JP2022076653A - Holding device - Google Patents

Abstract

To provide a holding device capable of increasing a creepage distance from a terminal pad to a base member to improve the insulating property between the terminal pad and the base member and also improving the heat equalizing property on the holding surface.SOLUTION: In an electrostatic chuck 1 that holds a semiconductor wafer W on a holding surface 11 of a plate-shaped member 10, a lower surface 12 of the plate-shaped member 10 is recessed on the holding surface 11 side and has a bottomed hole 15 in which a terminal pad 30 is arranged, and a bottom portion 15b or an inner peripheral surface 15a of the bottomed hole 15 has a cavity portion 16 extending outward from the inner peripheral surface 15a of the bottomed hole 15 in the radial direction orthogonal to the Z-axis direction.SELECTED DRAWING: Figure 3

Description

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

As the holding device, for example, the electrostatic chuck described in Patent Document 1 is known. This electrostatic chuck includes a ceramic plate (plate-shaped member) that holds an object on its surface (holding surface) and a metal base member joined to the ceramic plate. The chuck is inside the ceramic plate. Internal electrodes such as electrodes and heater electrodes are arranged. The electrostatic chuck is provided with a configuration for supplying power to the internal electrodes. That is, a terminal through hole is formed inside the base member to open on the surface of the base member facing the ceramic plate (hereinafter referred to as "upper surface"), and a columnar electrode terminal is formed in the terminal through hole. Have been placed. Further, an electrode pad (terminal pad) conducting to the internal electrode is arranged in a predetermined region in the surface of the ceramic plate facing the base member (hereinafter referred to as “lower surface”).

Here, if the creepage distance from the electrode pad to the base member is short along the lower surface of the ceramic plate, a short circuit may occur between the electrode pad and the base member. Therefore, in order to increase the creepage distance, in this electrostatic chuck, the first region (penetration for terminals when viewed from the thickness direction of the ceramic plate) on the second surface (the surface on the side facing the base member) of the ceramic plate is penetrated. In the area overlapping the holes), a concave portion recessed toward the internal electrode side from the position where the electrode pad is arranged in the thickness direction, and a convex portion protruding toward the side away from the internal electrode from the position where the electrode pad is arranged in the thickness direction. At least one of the above is continuously formed so as to surround the electrode pad when viewed from the thickness direction. As a result, in this electrostatic chuck, the creepage distance from the electrode pad to the base member is lengthened along the second surface of the ceramic plate, and the occurrence of a short circuit between the electrode pad and the base member is suppressed. I am doing it.

Japanese Unexamined Patent Publication No. 2018-101711

However, in the above electrostatic chuck, the thickness of the ceramic plate is reduced in the portion where the recess is formed, so that when the internal electrode is arranged near the recess, the distance between the bottom of the hole and the internal electrode becomes short. Dielectric breakdown may occur. Further, in the portion where the recess is formed, the volume of the ceramic plate is reduced, so that heat transfer is deteriorated, and the portion directly above the recess is locally heated on the holding surface, so that the temperature of the holding surface is uniformly controlled. This becomes difficult, and the heat soaking property on the holding surface may decrease.

Therefore, the present disclosure has been made in order to solve the above-mentioned problems, and the creepage distance from the terminal pad to the base member is increased to improve the insulating property between the terminal pad and the base member. It is an object of the present invention to provide a holding device capable of improving heat soaking property on a holding surface.

A form of this disclosure made to solve the above problems is
A first surface, a second surface provided on the side opposite to the first surface in the first direction, an internal electrode provided inside, and a terminal electrically connected to the internal electrode. A plate-shaped member with a pad and
The electrode terminals joined to the terminal pad and
An insulating member that covers the outer peripheral surface of the electrode terminal and
It has a through hole in which the electrode terminal and the insulating member are arranged, and has a metal base member joined to the second surface of the plate-shaped member.
In a holding device that holds an object on the first surface of the plate-shaped member,
The second surface of the plate-shaped member is recessed on the first surface side, and a bottomed hole in which the terminal pad is arranged is formed.
The bottom of the bottomed hole or the side surface of the opening is characterized in that a cavity extending outward from the side surface of the opening of the bottomed hole is formed in a second direction orthogonal to the first direction. And.

In this holding device, the side surface of the opening of the bottomed hole (in the radial direction) orthogonal to the first direction (axial direction) on the bottom surface or the side surface of the opening of the bottomed hole in which the terminal pad is arranged. That is, since the cavity portion extending outward from the inner peripheral surface) is formed, the creepage distance from the terminal pad to the base member can be lengthened. Therefore, the insulating property between the terminal pad and the base member can be improved.

Further, since the cavity portion is formed so as to expand outward in the second direction (diameter direction), the thickness of the plate-shaped member does not decrease in the bottomed hole arrangement region as in the conventional apparatus. Therefore, dielectric breakdown occurs between the internal electrode (which is arranged closest to the terminal pad and is a land pattern for supplying the electrode to the heater electrode or the heater electrode, such as a conductive layer) and the terminal pad. It can be prevented from occurring.

Here, on the first surface (holding surface), the volume of the bottomed hole arrangement region (position directly above the bottomed hole) is smaller than that of the other regions, so that the temperature tends to be high. Then, when the thickness (volume) of the plate-shaped member decreases in the bottomed hole arrangement region as in the conventional device, the temperature singularity that becomes locally high in the bottomed hole arrangement region on the first surface becomes extremely high. Is more likely to occur.

On the other hand, in this holding device, since the cavity is formed so as to expand outward in the second direction (diameter direction), the thickness (volume) of the plate-shaped member decreases in the arrangement region of the bottomed hole. There is nothing to do. Therefore, in the area where the bottomed hole is arranged, the deterioration of heat transfer due to the volume reduction of the plate-shaped member does not occur. Therefore, it is possible to suppress the generation of a temperature singularity that becomes locally high on the first surface (holding surface), and it is possible to improve the heat equalization property on the first surface.

In the above-mentioned holding device,
The maximum dimension of the cavity in the first direction is preferably ½ or less of the dimension of the bottomed hole in the first direction.

Here, if the maximum dimension of the cavity in the first direction (axial direction) is increased, the creepage distance from the terminal pad to the base member can be increased, but the volume of the plate-shaped member around the bottomed hole is reduced. Becomes larger. If the volume reduction of the plate-shaped member becomes large around the bottomed hole, heat transfer deteriorates, so that a temperature singular point that becomes locally high is generated on the first surface (holding surface). There is a risk.

Therefore, by defining the maximum dimension of the cavity in the first direction in this way, the required creepage distance (which does not cause a short circuit) is secured, and the volume reduction of the plate-shaped member around the bottomed hole is suppressed. As a result, it is possible to prevent the occurrence of a temperature singularity that becomes locally high in the vicinity of the bottomed hole, and it is possible to improve the heat soaking property on the first surface.

In the above-mentioned holding device,
It is preferable that the cavity portion includes a surface on which the terminal pad is arranged in the first direction.

By forming the cavity at the bottom of the bottomed hole in this way, the creepage distance from the terminal pad to reaching the side surface of the opening is longer than when the cavity is formed on the side surface of the opening of the bottomed hole. , The insulation between the terminal pad and the base member can be further improved.

In the above-mentioned holding device,
It is preferable that the cavity portion has a tapered portion whose dimension in the second direction gradually increases toward the bottom portion from the opening of the bottomed hole.

By doing so, the volume reduction of the plate-shaped member around the bottomed hole can be further suppressed, and the temperature gradient becomes gentle. It can be prevented and the heat soaking property on the first surface can be further improved.

Further, when the bottomed hole and the cavity are filled with an adhesive (silicone resin or the like), the adhesive can be smoothly filled in the cavity without any gap. As a result, the thermal conductivity of the cavity can be increased, so that it is possible to more reliably prevent the occurrence of temperature singular points that become locally hot around the bottomed hole. It is possible to effectively suppress the decrease in heat soaking property in the surface 1.

According to the present disclosure, a holding device capable of increasing the creepage distance from the terminal pad to the base member to improve the insulating property between the terminal pad and the base member and improving the heat equalizing property on the holding surface is provided. Can be provided.

It is a schematic perspective view of the electrostatic chuck of 1st Embodiment. It is a schematic block diagram of the XZ cross section of the electrostatic chuck of 1st Embodiment. It is an enlarged view of the vicinity of the cavity portion (X1 portion of FIG. 2). It is an enlarged view near the cavity part in the electrostatic chuck provided with a conductive layer. It is an enlarged view near the cavity part in the electrostatic chuck of 2nd Embodiment.

[First Embodiment]
The holding device according to the present disclosure will be described in detail with reference to the drawings. In the present embodiment, the electrostatic chuck 1 that holds the semiconductor wafer W, which is an object, will be illustrated and described. The electrostatic chuck 1 of the present embodiment will be described with reference to FIGS. 1 to 3.

The electrostatic chuck 1 of the present embodiment is a device that attracts and holds a semiconductor wafer W (object) by electrostatic attraction, and is used, for example, for fixing the semiconductor wafer W in a vacuum chamber of a semiconductor manufacturing apparatus. Will be done. As shown in FIG. 1, the electrostatic chuck 1 has a plate-shaped member 10, a base member 20, and a joining layer 40 for joining the plate-shaped member 10 and the base member 20.

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

As shown in FIG. 1, the plate-shaped member 10 is a disk-shaped member, and ceramics may be used as the material. Various ceramics are used as the ceramics, but from the viewpoint of strength, wear resistance, plasma resistance, etc., for example, ceramics containing aluminum oxide (alumina _{, Al2O3} ) or aluminum nitride (AlN) as a main component. Is preferably used. The main component referred to here means a component having the highest content ratio (for example, a component having a volume content of 90 vol% or more).

The diameter of the plate-shaped member 10 is, for example, about 150 to 300 mm in the upper part and about 180 to 350 mm in the lower part. The thickness of the plate-shaped member 10 is, for example, about 2 to 6 mm. The thermal conductivity of the plate-shaped member 10 is preferably in the range of 10 to 50 W / mK (more preferably, 18 to 30 W / mK).

As shown in FIGS. 1 and 2, the plate-shaped member 10 has a holding surface 11 for holding the semiconductor wafer W and a holding surface 11 in the thickness direction (direction corresponding to the Z-axis direction, vertical direction) of the plate-shaped member 10. It is provided with a lower surface 12 provided on the opposite side to the above. 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.

As shown in FIGS. 2 and 3, a chuck electrode 13 made of a conductive material (for example, tungsten, molybdenum, etc.) is provided inside the plate-shaped member 10. The shape of the chuck electrode 13 in the Z-axis direction is, for example, substantially circular. When a voltage is applied to the chuck electrode 13 from a power source (not shown), an electrostatic attraction is generated, and the wafer W is adsorbed and fixed to the holding surface 11 of the plate-shaped member 10 by this electrostatic attraction.

Further, as shown in FIG. 2, a heater electrode 14 made of a resistance heating element made of a conductive material (for example, tungsten, molybdenum, etc.) is provided inside the plate-shaped member 10. The shape of the heater electrode 14 in the Z-axis direction is, for example, substantially spiral.

The line width of the heater electrode 14 is, for example, about 0.1 to 10 mm, and the thickness of the heater electrode 14 (dimension in the Z-axis direction) is, for example, about 0.02 to 3 mm. When a voltage is applied to the heater electrode 14 from a power source (not shown), the heater electrode 14 generates heat and the holding surface 11 is heated, so that the semiconductor wafer W held by the holding surface 11 is heated. ..

A bottomed hole 15 is formed in the lower surface 12 of the plate-shaped member 10. The bottomed hole 15 is a circular recess, and the region overlapping the through hole 25 of the base member 20, which will be described later, is recessed toward the holding surface 11 in the Z-axis direction. The diameter of the bottomed hole 15 is, for example, 7 to 8 mm. A terminal pad 30 is arranged at the bottom portion 15b of the bottomed hole 15. The shape of the terminal pad 30 in the Z-axis direction is, for example, substantially circular. In this embodiment, for example, as shown in FIG. 2, one terminal pad 30 is electrically connected to the chuck electrode 13 via the via 31, and the other terminal pad 30 is electrically connected to the chuck electrode 13 via the via 31. It is electrically connected to the heater electrode 14. The terminal pad 30 and the via 31 are made of a conductive material (for example, tungsten, molybdenum, etc.). As shown in FIGS. 2 and 3, the terminal pad 30 is entirely exposed from the plate-shaped member 10 in the thickness direction (Z-axis direction). However, as long as the lower surface of the terminal pad 30 is exposed from the plate-shaped member 10, a part or the whole of the terminal pad 30 in the thickness direction may be embedded in the plate-shaped member 10.

Further, a hollow portion 16 is formed in the bottom portion 15b of the bottomed hole 15. That is, the cavity 16 includes a surface on which the terminal pad 30 is arranged in the Z-axis direction. The cavity 16 is an annular space extending radially outward from the inner peripheral surface 15a of the bottom hole 15, and the dimension in the radial direction gradually increases from the opening of the bottom hole 15 toward the bottom 15b. It has a tapered portion 16a that becomes large. That is, the cavity 16 is an annular space having a triangular cross section. The diameter of the cavity 16 is, for example, 9 to 10 mm. By forming such a cavity portion 16, the creepage distance CD from the terminal pad 30 to the base member 20 can be lengthened.

As shown in FIG. 1, the base member 20 has a columnar shape, specifically, two columns having different diameters, so that a lower surface portion of a columnar column having a small diameter is placed on an upper surface portion of a columnar column having a large diameter. , It is a stepped cylinder formed by being stacked coaxially (with a common central axis). The base member 20 is preferably made of a metal (for example, aluminum, an aluminum alloy, etc.), but may be other than the metal.

As shown in FIGS. 1 and 2, the base member 20 includes an upper surface 21 and a lower surface 22 provided on the side opposite to the upper surface 21 in the Z-axis direction of the base member 20 (plate-shaped member 10). ing. 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 in the upper part and about 180 mm to 350 mm in the lower part. The thickness (dimension in the Z-axis direction) of the base member 20 is, for example, about 20 mm to 50 mm. The thermal conductivity of the base member 20 (assuming aluminum) is larger than that of the plate-shaped member 10, and is preferably in the range of 180 to 250 W / mK (preferably about 230 W / mK).

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

The base member 20 is formed with a cylindrical through hole 25 that penetrates between the upper surface 21 and the lower surface 22 in the thickness direction (Z-axis direction, vertical direction in FIG. 2). An electrode terminal 35 and an insulating member 36 are arranged in the through hole 25.

Here, the electrode terminal 35 is a columnar terminal extending in the Z-axis direction, and in the present embodiment, for example, the cross section (cross section parallel to the plane direction) has a circular shape. The upper end of the electrode terminal 35 reaches the terminal pad 30, and the electrode terminal 35 is joined to the terminal pad 30 by, for example, a metal brazing material.

The insulating member 36 insulates between the base member 20 and the electrode terminal 35. The insulating member 36 continuously surrounds the electrode terminal 35 so as to be interposed between the electrode terminal 35 and the surface of the through hole 25. The insulating member 36 is made of an insulating material such as resin or ceramics. In the present embodiment, the thermal conductivity of the insulating member 36 is lower than the thermal conductivity of the plate-shaped member 10 (that is, the thermal conductivity of the plate-shaped member 10 is higher than the thermal conductivity of the insulating member 36).

Around the insulating member 36, specifically, between the insulating member 36 and the electrode terminal 35, between the insulating member 36 and the plate-shaped member 10, between the insulating member 36 and the base member 20, and a cavity. The portion 16 is filled with the adhesive 70 (see FIG. 3). The adhesive 70 is made of an adhesive such as a silicone resin, an acrylic resin, or an epoxy resin, and the insulating member 36 is bonded to the electrode terminal 35, the plate-shaped member 10, and the base member 20.

As shown in FIGS. 1 and 2, the joining layer 40 is arranged between the lower surface 12 of the plate-shaped member 10 and the upper surface 21 of the base member 20, and joins the plate-shaped member 10 and the base member 20. .. The lower surface 12 of the plate-shaped member 10 and the upper surface 21 of the base member 20 are thermally connected via the bonding layer 40.

The bonding layer 40 is made of an adhesive material such as a silicone resin, an acrylic resin, or an epoxy resin. The thickness of the bonding layer 40 (dimensions in the Z-axis direction) 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 resin) is preferably in the range of 0.1 to 2.0 W / mK (preferably 0.5 to 1.5 W / mK).

Further, as shown in FIG. 3, the joint layer 40 is formed with a through hole 45 that penetrates the joint layer 40 in the Z-axis direction. Through the through hole 45, the through hole 25 of the base member 20 and the bottomed hole 15 communicate with each other. That is, the through hole 25 formed in the base member 20 and the bottomed hole 15 formed in the plate-shaped member 10 form an integral hole communicating with each other through the through hole 45 formed in the joint layer 40. ing.

Since the electrostatic chuck 1 having the above configuration has a cavity portion 16 extending in the radial direction at the bottom portion 15b of the bottomed hole 15, the creepage distance from the position where the terminal pad 30 is arranged to the base member 20 is reached. The CD can be lengthened. As a result, according to the electrostatic chuck 1 of the present embodiment, it is possible to suppress the occurrence of a short circuit between the terminal pad 30 and the base member 20, and the insulation between the terminal pad 30 and the base member 20 can be improved. Can be improved. This makes it possible to prevent the occurrence of dielectric breakdown in the electrostatic chuck 1.

Since the cavity 16 provided to lengthen the creepage distance CD is provided in the radial direction instead of the Z-axis direction as in the conventional apparatus, the thickness (volume) of the plate-shaped member 10 does not decrease. That is, the distance between the bottom portion 15b of the bottomed hole 15 and the internal electrode closest to the terminal pad 30 (heater electrode 14 in this embodiment) does not change (does not shorten). Therefore, it is possible to suppress the occurrence of a short circuit between the terminal pad 30 and the internal electrode (heater electrode 14 in this embodiment), and it is possible to prevent the occurrence of dielectric breakdown in the electrostatic chuck 1.

In this embodiment, in order to homogenize the heat of the holding surface 11, the conductive layer which is a land pattern as a feeding path to the heater electrode 14 is not provided, but as shown in FIG. 4, the conductive layer 60 is provided. The conductive layer 60 is the inner electrode closest to the bottom portion 15b of the bottomed hole 15 and the terminal pad 30. In this case, the terminal pad 30 and the conductive layer 60 are electrically connected via the via 31, and the conductive layer 60 and the heater electrode 14 are electrically connected via the via 32. When the conductive layer 60 is provided in this way, the thickness of the plate-shaped member 10 does not decrease even if the hollow portion 16 is provided, so that the distance between the bottom portion 15b of the bottomed hole 15 and the conductive layer 60 does not change (does not shorten). Therefore, it is possible to suppress the occurrence of a short circuit between the terminal pad 30 and the conductive layer 60. The conductive layer 60 is made of a conductive material (for example, tungsten, molybdenum, etc.).

Here, on the holding surface 11, the region where the bottomed hole 15 is arranged (the position directly above the bottomed hole 15) tends to have a higher temperature than the other regions. This is because the through hole 25 and the through hole 45 are present in the bottomed hole 15 arrangement region, so that the heat transfer is worse than in the other regions and it is difficult to cool. Then, when the thickness of the plate-shaped member 10 is further reduced in the arrangement region of the bottomed hole 15 as in the conventional device, a temperature singularity that becomes locally high in the arrangement region of the bottomed hole 15 of the holding surface 11 is generated. Very likely to occur.

However, in the electrostatic chuck 1 of the present embodiment, since the cavity portion 16 is formed so as to expand outward in the radial direction, the thickness of the plate-shaped member 10 does not decrease in the arrangement region of the bottomed hole 15. .. Therefore, in the holding surface 11, the heat transfer does not deteriorate due to the volume reduction of the plate-shaped member 10 in the arrangement region of the bottomed hole 15. Therefore, on the holding surface 11, it is possible to suppress the generation of a temperature singular point that becomes locally high in the vicinity of the arrangement region of the bottomed hole 15, so that the heat equalization property on the holding surface 11 can be improved.

Then, since the cavity portion 16 has the tapered portion 16a whose radial dimension gradually increases as it goes from the opening of the bottomed hole 15 toward the bottom portion 15b, the volume of the plate-shaped member 10 around the bottomed hole 15 decreases. Can be further suppressed. Therefore, it is possible to surely prevent the occurrence of a temperature singularity that becomes locally high in the vicinity of the bottomed hole 15 on the holding surface 11, and it is possible to further improve the heat equalizing property on the holding surface 11.

Further, since the hollow portion 16 has the tapered portion 16a, the adhesive 70 for joining the insulating member 36 to the electrode terminal 35, the plate-shaped member 10, and the base member 20 is smoothly and tightly filled in the hollow portion 16. Can be done. As a result, the thermal conductivity of the cavity 16 can be increased, so that it is possible to more reliably prevent the generation of a temperature singularity that becomes locally high in the vicinity of the bottom hole 15 on the holding surface 11, and the cavity is formed. It is possible to effectively suppress a decrease in heat soaking property on the holding surface 11 due to the provision of the portion 16.

If the maximum dimension of the cavity 16 in the Z-axis direction or the radial direction is increased, the creepage distance CD from the terminal pad 30 to the base member 20 becomes longer, while the volume of the plate-shaped member 10 around the bottomed hole 15. The decrease will be large. If the volume reduction of the plate-shaped member 10 becomes large around the bottomed hole 15, heat transfer deteriorates, so that a temperature singular point that becomes locally high may occur on the holding surface 11. be.

Therefore, the maximum dimension of the cavity 16 in the Z-axis direction is preferably ½ or less of the dimension of the bottomed hole 15 in the Z-axis direction. Further, the radial dimension of the bottomed hole 15 is preferably ½ or more and 1 or less of the maximum radial dimension of the cavity portion 16. By defining the maximum dimension of the cavity 16 in the Z-axis direction and the radial dimension of the bottomed hole 15 in this way, the bottomed hole 15 is secured while ensuring the required creepage distance (which does not cause a short circuit). It is possible to suppress the decrease in volume of the plate-shaped member 10 in the vicinity of the holding surface 11 and prevent the generation of a temperature singularity that becomes locally high in the vicinity of the bottomed hole 15 in the holding surface 11, and the heat equalization property in the holding surface 11. Can be improved.

As described above, according to the electrostatic chuck 1 of the present embodiment, a hollow portion 16 extending outward from the inner peripheral surface 15a of the bottomed hole 15 in the radial direction is formed in the bottom portion 15b of the bottomed hole 15. There is. Therefore, in the arrangement region of the bottomed hole 15, the creepage distance CD from the terminal pad 30 to the base member 20 can be lengthened without reducing the thickness of the plate-shaped member 10. As a result, the insulating property between the terminal pad 30 and the base member 20 and the insulating property between the terminal pad 30 and the internal electrode can be improved, and the heat equalizing property on the holding surface 11 can be improved.

[Second Embodiment]
Next, the second embodiment will be described. In the second embodiment, the arrangement position of the cavity portion is different from that in the first embodiment. That is, in the second embodiment, the cavity 116 is provided not on the bottom 15b of the bottom hole 15, but on the inner peripheral surface 15a which is the side surface of the opening of the bottom hole 15. Therefore, the same components as those of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted as appropriate, and the differences from the first embodiment will be mainly described.

In the electrostatic chuck of the present embodiment, as shown in FIG. 5, a cavity 116 extending radially outward is formed on the inner peripheral surface 15a of the bottomed hole 15. The cavity 116 is an annular space that extends radially outward from the inner peripheral surface 15a of the bottomed hole 15. The hollow portion 116 has a tapered portion 16a. Further, the hollow portion 116 is filled with the adhesive 70.

Even if such a hollow portion 116 is formed, the creepage distance CD from the terminal pad 30 to the base member 20 can be lengthened. As a result, even in the electrostatic chuck of the present embodiment, it is possible to suppress the occurrence of a short circuit between the terminal pad 30 and the base member 20, and improve the insulating property between the terminal pad 30 and the base member 20. Can be done.

Since the cavity 116 provided to lengthen the creepage distance CD is provided in the radial direction instead of the Z-axis direction as in the conventional apparatus, the thickness (volume) of the plate-shaped member 10 does not decrease. That is, the distance between the bottom portion 15b of the bottomed hole 15 and the internal electrode closest to the terminal pad 30 (heater electrode 14 in this embodiment) does not change (does not shorten). Therefore, it is possible to suppress the occurrence of a short circuit between the terminal pad 30 and the internal electrode (heater electrode 14 in this embodiment). As described above, even in this embodiment, it is possible to prevent the occurrence of dielectric breakdown in the electrostatic chuck.

Further, since the hollow portion 116 has the tapered portion 16a, it is possible to further suppress the volume reduction of the plate-shaped member 10 around the bottomed hole 15. Therefore, since the temperature gradient becomes gentle around the bottomed hole 15 on the holding surface 11, it is possible to surely prevent the occurrence of a temperature singularity that becomes locally high, and the heat equalization property on the holding surface 11 is further improved. Can be made to.

Further, since the hollow portion 116 has the tapered portion 16a, the adhesive 70 can be smoothly filled into the hollow portion 116 without any gap. As a result, the thermal conductivity of the cavity 16 can be increased, so that it is possible to more reliably prevent the generation of a temperature singularity that becomes locally high in the vicinity of the bottom hole 15 on the holding surface 11, and the cavity is formed. It is possible to effectively suppress the decrease in heat soaking property on the holding surface 11 due to the provision of the portion 116.

As described above, according to the electrostatic chuck of the present embodiment, the hollow portion 116 extending outward from the inner peripheral surface 15a of the bottomed hole 15 in the radial direction is formed on the inner peripheral surface 15a of the bottomed hole 15. ing. Therefore, in the arrangement region of the bottomed hole 15, the creepage distance CD from the terminal pad 30 to the base member 20 can be lengthened without reducing the thickness of the plate-shaped member 10. As a result, the insulating property between the terminal pad 30 and the base member 20 and the insulating property between the terminal pad 30 and the internal electrode can be improved, and the heat equalizing property on the holding surface 11 can be improved.

It should be noted that the above embodiment is merely an example and does not limit the present disclosure in any way, and it goes without saying that various improvements and modifications can be made without departing from the gist thereof. For example, in the above embodiment, the case where the present disclosure is applied to the electrostatic chuck is exemplified, but the present disclosure is not limited to the electrostatic chuck, but is applied to all holding devices for holding an object on the surface. Can be done.

Further, in the above embodiment, the case where the cavities 16 and 116 are provided with the tapered portion 16a is illustrated, but the cavities 16 and 116 may not be provided with the tapered portions 16a. That is, the cavities 16 and 116 may be horizontal holes (rectangular annular spaces having a horizontally long cross section) that extend radially outward from the inner peripheral surface 15a.

1 Electrostatic chuck 10 Plate-shaped member 11 Holding surface 12 Bottom surface 13 Chuck electrode 14 Heater electrode 15 Bottom hole 15a Inner peripheral surface 15b Bottom 16 Cavity 16a Tapered part 20 Base member 25 Through hole 30 Terminal pad 35 Electrode terminal 36 Insulation member 116 Cavity CD creepage distance W semiconductor wafer

Claims (4)

A first surface, a second surface provided on the side opposite to the first surface in the first direction, an internal electrode provided inside, and a terminal electrically connected to the internal electrode. A plate-shaped member with a pad and
The electrode terminals joined to the terminal pad and
An insulating member that covers the outer peripheral surface of the electrode terminal and
It has a through hole in which the electrode terminal and the insulating member are arranged, and has a metal base member joined to the second surface of the plate-shaped member.
In a holding device that holds an object on the first surface of the plate-shaped member,
The second surface of the plate-shaped member is recessed on the first surface side, and a bottomed hole in which the terminal pad is arranged is formed.
The bottom of the bottomed hole or the side surface of the opening is characterized in that a cavity extending outward from the side surface of the opening of the bottomed hole is formed in a second direction orthogonal to the first direction. Holding device. In the holding device according to claim 1,
A holding device characterized in that the maximum dimension of the cavity portion in the first direction is ½ or less of the dimension of the bottomed hole in the first direction. In the holding device according to claim 1 or 2.
The holding device, wherein the cavity includes a surface on which the terminal pad is arranged in the first direction. In the holding device according to claim 1 or 2.
The holding device is characterized in that the cavity portion has a tapered portion whose dimension gradually increases in the second direction toward the bottom portion from the opening of the bottomed hole.

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