JP7667638B2 - Retaining device - Google Patents

Description

This disclosure relates to a holding device for holding an object.

For example, Patent Document 1 discloses a holding device having a first member (electrostatic chuck) with a first surface and a second surface provided on the opposite side of the first surface, and a second member (base) with a third surface and a fourth surface provided on the opposite side of 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 with the second surface facing the third surface. 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 the object up 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.

The holding device further includes a third member (base) having a fifth surface and a sixth surface provided on the opposite side of 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 also includes 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.

Two annular O-rings are arranged radially side by side (double) between the gas flow path and the third through hole 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 circumferential surface of the third through hole (so that it is exposed to the third through hole).

JP 2019-135737 A

Here, the first member and the second member are joined by a bonding layer disposed between the second surface of the first member and the third surface of the second member, for example. This 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, if plasma or the like flows into the holding device through the first through hole and this plasma or the like comes into contact with the bonding layer, there is a risk that the bonding layer will corrode. 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.

However, as with the O-ring described above, if the inner peripheral edge of the at least one (one or more) seal member that is located closest to the first through hole and the second through hole (referred to as the innermost seal member) is positioned inside the respective peripheral surfaces of the first through hole and the second through hole, there is a risk that the lift pin moving up and down will come into contact with the innermost seal member. And if the innermost seal member is damaged, it will no longer be possible to adequately prevent corrosion of the bonding layer.

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 pin from coming into contact with the sealing member that protects the bonding layer.

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 including 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;
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 .
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.

In this holding device, at least one annular seal member (e.g., an O-ring) is arranged 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 arranged for one through hole, the seal member arranged closest to the first through hole and the second through hole (hereinafter also referred to as the "innermost seal member") is arranged so that its inner peripheral edge is located outside the respective peripheral surfaces of the first through hole and the second through hole. In other words, 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 coming into contact with the seal member.

The entire innermost seal member is sandwiched between the second surface of the first member and the third surface of the second member, ensuring a large contact surface (sealing surface) between the seal member and the second and third surfaces. This improves the sealing performance of the seal member.

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 is pressed against the corner between the circumferential surface of the first through hole and the second surface of the first member, or against the corner between the circumferential surface of the second through hole and the third surface of the second member, causing stress to concentrate in that part of the innermost seal member, which may result in cracks or the like.

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.

In the above-mentioned holding device,
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;
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 including 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 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, 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.

By doing this, after the outer member of 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 placed 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 securely elastically deformed. Since misalignment of the seal member is suppressed in this way, the seal member provides good sealing properties, and it is possible to reliably prevent leakage of gas or plasma from the through hole to the joining layer.

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

Even when ceramic members are joined together using a joining layer in this manner, the sealing member (innermost sealing member) that is arranged closest to the first and second through holes among the sealing members arranged within one through hole is arranged so that its inner peripheral edge is positioned outside the respective peripheral surfaces of the first and second through holes. This makes it possible to prevent the lift pin from coming into contact with the sealing member.

In addition, since the sealing member is firmly sandwiched and fixed between the first member, which is a ceramic member, and the second member, which is also a ceramic member, the sealing performance between the first member, which is a ceramic member, and the second member, which is also a ceramic member, can be improved. 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.

In this case, it is preferable that the heating resistor is disposed on the third surface of the second member. For example, when manufacturing a ceramic member having a heating resistor inside 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, which is then pressed and fired together with the other green sheets. Therefore, if the temperature distribution on the first surface of the first member (the holding surface that holds the object) caused by the heat generated by the heating resistor is not the desired temperature distribution, since the heating resistor is embedded inside the ceramic member, the heating resistor itself cannot be processed (trimmed) to adjust the temperature distribution.

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 adjusting the third surface of the second member to the desired temperature distribution when the heating resistor is heated, the first member and the second member are joined by a joining layer to manufacture the holding device. With the holding device manufactured in this way, the first surface (the holding surface that holds the object) can be precisely adjusted to the desired temperature distribution by passing electricity through the heating resistor.

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. Furthermore, 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.

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.

By doing this, the number of sealing members interposed between the first and second members is reduced compared to when multiple sealing members are placed for one through hole, and the bonding layer can be placed up to the periphery of the through hole, so that the thermal conduction between the first and second members around the through hole can be increased. This can improve the thermal uniformity on the first surface of the first member.

The present disclosure provides a holding device that can prevent the lift pin from coming into contact with the sealing member that protects the bonding layer.

FIG. 1 is a perspective view showing an electrostatic chuck according to a first embodiment, a second embodiment, and a fourth embodiment. 1 is a cross-sectional view showing an electrostatic chuck according to a first embodiment. FIG. 2 is a partially enlarged plan view of the electrostatic chuck according to the first embodiment in a first direction. FIG. 11 is a cross-sectional view showing an electrostatic chuck according to a second embodiment. FIG. 11 is a partially enlarged plan view of the electrostatic chuck according to the second embodiment, viewed in a first direction. FIG. 13 is a perspective view showing an electrostatic chuck according to a third embodiment. FIG. 11 is a cross-sectional view showing an electrostatic chuck according to a third embodiment. FIG. 8 is a partially enlarged view of FIG. 7 . FIG. 11 is a partially enlarged plan view of the electrostatic chuck according to the third embodiment, viewed in a first direction. FIG. 13 is a cross-sectional view showing an electrostatic chuck according to a fourth embodiment. FIG. 13 is an enlarged view of the electrostatic chuck of the fourth embodiment when viewed in a plan view in a first direction.

[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 an object, that is, a semiconductor wafer W, will be described as an example. The electrostatic chuck 1 of this embodiment will be described with reference to FIGS. 1 to 3.

The electrostatic chuck 1 of this 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.

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).

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 of 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" of the present disclosure, and the lower surface 12 is an example of the "second surface" of the present disclosure. The first direction is the direction in which the lift pins 60 described later move.

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 preferably within a range of 10 to 50 W/mK (more preferably, 18 to 30 W/mK).

As shown in FIG. 1, the base member 20 is a cylindrical member. Specifically, the base member 20 has a stepped cylindrical shape in which two cylinders of different diameters are stacked on top of each other with a common central axis (more specifically, a cylindrical upper section with a smaller diameter is stacked on a cylindrical lower section with 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.

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 (the direction corresponding to 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" of the present disclosure, and the lower surface 22 is an example of a "fourth surface" of the present disclosure.

The diameter of the base member 20 is, for example, about 150 to 300 mm at the upper stage and about 180 to 350 mm at the lower stage. 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 preferably within the range of 180 to 250 W/mK (preferably about 230 W/mK).

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, the base member 20 is cooled by flowing the refrigerant through the refrigerant flow path of the base member 20, and the ceramic member 10 is cooled via the bonding layer 40.

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 silicone resin, acrylic resin, or 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.

The thickness of the bonding layer 40 (dimension in the first direction D1) 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 (assuming a silicone-based resin) is preferably in the range of 0.1 to 2.0 W/mK (preferably, 0.5 to 1.5 W/mK).

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 that penetrates the electrostatic chuck 1 in the first direction D1 (thickness direction). A lift pin 60 that pushes up the semiconductor wafer W from the suction surface 11 is inserted into this 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. This 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 (upper side in FIG. 2), the tip portion (upper end portion) of the lift pin 60 protrudes to the outside from the suction surface 11 of the ceramic member 10, so that the semiconductor wafer W placed on the suction surface 11 is separated from the suction surface 11 (the semiconductor wafer W is lifted by the lift pin 60).

In the electrostatic chuck 1 of this 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).

In this electrostatic chuck 1, an annular seal member 50 (e.g., an O-ring) is arranged 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, 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 Figures 2 and 3). This seal member 50 is intended to protect the bonding layer 40 and prevent corrosion of the bonding layer 40.

That is, when the electrostatic chuck 1 is used to fix a semiconductor wafer W in a vacuum chamber of a semiconductor manufacturing device, the process gas, plasma, etc. used to form 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 hermetically sealed, and the plasma, etc. that flows into the electrostatic chuck 1 through the first through hole 15 can be prevented from penetrating the bonding layer 40 through the intermediate through hole 45 and coming into contact with the bonding layer 40.

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."

Here, when the inner peripheral edge 51 of the seal member 50 is positioned inside (toward the center line CL) 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 positioned 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. If the lift pin 60 comes into contact with the seal member 50 and the seal member 50 is damaged, the corrosion of the bonding layer 40 cannot be appropriately prevented and particles may be generated.

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 Figures 2 and 3). That is, as shown in Figure 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.

The entirety of each of the sealing members 50 arranged in this manner is placed between the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20. This allows the sealing 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 evenly elastically deformed to be fixed, while ensuring a large contact surface (sealing surface) of the sealing member 50 with the lower surface 12 and upper surface 21. This improves the sealing (airtightness) between the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20, and reliably prevents leakage of plasma, which corrodes the bonding layer 40, into the bonding layer.

If the inner peripheral edge 51 of the sealing member 50 is positioned inside (radially inside) 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) and the lower surface 12 of the ceramic member 10, or the corner 27 between the peripheral surface 25b of the second through hole 25 (hole surface 25c that constitutes the second through hole 25) and the upper surface 21 of the base member 20, causing stress to concentrate in that part of the sealing member 50, which may cause cracks, etc.

Therefore, in the electrostatic chuck 1 of this embodiment, as described above, the seal member 50 is arranged so that its inner peripheral edge 51 is not positioned inside (radially inside) 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 prevents the seal member 50 from contacting the corner 17 between the peripheral surface 15b (hole configuration 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 configuration surface 25c constituting the second through hole 25) of the second through hole 25 of the base member 20 and the upper surface 21. Therefore, it is possible to prevent the above-mentioned cracks and the like from occurring in the seal member 50. In the electrostatic chuck 1 of this embodiment, only one seal member 50 is disposed in each intermediate through hole 45, so each seal member 50 becomes an "innermost seal member." This makes it possible to improve the durability of this innermost seal member.

However, the bonding layer 40 is not present at the location where the sealing member 50 is placed between the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20. In addition, in the electrostatic chuck 1 of this embodiment, the sealing member 50 (its constituent material) has a lower thermal conductivity than the bonding layer 40 (its constituent material). Therefore, the more sealing members 50 are placed in one intermediate through hole 45, the lower the thermal conductivity between the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20.

Therefore, in the electrostatic chuck 1 of this embodiment, only one seal member 50 is arranged 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 multiple seal members 50 are arranged in one intermediate through hole 45, and the bonding layer 40 can be arranged 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 on the suction surface 11 can be improved.

As described above, according to the electrostatic chuck 1 of this embodiment, one annular seal member 50 is disposed 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 pin 60 from contacting the seal member 50, and increases the thermal conduction around the lift pin insertion hole 35, thereby improving the thermal uniformity on the adsorption surface 11.

In addition, 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.

[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.

As shown in FIG. 4, the electrostatic chuck 101 of this 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.

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.

Here, the inner member 120A is fixed to the outer member 120B. In this embodiment, for example, a female screw hole 123 penetrating in the first direction D1 is formed in the outer member 120B. 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. On the other hand, 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 arranged in each of the three female screw holes 123. Therefore, the base member 120 in this embodiment is composed of one outer member 120B and three inner members 120A.

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. 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.

In the electrostatic chuck 101 of this embodiment, an annular seal member 50 is arranged 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 Figures 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 plasma, etc., 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.

Also, in the electrostatic chuck 101 of 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 125b of the second through hole 125 (see Figures 4 and 5). That is, as shown in Figure 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.

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 to fix the position of the outer member 120B relative to the ceramic member 10. Then, the inner member 120A is fixed to the outer member 120B so as to sandwich the seal member 50 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, by fixing the inner member 120A to the outer member 120B, the base member 120 is formed, and the seal member 50 can be arranged between the ceramic member 10 and the base member 120 (inner member 120A).

As a result, it becomes easier to place the seal member 50 in a predetermined position, and displacement of the seal member 50 can be suppressed. Since displacement of the seal member 50 is suppressed in this manner, the seal member 50 can be elastically deformed firmly, improving the sealability 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 and the like to the bonding layer 40.

As described above, the electrostatic chuck 101 of this embodiment can reliably prevent the lift pin 60 from coming into contact with the seal member 50, and the seal member 50 provides good sealing properties, more reliably preventing leakage of plasma and the like to the bonding layer 40.

[Third embodiment]
Next, a third embodiment will be described with reference to Figures 6 to 9. The third embodiment has the same basic configuration as the second embodiment, but the configuration of the ceramic members is different from that of the second embodiment. Therefore, the same components as those of the second embodiment are denoted by the same reference numerals and the description is omitted as appropriate, and the differences from the second embodiment will be mainly described.

As shown in Figs. 6 and 7, the electrostatic chuck 201 of this 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 the "first member" of the present disclosure, and the second ceramic member 220 is an example of the "second member" of the present disclosure.

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 the second ceramic member 220. In addition, the electrostatic chuck 201 also includes an annular seal member 50 disposed in each intermediate through-hole 45 in a manner that is sandwiched between the lower surface 222 of the second ceramic member 220 and the upper surface 121 of the base member 120 (specifically, the upper surface 127 of the inner member 120A) as in the second embodiment.

The first ceramic member 210 has a cylindrical first through hole 215 that penetrates 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 that penetrates 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.

The bonding layer 240 has a cylindrical intermediate through hole 245 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.

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

In each intermediate through hole 245, a ring-shaped seal member 250 (e.g., an O-ring) is arranged 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 exposed in the intermediate through hole 245 and the upper surface 221 of the second ceramic member 220, and prevents plasma, etc., that has flowed into the electrostatic chuck 201 through the first through hole 215 from penetrating into the bonding layer 240 and coming into contact with the bonding layer 240.

Also, in the electrostatic chuck 201 of this embodiment, each seal member 250 is arranged so 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 arranged in the intermediate through hole 245 of the bonding layer 240.

Furthermore, the sealing 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 the contact surface (sealing surface) of the sealing 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 secured large. 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 sealing member 250 arranged in the intermediate through hole 245 can reliably prevent plasma, etc. from entering the bonding layer 240 and coming into contact with the bonding layer 240.

As shown in FIG. 8, the electrostatic chuck 201 of this embodiment has 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, thereby heating the adsorption surface 211 of the first ceramic member 210 and the semiconductor wafer W held on the adsorption surface 211.

For example, when manufacturing a ceramic member having a heating resistor inside by pressing and firing multiple green sheets, a heating resistor of a predetermined pattern is formed in advance on the surface of the green sheet compression body, and another green sheet compression body is overlapped 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.

In contrast, in the electrostatic chuck 201 of this embodiment, during manufacturing, the temperature distribution can be adjusted while processing the heating resistor 270 so that the attraction 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 heated, 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 the desired temperature distribution (e.g., a substantially uniform temperature distribution across the entire upper surface 221).

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 the 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 the desired temperature distribution. Therefore, according to the electrostatic chuck 201 of this embodiment, the temperature controllability of the attraction surface 211 can be improved. In addition, 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, and is disposed in each intermediate through hole 245.

As described above, according to the electrostatic chuck 201 of this embodiment, the lift pin 60 can be reliably prevented from coming into contact with the sealing member 250, and the sealing member 250 can reliably prevent leakage of plasma and the like to the bonding layer 40. In addition, during manufacturing, the heating resistor 270 can be trimmed (shaved) so that the adsorption surface 211 has a desired temperature distribution, thereby improving the temperature controllability of the adsorption surface 211.

[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.

In the electrostatic chuck 301 of this embodiment, as shown in FIGS. 10 and 11, two seal members (seal member 50 and seal member 350) are arranged 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 in this embodiment differs from the bonding layer 40 in the first embodiment only in the diameter of the intermediate through hole. Specifically, the intermediate through hole 245 of the bonding layer 240 in this embodiment has a larger diameter than the intermediate through hole 45 of the bonding layer 40 in the first embodiment in order to arrange two seal members.

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

In this way, two seal members (seal member 50 and seal member 350) are arranged in one intermediate through hole 245, so that the airtightness between the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20 can be improved compared to the electrostatic chucks of other embodiments. This makes it possible to more reliably prevent plasma, etc., that has flowed into the electrostatic chuck 301 through the first through hole 15 from penetrating the intermediate through hole 245 and coming into contact with the bonding layer 240.

The seal member 50 (innermost seal member) that is disposed closest to the first through hole 15 and the second through hole 25 among the seal members 50 and 350 disposed in one intermediate through hole 245 is disposed so that its inner peripheral edge 51 is located outside the peripheral surfaces 15b and 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.

As described above, the electrostatic chuck 301 of this embodiment can reliably prevent the lift pin 60 from coming into contact with the seal member 50, which is the innermost seal member, and the double 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.

The above embodiments are merely examples and do not limit the present disclosure in any way. Needless to say, various improvements and modifications are possible without departing from the spirit of the present disclosure. For example, the above embodiments illustrate the application of the present disclosure 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.

In addition, in the above embodiment, an electrostatic chuck in which a seal 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 seal member 50 is placed in the countersunk hole.

In the second embodiment, the inner member 120A is fixed to the outer member 120B by forming a female screw hole 123 in the outer member 120B and a male screw 126 in the inner member 120A, and screwing the male screw 126 into the female screw of the female screw hole 123. However, the method of fixing the inner member 120A to the outer member 120B is not limited to this. For example, a flange with a through hole may be formed at the lower end of the inner member 120A, and a bolt hole (screw hole) may be formed on the lower surface of the outer member 120B, and the inner member 120A may be fixed to the outer member 120B with a bolt. Alternatively, the inner member 120A can be fixed to the outer member 120B using an adhesive.

In addition, in the above third embodiment, the base member 120 having the inner member 120A and the outer member 120B is exemplified as the base member, but the base member 20 similar to that of the first embodiment can also be used.

1 Electrostatic chuck 10 Ceramic member 11 Adsorption surface 12 Lower surface 15 First through hole 15b Circumferential surface 17 Corner 20 Base member 21 Upper surface 22 Lower surface 25 Second through hole 25b Circumferential surface 27 Corner 40 Bonding layer 50 Seal member 51 Inner peripheral edge 60 Lift pin 101 Electrostatic chuck 120 Base member 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 Circumferential surface 220 Second ceramic member 225 Second through hole 225b Circumferential surface 240 Bonding layer 250 Seal member 251 Inner peripheral edge 301 Electrostatic chuck 350 Seal member W Semiconductor wafer

Claims (6)

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. 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;
A holding device, wherein the seal member is disposed between the first member and the base member. 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;
A retaining device, wherein the seal member is disposed between the inner member and the first member. 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 2. The holding device according to claim 1,
A holding device, wherein the first member and the second member are both ceramic members. In any one of the holding devices according to claims 1 to 5,
A holding device, characterized in that one of the seal members is arranged for each of the first through hole and the second through hole.

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