JP2022178936A - holding device - Google Patents

Abstract

To provide a holding device capable of improving an insulation property.SOLUTION: An electrostatic chuck 1 holds a semiconductor wafer W on a holding surface 11 of a plate-like member 10, and comprises: the plate-like member 10 having a chuck electrode 50; a terminal pad 60 and a power feeding terminal 62 connected with the chuck electrode 50 and arranged on a lower surface 12; a base member 20 that has a through-hole 25 where the power feeding terminal 62 is arranged; and a bonding layer 40 arranged between the lower surface 12 of the plate-like member 10 and an upper surface 21 of the base member 20, bonding between the plate-like member 10 and the base member 20. The bonding layer 40 is formed with a bonding layer through-hole 45 communicating with the through-hole 25. An annular convex part 34 that protrudes from the lower surface 12 at least into the bonding layer through-hole 45 is formed around the terminal pad 60 and the power feeding terminal 62 integrally with the plate-like member 10.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a holding device for holding an object.

As a holding device, for example, an electrostatic chuck described in Patent Document 1 is known. This electrostatic chuck includes a ceramic substrate (first member) for holding a semiconductor wafer on its surface (holding surface), and a metal base member (second member) bonded to the ceramic substrate. Internal electrodes such as a chuck electrode and a heater electrode are arranged inside. In such an electrostatic chuck, a first terminal electrically connected to the internal electrode is arranged on the lower surface of the ceramic substrate as a configuration for supplying power to the internal electrode, and a first terminal is provided in a through hole formed in the base member. , a second terminal having one end connected to the external power supply and the other end connected to the first terminal. In order to insulate the base member from the first and second terminals, insulating tubes are arranged around the terminals. This insulating tube is joined to the electrostatic chuck with a resin adhesive.

JP 2010-103321 A

However, when the electrostatic chuck is used, the temperature of the electrostatic chuck rises/falls, and the resin adhesive may deteriorate. That is, when the temperature rises (when the temperature is high), the adhesive deteriorates due to the direct application of heat or the difference in thermal expansion, weakening the adhesiveness, creating a gap at the joint or damaging the adhesive itself. On the other hand, when the temperature drops (when the temperature is low), the adhesive itself becomes moist and hard, so it can no longer follow the difference in thermal expansion, weakening the adhesiveness and creating gaps at the joints. , the adhesive itself is damaged.

If the resin adhesive deteriorates and a gap is formed in the joint or the adhesive itself is damaged, the gap or damaged part becomes a leakage path, and the insulation between the terminal and the base member is destroyed, resulting in abnormal discharge. occurs. In recent years, the use of electrostatic chucks at high temperatures (250°C or higher) has increased, and resin adhesives are more likely to deteriorate. ing.

Accordingly, the present disclosure has been made to solve the above-described problems, and an object thereof is to provide a holding device capable of improving insulation.

One aspect of the present disclosure made to solve the above problems is
a first surface, a second surface provided opposite to the first surface in a thickness direction, and an internal electrode disposed between the first surface and the second surface a first member;
a terminal connected to the internal electrode and extending from the second surface in the thickness direction;
a third surface, a fourth surface provided opposite to the third surface, and a through hole penetrating through the third surface and the fourth surface and in which the terminal is arranged; a second member comprising
a bonding layer disposed between the second surface of the first member and the third surface of the second member and bonding the first member and the second member;
In a holding device that holds an object on the first surface of the first member,
A bonding layer through-hole communicating with the through-hole is formed in the bonding layer,
An annular projection projecting from the second surface at least into the bonding layer through-hole is formed around the terminal integrally with the first member.

In this holding device, the annular protrusion integrally formed on the second surface of the first member is arranged to protrude at least into the bonding layer through-hole. That is, the annular protrusion is arranged to cover at least part of the bonding layer from the second surface. As a result, the creepage distance between the terminal and the bonding layer (in the case of metal bonding material) or the second member (in the case of metal) becomes longer, so the terminal and the bonding layer (in the case of metal bonding material) or the second member ( If it is made of metal), it is possible to improve the insulation between.

In the holding device described above,
It is preferable that the bonding layer is formed of a bonding material containing a metal material as a main component.

In this way, when the bonding layer is composed of a bonding material (metal bonding material) containing a metal material as a main component, the creepage distance between the terminal and the bonding layer is the shortest. becomes more likely to occur.

Therefore, by providing the convex portion integrally formed on the second surface of the first member so as to cover at least a part of the bonding layer, the gap between the terminal and the bonding layer formed of the metal bonding material is reduced. Since the creepage distance is increased, the insulation between the terminal and the bonding layer formed of the metal bonding material can be improved.

In the holding device described above,
a concave portion for arranging the terminal is formed on the second surface,
It is preferable that the convex portion is formed such that the side surface of the concave portion and the inner peripheral surface of the convex portion are flush with each other.

Here, since heat transfer is not performed through the bonding layer in the through holes of the second member and the recesses of the first member, the first surface directly above the through holes of the second member and the recesses of the first member A temperature difference is more likely to occur in the vicinity than in other parts. Therefore, the temperature singularity tends to occur in the vicinity directly above the through hole of the second member and the concave portion of the first member.

Therefore, by providing the protrusions in this way, the sizes (diameters) of the recesses and the through holes can be made smaller than when the protrusions are provided inside the recesses. can be reduced and the heat uniformity at the first surface can be improved.

In the holding device described above,
A gap is preferably formed between the protrusion and the through hole.

If there is a difference in thermal expansion between the material forming the first member and the material forming the second member, when the temperature of the holding device rises/falls, the difference in thermal expansion causes the protrusion to expand to the second member. The protrusion may be damaged by contact with the

Therefore, by forming a gap between the protrusion and the second through hole, it is possible to reliably prevent damage to the protrusion. As a result, the convex portion can improve the insulation between the terminal and the bonding layer (in the case of metal bonding material) or the second member (in the case of metal).

Alternatively, in the holding device described above,
The convex portion and the bonding layer may be in contact with each other.

Here, since the through-holes of the second member do not conduct heat transfer with the first member via the bonding layer, on the first surface, the vicinity directly above the through-holes of the second member is temperature difference is likely to occur. Therefore, the temperature singularity tends to occur in the vicinity directly above the through-hole of the second member.

Therefore, by bringing the convex portion and the bonding layer into contact, heat transfer between the first member and the second member occurs via the bonding layer and the convex portion. Heat transfer is facilitated between the first member and the second member. Therefore, on the first surface, it is possible to suppress the occurrence of a temperature singularity in the vicinity directly above the through-hole of the second member.

ADVANTAGE OF THE INVENTION According to this indication, the holding|maintenance apparatus which can improve insulation can be provided.

1 is a schematic perspective view of an electrostatic chuck of an embodiment; FIG. It is a schematic block diagram of the XZ cross section of the electrostatic chuck of the embodiment. 1 is a schematic configuration diagram of an XY plane of an electrostatic chuck of an embodiment; FIG. It is a schematic block diagram of the XZ cross section near the terminal hole in the electrostatic chuck of the embodiment. FIG. 2 is a schematic configuration diagram of an XZ cross section near a terminal hole in the electrostatic chuck of the first embodiment; FIG. 11 is a schematic configuration diagram of an XZ cross section near a terminal hole in the electrostatic chuck of the second embodiment; FIG. 11 is a schematic configuration diagram of an XZ cross section near a terminal hole in the electrostatic chuck of the third embodiment; It is a schematic block diagram of the XZ cross section of terminal hole vicinity which shows a modification. It is a schematic block diagram of the XZ cross section of terminal hole vicinity which shows a modification. It is a schematic block diagram of the XZ cross section of terminal hole vicinity which shows a modification. It is a schematic block diagram of the XZ cross section of terminal hole vicinity which shows a modification. It is a schematic block diagram of the XZ cross section of the electrostatic chuck which shows a modification.

A holding device that is an embodiment according to the present disclosure will be described in detail with reference to the drawings. In this embodiment, as the holding device, for example, an electrostatic chuck used in a semiconductor manufacturing device such as a film forming device (CVD film forming device, sputtering film forming device, etc.) or an etching device (plasma etching device, etc.) is exemplified. explain.

Therefore, the electrostatic chuck 1 of this embodiment will be described with reference to FIGS. 1 to 4. FIG. The electrostatic chuck 1 of the present embodiment is a device that attracts and holds a semiconductor wafer W (object) by electrostatic attraction. be done. As shown in FIG. 1 , the electrostatic chuck 1 has a plate-like member 10 , a base member 20 , and a joining layer 40 that joins the plate-like member 10 and the base member 20 . The plate member 10 is an example of the "first member" of the present disclosure, and the base member 20 is an example of the "second member" of the present disclosure.

In the following description, the XYZ axes are defined as shown in FIG. 1 for convenience of explanation. Here, the Z-axis is the axis in the axial direction of the electrostatic chuck 1 (vertical direction in FIG. 1), and the X-axis and the Y-axis are the radial axes of the electrostatic chuck 1 .

As shown in FIG. 1, the plate-like member 10 is a disk-like member made of ceramics. Various ceramics are used as ceramics, but from the viewpoint of strength, wear resistance, plasma resistance, etc., for example, ceramics containing aluminum oxide (alumina, Al ₂ O ₃ ) or aluminum nitride (AlN) as a main component is preferably used. The term "main component" as used herein means a component with the highest content (for example, a component with a volume content of 90 vol % or more). The diameter of the plate member 10 is, for example, about 150 to 350 mm, and the thickness of the plate member 10 is, for example, about 2 to 6 mm.

As shown in FIGS. 1 and 2, the plate-like member 10 has a holding surface 11 for holding the semiconductor wafer W, and a holding surface 11 in the thickness direction of the plate-like member 10 (the direction coinciding with the Z-axis direction, the vertical direction). and a lower surface 12 provided on the opposite side. A semiconductor wafer W is held on this holding surface 11 . Note that the holding 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.

A holding surface 11 of the plate member 10 has an uneven shape. Specifically, as shown in FIGS. 2 and 3, the holding surface 11 is formed with an annular convex seal band 16 near its outer edge, and a plurality of independent columnar convex portions are formed inside the seal band 16. 17 is formed. The shape of the cross section (XZ cross section) of the seal band 16 is substantially rectangular as shown in FIG. The height (dimension in the Z-axis direction) of the seal band 16 is, for example, about 10 μm to 20 μm. The width (dimension in the X-axis direction) of the seal band 16 is, for example, approximately 0.5 mm to 5.0 mm.

As shown in FIG. 3, each convex portion 17 has a substantially circular shape when viewed in the Z-axis direction (planar view), and is arranged at substantially equal intervals. Moreover, the shape of the cross section (XZ cross section) of each convex portion 17 is substantially rectangular as shown in FIG. The height of the protrusion 17 is substantially the same as the height of the seal band 16, and is, for example, about 10 to 20 μm. Further, the width of the convex portion 17 (maximum diameter of the convex portion 17 when viewed in the Z-axis direction) is, for example, approximately 0.5 to 1.5 mm. A portion of the holding surface 11 of the plate-like member 10 inside the seal band 16 where the convex portion 17 is not formed serves as a concave portion 18 .

The semiconductor wafer W is held by the electrostatic chuck 1 by being supported by the seal band 16 and the plurality of projections 17 on the holding surface 11 of the plate member 10 . When the semiconductor wafer W is held by the electrostatic chuck 1, between the surface (lower surface) of the semiconductor wafer W and the holding surface 11 of the plate member 10 (more specifically, the recess 18 of the holding surface 11), There will be a space S (see FIG. 2). An inert gas (for example, helium gas) is supplied to the space S through a gas hole 30b penetrating the electrostatic chuck 1 .

Further, as shown in FIG. 2, the plate-like member 10 has a chuck electrode 50 therein. The chuck electrode 50 has, for example, a substantially circular shape when viewed in the Z-axis direction, and is made of a conductive material (eg, tungsten, molybdenum, etc.). The chuck electrode 50 is an example of the "internal electrode" of the present disclosure. A via 61 is connected to the chuck electrode 50 . The via 61 is arranged to extend in the Z-axis direction from the chuck electrode 50 toward the lower surface 12 side.

A bottomed hole 15 is formed in the lower surface 12 of the plate member 10 . The bottomed hole 15 is a circular recess, and when viewed in the Z-axis direction, a region overlapping a through hole 25 of the base member 20 described later has a shape recessed toward the holding surface 11 side. Also, the diameter of the bottomed hole 15 is, for example, 7 to 8 mm. A terminal pad 60 is arranged on the bottom portion 15 b of the bottomed hole 15 . The shape of the terminal pad 60 as viewed in the Z-axis direction is, for example, substantially circular. Note that the bottomed hole 15 is an example of the "recess" in the present disclosure.

The other end of via 61 connected to chuck electrode 50 is connected to the upper surface of terminal pad 60 . Thereby, the terminal pad 60 is electrically connected to the chuck electrode 50 through the via 61 . Terminal pads 60 and vias 61 are made of a conductive material (eg, tungsten, molybdenum, etc.). In this embodiment, as shown in FIG. 2, the terminal pads 60 are exposed entirely from the plate-like member 10 in the thickness direction (Z-axis direction), but the lower surfaces of the terminal pads 60 are exposed from the plate-like member. A part or the whole of the terminal pad 60 in the thickness direction may be embedded in the plate member 10 as long as it is exposed from the plate member 10 . A power supply terminal 62 for connecting to an external power supply is joined (brazed) to the lower surface (exposed surface) of the terminal pad 60 . Power is supplied to the chuck electrode 50 . The terminal pad 60 and the power supply terminal 62 are examples of the "terminal" of the present disclosure, and the outer peripheral portion of the power supply terminal 62 is covered with an insulating member.

Further, as shown in FIG. 2, on the lower surface 12 of the plate member 10, an annular projection 34 projecting in the Z-axis direction surrounds the terminal pad 60 and the power supply terminal 62 so as to surround the bottomed hole 15. is provided. The annular projection 34 is made of ceramics like the plate-like member 10 and is integrally formed with the plate-like member 10 . That is, the annular convex portion 34 may be formed integrally with the plate-like member 10 by firing at the same time, or may be formed integrally with the plate-like member 10 by diffusion bonding. Alternatively, after manufacturing the thick plate-like member 10, the annular projection 34 may be formed by machining such as polishing (parts other than the annular projection 34 are scraped off). The inner diameter of the annular protrusion 34 and the inner diameter of the bottomed hole 15 are the same, and the annular protrusion 34 is coaxial with the bottomed hole 15 . That is, the side surface of the bottomed hole 15 and the inner peripheral surface of the annular protrusion 34 are flush with each other.

By doing so, the sizes (diameters) of the bottomed hole 15 and the through hole 25 can be made smaller than when the annular projection 34 is provided in the bottomed hole 15 . Here, since the through holes 25 of the base member 20 and the bottomed holes 15 of the plate-like member 10 do not conduct heat transfer via the bonding layer 40 , the through holes 25 and the bottomed holes 15 of the holding surface 11 are A temperature difference is more likely to occur in the vicinity directly above than in other portions, and the vicinity directly above the through hole 25 and the bottomed hole 15 tends to be a temperature singular point. Therefore, by reducing the sizes (diameters) of the bottomed holes 15 and the through-holes 25 in this way, it is possible to reduce the areas that tend to become temperature singularities, thereby improving the uniformity of heat on the holding surface 11. can be done.

Here, the annular protrusion 34 may extend in the Z-axis direction so as to cover at least a portion of the bonding layer 40 . In other words, it is sufficient that the tip of the annular projection 34 is arranged in a bonding layer through-hole 45 of the bonding layer 40 described later. In this embodiment, the annular protrusion 34 protrudes halfway through the through-hole 25 of the base member 20 (to a depth of about ⅕ of the hole). The length (Z-axis direction dimension) of the annular protrusion 34 is preferably, for example, 3 mm (the length at which the tip of the annular protrusion 34 is positioned within the through hole 25) or more. This is because the annular convex portion 34 is arranged over the entire bonding layer through-hole 45 so as to cover the bonding layer 40 .

As shown in FIG. 1, the base member 20 has a cylindrical shape, more specifically, two cylinders having different diameters, and a cylindrical upper surface portion having a large diameter and a cylindrical lower surface portion having a small diameter placed thereon. , and a stepped cylindrical shape formed by overlapping with a common central axis Ca. The base member 20 may be made of metal (eg, aluminum, aluminum alloy, etc.), or may be made of materials other than metal (eg, ceramics, etc.).

As shown in FIGS. 1 and 2, the base member 20 has an upper surface 21 and a central axis Ca (see FIG. 2) of the base member 20 (plate-like member 10) (that is, the Z-axis direction). and a lower surface 22 provided on the opposite side. Note that the upper surface 21 is an example of the "third surface" of the present disclosure, and the lower surface 22 is an example of the "fourth surface" of the present disclosure.

The diameter of the base member 20 is, for example, about 150 mm to 300 mm at the upper portion and about 180 mm to 350 mm at the lower portion. Also, the thickness (dimension in the Z-axis direction) of the base member 20 is, for example, about 20 mm to 50 mm.

Further, as shown in FIG. 2, the base member 20 is formed with a coolant channel 23 for flowing a coolant (for example, fluorine-based inert liquid, water, etc.). The coolant channel 23 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 coolant supplied to the base member 20 from the supply port flows into the coolant channel 23 . It flows inside and is discharged to the outside of the base member 20 through the discharge port. In this manner, the base member 20 is cooled by causing the coolant to flow through the coolant passages 23 of the base member 20 , thereby cooling the plate-like member 10 via the joining layer 40 .

A cylindrical through-hole 25 is formed in the base member 20 so as to penetrate between the upper surface 21 and the lower surface 22 in the thickness direction (Z-axis direction, vertical direction in FIG. 2). The feed terminal 62 and the annular protrusion 34 are arranged in the through hole 25 . A gap 35 (see FIG. 4) is formed between the annular protrusion 34 and the through hole 25 .

The joining layer 40 is arranged between the lower surface 12 of the plate member 10 and the upper surface 21 of the base member 20 to join the plate member 10 and the base member 20 together. The bonding layer 40 thermally connects the bottom surface 12 of the plate member 10 and the top surface 21 of the base member 20 . The thickness (dimension in the Z-axis direction) of the bonding layer 40 is, for example, approximately 0.1 to 1.0 mm.

The bonding layer 40 is made of, for example, a resin bonding material such as a silicone resin, an acrylic resin, or an epoxy resin, or a metal bonding material whose main component is a metal material. Generally, a resin adhesive is often used as the bonding layer 40 , but when the electrostatic chuck 1 is used at high temperatures (for example, 250° C. or higher), the resin adhesive does not have sufficient heat resistance. A metal bonding material is used because there is a risk of poor bonding. As the metal bonding material, for example, a metal adhesive that bonds using metal powder or metal foil, a metal mesh such as metal fiber, a porous material, or a mesh structure and a brazing material, or a plurality of A columnar metal piece and brazing material can be used. Titanium, nickel, aluminum, copper, brass, alloys thereof, stainless steel, or the like can be used as the metal forming the metal adhesive, metal mesh, or metal piece.

As shown in FIG. 2, the bonding layer 40 is formed with a bonding layer through-hole 45 in which the annular protrusion 34 is arranged. That is, a cylindrical bonding layer through-hole 45 is formed between the bottomed hole 15 and the through-hole 25 . The bonding layer through-hole 45 is coaxial with the bottomed hole 15 and the through-hole 25, and the bottomed hole 15, the bonding layer through-hole 45, and the through-hole 25 extend in the Z-axis direction (the axial direction of the electrostatic chuck 1). A terminal hole 65 is formed in which the terminal pad 60 and the power supply terminal 62 are arranged in a row.

Here, the configuration inside the terminal hole 65 will be described with reference to FIG. As shown in FIG. 4, the terminal pad 60 and the power supply terminal 62 are arranged in the terminal hole 65, and the annular convex portion 34 integrally formed with the plate member 10 is arranged around them. The annular protrusion 34 extends from the lower surface 12 of the plate member 10 toward the lower surface 22 of the base member 20 , and its tip is positioned within the through hole 25 formed in the base member 20 . Note that, in the present embodiment, the annular convex portion 34 extends to a depth position of about ⅕ of the through hole 25 . As a result, the inner peripheral surface of the bonding layer through-hole 45 of the bonding layer 40 is covered with the annular protrusion 34 . A gap 35 is formed between the annular projection 34 and the through hole 25 .

In the electrostatic chuck 1, as shown in FIG. 3, lift pin insertion holes 30a in which lift pins for pushing up the semiconductor wafer W from the holding surface 11 are arranged, and recesses 18 are formed from the lower surface 22 side of the base member 20. Through-holes passing through the electrostatic chuck 1, such as gas holes 30b for supplying an inert gas to the space S, are formed. In the following description, the lift pin insertion holes 30a and the gas holes 30b may be simply referred to as "through holes 30".

As such an electrostatic chuck 1, the following three examples (first to third examples) can be given depending on the combination of materials forming the base member 20 and the bonding layer 40. FIG.

<First embodiment>
First, the first embodiment will be described. In the first embodiment, the base member 20 is made of ceramics, and the joining layer 40 is made of a metal joining material. That is, in the electrostatic chuck 1 of the first embodiment, as shown in FIG. 5, the plate member 10 made of ceramics and the base member 20a made of ceramics are joined by a joining layer 40a made of a metal joining material. ing.

Such an electrostatic chuck 1 of the first embodiment is suitable for use at a high temperature (for example, 250° C. or higher) at which a resin adhesive is insufficient in heat resistance to cause poor bonding. In the first embodiment, since the bonding layer 40a is made of a metal bonding material, the creepage distance from the terminal pad 60 is very small.

Here, when used at high temperatures, it is difficult to place an insulating tube around the terminals and bond the insulating tube to the electrostatic chuck with a resin adhesive, as with conventional electrostatic chucks. decreases. This is because the resin adhesive deteriorates under high temperature, so that a gap is formed in the joint portion or the adhesive itself is damaged, and the gap or the damaged portion becomes a leak path. If a leak path is formed, the insulation between the terminal pad 60 and the bonding layer 40a is destroyed, resulting in abnormal discharge.

Therefore, in the electrostatic chuck 1 of the first embodiment, an annular projection integrally formed with the terminal plate member 10 is formed on the lower surface 12 of the plate member 10 so as to surround the opening of the bottomed hole 15 (the terminal pad 60). A portion 34 is provided. The annular convex portion 34 is provided to a depth position of about 1/5 of the through hole 25, and completely covers the bonding layer 40a. Therefore, the annular protrusion 34 can increase the creepage distance between the terminal pad 60 and the bonding layer 40a. As a result, the withstand voltage between the terminal pad 60 and the bonding layer 40a is improved, so that the insulation between the terminal pad 60 and the bonding layer 40a can be improved.

In the electrostatic chuck 1 of the first embodiment, since the gap 35 is provided between the annular projection 34 and the through hole 25, the creeping distance between the terminal pad 60 and the bonding layer 40a can be further increased. can. Thereby, the insulation between the terminal pad 60 and the bonding layer 40a can be further enhanced. Since there is almost no difference in thermal expansion between the plate-shaped member 10 and the base member 20b, the gap 35 of about 0.5 mm (clearance required for manufacturing) is sufficient, for example.

<Second embodiment>
Next, a second embodiment will be described. In the second embodiment, the base member 20 is made of metal, and the joining layer 40 is made of a metal joining material. That is, in the electrostatic chuck 1 of the second embodiment, as shown in FIG. 6, the plate member 10 made of ceramics and the base member 20b made of metal are joined by a joining layer 40a made of a metal joining material. ing.

Like the first embodiment, the electrostatic chuck 1 of the second embodiment is also suitable for use at high temperatures (e.g., 250° C. or higher) where the heat resistance of the resin adhesive is insufficient. Also in the second embodiment, since the bonding layer 40a made of a metal bonding material is used, the creepage distance from the terminal pad 60 is very small.

However, even in the electrostatic chuck 1 of the second embodiment, the annular convex portion 34 integrally formed with the plate-like member 10 is provided on the lower surface 12 of the plate-like member 10 so as to surround the opening of the bottomed hole 15 . there is Therefore, the annular protrusion 34 can increase the creepage distance between the terminal pad 60 and the bonding layer 40a. This improves the withstand voltage between the terminal pad 60 and the bonding layer 40a, thereby preventing abnormal discharge from occurring between the terminal pad 60 and the bonding layer 40a. In addition, in the second embodiment, the length (Z-axis direction dimension) of the annular projection 34 is the same as in the first embodiment.

In the electrostatic chuck 1 of the second embodiment, there is a difference in thermal expansion between the plate member 10 and the base member 20b. As a result, the annular convex portion 34 contacts the base member 20b, and the annular convex portion 34 may be damaged, and the damaged portion may become a leak path.

Therefore, a gap 35 is formed between the annular protrusion 34 and the through hole 25 . The gap 35 is larger than that of the first embodiment, and is set to such an extent that the annular projection 34 does not come into contact with the base member 20b due to the difference in thermal expansion between the plate member 10 and the base member 20b (for example, about 0.5 mm). do it. By providing such a gap 35, damage to the annular projection 34 can be reliably prevented. As a result, the annular protrusion 34 can ensure insulation between the terminal pad 60 and the base member 20b.

<Third embodiment>
Finally, a third embodiment will be described. In the third embodiment, the base member 20 is made of metal, and the joining layer 40 is made of a resin adhesive. That is, in the electrostatic chuck 1 of the third embodiment, as shown in FIG. 7, the plate member 10 made of ceramics and the base member 20b made of metal are joined by a joining layer 40b made of a resin adhesive. ing.

In such an electrostatic chuck 1 of the third embodiment, it is necessary to ensure insulation between the terminal pads 60 and the base member 20a. Therefore, in a conventional electrostatic chuck, an insulating tube is arranged around the terminals, and the insulating tube is joined to the electrostatic chuck with a resin adhesive. However, even if the electrostatic chuck is not used at a high temperature, the temperature of the electrostatic chuck rises and falls during use. The adhesive itself can be damaged. Then, the gap or damaged portion becomes a leak path, and the insulation between the terminal and the base member is destroyed, resulting in abnormal discharge.

Therefore, in the electrostatic chuck 1 of the third embodiment as well, the lower surface 12 of the plate-like member 10 is provided with an annular convex portion 34 integrally formed with the plate-like member 10 so as to surround the opening of the bottomed hole 15 . there is Thereby, the annular protrusion 34 can increase the creeping distance between the terminal pad 60 and the base member 20b. Therefore, since the withstand voltage between the terminal pad 60 and the base member 20b is improved, the insulation between the terminal pad 60 and the base member 20b can be improved.

Also in the third embodiment, as in the second embodiment, there is a difference in thermal expansion between the plate member 10 and the base member 20b. A gap 35 having the same size as the example (for example, about 0.5 mm) is provided. As a result, damage to the annular protrusion 34 can be reliably prevented, and the annular protrusion 34 can ensure insulation between the terminal pad 60 and the base member 20b.

<Modification>
Next, a modified example will be described with reference to FIG. The modified example has the same basic structure as the above embodiment, but the diameter of the bonding layer through hole 45 of the bonding layer 40 is smaller than that of the above embodiment. That is, in the modified example, as shown in FIG. 8, (the outer peripheral surface of) the annular convex portion 34 and the bonding layer 40 (the inner peripheral surface of the bonding layer through hole 45) are in contact with each other.

Here, the bottomed hole 15 does not conduct heat transfer with the base member 20 via the bonding layer 40 . Therefore, the vicinity of the bottomed hole 15 in the holding surface 11 of the plate-like member 10 has a locally larger temperature difference than other portions, and tends to become a temperature singular point.

Therefore, by bringing the annular projection 34 protruding so as to surround the opening of the bottomed hole 15 into contact with the bonding layer 40 , the heat transfer between the plate-like member 10 and the base member 20 can be controlled by the bonding layer 40 . It arises via an annular projection 34 . This promotes heat transfer in the vicinity of the bottomed hole 15 . Therefore, it is possible to suppress the occurrence of a temperature singularity in the vicinity of the bottomed hole 15 on the holding surface 11 , and to ensure uniform heating on the holding surface 11 .

As described above, according to the electrostatic chuck 1 of the present embodiment, on the bottom surface 12 of the plate-like member 10 , the terminal pads 60 and the power supply terminals 62 are surrounded around the bottomed holes 15 so as to be integrated with the plate-like member 10 . An annular convex portion 34 is formed to cover the bonding layer 40 . Therefore, the annular protrusion 34 can increase the creepage distance between the terminal pad 60 and the bonding layer 40a (Examples 1 and 2) or the base member 20b (Examples 1 and 3).

This can prevent the occurrence of abnormal discharge between the terminal pad 60 and the bonding layer 40a (Examples 1 and 2) or the base member 20b (Examples 1 and 3). Therefore, the insulation around the terminals of the electrostatic chuck 1 can be improved.

It should be noted that the above-described embodiment is merely an example and does not limit the present disclosure in any way, and of course various improvements and modifications are possible without departing from the gist of the present disclosure. For example, in the above embodiment, the chuck electrode 50 is exemplified as the internal electrode, but the internal electrode is not limited to the chuck electrode 50, and may be a high-frequency electrode, a heater electrode, or the like. However, it is preferable to apply the present disclosure to the terminal portion connected to the chuck electrode 50 to which the highest voltage is applied among the internal electrodes.

In the above embodiment, the terminal pad 60 is directly connected to the chuck electrode 50 (internal electrode) by the via 61. may be electrically connected via connection pads 66, as shown in FIG. Specifically, the terminal pad 60 and the connection pad 66 are connected by the via 61a, and the connection pad 66 and the chuck electrode 50 are connected by the via 61b, so that the terminal pad 60 becomes the chuck electrode 50 (internal electrode). They may be electrically connected.

Further, in the above-described embodiment, the annular protrusion 34 is provided halfway through the through hole 25, but as shown in FIG. The lower surface 22 may be provided so as not to protrude from the base member 20). As a result, the insulation around the terminals of the electrostatic chuck 1 can be improved without providing an insulating member around the outer peripheral portion of the power supply terminal 62 . If the annular projection 34 is provided over the entire area of the through-hole 25 , the annular projection 34 becomes long and may be damaged during manufacturing of the electrostatic chuck 1 . Therefore, instead of providing the annular protrusion 34 over the entire area of the through hole 25, as shown in FIG. can also As a result, it is possible to improve the insulation around the terminals of the electrostatic chuck 1 while preventing the annular projection 34 from being damaged during manufacturing.

Further, in the above-described embodiment, the annular convex portion 34 extends to the base member 20 (inside the second through hole). In other words, the above effect can be obtained even when the tip of the annular protrusion 34 is positioned within the bonding layer through-hole 45 .

Further, the tip corner portion of the annular protrusion 34 may be rounded or tapered, or the annular protrusion 34 may be provided with a step (by changing the thickness of the annular protrusion 34). By doing so, the creepage distance between the terminal pad 60 and the bonding layer 40a or the base member 20b made of metal can be further increased.

Furthermore, in the above embodiment, the terminal hole 65 is provided with the annular projection 34, but as shown in FIG. 34 may be provided. As a result, the insulation between the semiconductor wafer W and the bonding layer 40a made of metal or the base member 20b can be improved.

1 electrostatic chuck 10 plate member 11 holding surface 12 lower surface 15 bottomed hole 20 base member 21 upper surface 22 lower surface 25 through hole 30 through hole 34 annular projection 35 gap 40 bonding layer 45 bonding layer through hole 50 chuck electrode 60 terminal pad 62 power supply terminal W semiconductor wafer

Claims (5)

a first member having a first surface, a second surface provided opposite to the first surface, and an internal electrode disposed between the first surface and the second surface; ,
a terminal connected to the internal electrode and arranged on the second surface;
a third surface, a fourth surface provided opposite to the third surface, and a through hole penetrating through the third surface and the fourth surface and in which the terminal is arranged; a second member comprising
a bonding layer disposed between the second surface of the first member and the third surface of the second member and bonding the first member and the second member;
In a holding device that holds an object on the first surface of the first member,
A bonding layer through-hole communicating with the through-hole is formed in the bonding layer,
A holding device according to claim 1, wherein an annular projection projecting from the second surface into at least the bonding layer through-hole is formed integrally with the first member around the terminal. A holding device according to claim 1,
The holding device, wherein the bonding layer is formed of a bonding material containing a metal material as a main component. In the holding device according to claim 1 or claim 2,
a concave portion for arranging the terminal is formed on the second surface,
The holding device, wherein the protrusion is formed so that the side surface of the recess and the inner peripheral surface of the protrusion are flush with each other. In any one holding device according to claims 1 to 3,
A holding device, wherein a gap is formed between the projection and the through hole. In any one holding device according to claims 1 to 3,
A holding device, wherein the protrusion and the bonding layer are in contact with each other.

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