wafer boat

Abstract

A wafer boat is provided. The wafer boat (10) includes an alumina base (20), a cooling base (30), and a ductile internally threaded member (38). The alumina base (20) has a wafer receiving surface (22a) on an upper surface and an electrode (26) built in. The cooling base (30) is joined to a lower surface of the alumina base (20) and has a coolant flow path (32) formed inside. The internally threaded member (38) is housed in a receiving hole (36) that is open on a lower surface of the cooling base (30) in a state in which rotation of a shaft is restricted and in a state in which the internally threaded member (38) is engaged with an engagement portion of the receiving hole (36). The internally threaded member (38) is capable of being screwed with an external thread of a bolt (98) that is inserted from the lower surface side of the cooling base (30).

Description

Technical Field

[0001] This invention relates to a wafer mounting stage. Background Technology

[0002] Conventionally, wafer mounting stages are known to be formed by bonding a ceramic substrate with built-in electrodes and a cooling substrate with internal refrigerant flow paths using an adhesive material. Patent Document 1 describes an example of placing the aforementioned wafer mounting stage on a mounting plate and fixing it with screws. Specifically, an internally threaded hole is provided on the lower surface of the cooling substrate, and the external thread of a bolt inserted from below into a screw insertion hole that extends vertically through the mounting plate engages with the internally threaded hole.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2014-150104 Summary of the Invention

[0006] However, when an internally threaded hole is provided on the lower surface of the cooling substrate and the external threads of a bolt inserted into the mounting plate are engaged, no problem arises if the cooling substrate material is a ductile material (e.g., aluminum), but a problem arises if it is a brittle material (e.g., a metal matrix composite). Specifically, because the bolt pulls the internally threaded hole of the cooling substrate downwards with a large force, cracking may occur if the material is not ductile.

[0007] The present invention was implemented to solve the above-mentioned problems, and its main objective is to enable a wafer stage with a brittle cooling substrate to be securely fastened to a mounting plate without causing problems.

[0008] [1] The wafer stage of the present invention comprises:

[0009] An alumina substrate having a wafer mounting surface on its upper surface and incorporating electrodes; a brittle cooling substrate bonded to the lower surface of the alumina substrate; and

[0010] An extendable connecting member is housed in a receiving hole that is open on the lower surface of the cooling substrate, in a state where the shaft rotation is restricted and the connecting part is engaged with the receiving hole, and has an external thread or an internal thread.

[0011] In this wafer stage, a connecting member with external or internal threads is housed within a receiving hole that is open on the lower surface of the cooling substrate, in a state where its shaft rotation is restricted and it engages with a receiving hole. Because the connecting member's shaft rotation is restricted, it can be screwed onto a connected member with internal or external threads disposed on the lower surface of the cooling substrate. Furthermore, even when the connecting member is pulled towards the mounting plate by the connected member provided on the mounting plate while engaged with the receiving hole, it is not prone to cracking due to its malleability. Therefore, a wafer stage with a brittle cooling substrate can be securely fastened to the mounting plate without problems.

[0012] It should be noted that in this specification, terms such as up and down, left and right, and front and back are sometimes used to describe the invention; however, these terms are merely relative positional relationships. Therefore, when the orientation of the wafer stage is changed, sometimes up and down becomes left and right, and left and right becomes up and down, and this situation is also included within the scope of the invention.

[0013] [2] In the above-mentioned wafer stage (the wafer stage described in [1] above), the connecting member may be a member having the internal thread portion and capable of engaging with the external thread of a bolt inserted from the lower surface side of the cooling substrate.

[0014] [3] In the above-described wafer stage (the wafer stage described in [1] or [2] above), the cooling substrate may be formed of a metal-ceramic composite material or an alumina material. Since metal-ceramic composite materials and alumina materials are brittle materials, the application of the present invention is of great significance. For example, when using a metal-ceramic composite material, it is preferable to use a composite material having the same coefficient of thermal expansion as alumina.

[0015] [4] In the wafer stage described above (the wafer stage described in any one of [1] to [3] above), the engaging portion may be a stepped portion or an inclined portion provided on the inner peripheral surface of the receiving hole, and the connecting member may have a engaged portion that engages with the engaging portion so that the connecting member will not fall out of the receiving hole. Accordingly, the engaging portion and the engaged portion can be manufactured relatively simply. For example, if the engaging portion is a stepped portion, the connecting member may be provided with an engaged portion that is engaged with its stepped portion. In addition, if the engaging portion is an inclined portion, the connecting member may be provided with an inclined surface that is consistent with its inclined portion as the engaged portion.

[0016] [5] In the above-described wafer stage (the wafer stage described in any of [1] to [4] above), the connecting member can restrict the rotation of the axis by hitting the wall of the receiving hole when the axis is to be rotated. Accordingly, the rotation of the axis of the connecting member can be restricted with a relatively simple configuration.

[0017] [6] In the above-described wafer stage (the wafer stage described in any one of [1] to [5] above), the cooling substrate may have a refrigerant flow path inside, and the receiving hole is provided in a region of the cooling substrate that is lower than the bottom surface of the refrigerant flow path. Accordingly, the receiving hole does not obstruct the refrigerant flow path, and therefore does not impair the design freedom of the refrigerant flow path.

[0018] [7] In the above-described wafer stage (the wafer stage described in any one of [1] to [6] above), the bonding member can be stored in the receiving hole in a free state without being bonded to the cooling substrate. Accordingly, it is only necessary to place the bonding member into the receiving hole, so it is not troublesome.

[0019] [8] In the above-described wafer stage (the wafer stage described in any of [1] to [7] above), the bonding member can be engaged with the engaging portion through a stress buffer member whose Young's modulus is lower than that of the bonding member. Accordingly, even if the bonding member is pulled toward the mounting plate by the bonding member provided on the mounting plate, the stress is easily dispersed because a stress buffer member is sandwiched between the bonding member and the engaging portion.

[0020] [9] In the above-described wafer stage (the wafer stage described in any one of [1] to [8] above), the gap between the bonding member and the receiving hole can be filled with a filling material. Accordingly, compared with the case where the gap between the bonding member and the receiving hole is empty, heat conduction becomes better. Therefore, the heat uniformity of the wafer is improved.

[0021]

[10] In the above-described wafer stage (the wafer stage described in any one of [1] to [9] above), the receiving hole may include: a first receiving portion for receiving the connecting member, and a second receiving portion provided from the first receiving portion to the lower surface of the cooling substrate, wherein the engaging portion may be a stepped surface provided at the joint between the first receiving portion and the second receiving portion.

[0022]

[11] In the wafer stage described above (the wafer stage described in

[10] above), the first receiving portion may have an opening on the upper surface of the cooling substrate, and the opening surface may be covered by a bonding layer that bonds the alumina substrate and the cooling substrate. Accordingly, the first receiving portion can be manufactured more easily than the case where the first receiving portion is built into the interior of the cooling substrate. In this structure, the coolant flow path (or coolant flow path trench) needs to be set away from the receiving hole, so the heat homogeneity near the receiving hole of the wafer is easily reduced. In order to suppress such a reduction in heat homogeneity, it is preferable to fill the gap between the bonding member and the receiving hole with a filling material. Accordingly, the heat conduction around the receiving hole becomes good, so the reduction in heat homogeneity can be suppressed.

[0023]

[12] In the above-described wafer stage (the wafer stage described in

[10] or

[11] above), the width of the annular region in which the step surface and the bonding member directly or indirectly contact each other is preferably 3 mm or more. If the width of the annular region is 3 mm or more, even if the bonding member is pulled toward the mounting plate by the bonding member provided on the mounting plate, the stress is easily dispersed because the annular region in which the step surface and the bonding member directly or indirectly contact each other is large. Attached Figure Description

[0024] Figure 1 This is a longitudinal cross-sectional view of the wafer stage 10 located in chamber 94.

[0025] Figure 2 This is a plan view of the chip placement stage 10.

[0026] Figure 3 This is an enlarged cross-sectional view showing the periphery of the receiving hole 36 and the internal thread component 38.

[0027] Figure 4 This is a cross-sectional view of the cooling substrate 30 when it is horizontally cut along the top surface of the receiving hole 36, viewed from above.

[0028] Figure 5 This is an enlarged cross-sectional view showing the refrigerant supply path 321 and the refrigerant discharge path 322.

[0029] Figure 6 This is a manufacturing process diagram of the chip carrier stage 10.

[0030] Figure 7 This is an enlarged cross-sectional view showing another example of the receiving hole 36 and the internal thread component 38.

[0031] Figure 8 This is an enlarged cross-sectional view showing another example of the receiving hole 36 and the internal thread component 38.

[0032] Figure 9 This is an enlarged cross-sectional view of an externally threaded component 80 used as a connecting part.

[0033] Figure 10 This is a longitudinal cross-sectional view of the wafer stage 510 located in chamber 94.

[0034] Figure 11 This is an enlarged cross-sectional view showing the periphery of the receiving hole 536 and the internal thread component 538.

[0035] Figure 12 This is a manufacturing process diagram of the 510 chip carrier stage.

[0036] Figure 13This is a cross-sectional view used to illustrate the dimensions of the receiving hole 536 and the internal thread component 538.

[0037] Figure 14 This is an explanatory diagram when a nut with a triangular prism shape is used as an internal thread component 538.

[0038] Figure 15 This is a longitudinal cross-sectional view of another example of the wafer stage 510. Detailed Implementation

[0039] [First Implementation Method]

[0040] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 This is a longitudinal cross-sectional view of the wafer stage 10 disposed in chamber 94 (a cross-sectional view cut along a surface including the central axis of the wafer stage 10). Figure 2 This is a plan view of the chip stage 10. Figure 3 This is an enlarged cross-sectional view showing the periphery of the receiving hole 36 and the internal thread component 38. Figure 4 This is a cross-sectional view of the cooling substrate 30 when it is horizontally cut along the top surface of the receiving hole 36, viewed from above.

[0041] The wafer stage 10 is a component used for CVD, etching, and other processes on a wafer W using plasma, and it is fixed to a mounting plate 96 disposed inside a semiconductor process chamber 94. The wafer stage 10 includes an alumina substrate 20, a cooling substrate 30, and a metal bonding layer 40.

[0042] The alumina substrate 20 has an outer peripheral portion 24 with an annular focusing ring mounting surface 24a around the outer periphery of the central portion 22 of the circular wafer mounting surface 22a. Hereinafter, the focusing ring is sometimes simply referred to as "FR". A wafer W is mounted on the wafer mounting surface 22a, and a focusing ring 78 is mounted on the FR mounting surface 24a. The FR mounting surface 24a is one level lower than the wafer mounting surface 22a.

[0043] A wafer adsorption electrode 26 is built into the central portion 22 of the alumina substrate 20 on the side near the wafer mounting surface 22a. The wafer adsorption electrode 26 is formed of a material containing, for example, W, Mo, WC, MoC, etc. The wafer adsorption electrode 26 is a unipolar electrostatic adsorption electrode in the shape of a disc or a mesh. The layer in the alumina substrate 20 above the wafer adsorption electrode 26 functions as a dielectric layer. A DC power supply 52 for wafer adsorption is connected to the wafer adsorption electrode 26 via a power supply terminal 54. The power supply terminal 54 is configured to pass through an insulating tube 55 arranged in a through hole that penetrates the cooling substrate 30 and the metal bonding layer 40 in the vertical direction, and reach the wafer adsorption electrode 26 from the lower surface of the alumina substrate 20. A low-pass filter (LPF) 53 is provided between the DC power supply 52 for wafer adsorption and the wafer adsorption electrode 26.

[0044] The cooling substrate 30 is a circular plate component. The material of the cooling substrate 30 is preferably a metal-ceramic composite material. Examples of such composite materials include metal matrix composites (also known as Metal Matrix Composites (MMC)) and ceramic matrix composites (also known as Ceramics Matrix Composites (CMC)). This composite material is a brittle material. The cooling substrate 30 has a refrigerant flow path 32 internally for refrigerant circulation. This refrigerant flow path 32 is connected to a refrigerant supply path and a refrigerant discharge path (not shown). The refrigerant discharged from the refrigerant discharge path is temperature-adjusted and then returns to the refrigerant supply path. The refrigerant flowing through the refrigerant flow path 32 is preferably a liquid, and preferably electrically insulating. Examples of electrically insulating liquids include, for example, fluorine-based inactive liquids. Examples of metal-ceramic composite materials include materials containing Si, SiC, and Ti; materials obtained by impregnating Al and / or Si into a porous SiC body; and composite materials of Al2O3 and TiC. Materials containing Si, SiC, and Ti are referred to as SiSiCTi, materials obtained by impregnating Al in porous SiC are referred to as AlSiC, and materials obtained by impregnating Si in porous SiC are referred to as SiSiC. As composite materials for the cooling substrate 30, AlSiC, SiSiCTi, etc., with coefficients of thermal expansion close to alumina, are preferred. The cooling substrate 30 is connected to the RF power supply 62 via a power supply terminal 64. A high-pass filter (HPF) 63 is disposed between the cooling substrate 30 and the RF power supply 62. The cooling substrate 30 has a flange portion 34 on its lower surface side for clamping the wafer stage 10 to the mounting plate 96.

[0045] A plurality of receiving holes 36 are provided on the cooling substrate 30, and internally threaded components 38 (connecting components) are received in the receiving holes 36. The plurality of receiving holes 36 are provided in a region of the cooling substrate 30 that is lower than the bottom surface 32a of the coolant flow path 32. The plurality of receiving holes 36 are provided at equal intervals (e.g., 6 or 8) along concentric circles (e.g., circles of 1 / 2 or 1 / 3 of the diameter of the wafer W) of the cooling substrate 30. That is, the plurality of receiving holes 36 are arranged as follows: Figure 2 The image shows a region near the center of the wafer stage 10. The receiving hole 36 is shown in the image. Figure 3 The cooling substrate 30 has an opening on its lower surface. The receiving hole 36 includes a first receiving portion 36a, a second receiving portion 36b, and a stepped portion 36c. The first receiving portion 36a is a cuboid space provided in the upper part of the receiving hole 36. The second receiving portion 36b is a cylindrical space provided in the lower part of the receiving hole 36. The stepped portion 36c is the joint between the first receiving portion 36a and the second receiving portion 36b. An internally threaded component 38 is received in the receiving hole 36. The internally threaded component 38 has a cuboid head 38a and a cylindrical portion 38b provided on the lower surface of the head 38a, with threads on the inner circumferential surface of the cylindrical portion 38b. The head 38a of the internally threaded component 38 is received in the first receiving portion 36a of the receiving hole 36. The internally threaded component 38 will not fall out of the receiving hole 36 because the lower surface of its head 38a engages with the stepped portion 36c of the receiving hole 36. The cylindrical portion 38b of the internally threaded component 38 is housed in the second receiving portion 36b of the receiving hole 36. When the internally threaded component 38 is to be rotated, as... Figure 4 As shown, the head 38a contacts the sidewall of the first receiving portion 36a, thus restricting the rotation of the shaft. The internally threaded component 38 is formed of a ductile material (e.g., Ti, Mo, W, etc.).

[0046] The metal bonding layer 40 bonds the lower surface of the alumina substrate 20 and the upper surface of the cooled substrate 30. The metal bonding layer 40 can be, for example, a layer formed of solder or brazing filler metal. The metal bonding layer 40 is formed using, for example, TCB (Thermal Compression Bonding). TCB refers to a known method in which a metal bonding material is sandwiched between two components to be bonded, and the two components are pressure-bonded while heated to a temperature below the solidus temperature of the metal bonding material.

[0047] The outer periphery 24 of the alumina substrate 20, the outer periphery of the metal bonding layer 40, and the side surface of the cooling substrate 30 are covered with an insulating film 42. Examples of insulating films 42 include spray-coated films of alumina, yttrium oxide, etc.

[0048] The aforementioned wafer stage 10 is mounted on a mounting plate 96 disposed inside a cavity 94 via a sealing ring 76. The sealing ring 76 is made of metal or resin, and its outer diameter is slightly smaller than that of the cooling substrate 30. The outer periphery of the wafer stage 10 is mounted to the mounting plate 96 using a clamping member 70. The clamping member 70 is an annular component with a roughly inverted L-shaped cross-section and has an inner peripheral stepped surface 70a. With the inner peripheral stepped surface 70a of the clamping member 70 placed on the flange 34 of the cooling substrate 30 of the wafer stage 10, a bolt 72 is inserted from the upper surface of the clamping member 70 and screwed into a screw hole provided on the upper surface of the mounting plate 96. The bolt 72 is installed at multiple locations (e.g., 8 or 12 locations) at equal intervals along the circumference of the clamping member 70. The clamping member 70 and the bolt 72 can be made of insulating material or conductive material (metal, etc.). Additionally, the central area of ​​the wafer stage 10 is mounted to the mounting plate 96 using bolts 98 (the joined parts). For example... Figure 3 As shown, an external thread 98a is provided at the foot of the bolt 98. The bolt 98 is inserted through the lower surface of the mounting plate 96 into a through hole 97 provided in the mounting plate 96 opposite to the receiving hole 36, and the external thread 98a is screwed into the internal thread member 38 in the receiving hole 36. The upper part of the through hole 97 has a small diameter and the lower part has a large diameter, and there is a step portion 97a between the upper and lower parts. The head of the bolt 98 is engaged in the step portion 97a of the through hole 97. The internal thread member 38 is housed in the first receiving portion 36a of the receiving hole 36 in a state where the shaft rotation is restricted, so the bolt 98 can be screwed into the internal thread member 38. When the bolt 98 is screwed into the internal thread member 38, the internal thread member 38 is pulled toward the mounting plate 96 with its head 38a engaged in the step portion 36c of the receiving hole 36.

[0049] When the wafer stage 10 is used, the wafer placement surface 22a side of the alumina substrate 20 is under vacuum, while the lower surface side of the cooling substrate 30 is exposed to atmospheric pressure. Therefore, the wafer stage 10 tends to convex upwards. Furthermore, when the wafer W is processed with high-power plasma, the wafer placement surface 22a side of the alumina substrate 20 is at a high temperature, while the lower surface side is cooled to a low temperature. Therefore, the wafer placement surface 22a side tends to expand, and the wafer stage 10 tends to convex upwards. However, in this embodiment, the central region of the wafer stage 10 is fixed by bolts 98, thus preventing the wafer stage 10 from convex upwards. Additionally, even though a sealing ring (not shown) is disposed between the central region of the lower surface of the cooling substrate 30 and the upper surface of the mounting plate 96, since the central region of the wafer stage 10 is fixed by bolts 98, the sealing ring is also maintained in a firmly pressed state.

[0050] For example, such as Figure 5As shown, the refrigerant supply path 321 consists of a first supply path 32p penetrating the mounting plate 96, the interior of a refrigerant supply sealing ring 32q disposed between the mounting plate 96 and the cooling substrate 30, and a second supply path 32r extending from the lower surface of the cooling substrate 30 to the refrigerant flow path 32. The refrigerant discharge path 322 consists of a first discharge path 32s extending from the refrigerant flow path 32 to the lower surface of the cooling substrate 30, the interior of a refrigerant discharge sealing ring 32t disposed between the cooling substrate 30 and the mounting plate 96, and a second discharge path 32u penetrating the mounting plate 96 to reach the lower surface of the mounting plate 96. In this case, the central region of the wafer stage 10 is fixed by screwing the internal threaded component 38 and the bolt 98 within the receiving hole 36, thus maintaining these sealing rings 32q and 32t in a firmly pressed state. Therefore, the sealing rings 32q and 32t can sufficiently ensure sealing performance.

[0051] Next, adopt Figure 6 A manufacturing example of the chip carrier stage 10 will be described. Figure 6 This is a manufacturing process diagram of the wafer placement stage 10. First, a molded alumina powder is hot-pressed and sintered to create a circular plate-shaped alumina sintered body 120, which forms the basis of the alumina substrate 20. Figure 6 (A)). The alumina sintered body 120 has a built-in wafer adsorption electrode 26. Next, a hole 27 is provided from the lower surface of the alumina sintered body 120 to the wafer adsorption electrode 26. Figure 6 (B) Insert the power supply terminal 54 into the hole 27, and connect the power supply terminal 54 and the wafer adsorption electrode 26. Figure 6 (C)).

[0052] At the same time, manufacture three MMC circular plate components 131, 133, and 135. Figure 6 (D)). Then, a groove 132 that ultimately becomes the refrigerant flow path 32 is formed on the lower surface of the upper MMC circular plate component 131, and a stepped hole 136 that ultimately becomes the receiving hole 36 is formed on the lower MMC circular plate component 135. Furthermore, through holes that extend in the vertical direction are formed in the three MMC circular plate components 131, 133, and 135. Figure 6 (E)). These through holes ultimately become the holes through which the power supply terminals 54 are inserted. When the alumina sintered body 120 is made of alumina, the MMC circular plate components 131, 133, and 135 are preferably made of SiSiCTi or AlSiC. This is because the coefficient of thermal expansion of alumina is approximately the same as that of SiSiCTi and AlSiC.

[0053] For example, a SiSiCTi circular plate component can be manufactured as follows: First, silicon carbide, metallic Si, and metallic Ti are mixed to prepare a powder mixture. Next, the resulting powder mixture is uniaxially pressurized to form a circular plate-shaped body, which is then hot-pressed and sintered in an inactive atmosphere to obtain the SiSiCTi circular plate component.

[0054] Next, the internal threaded component 38 is housed in the stepped hole 136 of the lower MMC circular plate component 135. Then, a metal bonding material is disposed between the lower surface of the upper MMC circular plate component 131 and the upper surface of the central MMC circular plate component 133, and a metal bonding material is disposed between the lower surface of the central MMC circular plate component 133 and the upper surface of the lower MMC circular plate component 135, and a metal bonding material is disposed on the upper surface of the upper MMC circular plate component 131. Through holes are pre-formed at the insertion positions of the power supply terminals 54 of each metal bonding material. Next, the power supply terminals 54 of the alumina sintered body 120 are inserted into the through holes of the MMC circular plate components 131, 133, and 135, and the alumina sintered body 120 is placed on the metal bonding material disposed on the upper surface of the upper MMC circular plate component 131. Accordingly, a laminate is obtained by stacking MMC disc component 135, metal bonding material, MMC disc component 133, metal bonding material, MMC disc component 131, metal bonding material, and alumina sintered body 120 in this order from bottom to top. The laminate is heated and pressurized (TCB) simultaneously to obtain a bonded body 110. Figure 6 (F)). The joint 110 is obtained by bonding the alumina sintered body 120 to the upper surface of the MMC block 130, which serves as the base of the cooling substrate 30, using a metal bonding layer 40. The MMC block 130 is obtained by bonding the upper MMC circular plate component 131 and the central MMC circular plate component 133 using a metal bonding layer, and by bonding the central MMC circular plate component 133 and the lower MMC circular plate component 135 using a metal bonding layer. The MMC block 130 has a refrigerant flow path 32 and a receiving hole 36 inside. In addition, an internally threaded component 38 is received in the receiving hole 36.

[0055] TCB is performed as follows: The laminate is bonded under pressure at a temperature below the solidus temperature of the metal bonding material (e.g., above the solidus temperature minus 20°C but below the solidus temperature), and then returned to room temperature. Accordingly, the metal bonding material becomes a metal bonding layer. Al-Mg based bonding materials or Al-Si-Mg based bonding materials can be used as the metal bonding material. For example, when using an Al-Si-Mg based bonding material for TCB, the laminate is pressurized under a vacuum atmosphere. Preferably, the metal bonding material has a thickness of approximately 100 μm.

[0056] Next, the outer periphery of the alumina sintered body 120 is cut to form steps, thereby producing an alumina substrate 20 having a central portion 22 and an outer peripheral portion 24. Additionally, the outer periphery of the MMC block 130 is cut to form steps, thereby producing a cooling substrate 30 having a flange portion 34. Furthermore, an insulating tube 55 is disposed in the insertion hole of the power supply terminal 54 provided in the MMC block 130 and the metal bonding layer 40. Then, alumina powder is sprayed onto the side surfaces of the outer peripheral portion 24 of the alumina substrate 20, the area around the metal bonding layer 40, and the side surfaces of the cooling substrate 30, thereby forming an insulating film 42. Figure 6 (G)). Accordingly, the chip carrier stage 10 is obtained.

[0057] It should be explained that Figure 1 The cooling substrate 30 is described as a single piece; however, it can also be as follows: Figure 6 The structure shown in (G) can be obtained by joining three components with a metal bonding layer, or it can be obtained by joining two or four or more components with a metal bonding layer.

[0058] Next, adopt Figure 1 An example of the use of the wafer stage 10 will be described. As described above, the outer peripheral region of the wafer stage 10 is fixed to the mounting plate 96 of the chamber 94 by clamping members 70, and the central region of the wafer stage 10 is fixed by bolts 98. A nozzle 95 is disposed on the top surface of the chamber 94 to release process gases from a plurality of gas injection holes into the interior of the chamber 94. The mounting plate 96 is formed of an insulating material such as alumina.

[0059] A focusing ring 78 is placed on the FR placement surface 24a of the wafer placement stage 10, and a disk-shaped wafer W is placed on the wafer placement surface 22a. The focusing ring 78 has a step along its inner periphery at its upper end to prevent interference with the wafer W. In this state, a DC voltage from the wafer adsorption DC power supply 52 is applied to the wafer adsorption electrode 26, causing the wafer W to be adsorbed onto the wafer placement surface 22a. Then, the interior of the chamber 94 is set to a predetermined vacuum atmosphere (or reduced pressure atmosphere), and while process gas is supplied from the nozzle 95, an RF voltage from the RF power supply 62 is applied to the cooling substrate 30. Plasma is then generated between the wafer W and the nozzle 95. Then, CVD film deposition or etching is performed on the wafer W using this plasma. It should be noted that the focusing ring 78 is also consumed during the plasma treatment of the wafer W; however, since the focusing ring 78 is thicker than the wafer W, the focusing ring 78 is replaced after processing multiple wafers W.

[0060] When processing wafer W with high-power plasma, efficient cooling of wafer W is required. In the wafer stage 10, a metal bonding layer 40 with high thermal conductivity is used as the bonding layer between the alumina substrate 20 and the cooling substrate 30, instead of a resin layer with low thermal conductivity. Therefore, the ability to remove heat from wafer W (heat dissipation capacity) is higher. In addition, since the difference in thermal expansion between the alumina substrate 20 and the cooling substrate 30 is small, problems are less likely to occur even if the stress relief of the metal bonding layer 40 is lower.

[0061] In the wafer stage 10 described above, the internal threaded member 38 is housed in the receiving hole 36, which is open on the lower surface of the cooling substrate 30, in a state where its shaft rotation is restricted and it is engaged with the stepped portion 36c (engaging portion) of the receiving hole 36 without falling out of the receiving hole 36. Since the internal threaded member 38 restricts its shaft rotation, the external thread 98a of the bolt 98 inserted from the lower surface side of the cooling substrate 30 can be screwed onto the internal threaded member 38. In addition, even when the internal threaded member 38 is engaged with the stepped portion 36c of the receiving hole 36 and is pulled toward the mounting plate 96 by the bolt 98 inserted into the mounting plate 96, it is not prone to cracking due to its ductility. Therefore, the wafer stage 10, which has a brittle cooling substrate 30, can be securely fastened to the mounting plate 96 without problems.

[0062] Furthermore, the cooling substrate 30 is formed of MMC. Since MMC is a brittle material, the application of this invention is of great significance.

[0063] Furthermore, the receiving hole 36 has a stepped portion 36c as an engaging portion, and the internal threaded component 38 has a head 38a as a engaged portion. Therefore, the engaging portion and the engaged portion can be manufactured relatively easily.

[0064] Furthermore, when the internal threaded component 38 attempts to rotate the shaft, it encounters the sidewall of the first receiving portion 36a of the receiving hole 36, thus restricting the shaft rotation. Therefore, the shaft rotation of the internal threaded component 38 can be restricted with a relatively simple configuration.

[0065] Furthermore, the receiving hole 36 is located in a region of the cooling substrate 30 that is lower than the bottom surface 32a of the refrigerant flow path 32. Therefore, the receiving hole 36 does not obstruct the refrigerant flow path 32, thus preserving the design freedom of the refrigerant flow path.

[0066] Furthermore, the internally threaded component 38 is housed in the receiving hole 36 in a free state, not engaged with the cooling substrate 30. When manufacturing the wafer stage 10, the internally threaded component 38 can be simply placed into the receiving hole 36, so it is not troublesome.

[0067] It should be noted that the present invention is not limited to the above embodiments in any way, and can be implemented in various ways as long as it falls within the technical scope of the present invention.

[0068] In the first embodiment described above, the receiving hole 36 is disposed in a region of the cooling substrate 30 that is lower than the bottom surface 32a of the refrigerant flow path 32, but this is not a limitation. For example, such as Figure 7 As shown, it can be set such that the top surface 36d of the receiving hole 36 is higher than the bottom surface 32a of the refrigerant flow path 32. Figure 7 In this document, the same symbols are used to mark the same constituent elements as in the first embodiment described above. Figure 7 In this embodiment, the first receiving portion 36a of the receiving hole 36 is the same size as in the first embodiment, however, the length of the second receiving portion 36b in the vertical direction is longer than in the first embodiment. Similarly, the head 38a of the internal thread member 38 is the same size as in the first embodiment, however, the length of the cylindrical portion 38b in the vertical direction is longer than in the first embodiment. Even so, the effect is roughly the same as in the first embodiment. However, the design freedom of the refrigerant flow path 32 is limited compared to the first embodiment.

[0069] In the first embodiment described above, a stepped portion 36c is provided on the inner peripheral surface of the receiving hole 36, but this is not a limitation. For example, as... Figure 8 As shown, the face-to-face sides of the head 38a of the internal threaded component 38 can be designed as inclined surfaces 38c, and an inclined portion 36e corresponding to the inclined surface 38c can be provided on the inner circumferential surface of the receiving hole 36. In this case, the inclined surface 38c of the internal threaded component 38 engages with the inclined portion 36e of the receiving hole 36, so the internal threaded component 38 will not fall out of the receiving hole 36. In addition, if the bolt 98 is screwed onto the internal threaded component 38, the internal threaded component 38 is pulled toward the mounting plate 96 with the inclined surface 38c engaged with the inclined portion 36e of the receiving hole 36.

[0070] In the first embodiment described above, the head 38a of the internal thread component 38 is shaped as a rectangular shape when viewed from above, but it is not particularly limited to this. For example, the head 38a can be shaped as a polygon such as a triangle or pentagon when viewed from above, or it can be shaped as a plus sign (+), or it can be elliptical. The shape of the first receiving portion 36a of the receiving hole 36 is such that the head 38a touches the sidewall when the internal thread component 38 is to be rotated on the shaft. In this respect, the internal thread component 538 of the second embodiment described later is also the same.

[0071] In the first embodiment described above, an internally threaded component 38 is used as the connecting component, and a bolt 98 is used as the joined component. However, as... Figure 9 As shown, it can be: an external threaded component 80 as the connecting component, and a nut 82 as the connected component. Figure 9 In this document, the same symbols are used for the same constituent elements as in the first embodiment described above. The external threaded component 80 is formed of a malleable material. The external threaded component 80 has: a head 80a with the same shape as the head 38a, a foot 80b provided at the center of the back side of the head 80a, and an external threaded portion 80c provided at the end of the foot 80b. The head 80a is housed in the first housing portion 36a of the housing hole 36. The foot 80b is inserted into the second housing portion 36b and the through hole 97 of the mounting plate 96. The external threaded portion 80c is screwed onto the nut 82. The nut 82 is engaged with the stepped portion 97a of the through hole 97. Because the lower surface of the head 80a is engaged with the stepped portion 36c of the housing hole 36, the external threaded component 80 will not fall out of the housing hole 36. When the external threaded component 80 is to rotate, the head 80a hits the side wall of the first housing portion 36a, thus restricting the rotation of the shaft. Therefore, the nut 82 can be screwed onto the external thread portion 80c of the external threaded component 80. When the nut 82 is screwed onto the external thread portion 80c of the external threaded component 80, the external threaded component 80 is pulled toward the mounting plate 96 with its head 80a engaged with the stepped portion 36c of the receiving hole 36. Figure 9 In the case of the configuration, the same effect as the first embodiment described above is obtained. In the second embodiment described later, an external threaded component may be used instead of an internal threaded component 538 as the connecting component, and a nut may be used instead of a bolt 98 as the joined component.

[0072] In the first embodiment described above, a hole penetrating the wafer stage 10 can be provided such that it extends from the lower surface of the cooling substrate 30 to the wafer mounting surface 22a. Examples of such holes include: a gas supply hole for supplying heat-conducting gas (e.g., He gas) to the back surface of the wafer W, and a lifting pin hole through which lifting pins for moving the wafer W up and down relative to the wafer mounting surface 22a are inserted. The heat-conducting gas is supplied through a plurality of small protrusions (not shown) provided on the wafer mounting surface 22a (which support the wafer W) and the space formed by the wafer W. The lifting pin holes are provided at three locations when the wafer W is supported by, for example, three lifting pins. A resin or metal sealing ring (e.g., an O-ring) is disposed between the lower surface of the cooling substrate 30 and the upper surface of the mounting plate 96, and opposite to this hole. Since the central region of the wafer stage 10 is fixed by bolts 98, these sealing rings are maintained in a firmly pressed state. Therefore, these sealing rings can sufficiently ensure a tight seal. In this respect, the second embodiment described later is also the same.

[0073] In the first embodiment described above, the cooling substrate 30 is made of MMC; however, it can be made of brittle materials other than MMC (e.g., alumina). In this respect, the cooling substrate 530 in the second embodiment described later is also made of the same material.

[0074] In the first embodiment described above, a wafer adsorption electrode 26 is built into the central portion 22 of the alumina substrate 20. However, instead, an RF electrode for plasma generation or a heater electrode (resistive heating element) may be built into the central portion 22 of the alumina substrate 20. Alternatively, in addition to the wafer adsorption electrode 26, an RF electrode for plasma generation or a heater electrode (resistive heating element) may also be built into the central portion 24 of the alumina substrate 20. Furthermore, a focusing ring (FR) adsorption electrode, an RF electrode, or a heater electrode may be built into the outer periphery 24 of the alumina substrate 20. In this respect, the second embodiment described later is also the same.

[0075] In the first embodiment described above, Figure 6 (A) The alumina sintered body 120 is produced by hot pressing and sintering a molded body of alumina powder. However, the molded body can be produced by stacking multiple cast bodies, by die casting, or by pressing alumina powder. In this respect, the second embodiment described later is also the same.

[0076] In the first embodiment described above, the alumina substrate 20 and the cooling substrate 30 are bonded using a metal bonding layer 40. However, a resin bonding layer can be used instead of the metal bonding layer 40. In this respect, the second embodiment described later is also the same.

[0077] In the first embodiment described above, a filler material can be filled into the gap between the internal threaded component 38 and the first receiving portion 36a of the receiving hole 36. This improves heat conduction compared to a spaced gap. Therefore, the heat uniformity of the wafer W is improved. Examples of filler materials include adhesive resins, non-adhesive resins, and materials obtained by adding thermally conductive powders (such as metal powders) to these resins. Preferably, a through hole (a through hole extending from the internal space of the cylindrical portion 38b to the top surface of the head 38a) is provided in the internal threaded component 38 in the vertical direction. Figure 6 In stage (F), a fluid filling material can be easily injected into the gap between the internal threaded component 38 and the first receiving portion 36a of the receiving hole 36 via the through hole.

[0078] [Second Implementation]

[0079] Figure 10 This is a longitudinal cross-sectional view of the wafer stage 510 disposed in chamber 94 (a cross-sectional view cut along a surface including the central axis of the wafer stage 510). Figure 11 This is an enlarged cross-sectional view showing the periphery of the receiving hole 536 and the internal thread component 538.

[0080] The wafer stage 510 is also a component used when performing CVD, etching, etc., on the wafer W using plasma, and it is fixed to a mounting plate 96 disposed inside a semiconductor process chamber 94. Regarding the chamber 94, since it has already been described in the first embodiment, the same reference numerals are used for the same constituent elements, and its description is omitted. The wafer stage 510 includes: an alumina substrate 20, a cooling substrate 530, and a metal bonding layer 540.

[0081] The alumina substrate 20 has been described in the first embodiment, so the same symbols are used to mark the same constituent elements and their descriptions are omitted.

[0082] The cooling substrate 530 is a circular plate component, formed from the same material as the cooling substrate 30. Here, the cooling substrate 530 is a circular plate component made of MMC. The cooling substrate 530 has a refrigerant flow channel 582. The refrigerant flow channel 582 is formed from one end to the other in a single stroke, and is provided on the cooling substrate 530 in an open manner on the lower surface of the cooling substrate 530. The opening of the refrigerant flow channel 582 is blocked by the upper surface of the mounting plate 96 of the chamber 94, thereby forming the refrigerant flow channel 532. Therefore, the refrigerant flow channel 582 constitutes the sidewall and top surface of the refrigerant flow channel 532. The refrigerant flow channel 532, like the refrigerant flow channel 32 of the first embodiment described above, is connected to a refrigerant supply channel and a refrigerant discharge channel (not shown). The refrigerant discharged from the refrigerant discharge channel is temperature-adjusted and then returns to the refrigerant supply channel. The thickness of the cooling substrate 530 above the refrigerant flow channel 582 is preferably 5 mm or less, more preferably 3 mm or less. Furthermore, the upper corner of the refrigerant flow channel 582 (the corner where the sidewall and top surface intersect) is preferably curved, and the radius of curvature of the curved surface is preferably, for example, 0.5 to 2 mm. The cooling substrate 530 is connected to the RF power supply 62 via a power supply terminal 64. An HPF 63 is disposed between the cooling substrate 530 and the RF power supply 62. The cooling substrate 530 has a flange portion 534 for clamping to the mounting plate 96.

[0083] A plurality of receiving holes 536 are provided on the cooling substrate 530, and internally threaded components 538 (connecting components) are received in the receiving holes 536. Similar to the receiving holes 36 in the first embodiment, a plurality of receiving holes 536 are provided at equal intervals along concentric circles of the cooling substrate 530. The receiving holes 536 are as follows... Figure 11The device includes: a first receiving portion 536a, a second receiving portion 536b, and a stepped portion 536c. The first receiving portion 536a is a space provided above the receiving hole 536, and is open on the upper surface of the cooling substrate 530. The open surface (upper surface) of the first receiving portion 536a is covered by a metal bonding layer 540. The second receiving portion 536b is a passageway narrower than the first receiving portion 536a, extending from the first receiving portion 536a to the lower surface of the cooling substrate 530. The stepped portion 536c is a stepped surface provided at the joint between the first receiving portion 536a and the second receiving portion 536b. An internally threaded component 538 is received in the first receiving portion 536a. The internally threaded component 538 is a cuboid-shaped (rectangular in top view) nut with a threaded hole (internal thread) in the center. The first receiving portion 536a is also a rectangular parallelepiped (roughly rectangular in top view) space, which houses the internally threaded component 538 with clearance. The gap between the internally threaded component 538 and the first receiving portion 536a is filled with a filler material 539. Specifically, the gap surrounded by the upper and side surfaces of the internally threaded component 538, the inner peripheral surface of the first receiving portion 536a, and the metal bonding layer 540 is filled with the filler material 539. Examples of filler material 539 include adhesive resins, non-adhesive resins, and materials obtained by adding thermally conductive powders (such as metal powders) to these resins. The thermal conductivity of the filler material 539 is preferably 1 × 10⁻⁶. -4 W / mm·K or higher, preferably 1×10 -3 W / mm·K or higher, more preferably 1×10 -2 W / mm·K or higher. The thermal conductivity of the filler material 539 can be adjusted, for example, by the amount of thermally conductive powder added to the resin. If it is considered that an uncured filler material with flowability is injected into the gap, the width d of the gap between the internal threaded member 538 and the first receiving portion 536a is preferably 0.2 mm or higher. The stepped portion 536c is disposed below the top surface of the refrigerant flow channel 582. The internal threaded member 538 engages with the stepped portion 536c of the receiving hole 536. When the internal threaded member 538 is to rotate, it encounters the sidewall of the first receiving portion 536a and restricts the rotation of the shaft. In this embodiment, since the filler material 539 is present, the internal threaded member 538 also restricts the rotation of the shaft by the filler material 539. The internal threaded member 538 is formed of a ductile material (e.g., Ti, Mo, W, etc.).

[0084] The metal bonding layer 540 bonds the lower surface of the alumina substrate 20 and the upper surface of the cooling substrate 530. The metal bonding layer 540 is the same as the metal bonding layer 40 in the first embodiment, so its description is omitted.

[0085] The outer periphery 24 of the alumina substrate 20, the outer periphery of the metal bonding layer 540, and the outer side of the cooling substrate 530 are covered with an insulating film 542. Examples of insulating films 542 include spray-coated films of alumina, yttrium oxide, etc.

[0086] The aforementioned wafer stage 510 is mounted on a mounting plate 96 disposed inside the chamber 94, separated by a large-diameter sealing ring 576 and small-diameter sealing rings 577-579. The sealing rings 576-579 are made of metal or resin. The sealing ring 576 is positioned slightly inside the outer edge of the cooling substrate 530 to prevent refrigerant leakage to the outside of the sealing ring 576. The sealing ring 577 is configured to surround the foot of the bolt 98 to prevent refrigerant from entering the inside of the sealing ring 577. The sealing ring 578 is positioned at the opening edge of the insulating tube 55 to prevent refrigerant from entering the inside of the sealing ring 578. The sealing ring 579 is configured to surround the power supply terminal 64 to prevent refrigerant from entering the inside of the sealing ring 579.

[0087] The flange 534 provided on the outer periphery of the cooling substrate 530 is mounted to the mounting plate 96 using clamping members 70 and bolts 72. The clamping members 70, bolts 72, and clamping method have already been described in the first embodiment, so their description is omitted. Furthermore, the central region of the cooling substrate 530 is mounted to the mounting plate 96 using bolts 98 (the joined parts). Figure 11 As shown, an external thread 98a is provided at the foot of the bolt 98. The bolt 98 is inserted through the lower surface of the mounting plate 96 into a through hole 97 provided in the mounting plate 96 opposite to the receiving hole 536, and the external thread 98a is screwed into the internal thread member 538 in the first receiving portion 536a. The upper part of the through hole 97 has a small diameter, the lower part has a large diameter, and there is a step portion 97a between the upper and lower parts. The head of the bolt 98 is engaged in the step portion 97a of the through hole 97. The internal thread member 538 is housed in the first receiving portion 536a in a state where the shaft rotation is restricted, so the bolt 98 can be screwed into the internal thread member 538. If the bolt 98 is screwed into the internal thread member 538, the internal thread member 538 is pulled toward the mounting plate 96 in a state where it is engaged with the step portion 536c of the receiving hole 536.

[0088] In this embodiment, the central region of the wafer stage 510 is fixed by bolts 98, thus preventing the wafer stage 510 from convex upwards, and maintaining the sealing rings 576-578 in a firmly pressed state.

[0089] It should be noted that the supply and discharge of refrigerant relative to refrigerant flow path 582 are carried out using the same method as described in the first embodiment. Figure 5 The same structure will be used.

[0090] Next, adopt Figure 12 A manufacturing example of the chip carrier stage 510 will be described. Figure 12 This is a manufacturing process diagram of the wafer placement stage 510. First, similar to the first embodiment, an alumina sintered body 120 having power supply terminals 54 is fabricated. Figure 12 (A)~(C)).

[0091] Meanwhile, the MMC circular plate component 630 was manufactured. Figure 12 (D) A refrigerant flow channel 582 is formed on the lower surface of the MMC circular plate component 630, and a receiving hole 536 (first receiving portion 536a, second receiving portion 536b and stepped portion 536c) is formed that runs through the MMC circular plate component 630 in the vertical direction, and a through hole for the power supply terminal 54 to be inserted. Figure 12 (E)). In this case, the MMC circular plate component 630 is preferably made of SiSiCTi or AlSiC. This is because the coefficient of thermal expansion of alumina is approximately the same as that of SiSiCTi and AlSiC.

[0092] Next, after the internally threaded component 538 is housed in the first housing portion 536a, a metal bonding material is disposed on the upper surface of the MMC disc component 630. A through-hole for the insertion of the power supply terminal 54 is pre-formed in the metal bonding material. Next, the power supply terminal 54 of the alumina sintered body 120 is inserted into the through-hole of the metal bonding material and the through-hole of the MMC disc component 630, and the alumina sintered body 120 is placed on the metal bonding material. Thus, a laminate obtained by stacking the MMC disc component 630, the metal bonding material, and the alumina sintered body 120 from below in this order is obtained. The laminate is heated and pressurized (TCB) simultaneously to obtain the bonded body 610. Figure 12 (F)). The joint 610 is obtained by joining the alumina sintered body 120 and the MMC circular plate component 630 by means of a metal bonding layer 540. An internally threaded component 538 is housed in the first receiving portion 536a of the joint 610. It should be noted that the description of the metal bonding material and TCB is omitted here since it has been described in the first embodiment.

[0093] Next, a fluid, uncured filler material is injected into the gap between the internally threaded component 538 and the first receiving part 536a through the threaded holes of the second receiving part 536b and the internally threaded component 538. Considering the ease of injection of the uncured filler material, this gap is preferably 0.2 mm or more. The injected uncured filler material is cured to form a filler material 539. Next, the outer periphery of the alumina sintered body 120 is cut to form steps, thereby forming an alumina substrate 20 having a central portion 22 and an outer peripheral portion 24. Additionally, the outer periphery of the MMC disc component 630 is cut to form steps, thereby forming a cooling substrate 530 having a flange portion 534. Furthermore, an insulating tube 55 is disposed in the insertion hole of the power supply terminal 54. Then, alumina powder is sprayed onto the sides of the outer peripheral portion 24 of the alumina substrate 20, the area around the metal bonding layer 540, and the sides of the cooling substrate 530, thereby forming an insulating film 542. Figure 12 (G)). Based on this, the chip carrier stage 510 is obtained.

[0094] The usage example of the wafer stage 510 is the same as that of the wafer stage 10 in the first embodiment described above, so its description is omitted.

[0095] In the wafer stage 510 described above, the internal threaded member 538 is housed within the receiving hole 536, which is open on the lower surface of the cooling substrate 530, in a state where its shaft rotation is restricted and it is engaged with the stepped portion 536c (engaging portion) of the receiving hole 536 without falling out of the receiving hole 536. Since the internal threaded member 538 restricts shaft rotation, the external thread 98a of the bolt 98 inserted from the lower surface side of the cooling substrate 530 can be screwed onto the internal threaded member 538. Furthermore, even when the internal threaded member 538 is engaged with the stepped portion 536c of the receiving hole 536 and pulled towards the mounting plate 96 by the bolt 98 inserted into the mounting plate 96, it is not prone to cracking due to its malleability. Therefore, the wafer stage 510, which has a brittle cooling substrate 530, can be securely fastened to the mounting plate 96 without problems.

[0096] Furthermore, the cooling substrate 530 is formed of MMC. Since MMC is a brittle material, the application of this invention is of great significance.

[0097] Furthermore, the receiving hole 536 has a stepped portion 536c as an engaging portion, and the bottom surface of the internal threaded component 538 functions as a engaged portion. Therefore, the engaging portion and the engaged portion can be manufactured relatively easily.

[0098] Furthermore, when the internal threaded component 538 attempts to rotate the shaft, it encounters the sidewall of the first receiving portion 536a of the receiving hole 536, thus restricting the shaft rotation. Therefore, the shaft rotation of the internal threaded component 538 can be restricted with a relatively simple configuration. In addition, the internal threaded component 538 is also restricted from rotating by the filler material 539.

[0099] Furthermore, the first receiving portion 536a has an opening on the upper surface of the cooling substrate 530, and the opening surface is covered by the metal bonding layer 540. Therefore, compared to the case where the first receiving portion 36a is built into the interior of the cooling substrate 30 as in the first embodiment, the first receiving portion 536a can be manufactured more easily. In this structure, the coolant flow path 532 (or coolant flow path trench 582) needs to be provided to avoid the receiving hole 536, so the heat homogenization near the receiving hole 536 of the wafer W is prone to decrease. In order to suppress such a decrease in heat homogenization, the gap between the internal thread member 538 and the first receiving portion 536a of the receiving hole 536 is filled with a filler material 539. Accordingly, the heat conduction around the receiving hole 536 becomes good, and thus, the decrease in heat homogenization can be suppressed.

[0100] It should be noted that the present invention is not limited to the above embodiments in any way, and can be implemented in various ways as long as it falls within the technical scope of the present invention.

[0101] In the second embodiment described above, as Figure 13 As shown, the internal threaded component 538 can engage with the stepped portion 536c of the receiving hole 536 through a stress-reducing component 537, whose Young's modulus is lower than that of the internal threaded component 538. For example, the internal threaded component 538 can be made of Ti alloy, and the stress-reducing component 537 can be made of pure Al. Accordingly, even if the internal threaded component 538 is pulled toward the mounting plate 96 by the bolt 98 provided on the mounting plate 96, the stress is easily dispersed because the stress-reducing component 537 is sandwiched between the internal threaded component 538 and the stepped portion 536c. In order to reduce the stress of the first receiving portion 536a, firstly, the width w of the annular region in which the stepped portion 536c and the internal threaded component 538 indirectly contact is preferably 3 mm or more, more preferably 5 mm or more. Secondly, the inner diameter x of the threaded hole of the internal threaded component 538 is preferably 10 mm or less, more preferably 7 mm or less. Third, when the corners of the bottom and side surfaces of the first receiving portion 536a are R-surfaces (arc-shaped surfaces), the radius of curvature r is preferably 0.3 mm or more, more preferably 0.5 mm or more. The first to third indicate the ranking of stress reduction effects, with the first condition showing the highest stress reduction effect. Furthermore, the corners of the bottom and side surfaces of the internally threaded component 538 are preferably R-surfaces or C-surfaces. The thickness t from the step portion 536c to the lower surface of the cooling substrate 530 is preferably 3 mm or more and 10 mm or less. These numerical ranges are the same in the case without the stress-reducing component 537 and in the first embodiment.

[0102] In the second embodiment described above, a refrigerant flow channel 582 is provided on the lower surface of the cooling substrate 530, and a mounting plate 96 (lower substrate) is disposed below the cooling substrate 530. A sealing ring for liquid-tightly sealing the refrigerant flow channel 582 is disposed between the lower surface of the cooling substrate 530 and the mounting plate 96, but this is not particularly limited. For example, the refrigerant flow channel can be provided on the upper surface of the mounting plate instead of the lower surface of the cooling substrate, and a sealing ring for liquid-tightly sealing the refrigerant flow channel can be disposed between the lower surface of the cooling substrate and the mounting plate. The cooling substrate is a brittle material such as MMC or alumina, and a first receiving portion is provided on this cooling substrate.

[0103] In the second embodiment described above, the internal thread component 538 is, for example... Figure 14 As shown in (A), a nut with a triangular prism shape (triangular from top view) and a threaded hole in the center can be used. In this case, it can be like... Figure 14 (B) That forms the storage hole 536. Figure 14 (B) is a magnified view of the periphery of the receiving hole 536 when viewed from below the cooling substrate 530. Figure 14 In (B), the second receiving portion 536b is configured as a top-view triangular hole through which the internal threaded component 538 can pass, and the first receiving portion 536a is configured as a space (a composite graphic of a top-view triangle and a circle) through which the internal threaded component 538 can rotate axially at a predetermined angle. The appearance of the internal threaded component 538 just inserted into the second receiving portion 536b and then received in the first receiving portion 536a is represented by a double-dotted line, and the appearance of the internal threaded component 538 received in the first receiving portion 536a having rotated axially at a predetermined angle along the direction of the arrow is represented by a single-dotted line. At this time, the stepped portion 536c is the portion inside the outer edge of the first receiving portion 536a and outside the opening edge of the second receiving portion 536b, and this portion engages with the internal threaded component 538. According to this structure, the internal threaded component 538 can be received in the first receiving portion 536a after the alumina substrate 20 and the cooling substrate 530 are joined. For example, firstly, without the internal threaded component 538 being housed in the first housing portion 536a, the alumina substrate 20 and the cooling substrate 530 are joined using a metal bonding layer 540. Next, a fluid, uncured filler material is injected into the first housing portion 536a with the lower surface of the cooling substrate 30 facing upwards. Next, the internal threaded component 538 is housed from the second housing portion 536b into the first housing portion 536a, and then the internal threaded component 538 is rotated at a predetermined angle. Accordingly, the space between the internal threaded component 538 and the first housing portion 536a is completely filled with uncured filler material. Then, the uncured filler material is cured to form filler material 539. It should be noted that this structure is applicable not only to triangular prism-shaped nuts but also to polyprism-shaped nuts (quadrilateral prism, hexagonal prism, etc.).

[0104] The internal threaded component 38 of the first embodiment can be used. Figure 3 , Figure 7 or Figure 8 The internal threaded component 538 of the second embodiment described above can be replaced by a through hole (a through hole extending from the internal space of the cylindrical portion 38b to the top surface of the head 38a) that runs vertically through the internal threaded component 38. This is because if this through hole is used, it is easy to fill the gap between the head 38a and the first receiving portion of the receiving hole with a fluid, uncured filler material.

[0105] In the second embodiment described above, as Figure 15 As shown, a refrigerant flow channel 91 can be provided on the upper surface of the mounting plate 96, and the upper opening of the refrigerant flow channel 91 can be sealed with the cooling substrate 530 to form a refrigerant flow channel 92, thereby replacing the provision of a refrigerant flow channel 582 (refrigerant flow channel 532) on the cooling substrate 530. Figure 15 In this text, the same symbols are used for the same constituent elements as in the second embodiment described above. It should be noted that in the first embodiment, similar symbols may also be used. Figure 15 In this way, a refrigerant flow channel is formed by setting a refrigerant flow channel on the upper surface of the setting plate 96 and sealing the upper opening of the refrigerant flow channel with the cooling substrate 30, thereby replacing the setting of the refrigerant flow channel 32 on the cooling substrate 30.

[0106] This application claims priority based on Japanese Patent Application No. 2021-185369, filed on November 15, 2021, the entire contents of which are incorporated herein by reference.

Claims

1. A wafer boat, comprising: have: An alumina substrate having a wafer mounting surface on its upper surface and having electrodes built into it; A brittle cooling substrate, which is bonded to the lower surface of the alumina substrate; and A flexible connecting component, which is housed in a state where shaft rotation is restricted and it engages with a receiving hole that is open on the lower surface of the cooling substrate, and has an external thread or an internal thread. The connecting component is a component having the internal thread portion and capable of engaging with the external thread of a bolt inserted from the lower surface side of the cooling substrate, or the connecting component is a component having the external thread portion and capable of engaging with the internal thread of a nut provided on the lower surface side of the cooling substrate.

2. The wafer stage according to claim 1, wherein, The cooling substrate is formed of a composite material of metal and ceramic or an alumina material.

3. The wafer stage according to claim 1 or 2, wherein, The engaging portion is a stepped or inclined portion provided on the inner circumferential surface of the receiving hole. The connecting component has a locking portion that engages with the locking portion to prevent the connecting component from falling out of the receiving hole.

4. The wafer stage according to claim 1 or 2, wherein, When the connecting component attempts to rotate the shaft, it encounters the wall of the receiving hole, thus restricting the shaft rotation.

5. The wafer stage according to claim 1 or 2, wherein, The cooling substrate has a refrigerant flow path inside. The receiving hole is located in a region of the cooling substrate that is lower than the bottom surface of the refrigerant flow path.

6. The wafer stage according to claim 1 or 2, wherein, The connecting component is housed in the receiving hole in a free state, not in contact with the cooling substrate.

7. The wafer stage according to claim 1 or 2, wherein, The connecting component engages with the engaging portion through a stress buffer component whose Young's modulus is lower than that of the connecting component.

8. The wafer stage according to claim 1 or 2, wherein, The gap between the connecting component and the receiving hole is filled with a filler material.

9. The wafer stage according to claim 1 or 2, wherein, The receiving hole includes: a first receiving portion for receiving the connecting component, and a second receiving portion extending from the first receiving portion to the lower surface of the cooling substrate. The engaging portion is a stepped surface provided at the joint between the first storage portion and the second storage portion.

10. The wafer stage according to claim 9, wherein, The first receiving portion has an opening on the upper surface of the cooling substrate, and the opening is covered by a bonding layer that joins the alumina substrate and the cooling substrate.

11. The wafer stage according to claim 9, wherein, The width of the annular area in which the stepped surface and the connecting component directly or indirectly contact each other is 3 mm or more.

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