Holding device

Abstract

To provide a holding device capable of uniformizing temperature as fully as up to a periphery of a through hole in a holding surface on which an object is held.SOLUTION: A holding device 1 comprises a tabular member 10, a base member 20, and a joint layer 40 disposed between a bottom face 12 of the tabular member 10 and a top face 21 of the base member 20 to join the tabular member 10 and the base member 20; and holds an object W on a holding surface 11 of the tabular member 10. Therein: first through holes 15a and 15b penetrating through the holding surface 11 and the bottom face 12 are formed in the tabular member 10, and second through holes 25a and 25b penetrating through the top face 21 and the bottom face 22 and communicating with the first through holes 15a and 15b are formed in the base member 20; recesses 13a and 13b are provided around openings of the first through holes 15a and 15b in the bottom face 12 of the tabular member 10; and the joint layer 40 includes thick layer parts 42a and 42b which are disposed filling at least partially the recesses 13a and 13b and thicker than other portions.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] As a holding device, for example, an electrostatic chuck described in Patent Document 1 is known. This electrostatic chuck includes an electrostatic chuck substrate (ceramic member) that holds a wafer as an object, a base plate (base member) for cooling, and a bonding layer that bonds the two members. The electrostatic chuck substrate incorporates a heating resistor. In addition, such an electrostatic chuck is provided with through holes such as lift pin holes into which lift pins for lifting up the wafer from the electrostatic chuck substrate are inserted, and gas holes for filling a gap between the surface (holding surface) of the electrostatic chuck substrate and the wafer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5891332 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned holding device, in order to prevent the heating resistor from being exposed, the heating resistor is arranged in a position slightly away from the through hole (in other words, to avoid the through hole) near the through hole. Therefore, the temperature of the holding surface that holds the object tends to be lower around the through hole than other areas. Therefore, it is difficult to uniform the temperature of the holding surface up to the vicinity of the through hole.

[0005] Therefore, the present disclosure has been made to solve the above-mentioned problems, and aims to provide a holding device that can uniformly distribute the temperature on the holding surface that holds the object, even around the through hole. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the present disclosure is to A holding device having a plate-shaped member having a first surface and a second surface provided on an opposite side to the first surface, a base member having a third surface and a fourth surface provided on an opposite side to the third surface, and a bonding layer disposed between the second surface of the plate-shaped member and the third surface of the base member, bonding the plate-shaped member and the base member, the holding device holding an object on the first surface of the plate-shaped member, a first through hole penetrating the first surface and the second surface is formed in the plate-like member; a second through hole penetrating the third surface and the fourth surface and communicating with the first through hole is formed in the base member; a recess is provided on the second surface around an opening of the first through hole; The bonding layer has a thick layer portion that is thicker than other portions and that is disposed in at least a portion of the recess. death, The recess has a tapered shape that gradually becomes deeper in a direction toward the first surface toward the first through hole, The thick layer portion is convex toward the first surface side, and a third through hole that communicates with the first through hole and the second through hole is formed in the center of the thick layer portion. It is characterized by:

[0007] In this holding device, a recess is provided on the second surface of the plate-like member around the opening of the first through hole, and the bonding layer has a thick layer portion that is thicker than other portions that are filled and arranged in at least a part of the recess. In other words, a thick layer portion is provided around the through hole of the plate-like member, where the bonding layer is thicker than other portions. This allows the thick layer portion of the bonding layer to be arranged around the through hole, which is likely to become cold on the first surface. Therefore, the thick layer portion suppresses heat transfer between the base member and the plate-like member (cooling by the base member), so that a drop in temperature around the through hole can be suppressed. Therefore, the temperature can be made uniform up to the periphery of the through hole on the first surface.

[0008] In addition, since the thick layer portion is provided on the plate-shaped member side rather than on the base member side, heat transfer between the base member and the plate-shaped member is further suppressed, and the thick layer portion is disposed in a position closer to the first surface, which makes it easier to control the temperature around the through holes, which tend to become cold on the first surface, and improves the temperature controllability of the first surface. Furthermore, by making the thick layer portion convex toward the first surface side where the third through hole that connects the first through hole and the second through hole is formed in the center, the thick layer portion can be easily formed in the bonding layer around the through hole. Also, since the thickness of the thick layer portion changes gradually, the temperature around the through hole, which tends to become low on the first surface, can be made more uniform by adjusting the rate of change in thickness according to the temperature distribution around the through hole on the first surface.

[0009] In the above-mentioned holding device, The plate-like member has a heating resistor therein, The heating resistor is preferably disposed so as to overlap the thick layer portion when viewed from the lamination direction of the plate-like member and the base member.

[0010] In this way, by arranging the heating resistor so that it overlaps the thick layer portion when viewed from the stacking direction of the plate-like member and the base member, heat from the heating resistor is less likely to be transferred to the base member. As a result, heat from the heating resistor is efficiently transferred to the upper side (first surface side) of the thick layer portion. Therefore, it is possible to suppress a temperature drop around the through hole where the thick layer portion is arranged, and it is possible to make the temperature more uniform up to the periphery of the through hole on the first surface.

[0011] In the above-mentioned holding device, The base member includes a coolant flow path for allowing a coolant to flow therethrough. It is preferable that the coolant flow passage is disposed so as not to overlap the thick layer portion when viewed from the stacking direction of the plate-like member and the base member.

[0012] In this way, by arranging the coolant flow paths in the base member so as not to overlap the thick layer portions when viewed from the stacking direction of the plate-like member and the base member, the thick layer portions are less likely to be cooled. As a result, it is possible to suppress a decrease in temperature around the through holes where the thick layer portions are arranged, and therefore it is possible to make the temperature more uniform up to the periphery of the through holes on the first surface.

[0015] As another aspect of the present disclosure made to solve the above problems, A holding device having a plate-shaped member having a first surface and a second surface provided on an opposite side to the first surface, a base member having a third surface and a fourth surface provided on an opposite side to the third surface, and a bonding layer disposed between the second surface of the plate-shaped member and the third surface of the base member, bonding the plate-shaped member and the base member, the holding device holding an object on the first surface of the plate-shaped member, a first through hole penetrating the first surface and the second surface is formed in the plate-like member; a second through hole penetrating the third surface and the fourth surface and communicating with the first through hole is formed in the base member; a recess is provided on the second surface so as to surround an opening of the first through hole; The recess has a shape that deepens in a direction toward the first surface, the bonding layer has a thick layer portion that is thicker than other portions filled in at least a portion of the recess, and is convex toward the first surface side, the third through hole being formed in the center thereof and connecting the first through hole and the second through hole; The diameter of the third through hole may be equal to the diameter of the first through hole.

[0016] This makes it easier to form a thick layer portion in the bonding layer around the through hole. Also, since the volume of the thick layer portion is larger than when the recess is tapered, it is easier to suppress erosion of the bonding layer caused by plasma or corrosive gas that has entered the through hole. This makes it possible to achieve both the protective performance of the bonding layer and temperature uniformity on the first surface. Effect of the Invention

[0017] According to the present disclosure, it is possible to provide a holding device that can uniformize the temperature in a holding surface that holds an object, even around a through hole. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic perspective view of an electrostatic chuck according to a first embodiment. [Diagram 2] 1 is a schematic configuration diagram of an XZ cross section of an electrostatic chuck according to a first embodiment. FIG. [Diagram 3] 1 is a schematic configuration diagram of an electrostatic chuck in an XY plane according to a first embodiment. FIG. [Figure 4] FIG. [Diagram 5] FIG. 11 is a schematic configuration diagram of an electrostatic chuck of a second embodiment in an XZ cross section. [Figure 6] FIG. 11 is a schematic configuration diagram of an electrostatic chuck of a second embodiment in an XZ cross section. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] [First embodiment] A holding device according to an embodiment of the present disclosure will be described in detail with reference to the drawings. In this embodiment, an electrostatic chuck 1 that holds a semiconductor wafer W as an object will be described as an example. The electrostatic chuck 1 of this embodiment will be described with reference to Figs. 1 to 4.

[0020] 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 plate-shaped member 10, a base member 20, and a bonding layer 40 that bonds the plate-shaped member 10 and the base member 20 together.

[0021] For convenience of explanation, in the following description, the XYZ axes are defined as shown in Fig. 1. Here, the Z axis is an axis in the axial direction of the electrostatic chuck 1 (the vertical direction in Fig. 1), and the X and Y axes are axes in the radial direction of the electrostatic chuck 1. The Z axis direction is an example of the "stacking direction" in the present disclosure.

[0022] The plate-like member 10 is a disk-like member as shown in Fig. 1, and may be made of ceramics. Various ceramics can be used as the ceramics, 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).

[0023] The diameter of the plate-shaped member 10 is, for example, about 150 to 300 mm at the upper portion and about 180 to 350 mm at the lower portion. The thickness of the plate-shaped member 10 is, for example, about 2 to 6 mm. The thermal conductivity of the plate-shaped member 10 is preferably within a range of 10 to 50 W / mK (more preferably, 18 to 30 W / mK). The plate-shaped member 10 is formed so that the thermal conductivity of the plate-shaped member 10 is higher than the thermal conductivity of the bonding layer 40.

[0024] 1 and 2, the plate-shaped member 10 has a holding surface 11 for holding a semiconductor wafer W, and a bottom surface 12 provided on the opposite side to the holding surface 11 in the thickness direction (the direction corresponding to the Z-axis direction, the up-down direction) of the plate-shaped member 10. Note that the holding surface 11 is an example of a "first surface" in the present disclosure, and the bottom surface 12 is an example of a "second surface" in the present disclosure.

[0025] The holding surface 11 of the plate-like member 10 has an uneven shape. Specifically, as shown in Figs. 2 and 3, an annular convex portion 16 is formed in the vicinity of the outer edge of the holding surface 11, and a plurality of independent columnar convex portions 17 are formed inside the annular convex portion 16. The annular convex portion 16 is also called a seal band. As shown in Fig. 2, the cross section (XZ cross section) of the annular convex portion 16 is substantially rectangular. The height (dimension in the Z-axis direction) of the annular convex portion 16 is, for example, about 10 µm to 20 µm. The width (dimension in the X-axis direction) of the annular convex portion 16 is, for example, about 0.5 mm to 5.0 mm.

[0026] As shown in FIG. 3, each of the protrusions 17 has a substantially circular shape when viewed in the Z-axis direction (plan view), and is disposed at substantially equal intervals. The shape of the cross section (XZ cross section) of each of the protrusions 17 is substantially rectangular, as shown in FIG. 2. The height of the protrusions 17 is substantially the same as the height of the annular protrusions 16, and is, for example, about 10 to 20 μm. The width of the protrusions 17 (maximum diameter of the protrusions 17 when viewed in the Z-axis direction) is, for example, about 0.5 to 1.5 mm. The portion of the holding surface 11 of the plate-like member 10 on the inside of the annular protrusions 16 where the protrusions 17 are not formed is a recess 18.

[0027] The semiconductor wafer W is supported by the annular convex portion 16 and the multiple convex portions 17 on the holding surface 11 of the plate-like member 10 and is held by the electrostatic chuck 1. When the semiconductor wafer W is held by the electrostatic chuck 1, a space S exists between the surface (lower surface) of the semiconductor wafer W and the holding surface 11 of the plate-like member 10 (more specifically, the recessed portion 18 of the holding surface 11) (see FIG. 2). An inert gas (e.g., helium gas) is supplied to this space S via a gas hole 31, which will be described later.

[0028] In such plate-like member 10, cylindrical first through holes 15a, 15b are formed penetrating between holding surface 11 and lower surface 12 in the thickness direction (Z-axis direction, up-down direction in FIG. 2). In addition, in lower surface 12 of plate-like member 10, recess 13a is formed around the opening of first through hole 15a, and recess 13b is formed around the opening of first through hole 15b. In this embodiment, recess 13a, 13b have a tapered shape that gradually becomes deeper in the direction of holding surface 11 toward first through hole 15a, 15b.

[0029] The plate-like member 10 also includes a heater electrode 14 (heat generating resistor) therein. The heater electrode 14, for example, as shown in FIG. 4, forms a pattern extending in a substantially spiral shape as viewed in the Z-axis direction, and is made of a conductive material (for example, tungsten, molybdenum, platinum, etc.). The heater electrode 14 is disposed around the first through holes 15a, 15b (apart from the first through holes 15a, 15b) as viewed in the Z-axis direction so as not to expose the heater electrode 14 in the vicinity of the first through holes 15a, 15b as viewed in the Z-axis direction. The heater electrode 14 is disposed so as to overlap thick layer portions 42a, 42b of the bonding layer 40, which will be described later, as viewed in the Z-axis direction (see FIG. 2).

[0030] The heater electrode 14 has a line width of, for example, about 0.1 to 10 mm and a thickness (dimension in the Z-axis direction) of, 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, whereby the semiconductor wafer W held by the holding surface 11 is heated.

[0031] 1, the base member 20 is cylindrical, more specifically, a stepped cylindrical shape formed by stacking two cylinders of different diameters with a common central axis Ca, with the lower surface of the cylinder with the smaller diameter placed on the upper surface of the cylinder with the larger diameter. The base member 20 is preferably made of a metal (e.g., aluminum or an aluminum alloy), but may be made of a material other than metal.

[0032] 1 and 2, the base member 20 has an upper surface 21 and a lower surface 22 provided on the opposite side to the upper surface 21 in the direction of the central axis Ca (see FIG. 2) of the base member 20 (plate-shaped member 10) (i.e., the Z-axis direction). The upper surface 21 is an example of a "third surface" in the present disclosure, and the lower surface 22 is an example of a "fourth surface" in the present disclosure.

[0033] The diameter of the base member 20 is, for example, about 150 mm to 300 mm at the upper stage and about 180 mm to 350 mm at the lower stage. 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 (assumed to be aluminum) is greater than that of the plate-like member 10, and is desirably within the range of 180 to 250 W / mK (preferably about 230 W / mK).

[0034] 2, the base member 20 is formed with a coolant flow passage 23 for flowing a coolant (e.g., a fluorine-based inert liquid, water, etc.). The coolant flow passage 23 is arranged so as not to overlap the recesses 13a, 13b (i.e., the thick layer portions 42a, 42b of the bonding layer 40 described later) when viewed in the Z-axis direction. The coolant flow passage 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 through the coolant flow passage 23 and is discharged from the discharge port to the outside of the base member 20. In this way, the coolant is caused to flow through the coolant flow passage 23 of the base member 20, whereby the plate-like member 10 is cooled via the bonding layer 40.

[0035] Further, cylindrical second through holes 25a, 25b are formed in the base member 20, penetrating in the thickness direction (Z-axis direction, up-down direction in FIG. 2) between the upper surface 21 and the lower surface 22. The second through holes 25a, 25b are coaxial with the first through holes 15a, 15b, and the diameters of the second through holes 25a, 25b are larger than the diameters of the first through holes 15a, 15b.

[0036] Furthermore, an insulating sleeve having a through hole may be fitted into the second through holes 25a and 25b of the base member 20. In this case, the second through holes 25a and 25b refer to the through holes of the sleeve rather than the second through holes of the base member 20.

[0037] The bonding layer 40 is disposed between the lower surface 12 of the plate-shaped member 10 and the upper surface 21 of the base member 20, and bonds the plate-shaped member 10 to 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.

[0038] The bonding layer 40 includes thick layer portions 42a, 42b arranged in the recesses 13a, 13b provided on the lower surface 12 of the plate-like member 10 around the first through holes 15a, 15b, and a thin layer portion 41 having a thickness smaller than that of the thick layer portions 42a, 42b. That is, the portions of the bonding layer 40 arranged in the recesses 13a, 13b are the thick layer portions 42a, 42b, and the portions of the bonding layer 40 arranged other than the recesses 13a, 13b are the thin layer portions 41. The thick layer portions 42a, 42b are convex toward the holding surface 11, in which third through holes 45a, 45b that communicate the first through holes 15a, 15b and the second through holes 25a, 25b are formed in the center. In addition, the periphery of the first through holes 15a, 15b refers to the area from the outer edge of the first through holes 15a, 15b to a point 10.0 mm away in the planar direction of the lower surface 12 of the plate-like member 10 when viewed in the axial direction of the electrostatic chuck 1.

[0039] The bonding layer 40 is made of an adhesive material such as silicone resin, acrylic resin, or epoxy resin. The thickness (dimension in the Z-axis direction) of the bonding layer 40 is, for example, about 0.1 to 1.0 mm. The thermal conductivity of the bonding layer 40 is, for example, 1.0 W / mK. The thermal conductivity of the bonding layer 40 (assuming a silicone resin) is preferably within a range of 0.1 to 2.0 W / mK (preferably 0.5 to 1.5 W / mK).

[0040] As described above, the bonding layer 40 has the cylindrical third through holes 45a, 45b located between the first through holes 15a, 15b and the second through holes 25a, 25b (see FIG. 2). That is, in the present embodiment, when the openings of the first through holes 15a, 15b are formed inside the recesses 13a, 13b, the bonding layer 40 is not disposed in the spaces (third through holes 45a, 45b) in the recesses 13a, 13b that communicate with the first through holes 15a, 15b and the second through holes 25a, 25b.

[0041] The third through holes 45a, 45b are coaxial with the first through holes 15a, 15b and the second through holes 25a, 25b. The diameters of the third through holes 45a, 45b are larger than the first through holes 15a, 15b and are equal to the diameters of the second through holes 25a, 25b. The first through holes 15a, 15b, the third through holes 45a, 45b, and the second through holes 25a, 25b are arranged in series in the Z-axis direction (the axial direction of the electrostatic chuck 1).

[0042] The first through hole 15a, the third through hole 45a, and the second through hole 25a form a lift pin insertion hole 30 that penetrates the electrostatic chuck 1 in the Z-axis direction. A lift pin 60 that pushes up the semiconductor wafer W from above the holding surface 11 is inserted into the lift pin insertion hole 30 from the lower surface 22 side of the base member 20. The lift pin 60 has a cylindrical shape (round bar shape) and moves in the Z-axis direction inside the lift pin insertion hole 30. When the lift pin 60 moves to one side in the Z-axis direction (upper side in FIG. 2), the tip portion (upper end portion) of the lift pin 60 protrudes outward from the holding surface 11 of the plate-like member 10, so that the semiconductor wafer W placed on the holding surface 11 is separated from the holding surface 11 (the semiconductor wafer W is lifted by the lift pin 60).

[0043] In the electrostatic chuck 1 of the present embodiment, three lift pin insertion holes 30 are formed, and a lift pin 60 is inserted into each of the lift pin insertion holes 30. The three lift pin insertion holes 30 are formed at equal intervals in the circumferential direction of the electrostatic chuck 1 (see FIG. 3).

[0044] Further, the first through hole 15b, the third through hole 45b, and the second through hole 25b form a gas hole 31 penetrating the electrostatic chuck 1 in the Z-axis direction. The gas hole 31 is a gas flow path through which an inert gas (e.g., helium gas) flows. This allows the inert gas (e.g., helium gas) to be supplied into the gas hole 31 from the lower surface 22 side of the base member 20, thereby filling the space S between the lower surface of the semiconductor wafer W and the holding surface 11 (recess 18) of the plate-like member 10 with the inert gas.

[0045] One of the requirements for the electrostatic chuck 1 is to make the temperature uniform on the holding surface 11. However, in the electrostatic chuck 1, the heater electrode 14 is disposed at a position slightly away from the first through holes 15a, 15b (see FIG. 4). Therefore, in the holding surface 11, cooling by the base member 20 is promoted around the first through holes 15a, 15b more than in other parts. As a result, the temperature around the first through holes 15a, 15b is likely to be lower than in other parts, and there is a risk that the temperature on the holding surface 11 cannot be made uniform up to the periphery of the first through holes 15a, 15b. Further, the location slightly distant from the first through holes 15a, 15b refers to a region from a point 1.0 mm away from the outer edge of the first through holes 15a, 15b in the planar direction of the lower surface 12 of the plate-shaped member 10 to a point 7.0 mm away from the outer edge of the first through holes 15a, 15b in the planar direction of the lower surface 12 of the plate-shaped member 10, as viewed in the axial direction of the electrostatic chuck 1. The portions of the heater electrode 14 closest to the first through holes 15a, 15b are disposed within this region.

[0046] 2, in the electrostatic chuck 1, recesses 13a, 13b are provided around the openings of the first through holes 15a, 15b on the lower surface 12 of the plate-shaped member 10, and thick layer portions 42a, 42b of the bonding layer 40 are formed in the recesses 13a, 13b. That is, the thick layer portions 42a, 42b are provided around the first through holes 15a, 15b of the plate-shaped member 10. As a result, the thickness of the bonding layer 40 is greater around the first through holes 15a, 15b than in other portions.

[0047] Therefore, the thick layer portions 42a, 42b suppress heat transfer (cooling by the base member 20) between the base member 20 and the plate-like member 10. This suppresses a decrease in temperature around the first through holes 15a, 15b, making it possible to make the temperature uniform on the holding surface 11 up to the periphery of the first through holes 15a, 15b.

[0048] Since the thick layer portions 42a, 42b are provided on the plate-shaped member 10 side, not on the base member 20 side, the heat transfer between the base member 20 and the plate-shaped member 10 is further suppressed, and the thick layer portions 42a, 42b are disposed in a position closer to the holding surface 11. Therefore, the temperature control around the first through holes 15a, 15b, which are likely to become low temperature on the holding surface 11, is facilitated, so that the temperature controllability on the holding surface 11 can be improved. Furthermore, when the thermal expansion coefficient of the plate-shaped member 10 is smaller than that of the base member 20, the plate-shaped member 10 has a smaller deformation amount due to temperature change than the base member 20. Therefore, compared to when the thick layer portions 42a, 42b are provided on the base member 20 side, the deformation of the thick layer portions 42a, 42b can be suppressed by providing the thick layer portions 42a, 42b on the plate-shaped member 10 side, so that the decrease in the temperature uniformity of the holding surface 11 due to the deformation of the thick layer portions 42a, 42b can be suppressed.

[0049] In addition, in the electrostatic chuck 1, the recesses 13a, 13b have a tapered shape that gradually deepens toward the holding surface 11, and the thick layer portions 42a, 42b are convex toward the holding surface 11 side where the third through holes 45a, 45b that communicate the first through holes 15a, 15b and the second through holes 25a, 25b are formed in the center. Therefore, the thick layer portions 42a, 42b can be easily formed in the bonding layer 40 around the first through holes 15a, 15b. Since the thickness of the thick layer portions 42a, 42b gradually changes, the temperature around the first through holes 15a, 15b, which is likely to become low, on the holding surface 11 can be made more uniform by adjusting the rate of change in the thickness according to the temperature distribution around the first through holes 15a, 15b on the holding surface 11.

[0050] Furthermore, in the electrostatic chuck 1, the heater electrode 14 is disposed so as to overlap the thick layer portions 42a, 42b when viewed in the Z-axis direction, so that heat from the heater electrode 14 is not easily transferred to the base member 20. Therefore, the heat from the heater electrode 14 is efficiently transferred upward (to the holding surface 11 side) of the thick layer portions 42a, 42b. Therefore, a decrease in temperature around the first through holes 15a, 15b where the thick layer portions 42a, 42b are disposed can be effectively suppressed, so that the temperature can be made more uniform on the holding surface 11 up to the vicinity of the first through holes 15a, 15b.

[0051] In addition, in the electrostatic chuck 1, the coolant flow passage 23 provided in the base member 20 is arranged so as not to overlap with the thick portions 42a, 42b when viewed in the Z-axis direction, so that the thick portions 42a, 42b are less likely to be cooled. This makes it possible to suppress a decrease in temperature around the first through holes 15a, 15b in which the thick portions 42a, 42b are arranged. This makes it possible to make the temperature on the holding surface 11 more uniform up to the vicinity of the first through holes 15a, 15b.

[0052] As described above, according to the electrostatic chuck 1 of the present embodiment, by providing recesses 13a, 13b around the first through holes 15a, 15b and forming thick layer portions 42a, 42b in the recesses 13a, 13b, the temperature on the holding surface 11 can be made uniform up to the periphery of the first through holes 15a, 15b.

[0053] [Second embodiment] Next, the second embodiment will be described. The second embodiment has the same basic structure as the first embodiment, but the shapes of the recesses provided on the lower surface of the plate-like member and the thick layer portions provided in the bonding layer are different from those of the first embodiment. That is, in the second embodiment, the recesses 113a, 113b and the thick layer portions 142a, 142b are cylindrical rather than tapered. Therefore, the same reference numerals are used for the same configurations as the first embodiment, and the description is omitted as appropriate, and the differences from the first embodiment will be mainly described.

[0054] 5, in the electrostatic chuck 101 of the present embodiment, recesses 113a and 113b provided in the lower surface 12 of the plate-like member 110 are recesses that create a step in the lower surface 12, and in this embodiment, are cylindrical spaces. The recess 113a is provided around the opening of the first through hole 15a, and the recess 113b is provided around the opening of the first through hole 15b.

[0055] The recesses 113a and 113b are filled with the bonding layer 140 to form the thick portions 142a and 142b. In this manner, the thick portions 142a and 142b can be formed in the bonding layer 140 very easily around the openings of the first through holes 15a and 15b.

[0056] 5, in the electrostatic chuck 101, recesses 113a, 113b are provided around the openings of the first through holes 15a, 15b on the lower surface 12 of the plate-like member 110, and thick layer portions 142a, 142b of the bonding layer 140 are formed in the recesses 113a, 113b. That is, the thick layer portions 142a, 142b are provided around the first through holes 15a, 15b of the plate-like member 110. As a result, the thickness of the bonding layer 140 is greater around the first through holes 15a, 15b than in other portions.

[0057] Therefore, the thick layer portions 142a and 142b suppress heat transfer (cooling by the base member 20) between the base member 20 and the plate-like member 110. This suppresses a drop in temperature around the first through holes 15a and 15b, making it possible to make the temperature uniform on the holding surface 11 up to the periphery of the first through holes 15a and 15b.

[0058] In addition, since the thick layer portions 142a, 142b are provided on the plate-shaped member 110 side rather than on the base member 20 side, heat transfer between the base member 20 and the plate-shaped member 110 is further suppressed, and the thick layer portions 142a, 142b are disposed at positions closer to the holding surface 11. This makes it easier to control the temperature around the first through holes 15a, 15b on the holding surface 11, which tends to become low temperature, and therefore the temperature controllability on the holding surface 11 can be improved.

[0059] Furthermore, in this embodiment, the volumes of the thick layer portions 142a, 142b are larger than when the recesses are tapered as in the first embodiment, and this makes it easier to suppress erosion of the bonding layer 140 due to plasma or corrosive gas that has entered the first through holes 15a, 15b during use of the electrostatic chuck 101. Therefore, it is possible to achieve both the protection performance of the bonding layer 140 and the temperature uniformity on the holding surface 11.

[0060] As described above, in the electrostatic chuck 101 of this embodiment, by providing recesses 113a, 113b around the first through holes 15a, 15b and forming thick layer portions 142a, 142b in the recesses 113a, 113b, the temperature can be made uniform on the holding surface 11 up to the periphery of the first through holes 15a, 15b.

[0061] It should be noted that the above-described embodiment is merely an example, does not limit the present disclosure in any way, and various improvements and modifications are possible without departing from the spirit and scope of the present disclosure. For example, in the above-described embodiment, the present disclosure is applied to an electrostatic chuck, but the present disclosure is not limited to electrostatic chucks and can be applied to any holding device that holds an object on its surface.

[0062] In the second embodiment, the first through holes 15a, 15b are formed in the recesses 113a, 113b provided in the lower surface 12 of the plate-like member 110, but the positions of the recesses 113a, 113b and the first through holes 15a, 15b are not limited to this. That is, the recesses 113a, 113b may be provided around the first through holes 15a, 15b, and the first through holes 15a, 15b may be arranged close to the recesses 113a, 113b at the portion where the recesses 113a, 113b are formed, as shown in FIG. Even in this case, the temperature drop around the first through holes 15a, 15b can be suppressed, so that the temperature can be made uniform up to the vicinity of the first through holes 15a, 15b on the holding surface 11.

[0063] In the above embodiment, the thick layer portions 42a, 42b, 142a, 142b are formed by filling the bonding layer 40 from the upper surface 21 of the base member 20 to the upper surface of the recesses 13a, 13b, 113a, 113b, but the thick layer portions 42a, 42b, 142a, 142b may be filled so as not to contact the upper surface of the recesses 13a, 13b, 113a, 113b as long as they are thicker than the thin layer portions 41, 141. Furthermore, depending on the temperature distribution, the thick layer portions 42a, 42b, 142a, 142b may be filled so as not to be flush with the side surfaces of the first through holes 15a, 15b or the second through holes 25a, 25b. This creates spaces in the third through holes 45a, 45b, which act as heat insulating layers, making it difficult for heat to escape from the plate-shaped component 10, and thus makes it possible to suppress a decrease in temperature around the first through holes 15a, 15b. [Explanation of symbols]

[0064] 1. Electrostatic chuck 10 Plate-shaped member 11 Holding surface 12 Bottom side 13a Recess 13b Recess 14 Heater electrode 15a 1st through hole 15b 1st through hole 20 Base material 21 Top side 22 Bottom side 23 Coolant flow path 25a 2nd through hole 25b 2nd through hole 40 Bonding layer 42a Thick layer 42b Thick layer 101 Electrostatic Chuck 110 Plate-shaped member 113a Recess 113b Recess 140 Bonding layer 142a Thick layer 142b Thick layer W Semiconductor wafer

Claims

1. A holding device having a plate-shaped member having a first surface and a second surface provided on an opposite side to the first surface, a base member having a third surface and a fourth surface provided on an opposite side to the third surface, and a bonding layer disposed between the second surface of the plate-shaped member and the third surface of the base member, bonding the plate-shaped member and the base member, the holding device holding an object on the first surface of the plate-shaped member, a first through hole penetrating the first surface and the second surface is formed in the plate-like member; a second through hole penetrating the third surface and the fourth surface and communicating with the first through hole is formed in the base member; a recess is provided on the second surface around an opening of the first through hole; the bonding layer has a thick layer portion that is disposed in at least a portion of the recess and is thicker than other portions of the recess; The recess has a tapered shape that gradually becomes deeper in a direction toward the first surface toward the first through hole, The thick layer portion is convex toward the first surface side, and a third through hole that communicates with the first through hole and the second through hole is formed in the center of the third through hole. A holding device characterized in that

2. 2. The holding device according to claim 1, The plate-like member has a heating resistor therein, The heating resistor is disposed so as to overlap the thick layer portion when viewed from the lamination direction of the plate-like member and the base member. A holding device characterized in that

3. The holding device according to claim 1 or 2, The base member includes a coolant flow path for allowing a coolant to flow therethrough. The coolant flow path is disposed so as not to overlap the thick layer portion when viewed from a lamination direction of the plate-like member and the base member. A holding device characterized in that

4. A holding device having a plate-like member having a first surface and a second surface provided opposite the first surface, a base member having a third surface and a fourth surface provided opposite the third surface, and a bonding layer disposed between the second surface of the plate-like member and the third surface of the base member, bonding the plate-like member and the base member, the holding device holding an object on the first surface of the plate-like member, a first through hole penetrating the first surface and the second surface is formed in the plate-like member; a second through hole penetrating the third surface and the fourth surface and communicating with the first through hole is formed in the base member; a recess is provided on the second surface so as to surround an opening of the first through hole; The recess has a shape that deepens in a direction toward the first surface, the bonding layer has a thick layer portion that is thicker than other portions filled in at least a portion of the recess, and is convex toward the first surface side, the third through hole being formed in the center thereof and connecting the first through hole and the second through hole; The diameter of the third through hole is equal to the diameter of the first through hole. A holding device characterized in that

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