member and the third surface of the second member, bonding the first member and the second member; A holding device for holding an object on the first surface of the first member, a first through hole through which a lift pin that pushes up the object from above the first surface is inserted is formed in the first member; a second through hole communicating with the first through hole and through which the lift pin is inserted is formed in the second member; at least one annular seal member is sandwiched between the first member and the second member and arranged to surround the first through hole and the second through hole in a plan view; the bonding layer is disposed on an outer side of the seal member, Among the sealing members, one that is disposed closest to the first through hole and the second through hole is disposed such that an inner peripheral edge thereof is positioned outside the respective peripheral surfaces of the first through hole and the second through hole, a space communicating with the first through hole and the second through hole is provided between the first member and the second member and on the inner side of the seal member; The entire inner peripheral edge of the seal member is exposed to the space, no step portion is formed between a region on the second surface of the first member where the sealing member is disposed and a region on the second surface of the first member where the bonding layer is disposed; No step is formed between a region on the third surface of the second member where the sealing member is disposed and a region on the third surface where the bonding layer is disposed. A holding device characterized in that

2. 2. The holding device according to claim 1, the second member is a base member having a refrigerant flow path, and the second through hole is provided in the base member itself; The seal member is disposed between the first member and the base member. A holding device characterized in that

3. 2. The holding device according to claim 1, The second member is an inner member having the second through hole formed therein; an outer member disposed outside the inner member and joined to the first member by the joining layer; The seal member is disposed between the inner member and the first member. A holding device characterized in that

4. A first member having a first surface and a second surface provided on an opposite side to the first surface; a second member having a third surface and a fourth surface provided on the opposite side to the third surface; and a bonding layer disposed between the second surface of the first member and the third surface of the second member, bonding the first member and the second member; A holding device for holding an object on the first surface of the first member, a first through hole through which a lift pin that pushes up the object from above the first surface is inserted is formed in the first member; The second member is an inner member having a second through hole formed therein, the second through hole communicating with the first through hole and through which the lift pin is inserted; an outer member disposed outside the inner member and joined to the first member by the joining layer; Equipped with at least one annular seal member is sandwiched between the first member and a leading end of the inner member on the first member side and is arranged to surround the first through hole and the second through hole in a plan view; the bonding layer is disposed on an outer side of the seal member, Among the sealing members, one that is disposed closest to the first through hole and the second through hole is disposed such that an inner peripheral edge thereof is positioned outside the respective peripheral surfaces of the first through hole and the second through hole, no step portion is formed between a region on the second surface of the first member where the sealing member is disposed and a region on the second surface of the first member where the bonding layer is disposed; No step is formed between a region on the third surface of the second member where the sealing member is disposed and a region on the third surface where the bonding layer is disposed. A holding device characterized in that

5. 2. The holding device according to claim 1, The first member and the second member are both ceramic members. A holding device characterized in that

6. In any one of the holding devices according to claims 1 to 5, One of the seal members is disposed for each of the first through holes and the second through holes. A holding device characterized in that

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