Holding device

Abstract

To provide a holding device capable of securing airtightness even when a bonding layer is formed of an air-permeable metal bonding material.SOLUTION: An electrostatic chuck 1 that holds a semiconductor wafer W on a holding surface 11 of a plate-like member 10, has: the plate-like member 10 that comprises a first through-hole 15; a base member 20 that comprises cooling medium passages 23 in which a cooling medium flows and a second through-hole 25 communicated with the first through-hole 15; and a bonding layer 40 formed with a third through-hole 45 that makes the first through-hole 15 and the second through-hole 25 communicate with each other, and bonding between the plate-like member 10 and the base member 20. The bonding layer 40 is formed of an air-permeable metal bonding material and has a cylindrical member 35 arranged inside the second through-hole 25 and the third through-hole 45 so as to surround an opening of the first through-hole 15. The cylindrical member 35 is arranged between the cooling medium passages 23 of the base member 20 and bonded with the base member 20 with an adhesive agent 36 arranged between an outer peripheral surface and an inner peripheral surface of the second through-hole 35.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] A known holding device includes a first member having a holding surface on which a semiconductor wafer is held, a second member for cooling the semiconductor wafer, and a bonding layer for bonding the first member body and the second member. Generally, a resin adhesive is used as the bonding layer, but when the holding device is used at high temperatures (e.g., 250°C or higher), the resin adhesive may not have sufficient heat resistance to cause bonding failure, and therefore an inorganic bonding material may be used. For example, Patent Document 1 discloses an electrostatic chuck (holding device) in which a bonding layer for bonding a ceramic body (first member) and a base plate (second member) is formed of a metal adhesive. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 345390 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned holding device, since the bonding layer is formed by a metal adhesive, the stress relaxation function is low and it may not be possible to sufficiently relax the stress caused by the thermal expansion difference between the first member and the second member. As a result, poor bonding of the bonding layer and deformation of the holding device may occur due to the thermal expansion difference.

[0005] Therefore, in order to effectively relieve the stress caused by the difference in thermal expansion between the first member and the second member, a metal bonding material having air permeability is sometimes used as the bonding layer. However, when the bonding layer is formed from a metal bonding material having air permeability, it becomes difficult to maintain the airtightness of the through-holes and the like provided in the holding device, and the airtightness of the holding device cannot be ensured.

[0006] Therefore, the present disclosure has been made to solve the above-mentioned problems, and aims to provide a holding device that can ensure airtightness even when the bonding layer is formed from a breathable metal bonding material. [Means for solving the problem]

[0007] In order to solve the above problems, one aspect of the present disclosure is to A first member including a first surface, a second surface provided on an opposite side to the first surface, and a first through hole penetrating the first surface and the second surface; a second member including a third surface, a fourth surface provided on the opposite side to the third surface, a refrigerant flow path through which a refrigerant flows, and a second through hole penetrating the third surface and the fourth surface and communicating with the first through hole; a third through hole that communicates with the first through hole and the second through hole is formed, and a bonding layer is disposed between the second surface of the first member and the third surface of the second member to bond the first member and the second member, A holding device for holding an object on the first surface of the first member, The bonding layer is formed of a breathable metal bonding material, a cylindrical member disposed inside the second through hole and the third through hole so as to surround an opening of the first through hole; The tubular member is characterized in that it is arranged between the refrigerant flow paths of the second member and joined to the second member by an adhesive arranged between its outer surface and the inner surface of the second through hole. It should be noted that a breathable metal bonding material is a bonding material whose main component is a metal material that has gaps through which a fluid (gas) can flow.

[0008] In this holding device, the bonding layer that bonds the first member and the second member is formed of a metal bonding material that has air permeability, and therefore a fluid (gas) can flow through the bonding layer, and the first through hole and the second through hole communicate with the atmosphere (outside) through the third through hole. This makes it difficult to ensure airtightness of the holding device. Therefore, in this holding device, a cylindrical member is disposed inside the second through hole and the third through hole so as to surround the opening of the first through hole, and the cylindrical member is bonded to the second member by an adhesive. Therefore, the adhesive seals the space formed by the outer peripheral surface of the cylindrical member and the inner peripheral surfaces of the second through hole and the third through hole. As a result, even if the bonding layer is formed of a metal bonding material that has air permeability, the cylindrical member and the adhesive can ensure airtightness of the holding device. By ensuring airtightness in this manner, it is possible to suppress exposure of the metal bonding material to a vacuum.

[0009] Since the cylindrical member is disposed between the refrigerant passages and the temperature of the cylindrical member can be lowered, deterioration of the adhesive caused by heat can be suppressed, and deterioration of the sealing performance caused by the adhesive can be prevented. Therefore, with this holding device, airtightness can be reliably ensured even when used at high temperatures.

[0010] In the above-mentioned holding device, the first member has an internal electrode and a terminal pad connected to the internal electrode; the second member has a fourth through hole that penetrates the third surface and the fourth surface and is different from the second through hole; a terminal member disposed inside the fourth through hole, the terminal member having one end connected to the terminal pad and the other end connected to a connector; a terminal cylindrical member disposed in the fourth through hole so as to cover an outer periphery of the terminal member; It is preferable that the tubular member for the terminal is integrally formed with the first member, is disposed between the refrigerant flow paths of the second member, and is joined to the second member by an adhesive disposed between its outer peripheral surface and the inner peripheral surface of the fourth through hole.

[0011] In addition to the through holes (thrust holes formed by the first through hole, the second through hole, and the third through hole), the holding device is provided with terminal holes (holes formed by the third through hole and the fourth through hole) in which a terminal member for electrically connecting an external power supply and an internal electrode is placed, and these through holes and terminal holes are connected to the atmosphere. Therefore, if the bonding layer is formed of a breathable metal bonding material, it is necessary to maintain airtightness not only for the through holes but also for the terminal holes.

[0012] Therefore, a tubular member for a terminal is disposed in the fourth through hole so as to cover the outer periphery of the terminal member, and the tubular member for a terminal is joined to the second member by an adhesive. Therefore, the adhesive seals the space formed by the outer periphery of the tubular member for a terminal and the inner periphery of each of the third through hole and the fourth through hole. As a result, even if the joining layer is formed of a gas-permeable metal joining material, the tubular member for a terminal and the adhesive can ensure airtightness of the terminal hole.

[0013] In addition, in the above-mentioned holding device, It is preferable that the cylindrical member is joined to the second member by the adhesive on the fourth surface side of an upper surface that forms the refrigerant flow path.

[0014] In this way, by bonding the cylindrical member and the second member with an adhesive on the fourth surface side of the second member where the temperature is lower, the adhesive is cooled by the second member, and deterioration of the adhesive due to heat can be reliably prevented. Therefore, deterioration of the sealing performance due to the adhesive can be reliably prevented, and the cylindrical member and the adhesive can ensure the airtightness of the holding device.

[0015] In addition, in the above-mentioned holding device, the cylindrical member and the first member are both made of ceramics, The tubular member is preferably formed integrally with the first member.

[0016] Here, if the tubular member is joined to the first member with an adhesive, when the first member becomes hot (e.g., 250°C or higher), the adhesive deteriorates and the tubular member and the first member separate (a gap forms between the tubular member and the first member), which may make it impossible to ensure the airtightness of the holding device.

[0017] Therefore, by forming the tubular member and the first member from ceramics and forming the tubular member integrally with the first member, even if the first member becomes hot, the tubular member and the first member will not separate (no gap will be created between the tubular member and the first member), thereby firmly ensuring the airtightness of the holding device.

[0018] In addition, in the above-mentioned holding device, a ring-shaped ceramic member formed integrally with the first member on an outer periphery of the second surface; It is preferable that the ceramic member has an end portion joined to the second member by an adhesive disposed between its inner surface and the outer surface of the second member, on the fourth surface side of the upper surface forming the refrigerant passage.

[0019] In this way, the annular ceramic member and adhesive ensure airtightness of the holding device at the outer periphery of the holding device. Also, since the annular ceramic member and the second member are joined by adhesive on the fourth surface side of the second member, where the temperature is lower, the adhesive is cooled by the second member, and deterioration of the adhesive due to heat can be reliably prevented. Effect of the Invention

[0020] According to the present disclosure, it is possible to provide a holding device that can ensure airtightness even when the bonding layer is formed from a breathable metal bonding material. [Brief description of the drawings]

[0021] [Figure 1] 1 is a schematic perspective view of an electrostatic chuck according to an embodiment; [Diagram 2]1 is a schematic configuration diagram of an electrostatic chuck of an embodiment of the present invention taken along an XZ cross section. [Diagram 3] 1 is a schematic configuration diagram of an electrostatic chuck in an XY plane according to an embodiment. [Figure 4] FIG. [Diagram 5] FIG. 2 is a schematic diagram of the XY cross section of the base member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] A holding device according to an embodiment of the present disclosure will be described in detail with reference to the drawings. In this embodiment, the holding device will be described by taking as an example an electrostatic chuck used in a semiconductor manufacturing device such as a film forming device (such as a CVD film forming device or a sputtering film forming device) or an etching device (such as a plasma etching device).

[0023] Therefore, the electrostatic chuck 1 of this embodiment will be described with reference to Figs. 1 to 5. 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 Figs. 1 and 2, 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. The plate-shaped member 10 is an example of a "first member" in the present disclosure, and the base member 20 is an example of a "second member" in the present disclosure.

[0024] In the following description, for convenience of explanation, the X, Y and Z 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 directions of the electrostatic chuck 1.

[0025] As shown in Fig. 1, the plate-shaped member 10 is a plate-shaped, more specifically, disk-shaped member, and is made of ceramics. Specifically, the plate-shaped member 10 has a stepped disk shape in which two disks of different diameters overlap each other with a common central axis Ca (see Fig. 2) (more specifically, a disk-shaped upper stage portion 10a having a smaller diameter overlaps a disk-shaped lower stage portion 10b having a larger diameter). In this way, the lower stage portion 10b is provided on the opposite side of the holding surface 11 side with respect to the upper stage portion 10a in the thickness direction of the plate-shaped member 10 (a direction that coincides with the Z-axis direction, a vertical direction), and has a larger outer periphery than the upper stage portion 10a as viewed in the Z-axis direction.

[0026] As the ceramic, various ceramics are used, 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).

[0027] The plate-like member 10 has a holding surface 11 (upper surface) for holding a semiconductor wafer W, and a lower surface 12 provided on the opposite side to the holding surface 11 in the thickness direction (i.e., the Z-axis direction) of the plate-like member 10. In this embodiment, the upper portion 10a has the holding surface 11. Note that the holding surface 11 is an example of a "first surface" in the present disclosure, and the lower surface 12 is an example of a "second surface" in the present disclosure.

[0028] The diameter of the lower portion 10b of the plate-like member 10 is larger than that of the upper portion 10a, for example, about 150 to 300 mm for the upper portion 10a, and about 180 to 400 mm for the lower portion 10b. The thickness of the plate-like member 10 is, for example, about 2 to 6 mm. The thermal conductivity of the plate-like member 10 is preferably within a range of 10 to 50 W / mK (more preferably, 18 to 30 W / mK).

[0029] The holding surface 11 of the plate-like member 10 has an uneven shape. Specifically, as shown in Figs. 2 and 3, a ring-shaped convex seal band 16 is formed near the outer edge of the holding surface 11, and a plurality of independent columnar convex portions 17 are formed inside the seal band 16. The cross section (XZ cross section) of the seal band 16 is substantially rectangular as shown in Fig. 2. 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, about 0.5 mm to 5.0 mm.

[0030] 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 seal band 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 portions of the holding surface 11 of the plate-like member 10 on the inner side of the seal band 16 where the protrusions 17 are not formed are recesses 18.

[0031] The semiconductor wafer W is supported by the seal band 16 and a plurality of protrusions 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, as shown in Fig. 2, 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 recesses 18 of the holding surface 11). An inert gas (e.g., helium gas) is supplied to this space S via gas holes 30b.

[0032] In such a plate-like member 10, cylindrical first through holes 15a, 15b are formed penetrating between the holding surface 11 and the lower surface 12 in the thickness direction (Z-axis direction, up-down direction in FIG. 2). The first through hole 15a is a part of the lift pin insertion hole 30a, and the first through hole 15b is a part of the gas hole 30b. In the following description, the first through holes 15a, 15b may be referred to as "first through hole 15," and the lift pin insertion hole 30a and the gas hole 30b may be referred to as "through hole 30."

[0033] 4, a circular bottomed hole 19 is provided in the bottom surface 12 of the plate-like member 10 so as to include the opening of the first through hole 15. An end of a cylindrical member 35 is placed in the bottomed hole 19, and the cylindrical member 35 is joined to the plate-like member 10. The cylindrical member 35 is made of ceramics, like the plate-like member 10, and is made of the same material as the plate-like member 10. The cylindrical member 35 and the plate-like member 10 are separately produced, and the cylindrical member 35 is joined to the plate-like member 10. The cylindrical member 35 is formed integrally with the plate-like member 10 by diffusion bonding within the bottomed hole 19 of the plate-like member 10. The cylindrical member 35 and the plate-like member 10 may be integrated together by simultaneously firing the cylindrical member 35 and the plate-like member 10. The tip (lower end) of the cylindrical member 35 is located at approximately the same position as the lower surface 22 of the base member 20.

[0034] As a method for producing (co-firing) the tubular member 35, a cylindrical tubular member (tubular member 35 before sintering) may be produced in advance from a green sheet, and then the tubular member may be inserted into the countersunk hole (bottomed hole 19) on the lower surface of the plate-like member before sintering, and the tubular member and the plate-like member before sintering may be bonded together by a solvent and thermocompression bonding, and then the two may be sintered (co-firing). Alternatively, a plate-like member in a thick green sheet state may be formed at the position where the tubular member 35 will be disposed, and after the plate-like member is sintered, unnecessary parts other than the plate-like member 10 and the tubular member 35 may be scraped off from the sintered plate-like member by mechanical processing such as grinding. Alternatively, the plate-like member before sintering and the cylindrical tubular member may be formed together from green sheets, and then sintered.

[0035] 2, the plate-like member 10 has therein a chuck electrode 50 and a heater electrode 52. 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 (for example, tungsten, molybdenum, etc.). The heater electrode 52 has, for example, a pattern extending in a substantially spiral shape when viewed in the Z-axis direction, and is made of a conductive material (for example, tungsten, molybdenum, platinum, etc.).

[0036] The power supply to the chuck electrode 50 is performed by connecting a connector 80 connected to an external power source to a terminal member 70 having an internal conductive member 71 joined to a terminal pad 60 connected to the chuck electrode 50 through a via 61. That is, the external power source is electrically connected to the terminal pad 60 through the connector 80 and the terminal member 70, and power is supplied from the external power source to the chuck electrode 50 through the connector 80, the terminal member 70 (conductive member 71), the terminal pad 60, and the via 61. As a result, a voltage is applied from the external power source to the chuck electrode 50, an electrostatic attractive force is generated in the chuck electrode 50, and the semiconductor wafer W is attracted to and held on the holding surface 11 by this electrostatic attractive force. Although the power supply structure to the heater electrode 52 is not shown, it is basically the same as the power supply structure of the chuck electrode 50.

[0037] Furthermore, an annular member 13 is provided on the outer periphery of the lower surface of the plate-shaped member 10 (lower stage portion 10b) so as to cover the base member 20. The annular member 13 is made of ceramics, like the plate-shaped member 10, and is diffusion-bonded to the lower surface 12 of the plate-shaped member 10 to be formed integrally with the plate-shaped member 10. The annular member 13 and the plate-shaped member 10 may be integrated by simultaneously firing the annular member 13 and the plate-shaped member 10. The tip (lower end) of the annular member 13 is located at approximately the same position as the lower surface 22 of the base member 20. The tip of the annular member 13 is bonded to the base member 20 by an adhesive 76 disposed between the inner periphery of the annular member 13 and the outer periphery of the base member 20, on the lower surface 22 side of the base member 20 from the upper surface 23a that forms the refrigerant flow path 23 of the base member 20. In this embodiment, the annular member 13 is bonded to the base member 20 by the adhesive 76 near the lower surface 22 of the base member 20.

[0038] A gap 77 is formed between the annular member 13 and the base member 20. The gap 77 may be set to a size (e.g., about 0.1 to 2.0 mm) that prevents the annular member 13 from contacting the base member 20 even due to a difference in thermal expansion between the annular member 13 and the base member 20. By forming such a gap 77, damage to the annular member 13 can be reliably prevented.

[0039] 2, the base member 20 is disposed on the side opposite to the holding surface 11 with respect to the plate-like member 10. The base member 20 is formed, for example, in a cylindrical shape. The base member 20 is formed, for example, from a metal (for example, aluminum or an aluminum alloy), but may be formed from a material other than metal.

[0040] 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 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.

[0041] The diameter of the base member 20 is, for example, about 180 to 400 mm. The thickness (dimension in the Z-axis direction) of the base member 20 is, for example, about 20 to 50 mm. The thermal conductivity of the base member 20 (assumed to be aluminum) is desirably within a range of 160 to 250 W / mK (preferably, about 230 W / mK).

[0042] Further, the base member 20 is formed with a coolant flow passage 23 for flowing a coolant (for example, a fluorine-based inert liquid, water, etc.). As shown in FIG. 5, the coolant flow passage 23 is formed in a spiral shape when viewed in the Z-axis direction, and is connected to a supply port 27 provided on the radially outer side of the base member 20 and an exhaust port 28 provided on the center of the base member 20. Then, the coolant supplied to the base member 20 from the supply port 27 flows through the coolant flow passage 23 and is discharged from the exhaust port 28 to the outside of the base member 20 as shown by the arrows in FIG. 5. The supply port 27 and the exhaust port 28 may be reversed. In this way, the base member 20 is cooled by flowing the coolant through the coolant flow passage 23 of the base member 20, and the plate-like member 10 is thereby cooled through the bonding layer 40.

[0043] As shown in FIG. 2, the base member 20 has a cylindrical second through hole 25 penetrating between the upper surface 21 and the lower surface 22 in the thickness direction (Z-axis direction, vertical direction in FIG. 2). The second through hole 25 is provided between the refrigerant flow paths 23 in the XZ cross-sectional view (a position sandwiched between adjacent refrigerant flow paths 23 in the Z-axis view). A tubular member 35 integrally formed with the plate-like member 10 is disposed in the second through hole 25. A tip portion of the tubular member 35 is bonded to the base member 20 by an adhesive 36 on the lower surface 22 side of the base member 20 from the upper surface 23a forming the refrigerant flow path 23 (that is, between the upper surface 23a and the lower surface 22 in the Z-axis direction). In this embodiment, the tubular member 35 is bonded to the base member 20 by an adhesive 36 in the vicinity of the lower surface 22 of the base member 20.

[0044] A gap 37 (see FIG. 4) is formed between the cylindrical member 35 and the second through hole 25. The gap 37 may be set to a size (for example, about 0.1 to 2.0 mm) that prevents the cylindrical member 35 from contacting the base member 20 even due to a difference in thermal expansion between the cylindrical member 35 and the base member 20. By forming such a gap 37, damage to the cylindrical member 35 can be reliably prevented.

[0045] Further, the base member 20 is formed with a fourth through hole 29 different from the second through hole 25. The fourth through hole 29 is also provided between the refrigerant channels 23 in the XZ cross-sectional view (at a position sandwiched between adjacent refrigerant channels 23 in the Z-axis direction view), similar to the second through hole 25. The terminal member 70 and an insulating sleeve 75 (terminal cylindrical member) are arranged in the fourth through hole 29. The insulating sleeve 75 is a cylindrical member made of ceramics, and is arranged in the fourth through hole 29 so as to surround the outer periphery of the terminal member 70. The insulating sleeve 75 is integrally formed with the plate-shaped member 10 by diffusion bonding an end portion to the plate-shaped member 10 (bottomed hole 19). By providing such an insulating sleeve 75, insulation between the conductive member 71 provided in the terminal pad 60 or the terminal member 70 and the base member 20 and the bonding layer 40 can be ensured even at high temperatures.

[0046] The tip portion of the insulating sleeve 75 is bonded to the base member 20 by the adhesive 36 on the lower surface 22 side of the base member 20 from the upper surface 23a forming the refrigerant flow path 23 (i.e., between the upper surface 23a and the lower surface 22 in the Z-axis direction). In this embodiment, the cylindrical member 35 is bonded to the base member 20 by the adhesive 36 in the vicinity of the lower surface 22 of the base member 20, and a gap 77 is formed between the insulating sleeve 75 and the fourth through hole 29. The gap 77 may be set to a degree (for example, about 0.1 to 2.0 mm) that prevents the insulating sleeve 75 from contacting the base member 20 even due to a difference in thermal expansion between the insulating sleeve 75 and the base member 20. By forming such a gap 77, damage to the insulating sleeve 75 can be reliably prevented. The tip of the terminal member 70 is bonded to the insulating sleeve 75 by the adhesive 26 in the vicinity of the lower surface 22 of the base member 20.

[0047] 2, 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. The thickness of the bonding layer 40 (the dimension in the Z-axis direction) is, for example, about 0.1 to 1.0 mm.

[0048] The bonding layer 40 is made of a metal bonding material having air permeability. 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 may cause bonding defects due to insufficient heat resistance, so the metal bonding material is used as the bonding layer 40. In order to effectively relieve stress caused by the difference in thermal expansion between the plate-like member 10 and the base member 20, the metal bonding material having air permeability is used as the bonding layer 40. In this way, by using the metal bonding material having air permeability as the bonding layer 40, heat resistance and stress relaxation performance are improved, so that it is possible to prevent bonding defects between the plate-like member 10 and the base member 20 from occurring even when the electrostatic chuck 1 is used at high temperatures.

[0049] The breathable metal bonding material is a bonding material mainly composed of a metal material having gaps through which a fluid (gas) can flow, and may be, for example, a material made of a metal mesh such as metal fiber, porous material, or mesh structure and a bonding material such as a brazing material, in which the bonding material such as the brazing material is inserted between the fibers or in some of the pores, and gaps through which a fluid (gas) can flow, or a material made of a plurality of columnar metal pieces and a brazing material, and gaps through which a fluid (gas) can flow, etc. Examples of metals that can be used to form the metal mesh or metal pieces include titanium, nickel, aluminum, copper, brass, alloys of these, and stainless steel.

[0050] 4, a cylindrical third through hole 45 is formed in the bonding layer 40 and is located between the first through hole 15 and the second through hole 25. The third through hole 45 is coaxial with the first through hole 15 and the second through hole 25. The diameter of the third through hole 45 is larger than that of the first through hole 15 and is equal to that of the second through hole 25. The first through hole 15, the third through hole 45, and the second through hole 25 are arranged in series in the Z-axis direction (the axial direction of the electrostatic chuck 1).

[0051] The first through hole 15a, the third through hole 45, and the second through hole 25 form a lift pin insertion hole 30a that penetrates the electrostatic chuck 1 in the Z-axis direction. A lift pin (not shown) that pushes up the semiconductor wafer W from above the holding surface 11 is inserted into the lift pin insertion hole 30a from the lower surface 22 side of the base member 20.

[0052] Further, the first through hole 15b, the third through hole 45, and the second through hole 25 form a gas hole 30b penetrating the electrostatic chuck 1 in the Z-axis direction. The gas hole 30b 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 30b 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.

[0053] In such an electrostatic chuck 1, a permeable metal bonding material is used as the bonding layer 40 in order to effectively relieve stress caused by the difference in thermal expansion between the plate-like member 10 and the base member 20, and therefore a fluid (gas) can flow through the bonding layer 40. Therefore, the through hole 30 and the like provided in the electrostatic chuck 1 are connected to the atmosphere (outside) via the bonding layer 40 (third through hole 45), making it difficult to maintain the airtightness of the electrostatic chuck 1, and there is a risk that the airtightness of the electrostatic chuck 1 cannot be ensured.

[0054] Therefore, in the electrostatic chuck 1 of the present embodiment, the cylindrical member 35 formed integrally with the plate-like member 10 so as to surround the opening of the first through hole 15 is disposed inside the second through hole 25 and the third through hole 45, and the cylindrical member 35 is bonded to the base member 20 by the adhesive 36. Therefore, the adhesive 36 seals the space formed by the outer circumferential surface of the cylindrical member 35 and the inner circumferential surfaces of the second through hole 25 and the third through hole 45. As a result, even if the bonding layer 40 is formed of a gas-permeable metal bonding material, the cylindrical member 35 and the adhesive 36 can ensure the airtightness of the electrostatic chuck 1. By ensuring the airtightness of the electrostatic chuck 1 in this manner, it is possible to prevent the metal bonding material constituting the bonding layer 40 from being exposed to a vacuum.

[0055] Furthermore, since the cylindrical member 35 and the plate-shaped member 10 are made of ceramics and the cylindrical member 35 is formed integrally with the plate-shaped member 10, even if the plate-shaped member 10 becomes hot, the cylindrical member 35 and the plate-shaped member 10 will not separate (no gap will be formed between the cylindrical member 35 and the plate-shaped member 10), and the airtightness of the electrostatic chuck 1 can be firmly ensured.

[0056] Moreover, the cylindrical member 35 is disposed between the coolant passages 23, and the cylindrical member 35 and the base member 20 are joined by the adhesive 36 in the vicinity of the lower surface 22 of the base member 20, where the temperature is low. Therefore, even at high temperatures, the adhesive 36 is cooled by the base member 20, so that deterioration of the adhesive 36 due to heat can be reliably prevented. Therefore, even when used at high temperatures, deterioration of the sealing performance of the adhesive 36 can be reliably prevented, and the cylindrical member 35 and the adhesive 36 can reliably ensure the airtightness of the electrostatic chuck 1.

[0057] Furthermore, in the electrostatic chuck 1 of this embodiment, a ceramic annular member 13 formed integrally with the plate-shaped member 10 is provided on the outer periphery of the lower surface 12 of the plate-shaped member 10 (lower stage portion 10b). The tip of the annular member 13 is bonded to the base member 20 in the vicinity of the lower surface 22 of the base member 20 by an adhesive 36 disposed between the inner periphery of the annular member 13 and the outer periphery of the base member 20. Therefore, airtightness can be ensured by the annular member 13 and the adhesive 36 in the outer periphery of the electrostatic chuck 1. The annular member 13 and the base member 20 are bonded to each other by the adhesive 36 in the vicinity of the lower surface 22 of the base member 20 where the temperature is low. Therefore, the adhesive 36 is cooled by the base member 20, and deterioration of the adhesive 36 due to heat can be reliably prevented, and deterioration of the sealing performance of the adhesive 36 can be reliably prevented even when used at high temperatures.

[0058] In the electrostatic chuck 1 of the present embodiment, an insulating sleeve 75 formed integrally with the plate-shaped member 10 is disposed in a terminal hole (a hole formed by the third through hole 45 and the fourth through hole 29) in which a terminal member 70 for electrically connecting the chuck electrode 50 and the heater electrode 52 to an external power supply is disposed, so as to cover the outer periphery of the terminal member 70. The insulating sleeve 75 is bonded to the base member 20 by an adhesive 36 in the vicinity of the lower surface 22 of the base member 20. This ensures airtightness of the terminal hole, and therefore ensures airtightness of the electrostatic chuck 1.

[0059] As described above, according to the electrostatic chuck 1 of the present embodiment, the cylindrical member 35 is disposed inside the second through hole 25 and the third through hole 45 so as to surround the opening of the first through hole 15, and the cylindrical member 35 is bonded to the base member 20 by the adhesive 36. Therefore, the adhesive 36 seals the space formed by the outer circumferential surface of the cylindrical member 35 and the inner circumferential surfaces of the second through hole 25 and the third through hole 45. Therefore, even if the bonding layer 40 is formed of a gas-permeable metal bonding material, the cylindrical member 35 and the adhesive 36 can ensure the airtightness of the electrostatic chuck 1.

[0060] Moreover, since the cylindrical member 35 is disposed between the coolant passages 23, the temperature of the cylindrical member 35 can be lowered, and deterioration of the adhesive 36 due to heat can be suppressed. This makes it possible to prevent deterioration of the sealing performance of the adhesive 36. Therefore, according to the electrostatic chuck 1 of the present embodiment, airtightness can be reliably ensured even when used at high temperatures.

[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 a holding surface. [Explanation of symbols]

[0062] 1. Electrostatic chuck 10 Plate-shaped member 11 Holding surface 12 Bottom side 13 Annular member 15 First through hole 20 Base material 21 Top side 22 Bottom side 23 Coolant flow path 23a Top side 25 Second through hole 29 4th Through Hole 35 Cylindrical member 36 Adhesive 40 Bonding layer 45 3rd Through Hole 50 Chuck electrode 52 Heater electrode 60 Terminal Pad 70 Terminal material 71 Conductive materials 75 Insulating sleeve W Semiconductor wafer

Claims

1. A first member including a first surface, a second surface provided on an opposite side to the first surface, and a first through hole penetrating the first surface and the second surface; a second member including a third surface, a fourth surface provided on the opposite side to the third surface, a refrigerant flow path through which a refrigerant flows, and a second through hole penetrating the third surface and the fourth surface and communicating with the first through hole; a third through hole that communicates with the first through hole and the second through hole is formed, and a bonding layer is disposed between the second surface of the first member and the third surface of the second member to bond the first member and the second member, A holding device for holding an object on the first surface of the first member, The bonding layer is formed of a metal bonding material having a gap, a cylindrical member disposed inside the second through hole and the third through hole so as to surround an opening of the first through hole; The cylindrical member is disposed between the refrigerant flow paths of the second member, and is joined to the second member by an adhesive disposed between an outer circumferential surface of the cylindrical member and an inner circumferential surface of the second through hole on the fourth surface side from an upper surface that forms the refrigerant flow path. A holding device characterized in that

2. 2. The holding device according to claim 1, the first member has an internal electrode and a terminal pad connected to the internal electrode; the second member has a fourth through hole that penetrates the third surface and the fourth surface and is different from the second through hole; a terminal member disposed inside the fourth through hole, the terminal member having one end connected to the terminal pad and the other end connected to a connector; a terminal tubular member disposed in the fourth through hole so as to cover an outer periphery of the terminal member; The terminal tubular member is integrally formed with the first member, and is disposed between the refrigerant flow paths of the second member. The terminal tubular member is joined to the second member by an adhesive disposed between an outer circumferential surface of the terminal tubular member and an inner circumferential surface of the fourth through hole. A holding device characterized in that

3. The holding device according to claim 1 or 2, the cylindrical member and the first member are both made of ceramics, The cylindrical member is integrally formed with the first member. A holding device characterized in that

4. A first member having a first surface, a second surface provided on the opposite side of the first surface, and a first through hole penetrating the first surface and the second surface; a second member including a third surface, a fourth surface provided on the opposite side to the third surface, a refrigerant flow path through which a refrigerant flows, and a second through hole penetrating the third surface and the fourth surface and communicating with the first through hole; a third through hole that communicates with the first through hole and the second through hole is formed, and a bonding layer is disposed between the second surface of the first member and the third surface of the second member to bond the first member and the second member, A holding device for holding an object on the first surface of the first member, The bonding layer is formed of a metal bonding material having a gap, a cylindrical member disposed inside the second through hole and the third through hole so as to surround an opening of the first through hole; the cylindrical member is disposed between the refrigerant flow paths of the second member and joined to the second member by an adhesive disposed between an outer circumferential surface of the cylindrical member and an inner circumferential surface of the second through hole; a ring-shaped ceramic member formed integrally with the first member on an outer periphery of the second surface; The ceramic member has an end portion bonded to the second member by an adhesive disposed between an inner peripheral surface of the ceramic member and an outer peripheral surface of the second member on the fourth surface side from an upper surface that forms the refrigerant flow path. A holding device characterized in that

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