Bonding body and electrostatic chuck

Abstract

This joined body comprises a plate-form first member, a flat plate-form second member, and a joining part that is positioned between the first and second members and that joins the first and second members, wherein the joining part is provided with: a first joining layer that is formed from a first joining material and that is positioned on the first-member side; a second joining layer that is formed from a second joining material and that is positioned on the second-member side; and a flat plate-form metal layer that is positioned between the first and second joining layers and that has formed therein a plurality of holes that communicate with each other, the metal layer having a first joining material impregnation layer, which is positioned on the first-joining-layer side and in which the plurality of holes are impregnated with the first joining material, a second joining material impregnation layer, which is positioned on the second-joining-layer side and in which the plurality of holes are impregnated with the second joining material, and an empty-hole layer, which is positioned between the first and second joining material impregnation layers and in which the plurality of holes are empty.

Description

[Technical field]

[0001] The present invention relates to a joined body in which two members are joined together. [Background technology]

[0002] Conventionally, in a joint in which two components made of metal, ceramic, etc. are joined using a filler metal such as a brazing material, or a joining material such as an adhesive, techniques have been proposed for suppressing distortion caused by differences in the thermal expansion coefficients of the two components (see, for example, Patent Documents 1 and 2).

[0003] Patent document 1 discloses a technology in which a bonding layer that joins two components has solder and wire mesh, thereby making the thickness of the bonding layer uniform and ensuring the thickness, and suppressing the decrease in the ability to relieve thermal stress.

[0004] Patent Document 2 discloses a technique in which a ceramic material and a metal material are joined together by interposing a metal porous material as an intermediate layer, thereby alleviating thermal stress by deformation of the intermediate layer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2010-179313 A [Patent Document 2] JP 2012-91975 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the technology described in Patent Document 1, the cell structure is fixed by a bonding layer after bonding, so there is a problem that the stress buffering effect is reduced when the bonded body is used. In addition, Patent Document 2 does not mention the degree of impregnation of the brazing material into the metal porous material, and depending on the degree of impregnation of the brazing material into the metal porous material, bonding may not be performed sufficiently or the stress buffering effect may be reduced.

[0007] The present invention has been made to solve the above-mentioned problems, and aims to provide another technique capable of buffering stress in a bonded structure in which two components are bonded using a bonding material. [Means for solving the problem]

[0008] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following forms.

[0009] (1) According to one aspect of the present invention, there is provided a bonded body comprising a plate-like first member, a flat-plate-like second member, and a bonding portion disposed between the first member and the second member to bond the first member and the second member, the bonding portion comprising a first bonding layer made of a first bonding material and disposed on the first member side, a second bonding layer made of a second bonding material and disposed on the second member side, and a flat metal layer disposed between the first bonding layer and the second bonding layer and having a plurality of holes communicating with each other, the metal layer having a first bonding material-impregnated layer disposed on the first bonding layer side and having the first bonding material impregnated into the plurality of holes, a second bonding material-impregnated layer disposed on the second bonding layer side and having the second bonding material impregnated into the plurality of holes, and a void layer disposed between the first bonding material-impregnated layer and the second bonding material-impregnated layer and having the plurality of holes vacant.

[0010] According to this configuration, since the metal layer of the joint has a void layer, the metal layer can be deformed in a heating and cooling environment during use of the joint body. Therefore, the metal layer can buffer the stress caused by the deformation of the first member and the second member, and can suppress distortion, warping, peeling, etc. of the joint body. In addition, since the metal layer is impregnated with the bonding material and the first bonding material-impregnated layer and the second bonding material-impregnated layer are formed on the metal layer, the first bonding layer and the second bonding layer can be sufficiently bonded to the metal layer. As a result, the first member and the second member can be sufficiently bonded to each other, and peeling can be suppressed.

[0011] (2) In the bonded body of the above embodiment, the void layer of the metal layer may be formed from the center to the periphery of the metal layer, whereby stress can be buffered over the entire surfaces of the main surfaces of the first member and the second member, thereby achieving a greater stress buffering effect.

[0012] (3) In the bonded structure of the above embodiment, the metal layer may be metal fiber felt, which allows the fibers to move easily, and thus can more appropriately relieve stress.

[0013] (4) In the bonded body of the above embodiment, the metal fibers may have a fiber diameter of 1 μm or more and 30 μm or less, which allows a pore layer in the metal layer to be appropriately formed.

[0014] (5) In the bonded body of the above embodiment, the porosity of the metal layer may be 50% or more and 90% or less, whereby the stress relaxation effect due to the porous layer of the metal layer can be sufficiently obtained.

[0015] (6) In the bonded body of the above embodiment, the average area of ​​the bonding area of ​​the metal layer with the first bonding layer and the bonding area of ​​the metal layer with the second bonding layer is S mm 2 and the thickness of the metal layer is t mm, t may be 0.07 log(S)-0.1, where t mm is an integer of 1 to 5. In this way, a greater stress relaxation effect can be obtained.

[0016] (7) In the bonded body of the above embodiment, the first bonding material and the second bonding material are each made of an inorganic material or a metal. Since inorganic bonding materials and metal bonding materials have a higher heat resistance than organic bonding materials such as resins, the bonded body can be used in a high-temperature environment, for example, at 300° C. or higher.

[0017] (8) According to another aspect of the present invention, there is provided an electrostatic chuck. The electrostatic chuck includes a bonded body, and a main surface of the first member is a support surface on which an object to be held is placed. According to this configuration, the pore layer of the metal layer relieves stress and suppresses deformation of the first member when the electrostatic chuck is used, thereby suppressing deformation of the support surface of the object to be held and improving the holding performance of the electrostatic chuck.

[0018] The present invention can be realized in various forms, for example, in the form of a holding device including a bonded body, a semiconductor component including a bonded body, a wavelength conversion component including a bonded body, a method for manufacturing a bonded body, and a method for manufacturing an electrostatic chuck including a bonded body. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is an explanatory view illustrating a schematic XZ cross-sectional configuration of a bonded body according to the first embodiment. [Diagram 2] 6 is a diagram showing the relationship between the porosity of a metal layer and the deformation amount of a first member. [Diagram 3] FIG. 11 is a diagram showing the relationship between the thickness of a metal layer and the stress buffering effect. [Figure 4] FIG. 4 is a diagram showing the relationship between the wire diameter of the metal fibers in the metal layer and the stress buffering effect. [Diagram 5] FIG. 11 is an explanatory view illustrating a schematic XZ cross-sectional configuration of a bonded body according to a second embodiment. [Figure 6] FIG. 11 is an explanatory diagram illustrating a schematic planar configuration of a metal layer in a second embodiment. [Figure 7] FIG. 11 is a perspective view illustrating an external configuration of an electrostatic chuck according to a third embodiment. [Figure 8] FIG. 2 is an explanatory diagram illustrating a schematic XZ cross-sectional configuration of the electrostatic chuck. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] First Embodiment FIG. 1 is an explanatory diagram that shows a schematic XZ cross-sectional configuration of the bonded body 10 of the first embodiment. In FIG. 1, the positive Y-axis direction is the direction toward the back side of the paper. In FIG. 1, mutually orthogonal X, Y and Z axes are shown to specify the directions. In this specification, for convenience, the positive Z-axis direction is referred to as the upward direction, and the negative Z-axis direction is referred to as the downward direction, but the bonded body 10 may actually be used in a direction different from these directions.

[0021] The joined body 10 includes a flat plate-like first member 100, a flat plate-like second member 200, and a joining portion 300 disposed between the first member 100 and the second member 200 and joining the first member 100 and the second member 200. The joined body 10 is formed in a substantially cylindrical shape.

[0022] The first member 100 is a plate-like member having a substantially circular flat main surface, and is made of ceramic. The diameter of the first member 100 is, for example, about 5 mm to 350 mm, and the thickness of the first member 100 is, for example, about 0.5 mm to 6 mm. The type of ceramic is, for example, alumina (Al 2 0 3 ), aluminum nitride (AlN), zirconia (ZrO 2 ), silicon nitride (Si 3 N 4 Various ceramics such as silicon carbide (SiC) can be used. Furthermore, the first member 100 may be plated with a metal. The dimensions of the first member 100 can be set appropriately depending on the intended use, etc.

[0023] The second member 200 is, for example, a plate-like member having a substantially circular flat main surface with the same diameter as the first member 100, and is made of metal. In this embodiment, the thickness of the second member 200 is, for example, about 1 mm to 30 mm. The second member 200 may be a substantially circular plate with a different diameter from that of the first member 100. As for the type of metal, various metals such as stainless steel, copper, aluminum, and aluminum alloy can be used. The dimensions of the second member 200 can be appropriately set depending on the purpose of use, etc.

[0024] Bonding portion 300 bonds first member 100 and second member 200. Bonding portion 300 includes a first bonding layer 310 made of a first bonding material and disposed on the first member 100 side, a second bonding layer 320 made of a second bonding material and disposed on the second member 200 side, and a metal layer 330 disposed between first bonding layer 310 and second bonding layer 320.

[0025] The first and second bonding materials may be, for example, a brazing material containing titanium (Ti), a brazing material such as silver brazing, a filler material such as solder, an adhesive material such as silicone resin, acrylic resin, epoxy resin, or an inorganic adhesive such as glass paste. When an inorganic or metal material is used as the first and second bonding materials, the heat resistance temperature is higher than that of an organic adhesive such as resin, so that the bonded body 10 can be used even in a high temperature environment such as 300°C or higher, which is preferable. The first and second bonding materials may be different from each other or may be the same. In this embodiment, the thickness of the first bonding layer 310 and the second bonding layer 320 is, for example, about 0.05 mm. The thickness of the first bonding layer 310 and the second bonding layer 320 may be set appropriately. In the following description, when the first bonding material and the second bonding material are not distinguished from each other, they are also simply called "bonding materials", and when the first bonding layer and the second bonding layer are not distinguished from each other, they are also simply called "bonding layers".

[0026] The metal layer 330 is a plate-like member having a substantially circular planar main surface with the same diameter as the first member 100 and the second member 200, and has a plurality of holes that communicate with each other. The metal layer 330 of this embodiment is a metal fiber felt. Nickel, aluminum, copper, brass, stainless steel, alloys thereof, etc. can be used as the material of the metal fiber. The thickness t (FIG. 1) of the metal layer 330 is not particularly limited, but is, for example, about 0.2 mm to 3 mm. The thickness of the metal layer 330 can be appropriately set, for example, based on the relationship with the bonding area of ​​the first bonding layer 310 and the second bonding layer 320. The porosity of the metal layer 330 is not particularly limited, but is, for example, 50% to 90%. The wire diameter of the metal fiber is not particularly limited, but is, for example, 1 μm to 30 μm.

[0027] The metal layer 330 has a first bonding material-impregnated layer 331 disposed on the first bonding layer 310 side and having a plurality of holes impregnated with the first bonding material, a second bonding material-impregnated layer 332 disposed on the second bonding layer 320 side and having a plurality of holes impregnated with the second bonding material, and a void layer 333 disposed between the first bonding material-impregnated layer 331 and the second bonding material-impregnated layer 332 and having a plurality of voids. The bonded body 10 of this embodiment is formed by bonding the first member 100 and the second member 200 with the first bonding material and the second bonding material via the metal layer 330. When manufacturing the bonded body 10, a part of the first bonding material permeates a part of the metal layer 330 to form the first bonding material-impregnated layer 331, and a part of the second bonding material permeates a part of the metal layer 330 to form the second bonding material-impregnated layer 332. At this time, in the metal layer 330, a portion into which neither the first bonding material nor the second bonding material permeates is formed in a layer shape, and this portion becomes a void layer 333. In the bonded body 10 of the present embodiment, as shown in the figure, the void layer 333 is formed from the center CP of the metal layer 330 to the outer periphery OP1.

[0028] As described above, in the joined body 10 of this embodiment, the first member 100 is made of ceramic, and the second member 200 is made of metal, and the thermal expansion coefficients of the first member 100 and the second member 200 may differ from each other. Therefore, the deformation amount of the first member 100 and the second member 200 may differ with the change in the temperature of use of the joined body 10. According to the joined body 10 of this embodiment, the metal layer 330 of the joint 300 has a void layer 333, and the void layer 333 can deform relatively freely. Therefore, even if the first member 100 and the second member 200 deform at different deformation rates with the change in the temperature of use of the joined body 10, the void layer 333 of the metal layer 330 deforms, and the stress generated with the deformation of the first member 100 and the second member 200 can be alleviated. As a result, peeling and warping of the first member 100 and the second member 200 can be suppressed.

[0029] In the bonded body 10 of the present embodiment, the void layer 333 is formed from the center CP to the outer periphery OP1 of the metal layer 330, and therefore the stress buffering effect of the void layer 333 can be obtained over the entire main surfaces of the first member 100 and the second member 200. Therefore, peeling and warping can be further suppressed.

[0030] Furthermore, according to the bonded body 10 of the present embodiment, the metal layer 330 is impregnated with the bonding material, and the first bonding material-impregnated layer 331 and the second bonding material-impregnated layer 332 are formed on the metal layer 330, so that the first bonding layer 310 and the second bonding layer 320 can be sufficiently bonded to the metal layer 330. As a result, the first member 100 and the second member 200 can be sufficiently bonded to each other, and peeling between the first member 100 and the second member 200 can be suppressed.

[0031] The results of examining the porosity, thickness, and diameter of the metal fibers of the metal layer 330 will be described below. FIG. 2 is a diagram showing the relationship between the porosity of the metal layer 330 and the deformation amount of the first member 100. The joined body 10 shown in FIG. 2 is a substantially cylindrical body having a diameter of 36 mm. The first member 100 is made of alumina (Al 2 O 3 ) and has a thickness of 3.6 mm. The second member 200 is made of stainless steel and has a thickness of 30 mm. The metal layer 330 is a metal fiber felt, the type of metal is stainless steel, and the fiber material has a wire diameter of 10 μm. The first bonding material and the second bonding material are brazing materials containing titanium (Ti) and are sheet materials with a thickness of 0.05 mm.

[0032] In the bonded body 10 of the example shown in FIG. 2, the porosity of the metal layer 330 was changed to 30%, 50%, 90%, and 95% as shown in the figure, and the deformation amount of the first member 100 after bonding and after a thermal cycle test was examined. Here, the bonding temperature was 930°C. The thermal cycle test was performed for 50 cycles, with one cycle being from room temperature to 350°C. The deformation amount of the first member 100 is the difference in height between the center and the end of the surface (main surface) of the first member 100. The porosity was also calculated by the basis weight A (g / cm) of the metal fibers. 2 ) and thickness B (cm) to calculate the density C (g / cm 3 ) was used to calculate the fiber weight per unit area as follows. Porosity=1-(A / B) / C

[0033] Samples 2 to 5 have the same configuration except for the porosity of metal layer 330. Sample 1 does not include metal layer 330, but the other configuration is the same as Samples 2 to 5.

[0034] In sample 1, the joint 300 does not include the metal layer 330. In this configuration, when the first member 100 and the second member 200 were joined, a crack occurred in the first member 100, and the joining was not possible.

[0035] In sample 2, the porosity of the metal layer 330 is 30%. In sample 2, the deformation amount of the first member 100 during bonding was 30 μm, which was a relatively large deformation. After the thermal cycle test, the deformation amount decreased to 18 μm, but metal fibers were torn in part of the porous layer 333. It is believed that the porosity of the metal layer 330 was 30%, which means there were relatively few voids, and the bonding area and the contact area between the metal fibers increased, reducing the stress buffering effect, and large stress was generated at the contact parts between the metal fibers, which is why the tear occurred.

[0036] In Sample 3, the porosity of the metal layer 330 is 50%, and in Sample 4, the porosity of the metal layer 330 is 90%. In Samples 3 and 4, the deformation of the first component 100 after bonding is suppressed compared to Sample 1, and the amount of deformation of the first component 100 after bonding and after the thermal cycle test is the same. In other words, the metal layer provided a stress buffering effect.

[0037] In sample 5, the porosity of the metal layer 330 is 95%. In this configuration, when the first member 100 and the second member 200 were joined together, the metal layer 330 was almost entirely impregnated with the joining material, and the first member 100 and the second member 200 could not be joined together.

[0038] As shown in FIG. 2, when the porosity of the metal layer 330 is 50% or more and 90% or less, a sufficient stress buffering effect is obtained, and deterioration of the bonded structure 10, such as deformation, peeling, and cracking, can be suppressed.

[0039] Fig. 3 is a diagram showing the relationship between the thickness of the metal layer and the stress buffering effect. The bonded bodies 10 shown in Fig. 3 are of two types, approximately cylindrical, with diameters (indicated as "bonded body diameter" in Fig. 3) of 100 mm and 350 mm. The first member 100 is made of alumina (Al 2 O 3 ) and has a thickness of 6 mm. The second member 200 is made of stainless steel and has a thickness of 23 mm. The metal layer 330 is a metal fiber felt, the type of metal being stainless steel, the fiber material having a wire diameter of 10 μm, and a porosity of 80%. The first bonding material and the second bonding material are brazing materials containing titanium (Ti) and are sheet materials having a thickness of 0.05 mm.

[0040] 3, the first member 100 and the second member 200 having diameters of 100 mm and 350 mm were bonded with a bonding material using metal layers 330 having thicknesses of 0.5 mm, 1.0 mm, and 3.0 mm, respectively. The bonding temperature was 930° C. In this example, the first member 100, the second member 200, the metal layer 330, and the bonding material each having the same diameter were used for bonding.

[0041] As shown in the figure, for both the bonded body diameters of 100 mm and 350 mm, when the thickness of the metal layer 330 was 0.5 mm, some of the metal fibers of the metal layer were torn. When the thickness of the metal layer 330 was 1.0 mm and 3.0 mm, the bonding state was good. In other words, when the thickness of the metal layer 330 was 1.0 mm and 3.0 mm, it can be said that the metal layer provided a stress buffering effect.

[0042] The relationship between the thickness of the metal layer 330 and the stress buffering effect also varies depending on the bonding area. The average area of ​​the bonding area S1 (FIG. 1) between the metal layer 330 and the first bonding layer 310 and the bonding area S2 (FIG. 1) between the metal layer 330 and the second bonding layer 320 is defined as S mm 2 When the thickness of the metal layer 330 is t mm, a greater stress relaxation effect can be obtained by making t≧0.07 log(S)−0.1.

[0043] FIG. 4 is a diagram showing the relationship between the wire diameter of the metal fiber of the metal layer and the stress buffering effect. In the bonded body 10 shown in FIG. 4, the first member 100 is made of silicon (Si) and is a substantially circular plate with a diameter of 5 mm and a thickness of 0.5 mm, which is plated with metal. The second member 200 is made of copper and is a substantially circular plate with a diameter of 20 mm and a thickness of 1 mm. The metal layer is a felt of metal (copper) fiber material with a porosity of 80%, and is a substantially circular plate with a diameter of 7 mm and a thickness of 0.2 mm. These are bonded at a bonding temperature of 280° C. with a sheet-like bonding material made of gold-tin (AuSn) solder with a thickness of 0.05 mm. In this example, the first member 100, the first bonding layer 310, and the second bonding layer 320 have the same diameter, the metal layer 330 has a larger diameter than them, and the second member 200 has an even larger diameter than the metal layer 330.

[0044] In the example shown in FIG. 4, metal fiber felt with different wire diameters (10 μm, 30 μm, 50 μm) was used as the metal layer 330, and after the first member 100 and the second member 200 were joined, observation was performed using transmitted X-rays and cross-sectional observation to confirm the presence or absence of voids.

[0045] As shown in the figure, when the metal fiber diameter was 10 μm and 30 μm, voids were observed after bonding, but when the metal fiber diameter was 50 μm, no voids were observed.

[0046] This is thought to be because when the metal fiber has a wire diameter of 50 μm, even if the porosity is the same as when the metal fiber has a wire diameter of 10 μm or 30 μm, each void becomes larger and is easily impregnated with the bonding material. When metal fiber felt is used as the metal layer 330, if the wire diameter is 30 μm or less, a porous layer can be formed, and therefore, a stress buffering effect can be preferably obtained.

[0047] <Second embodiment> FIG. 5 is an explanatory diagram schematically showing the XZ cross-sectional configuration of the bonded body 10A in the second embodiment. In FIG. 5, the positive Y-axis direction is the direction toward the back side of the paper surface. FIG. 6 is an explanatory diagram schematically showing the planar configuration of the metal layer 330A in the second embodiment. In FIG. 6, the metal layer 330A is shown when viewed from above (the positive Z-axis direction). FIG. 5 can also be said to be a cross-sectional view taken along line A-A in FIG. 6. In FIGS. 5 and 6, the center CP and the outer periphery OP1 of the metal layer 330A are illustrated. In FIG. 6, the outer periphery OP2 of the hole layer 333 of the metal layer 330A is illustrated by a dashed line.

[0048] In the bonded body 10A of the present embodiment, the hole layer 333 of the metal layer 330 is not formed from the center to the outer periphery of the metal layer 330. The outer periphery OP2 of the hole layer 333 is disposed inward by a distance d from the outer periphery OP1 of the metal layer 330A. That is, in the metal layer 330A, between the outer periphery OP1 and the inner side by the distance d, the first bonding material and the second bonding material are impregnated. The metal layer 330A is a disk having a radius R1, and the hole layer 333 is formed in a disk shape having a radius R2 (R2 < R1).

[0049] Also in the bonded body 10A of the present embodiment, since the metal layer 330A includes the hole layer 333, it is possible to buffer the stress accompanying the deformation of the first member 100 and the second member 200, and it is possible to suppress distortion, warpage, peeling, etc. of the bonded body 10A.

[0050] <Third Embodiment> FIG. 7 is a perspective view schematically showing the external appearance configuration of the electrostatic chuck 500 in the third embodiment. FIG. 8 is an explanatory diagram schematically showing the XZ cross-sectional configuration of the electrostatic chuck 500. In FIGS. 7 and 8, for specifying directions, XYZ axes orthogonal to each other are shown. In FIG. 8, the positive Y-axis direction is the direction toward the back side of the paper surface. In this specification, for convenience, the positive Z-axis direction is referred to as the upward direction, and the negative Z-axis direction is referred to as the downward direction, but the electrostatic chuck 500 may actually be installed in a direction different from such a direction.

[0051] The electrostatic chuck 500 is a holding device that attracts and holds an object (e.g., a wafer W) by electrostatic attraction, and is used, for example, to fix the wafer W in a vacuum chamber of a semiconductor manufacturing device. The electrostatic chuck 500 includes a bonded body 10B. The bonded body 10B includes a first member 100B and a second member 200B that are arranged side by side in the vertical direction (Z-axis direction), and a bonding portion 300 that bonds the first member 100B and the second member 200B together.

[0052] The first member 100B is a plate-like member having a substantially circular, flat mounting surface SS, and is made of ceramic (e.g., alumina, aluminum nitride, etc.). That is, the main surface of the first member 100B is the mounting surface SS on which an object to be held is placed. The diameter of the first member 100B is, for example, about 50 mm to 500 mm (usually about 200 mm to 350 mm), and the thickness of the first member 100B is, for example, about 1 mm to 10 mm.

[0053] An chucking electrode 400 (FIG. 8) made of a conductive material (e.g., tungsten or molybdenum) is disposed inside the first member 100B. The chucking electrode 400 has, for example, a substantially circular shape as viewed in the Z-axis direction. When a voltage is applied to the chucking electrode 400 from a power source (not shown), an electrostatic attraction is generated, and the wafer W is attracted and fixed to the mounting surface SS of the first member 100B by this electrostatic attraction.

[0054] The second member 200B is a substantially circular, flat, plate-like member having a larger diameter than the first member 100B. The second member 200B is made of a metal such as aluminum or an aluminum alloy. The diameter of the second member 200B is, for example, about 220 mm to 550 mm (usually 220 mm to 350 mm), and the thickness of the second member 200B is, for example, about 20 mm to 40 mm.

[0055] A coolant flow passage 210 (FIG. 8) is formed inside the second member 200B. When the wafer W held by the first member 100B of the electrostatic chuck 500 is processed using plasma, heat is input from the plasma to the wafer W, and the temperature of the wafer W rises. When a coolant (e.g., a fluorine-based inert liquid or water) flows through the coolant flow passage 210 formed in the second member 200B, the second member 200B is cooled, and the first member 100B is cooled by heat transfer between the second member 200B and the first member 100B via the bonding portion 300, and the wafer W held on the mounting surface SS of the first member 100B is cooled. This realizes temperature control of the wafer W.

[0056] The joint 300 is a plate-like member having a substantially circular flat shape with a diameter equal to that of the first member 100B, and its configuration is similar to that of the first embodiment.

[0057] According to the electrostatic chuck 500 of this embodiment, since the metal layer 330 of the joint 300 includes the void layer 333, it is possible to buffer the stress caused by the deformation of the first member 100B and the second member 200B, and it is possible to suppress peeling and warping of the first member 100B and the second member 200B. Therefore, it is possible to suppress a decrease in the holding performance of the electrostatic chuck 500. In addition, it is possible to suppress deterioration of the electrostatic chuck 500.

[0058] <Modifications of this embodiment> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit and scope of the invention. For example, the following modifications are also possible.

[0059] In the above embodiment, the first member is made of ceramic and the second member is made of metal, but the present invention is not limited to this. For example, the first member and the second member may both be ceramic members, or the first member and the second member may both be metal members. Furthermore, the first member and the second member may be made of materials other than ceramic and metal. For example, the first member and the second member may be made of glass, glass epoxy, resin such as thermoplastic resin and thermosetting resin, paper phenol, paper epoxy, glass composite, metal members having these insulating members formed on the surface, etc.

[0060] The thermal expansion coefficient of the material constituting the first member and the thermal expansion coefficient of the material constituting the second member may be the same or different. Even if the thermal expansion coefficients of both materials are the same, the amount of deformation of each will differ due to the difference in temperature between the first member and the second member. Therefore, when the first member and the second member are joined by the joint 300 of the above embodiment, the stress accompanying the deformation of the first member and the second member can be alleviated.

[0061] The bonded body may further include another layer, such as a metal layer, between at least one of the first member and the bonded portion and the second member and the bonded portion. The other layer may be, for example, a layer formed by evaporation of titanium (Ti) in the brazing material that forms the bonded portion, a pre-formed metallized layer, etc.

[0062] In the above embodiment, metal fiber felt is used as the metal layer, but the present invention is not limited to this, and various metal layers can be used. For example, a metal fiber composite manufactured by weaving metal fibers, such as a metal fiber net or woven fabric, may be used. Also, a metal fiber composite manufactured by intertwining a large number of metal fibers with each other or by bonding them with heat or adhesive, without weaving the metal fibers, such as a web or nonwoven fabric, may be used. Also, a metal foam may be used. A foam is a material having a large number of pores inside.

[0063] The bonding area between the metal layer 330 and the first bonding layer 310 and the bonding area between the metal layer 330 and the second bonding layer 320 may be the same or different.

[0064] In the above embodiment, an electrostatic chuck is used as an example of the holding device, but the holding device is not limited to an electrostatic chuck. For example, the holding device may be configured as a heater device, susceptor, or mounting table for a vacuum device such as CVD, PVD, or PLD (Pulsed Laser Deposition).

[0065] In the above embodiment, the joint body is an approximately circular flat body, but the flat shape is not limited to the above embodiment. For example, the joint body may have a rectangular flat shape, a polygonal flat shape, or the like.

[0066] The present invention has been described above based on the embodiments and modifications, but the above-mentioned embodiments are intended to facilitate understanding of the present invention and do not limit the present invention. The present invention may be modified or improved without departing from the spirit and scope of the claims, and the present invention includes equivalents thereof. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate. [Explanation of symbols]

[0067] 10, 10A, 10B... Joint 100, 100B...First member 200, 200B…Second member 210... Coolant flow path 300…Joint part 310…first bonding layer 320…Second bonding layer 330, 330A…metal layer 331…First bonding material impregnated layer 332…Second bonding material impregnated layer 333…Vacant layer 400...Adsorption electrode 500...Electrostatic chuck CP…center OP1, OP2...Outer circumference R1, R2…Radius SS: Placement surface S1, S2...joint area W…wafer d…Distance

Claims

1. A joint body including a flat-plate-like first member, a flat-plate-like second member, and a joint portion disposed between the first member and the second member and joining the first member and the second member, The joint is A first bonding layer made of a first bonding material and disposed on the first member side; A second bonding layer made of a second bonding material and disposed on the second member side; a flat metal layer disposed between the first bonding layer and the second bonding layer and having a plurality of holes communicating with each other, the metal layer having: a first bonding material-impregnated layer disposed on the first bonding layer side and having the first bonding material impregnated into the plurality of holes; a second bonding material-impregnated layer disposed on the second bonding layer side and having the second bonding material impregnated into the plurality of holes; and a void layer disposed between the first bonding material-impregnated layer and the second bonding material-impregnated layer and having the plurality of holes void; Equipped with The metal layer is a nonwoven felt made of metal fibers, When the average area of ​​the bonding area of ​​the metal layer with the first bonding layer and the bonding area of ​​the metal layer with the second bonding layer is S mm 2 and the thickness of the metal layer is t mm, t≧0.07log(S)−0.1 and 1.0≦t≦3.0, zygote.

2. The joint body according to claim 1 , The void layer of the metal layer is formed from the center to the outer periphery of the metal layer. zygote.

3. The joint body according to claim 1, The outer periphery of the hole layer is disposed inside the outer periphery of the metal layer. zygote.

4. The bonded body according to any one of claims 1 to 3, The wire diameter of the metal fiber is 1 μm or more and 30 μm or less. zygote.

5. The bonded body according to any one of claims 1 to 4, The porosity of the metal layer is 50% or more and 90% or less. zygote.

6. The bonded body according to any one of claims 1 to 5, The first bonding material and the second bonding material are each made of an inorganic material or a metal. zygote.

7. 1. An electrostatic chuck comprising: The bonded body according to any one of claims 1 to 6 is provided, The main surface of the first member is a mounting surface on which an object to be held is placed. Electrostatic chuck.

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