Wafer loading platform

Abstract

The present invention provides a wafer carrier, which reduces the influence of the wafer on the thermal uniformity. The wafer carrier (10) comprises: a ceramic substrate (20), a cooling substrate (30), a bonding layer (40), a hole (81) with a step, an insulating tube (84) with a step, and a power supply terminal (82). The hole (81) with a step has a small diameter upper hole portion (81a), a large diameter lower hole portion (81b) and a hole step portion (81c), and the upper hole portion (81a) passes through the formation area (37) of the coolant flow path (31). The insulating tube (84) with a step is inserted into the hole (81) with a step, and has a small diameter upper tube portion (84a), a large diameter lower tube portion (84b) and a tube step portion (84c). The upper end of the power supply terminal (82) is connected to the electrode (27).

Description

Technical Field

[0001] The present invention relates to a wafer placing table. Background Art

[0002] In the past, it is known that a ceramic substrate with an electrostatic electrode implanted therein and a cooling substrate with a built-in coolant flow path are joined by means of a bonding layer (for example, see patent documents 1 and 2). The electrostatic electrode can apply a DC voltage using an external power supply via a rod-shaped power supply terminal. The power supply terminal passes through a hole that penetrates the cooling substrate and the bonding layer, and then passes through a hole provided in the ceramic substrate to reach the electrostatic electrode. The end face of the power supply terminal is sometimes used as a contact surface that contacts an external contact pin. If the connection with the contact pin is considered, the contact surface needs to be enlarged.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 5666748

[0006] Patent Document 2: Japanese Patent No. 5666749 Summary of the invention

[0007] However, if the contact surface is increased, the power supply terminal becomes thicker, which may adversely affect the thermal uniformity of the wafer. For example, when a thick power supply terminal is provided, the heat dissipation capacity of the portion provided with the power supply terminal is reduced for the plasma heat input, so it is easy to become a hot spot.

[0008] The present invention has been made to solve the above-mentioned problems, and a main object of the present invention is to reduce the influence on the thermal uniformity of a wafer.

[0009] The wafer loading platform of the present invention comprises:

[0010] A ceramic substrate having a wafer placement surface on an upper surface and having electrodes built therein;

[0011] A cooling substrate having a refrigerant flow path formed therein;

[0012] a bonding layer bonding the lower surface of the ceramic substrate and the upper surface of the cooling substrate;

[0013] a hole with a step, the hole penetrating the bonding layer and the cooling substrate in the up-down direction, and having a hole upper portion with a small diameter, a hole lower portion with a large diameter, and a hole step portion between the hole upper portion and the hole lower portion, the hole upper portion passing through the region where the coolant flow path is formed;

[0014] an insulating tube with a step, the insulating tube being inserted into the hole with the step and having a tube upper portion with a small diameter, a tube lower portion with a large diameter, and a tube step portion between the tube upper portion and the tube lower portion; and

[0015] A connecting terminal is inserted into the insulating tube with the step and the upper end of the connecting terminal is connected to the electrode.

[0016] In the wafer placing table, the hole with a step has a small diameter upper portion of the hole, and the upper portion of the hole passes through the formation area of ​​the coolant flow path. That is, the large diameter lower portion of the hole with a step is arranged on the lower side of the coolant flow path. Therefore, the heat dissipation capacity of the coolant flow path will not be greatly impaired, and the influence on the thermal uniformity of the wafer can be reduced.

[0017] It should be noted that in this specification, up and down, left and right, front and back, etc. are sometimes used to describe the present invention, but up and down, left and right, front and back are only relative positional relationships. Therefore, when the orientation of the wafer stage is changed, up and down may become left and right, and left and right may become up and down, and this situation is also included in the technical scope of the present invention.

[0018] In the wafer placement table of the present invention, it is preferred that the length of the upper portion of the hole is longer than the length of the lower portion of the hole. The longer the upper portion of the small-diameter hole is, the less influence on thermal uniformity can be achieved.

[0019] The wafer placement table of the present invention may include a socket, which is arranged in the lower part of the insulating tube with a step, and has an elastic support portion that elastically supports the outer peripheral surface of the connecting terminal without contacting the lower end surface of the connecting terminal. The socket is arranged in the lower part of the insulating tube with a step, and therefore the diameter of the socket can be larger than the diameter of the upper part of the tube and the diameter of the connecting terminal. As a result, the contact surface between the socket and the external contact member becomes larger, and it is possible to suppress the occurrence of problems in their connection. In addition, even if a force in the direction toward the electrode is applied to the socket, the connecting terminal is not pressed because the socket does not contact the lower end surface of the connecting terminal. In addition, the socket elastically supports the outer peripheral surface of the connecting terminal without contacting the lower end surface of the connecting terminal. Therefore, the load when the external contact member contacts the socket and the load when the connecting terminal is connected to the socket are not applied to the connecting portion between the connecting terminal and the electrode, and it is possible to suppress the occurrence of defects in the connecting portion.

[0020] In the wafer stage of the present invention provided with the socket, the socket can be in contact with the tube step portion. Thus, even if a force in the direction toward the electrode is applied to the socket, the force is applied to the tube step portion or the hole step portion, so that the bonding terminal is not pressed.

[0021] In the wafer carrier of the present invention having a socket, the elastic support portion may include a plurality of leaf springs. Accordingly, the elastic support portion can be made into a relatively simple structure. In this case, the elastic support portion may include a plurality of leaf springs arranged vertically at intervals along the circumferential direction. Alternatively, the elastic support portion may include: a plurality of plate members arranged vertically at intervals along the circumferential direction, and an elastic member fastening the plurality of plate members from the outside. Even so, the elastic support portion can be made into a relatively simple structure.

[0022] In the wafer stage of the present invention having a socket, the diameter of the connecting terminal may be less than half the diameter of the lower surface of the socket. Thus, the diameter of the connecting terminal can be sufficiently reduced relative to the lower surface (contact surface) of the socket.

[0023] In the wafer stage of the present invention having a socket, the lower surface of the socket may be concave toward the center, so that when an external contact member is elastically contacted with the lower surface of the socket, the tip of the contact member is unlikely to deviate from the center of the lower surface of the socket.

[0024] In the wafer stage of the present invention provided with a socket, the socket may have a plug insertion port into which a plug can be inserted. Thus, a plug can be used as an external contact member. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a longitudinal cross-sectional view of the wafer stage 10 installed in the chamber 100 .

[0026] Figure 2 It is a plan view of the wafer stage 10 .

[0027] Figure 3 yes Figure 1 A partial enlarged view of .

[0028] Figure 4 It is a perspective view of the louver plate 86.

[0029] Figure 5 It is a manufacturing process diagram of the wafer stage 10.

[0030] Figure 6 It is a manufacturing process diagram of the wafer stage 10.

[0031] Figure 7 It is a cross-sectional view of the socket 185 and its surrounding structure.

[0032] Figure 8 It is a three-dimensional diagram of the socket 185.

[0033] Fig. 9 It is a cross-sectional view showing another embodiment of the socket 85 .

[0034] Explanation of symbols

[0035] 10 wafer placement table, 20 ceramic substrate, 22 central portion, 22a wafer placement surface, 24 peripheral portion, 24a focus ring placement surface, 25 wafer adsorption electrode, 26 central heater electrode, 27FR adsorption electrode, 27a terminal hole, 27b metal brazing material layer, 28 peripheral heater electrode, 30 cooling substrate, 30a lower component, 30b upper component, 30c conductive bonding layer, 31 coolant flow path, 32 coolant supply path, 33 Refrigerant discharge path, 34 refrigerant circulator, 36 high frequency power source, 37 refrigerant flow path formation area, 40 metal bonding layer, 42 BS gas passage, 42a hole with step, 42b through hole, 43 BS gas supply source, 61, 71, 81, 91 hole with step, 62, 72, 82, 92 power supply terminal, 63, 73, 83, 93 power supply rod, 63a, 73a, 83a, 93a spring, 64, 74 , 84, 94 insulating tube with step, 65, 75, 85, 95 socket, 66, 76, 86, 96 shutter, 78 focusing ring, 81a hole upper part, 81b hole lower part, 81c hole step part, 84a tube upper part, 84b tube lower part, 84c tube step part, 85a bottom hole, 85b upper surface, 85c lower surface, 85d plug insertion port, 86a ring part, 86b thin plate part, 88 adhesive layer, 89 adhesive layer, 1 00 chamber, 100a nozzle, 101 setting plate, 110 joint body, 120 ceramic sintered body, 130c metal bonding material, 131 flow path groove, 140 metal bonding material, 184 insulating tube, 184a tube upper part, 184b tube lower part, 184c tube step part, 184d space, 185 socket, 185b upper surface, 185c lower surface, 185d elastic support part, 185e plate component, 185f external spring. DETAILED DESCRIPTION

[0036] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 1 is a longitudinal cross-sectional view of the wafer stage 10 provided in the chamber 100 (a cross-sectional view when cut along a plane including the central axis of the wafer stage 10). Figure 2 is a plan view of the wafer stage 10, Figure 3 yes Figure 1 A partial enlarged view (a cross-sectional view of the socket 85 and its surrounding structure), Figure 4 It is a perspective view of the louver 86. In this specification, "to" which indicates a numerical range is used to mean that the numerical values ​​described before and after it are included as the lower limit and the upper limit.

[0037] The wafer stage 10 is a member used when CVD or etching is performed on a wafer W using plasma, and is fixed to a mounting plate 101 provided inside a chamber 100 for semiconductor processes. The wafer stage 10 includes a ceramic substrate 20 , a cooling substrate 30 , and a metal bonding layer 40 .

[0038] The ceramic substrate 20 has an outer peripheral portion 24 having an annular focus ring placement surface 24a on the outer periphery of a central portion 22 having a circular wafer placement surface 22a. Hereinafter, the focus ring is sometimes referred to as "FR". The wafer W is placed on the wafer placement surface 22a, and the focus ring 78 is placed on the FR placement surface 24a. The ceramic substrate 20 is formed of a ceramic material represented by aluminum oxide, aluminum nitride, etc. The FR placement surface 24a is one level lower than the wafer placement surface 22a.

[0039] The central portion 22 of the ceramic substrate 20 has a wafer adsorption electrode 25 and a central heater electrode 26 built therein in order from the wafer placement surface 22a side. The electrodes 25 and 26 are formed of a material including, for example, W, Mo, WC, MoC, or the like.

[0040] The chip adsorption electrode 25 is a disk-shaped or mesh-shaped monopolar electrostatic electrode. The layer on the upper side of the chip adsorption electrode 25 in the ceramic substrate 20 functions as a dielectric layer. A DC power supply for chip adsorption (not shown) is connected to the chip adsorption electrode 25 via a power supply terminal (joining terminal) 62 and a power supply rod 63. The power supply terminal 62 is inserted into an insulating tube 64 with a step. The insulating tube 64 with a step is inserted into a hole with a step that penetrates the cooling substrate 30 and the joining layer 40. The upper surface of the power supply terminal 62 is joined to the lower surface of the chip adsorption electrode 25. A socket 65 is arranged at the lower part of the expanded tube of the insulating tube 64 with a step. The lower part of the power supply terminal 62 is inserted into a louver 66 arranged in a bottomed hole provided on the upper surface of the socket 65, and is electrically connected to the socket 65. The lower surface of the socket 65 is in contact with the upper surface of the power supply rod 63 that is biased upward by a spring 63a.

[0041] The central heater electrode 26 is provided with a resistive heating element in a one-stroke manner from one end to the other end in a manner that covers the entire surface of the chip loading surface 22a when viewed from above. A central heater power source (not shown) is connected to one end of the central heater electrode 26 by means of a power supply terminal 72 and a power supply rod 73. The upper surface of the power supply terminal 72 is bonded to the lower surface of one end of the central heater electrode 26. The power supply terminal 72 is inserted into an insulating tube 74 with a step. The insulating tube 74 with a step is inserted into a hole with a step that penetrates the cooling substrate 30 and the bonding layer 40. The upper surface of the power supply terminal 72 is bonded to the lower surface of the central heater electrode 26. A socket 75 is arranged at the lower part of the expanded tube of the insulating tube 74 with a step. The lower part of the power supply terminal 72 is inserted into a louver 76 arranged in a bottomed hole provided on the upper surface of the socket 75, and is electrically connected to the socket 75. The lower surface of the socket 75 is in contact with the upper surface of the power supply rod 73 that is biased upward by a spring 73a. Although not shown, the other end of the central heater electrode 26 is connected to the central heater power supply via a power supply terminal and a power supply rod, similarly to the one end of the central heater electrode 26 .

[0042] The outer peripheral portion 24 of the ceramic substrate 20 has a FR adsorption electrode 27 and an outer peripheral heater electrode 28 built therein in order from the FR placement surface 24a side. The electrodes 27 and 28 are formed of a material containing, for example, W, Mo, WC, MoC, or the like.

[0043] The FR adsorption electrode 27 is a monopolar electrostatic electrode in the shape of a circular ring plate or a mesh. The layer on the upper side of the FR adsorption electrode 27 in the ceramic substrate 20 functions as a dielectric layer. A DC power supply for FR adsorption (not shown) is connected to the FR adsorption electrode 27 by means of a power supply terminal 82 and a power supply rod 83. The upper surface of the power supply terminal 82 is bonded to the lower surface of the FR adsorption electrode 27. The power supply terminal 82 is inserted into an insulating tube 84 with a step. The insulating tube 84 with a step is inserted into a hole with a step that penetrates the cooling substrate 30 and the bonding layer 40. The upper surface of the power supply terminal 82 is bonded to the lower surface of the FR adsorption electrode 27. A socket 85 is arranged at the lower part of the expanded diameter of the insulating tube 84 with a step. The lower part of the power supply terminal 82 is inserted into a louver 86 arranged in a bottomed hole provided on the upper surface of the socket 85, and is electrically connected to the socket 85. The lower surface of the socket 85 contacts the upper surface of the power supply rod 83 which is biased upward by the spring 83a.

[0044] The peripheral heater electrode 28 is provided with a resistive heating element in a one-stroke manner from one end to the other end in a manner that covers the entire surface of the FR loading surface 24a when viewed from above. A peripheral heater power source (not shown) is connected to one end of the peripheral heater electrode 28 by means of a power supply terminal 92 and a power supply rod 93. The upper surface of the power supply terminal 92 is joined to the lower surface of one end of the peripheral heater electrode 28. The power supply terminal 92 is inserted into an insulating tube 94 with a step. The insulating tube 94 with a step is inserted into a hole with a step that penetrates the cooling substrate 30 and the bonding layer 40. The upper surface of the power supply terminal 92 is joined to the lower surface of the peripheral heater electrode 28. A socket 95 is arranged at the lower part of the expanded diameter of the insulating tube 94 with a step. The lower part of the power supply terminal 92 is inserted into a louver 96 arranged in a bottomed hole provided on the upper surface of the socket 95, and is electrically connected to the socket 95. The lower surface of the socket 95 is in contact with the upper surface of the power supply rod 93 that is biased upward by a spring 93a. Although not shown, the other end of the peripheral heater electrode 28 is also connected to the peripheral heater power supply via a power supply terminal and a power supply rod, similarly to the one end of the peripheral heater electrode 28 .

[0045] It should be noted that the stepped insulating tubes 64 , 74 , 84 , 94 may be formed of a ceramic material such as alumina.

[0046] The cooling substrate 30 is a conductive circular plate component, which is obtained by bonding the lower component 30a and the upper component 30b with the aid of a conductive bonding layer 30c. The conductive bonding layer 30c can be made of the same material as the metal bonding layer 40 described later. The cooling substrate 30 has a refrigerant flow path 31 inside in which a refrigerant can circulate. The refrigerant flow path 31 is formed in a one-stroke manner from one end to the other end in a top view across the entire surface of the ceramic substrate 20. The refrigerant flow path 31 is formed by a flow path groove formed on the lower surface of the upper component 30b and a conductive bonding layer 30c covering the flow path groove from below. One end of the refrigerant flow path 31 is connected to the refrigerant supply path 32, and the other end is connected to the refrigerant discharge path 33. The refrigerant circulator 34 is a circulating pump with a temperature regulating function, which introduces the refrigerant adjusted to the desired temperature into the refrigerant supply path 32, and after adjusting the refrigerant discharged from the refrigerant discharge path 33 of the refrigerant flow path 31 to the desired temperature, it is introduced into the refrigerant supply path 32 again. The cooling substrate 30 is made of a conductive material containing metal. As a conductive material, for example, composite materials, metals, etc. can be cited. As a composite material, a metal-based composite material (also called Metal·Matrix·Composite(MMC)) can be cited, and as MMC, a material containing Si, SiC and Ti, a material obtained by impregnating Al and / or Si in a SiC porous body, etc. can be cited. The material containing Si, SiC and Ti is called SiSiCTi, the material obtained by impregnating Al in a SiC porous body is called AlSiC, and the material obtained by impregnating Si in a SiC porous body is called SiSiC. As a metal, Mo can be cited. The cooling substrate 30 is connected to a high-frequency power supply 36 for generating plasma and used as a high-frequency electrode.

[0047] The metal bonding layer 40 bonds the lower surface of the ceramic substrate 20 and the upper surface of the cooling substrate 30. The metal bonding layer 40 may be, for example, a layer formed of solder or metal brazing material. The metal bonding layer 40 is formed using, for example, TCB (Thermal Compression Bonding). TCB refers to a well-known method of sandwiching a metal bonding material between two components to be bonded, and bonding the two components under pressure while heating to a temperature below the solidus temperature of the metal bonding material.

[0048] The wafer stage 10 has a BS gas passage 42 for supplying a backside gas (BS gas) to the back side of the wafer W. The BS gas passage 42 is composed of a stepped hole 42a penetrating the cooling substrate 30 and the metal bonding layer 40 in the vertical direction, and a through hole 42b communicating with the stepped hole 42a and penetrating the ceramic substrate 20 in the vertical direction. The BS gas passage 42 is connected to a BS gas supply source 43. As the BS gas, a heat conductive gas (for example, He gas) can be cited.

[0049] Next, the power supply terminals 62, 72, 82, 92 of the wafer stage 10 and the structures around them are described. Since these structures are common, the following uses Figure 3 The power supply terminal 82 and its peripheral structure will be described.

[0050] The hole 81 with a step is a hole with a circular cross section that penetrates the metal bonding layer 40 and the cooling substrate 30 in the up-down direction, and has: a small-diameter upper hole portion 81a, a large-diameter lower hole portion 81b, and a hole step portion 81c between the upper hole portion 81a and the lower hole portion 81b. The upper hole portion 81a penetrates the metal bonding layer 40, the upper component 30b of the cooling substrate 30, and the conductive bonding layer 30c and reaches the lower component 30a. The upper hole portion 81a passes through the formation area 37 of the coolant flow path 31 in the cooling substrate 30 (the part of the wall that separates the coolant flow paths 31 from each other in the cooling substrate 30) in the up-down direction. The lower hole portion 81b is formed to reach the lower surface of the lower component 30a from the outer peripheral position of the hole step portion 81c. The length of the upper hole portion 81a is longer than that of the lower hole portion 81b. Accordingly, the height (length in the up-down direction) of the coolant flow path 31 can be fully obtained, and therefore, the heat removal capacity of the coolant flow path 31 is improved.

[0051] The stepped insulating tube 84 is inserted into the stepped hole 81 and is bonded to the inner surface of the stepped hole 81 via an adhesive layer 88 made of silicone. The outer shape of the stepped insulating tube 84 is consistent with the shape of the stepped hole 81. The stepped insulating tube 84 has a thin-diameter upper tube portion 84a, a thick-diameter lower tube portion 84b, and a tube step portion 84c between the upper tube portion 84a and the lower tube portion 84b. The upper tube portion 84a is located at the upper hole portion 81a, and the lower tube portion 84b is located at the lower hole portion 81b. The outer surface of the tube step portion 84c is bonded to the hole step portion 81c via an adhesive layer 88.

[0052] The ceramic substrate 20 is provided with a terminal hole 27 a extending from the lower surface of the FR adsorption electrode 27 to the lower surface of the ceramic substrate 20 .

[0053] The power supply terminal 82 is inserted through the terminal hole 27a and the tube upper portion 84a of the insulating tube 84 with a step, and is bonded to the inner surface of the tube upper portion 84a via a silicone adhesive layer 89. The upper surface of the power supply terminal 82 is bonded to the FR adsorption electrode 27 via a metal brazing material layer 27b, and the lower portion of the power supply terminal 82 reaches the inside of the tube lower portion 84b of the insulating tube 84 with a step.

[0054] The socket 85 is a cylindrical component made of metal (e.g., Cu), and is embedded in the lower tube portion 84b of the stepped insulating tube 84. The socket 85 has a bottomed hole 85a at the center of the upper surface. The annular upper surface 85b of the socket 85 abuts against the tube step portion 84c of the stepped insulating tube 84. The diameter of the circular lower surface 85c of the socket 85 is The inner diameter of the lower portion 84b of the insulating tube 84 with a step is roughly the same. The lower surface 85c is a concave surface that is concave from the outer periphery to the center. The taper angle θ of the concave surface is preferably greater than 90° and less than 180°. A louver plate 86 made of metal (for example, beryllium copper) is arranged in the bottomed hole 85a of the socket 85. The louver plate 86 has a ring portion 86a at the top and bottom, and has a plurality of thin plate portions 86b (see Figure 86b) that are erected at intervals along the circumferential direction of the ring portion 86a. Figure 4 ). The ring portion 86a contacts the inner circumferential wall of the bottomed hole 85a of the socket 85. The ring portion 86a can be annular or C-shaped. The thin plate portion 86b connects the upper and lower ring portions 86a to each other, and is in a shape that is bent toward the central axis of the louver 86. The lower portion of the power supply terminal 82 is inserted into the louver 86. The outer circumferential surface of the power supply terminal 82 contacts a plurality of thin plate portions 86b, and the lower end surface of the power supply terminal 82 does not abut against the bottom surface of the bottomed hole 85a but is separated. The thin plate portion 86b is in a state of elastic deformation due to the power supply terminal 82 being pressed toward the outside of the radius. That is, the louver 86 elastically supports the outer circumferential surface below the power supply terminal 82 in a state in which the lower end surface of the power supply terminal 82 does not abut against the bottom surface of the bottomed hole 85a of the socket 85. The diameter of the lower surface of the socket 85 The relationship between the diameter ψ of the power supply terminal 82 is preferably

[0055] Next, use Figure 5 and Figure 6 , a manufacturing example of the wafer placement table 10 is described. Figure 5 and Figure 6 1 is a manufacturing process diagram of the wafer stage 10. First, a disc-shaped ceramic sintered body 120 ( Figure 5 (A)). Specifically, the molded body of the ceramic powder is hot-pressed and sintered, and then various holes are formed by cutting to produce a ceramic sintered body 120. The ceramic sintered body 120 has a wafer adsorption electrode 25, a central heater electrode 26, an FR adsorption electrode 27, and a peripheral heater electrode 28 built therein. The various holes are a through hole 42b that forms a part of the BS gas passage 42 and holes for inserting the power supply terminals 62, 72, 82, and 92.

[0056] At the same time, the lower part 30a and the upper part 30b are made ( Figure 5(A)). In the lower part 30a, a refrigerant supply path 32, a refrigerant discharge path 33, and a hole forming a part of the holes 42a, 61, 71, 81, and 91 with steps are formed by cutting. In the upper part 30b, a flow path groove 131 that becomes the basis of the refrigerant flow path 31, and a hole forming a part of the holes 42a, 61, 71, 81, and 91 with steps are formed by cutting. In the case where the ceramic sintered body 120 is made of alumina, the lower part 30a and the upper part 30b are preferably made of SiSiC or AlSiC. This is because: the thermal expansion coefficient of alumina is substantially the same as the thermal expansion coefficient of SiSiC and AlSiC. In the case where the ceramic sintered body 120 is made of AlN, the lower part 30a and the upper part 30b are preferably made of Mo. This is because: the thermal expansion coefficient of AlN is substantially the same as the thermal expansion coefficient of Mo.

[0057] The SiSiCTi disc component can be made, for example, as follows. First, silicon carbide, metal Si and metal Ti are mixed to make a powder mixture. Next, the obtained powder mixture is formed into a disc-shaped molded body by uniaxial pressure molding, and the molded body is hot-pressed and sintered in an inert atmosphere to obtain the SiSiCTi disc component.

[0058] A metal bonding material 130c having through holes provided at necessary locations is disposed between the lower member 30a and the upper member 30b, and a metal bonding material 140(mm) having through holes provided at necessary locations is disposed between the upper member 30b and the ceramic sintered body 120. Figure 5 (A)). Then, these are stacked to obtain a stacked body.

[0059] Next, the laminate is pressed (TCB) while being heated, thereby obtaining a bonded body 110 ( Figure 5 (B)). The joint body 110 is obtained by joining the ceramic sintered body 120 to the upper surface of the cooling substrate 30 obtained by joining the lower part 30a and the upper part 30b by means of the conductive bonding layer 30c. The opening of the flow path groove 131 of the upper part 30b is covered by the conductive bonding layer 30c and the lower part 30a inside the cooling substrate 30, thereby forming a coolant flow path 31. Holes 42a, 61, 71, 81, 91 with steps are formed in the metal bonding layer 40 and the cooling substrate 30.

[0060] For example, TCB is performed as follows. That is, the stack is pressurized and joined at a temperature below the solidus temperature of the metal bonding material (for example, a temperature above the solidus temperature minus 20°C and below the solidus temperature), and then returned to room temperature. Accordingly, the metal bonding material becomes a metal bonding layer. As the metal bonding material at this time, Al-Mg bonding materials and Al-Si-Mg bonding materials can be used. For example, when TCB is performed using an Al-Si-Mg bonding material, the stack is pressurized in a heated state under a vacuum atmosphere. The metal bonding material preferably uses a material with a thickness of about 100 μm.

[0061] Next, the outer periphery of the ceramic sintered body 120 is cut to form a step, thereby manufacturing a ceramic substrate 20 ( Figure 5 (C)).

[0062] Next, necessary components are installed in the stepped holes 61, 71, 81, and 91, thereby obtaining the wafer placement table 10. Here, the case where necessary components are installed in the stepped hole 81 is described as an example. It should be noted that necessary components are installed in the other stepped holes 61, 71, and 91 in the same manner.

[0063] First, the upper surface of the power supply terminal 82 is bonded to the lower surface of the ceramic substrate 20 up to the terminal hole 27a of the FR adsorption electrode 27 using a metal brazing material, thereby bonding the power supply terminal 82 and the FR adsorption electrode 27 via the metal brazing material layer 27b ( Figure 6 (A) and (B)). For example, the power supply terminal 72 made of Mo is joined to the FR adsorption electrode 27 made of WC or Mo using a metal brazing material (for example, Au—Ge, Al, Ag, etc.).

[0064] Next, a silicone adhesive is applied to the outer circumference of the stepped insulating tube 84 and the inner circumference of the thin-diameter tube upper portion 84a, and then the power supply terminal 82 is inserted into the stepped insulating tube 84, and the stepped insulating tube 84 is inserted into the stepped hole 81, and the adhesive is cured to obtain adhesive layers 88, 89 ( Figure 6 (B) and (C)). The lower end of the power supply terminal 82 is in a state of protruding into the inside of the large-diameter tube lower portion 84b.

[0065] Next, a socket 85 with a louver 86 is prepared, and the power supply terminal 82 is inserted into the louver 86. At the same time, the socket 85 is assembled to the thick-diameter lower portion 84b of the insulating tube 84 with a step ( Figure 6(C) and (D)). At this time, even if a force is applied to the socket 85 in the direction toward the FR adsorption electrode 27, since the socket 85 does not abut against the lower end surface of the power supply terminal 82, the force is applied to the tube step portion 84c and the hole step portion 81c. Therefore, the socket 85 does not press the power supply terminal 82. In addition, the louver 86 of the socket 85 does not abut against the lower end surface of the power supply terminal 82 to elastically support the outer peripheral surface of the power supply terminal 82. Therefore, the load when connecting the power supply terminal 82 and the louver 86 of the socket 85 is not applied to the joint between the power supply terminal 82 and the FR adsorption electrode 27, that is, the metal brazing material layer 27b.

[0066] Necessary components are similarly mounted in the other stepped holes 61, 71, and 91. Thus, the wafer placement table 10 is obtained.

[0067] Next, use Figure 1 , an example of using the wafer stage 10 is described. As described above, the wafer stage 10 is installed on the installation plate 101 of the chamber 100. A shower head 100a for releasing a process gas into the chamber 100 from a plurality of gas injection holes is arranged on the top surface of the chamber 100.

[0068] A focus ring 78 is placed on the FR placement surface 24a of the wafer placement table 10, and a disc-shaped wafer W is placed on the wafer placement surface 22a. The focus ring 78 has a step along the inner circumference of the upper end so that it does not interfere with the wafer W. In this state, a DC voltage is applied to the wafer adsorption electrode 25 to adsorb the wafer W to the wafer placement surface 22a, and a DC voltage is applied to the FR adsorption electrode 27 to adsorb the focus ring 78 to the FR placement surface 24a. In addition, BS gas (for example, helium) is supplied from the BS gas passage 42 to the back side of the wafer W, and the central heater electrode 26 and the peripheral heater electrode 28 are energized to control the wafer W to a high temperature. Then, the interior of the chamber 100 is set to a predetermined vacuum atmosphere (or a reduced pressure atmosphere), and a high frequency voltage is applied from the high frequency power supply 36 to the cooling substrate 30 while a process gas is supplied from the shower head 100a. Then, plasma is generated between the cooling substrate 30 and the shower head 100a. Then, the wafer W is processed by the plasma. Furthermore, the temperature of the wafer W is adjusted by circulating the coolant in the coolant flow path 31 as necessary.

[0069] In the wafer stage 10 of the present embodiment described above, the stepped hole 81 has a small-diameter upper hole portion 81a, and the upper hole portion 81a passes through the formation region 37 of the coolant flow path 31 (the portion of the wall that separates the coolant flow paths 31 from each other in the cooling substrate 30). That is, the large-diameter lower hole portion 81b of the stepped hole 81 is provided on the lower side of the coolant flow path 31. Therefore, the heat dissipation capacity of the coolant flow path 31 is not greatly impaired, and the influence on the thermal uniformity of the wafer W can be reduced.

[0070] In addition, since the length of the hole upper portion 81 a is longer than the hole lower portion 81 b , the influence on the heat uniformity can be further reduced.

[0071] In addition, the socket 85 is arranged in the thick-diameter lower portion 84b of the insulating tube 84 with a step, so the diameter of the lower surface of the socket 85 is It can be thicker than the diameter of the upper part 84a of the tube and the diameter ψ of the power supply terminal 82. As a result, the contact surface between the lower surface of the socket 85 and the power supply rod 83 as the external contact member becomes larger, which can suppress interference with their connection. In addition, even if a force is applied to the socket 85 in the direction toward the FR adsorption electrode 27, the socket 85 does not abut the lower end surface of the power supply terminal 82, so the power supply terminal 82 will not be pressed. In addition, the louver 86 of the socket 85 does not abut the lower end surface of the power supply terminal 82 to elastically support the outer peripheral surface of the power supply terminal 82. Therefore, the load when the power supply rod 83 is in contact with the socket 85 and the load when the power supply terminal 82 and the socket 85 are connected will not be applied to the metal brazing material layer 27b, which is the joint between the power supply terminal 82 and the FR adsorption electrode 27, and defects in the metal brazing material layer 27b can be suppressed.

[0072] Furthermore, since the socket 85 is in contact with the tube step 84 c , even if a force is applied to the socket 85 in the direction toward the FR adsorption electrode 27 , the power supply terminal 82 is not pressed because the force is applied to the tube step 84 c and the hole step 81 c .

[0073] In addition, as the elastic support part, a plurality of thin plate parts 86b (leaf springs) are used. Specifically, as the elastic support part, a louver plate 86 having a plurality of thin plate parts 86b (leaf springs) erected at intervals along the circumferential direction is used. Therefore, the elastic support part can be made into a relatively simple structure.

[0074] In addition, the diameter ψ of the power supply terminal 82 is preferably equal to the diameter of the lower surface 85c of the socket 85. less than half (i.e. ). According to this, the diameter of the power supply terminal 82 can be sufficiently reduced relative to the lower surface 85c (contact surface) of the socket 85. As a result, the reduction in thermal uniformity of the wafer W due to the power supply terminal 82 can be sufficiently suppressed.

[0075] The lower surface 85c of the socket 85 is concave from the periphery toward the center. Therefore, when the external power supply rod 83 is in elastic contact with the lower surface 85c of the socket 85 by the spring 83a, the tip of the power supply rod 83 is not easy to deviate from the center of the lower surface 85c of the socket 85.

[0076] The above effects can not only be achieved through Figure 3The power supply terminal 82 and its peripheral structure shown are obtained, and can also be obtained by other power supply terminals 62, 72, 92 and their peripheral structures having the same structure.

[0077] It should be noted that the present invention is not limited to the above-described embodiment and can be implemented in various forms as long as they fall within the technical scope of the present invention.

[0078] For example, in the above embodiment, the socket 85 assembled with the louver plate 86 is used, but instead, a socket 85 assembled with the louver plate 86 may be used. Figure 7 and Figure 8 Socket 185 is shown. Figure 7 is a cross-sectional view of the socket 185 and its surrounding structure, Figure 8 It is a three-dimensional diagram of the socket 185. Figure 7 In the embodiment, the same reference numerals are used for the same components as those in the above-mentioned embodiment, and their description is omitted. The insulating tube 184 with a step is inserted into the hole 81 with a step, and its outer shape is consistent with the shape of the hole 81 with a step, and it has a small diameter upper tube portion 184a, a large diameter lower tube portion 184b, and a tube step portion 184c between the upper tube portion 184a and the lower tube portion 184b. The tube step portion 184c abuts against the upper surface 185b of the socket 185. A space 184d for accommodating the elastic support portion 185d is provided at the boundary between the upper tube portion 184a and the tube step portion 184c. The elastic support portion 185d includes: a plurality of plate members 185e erected at intervals in the circumferential direction, and an external spring (elastic member) 185f that fastens the plurality of plate members 185e from the outside. The plate member 185e is made of metal and is a member having an arc-shaped cross section obtained by dividing a cylinder into a plurality of (here, four) slits in the vertical direction. Figure 8). The lower end of the plate member 185e is integrated with the socket 185 to form a fixed end, and the upper end of the plate member 185e is a free end. The external spring 185f is made of metal, preferably formed of a non-magnetic metal material (such as chromium-nickel-inconel) or a metal material that is not magnetized at high temperatures. The diameter of the circle in which the multiple plate members 185e are arranged in parallel is slightly smaller than the diameter of the power supply terminal 82. Therefore, when the power supply terminal 82 is inserted into the space in the center of the elastic support portion 185d, the multiple plate members 185e expand toward the outside of the radius, but the external spring 185f fastens the multiple plate members 185e and the power supply terminal 82 from the outside. As a result, the power supply terminal 82 is elastically supported by the elastic support portion 185d. At this time, the lower end surface of the power supply terminal 82 is separated from the upper surface 185b of the socket 185 (not abutting against the upper surface 185b of the socket 185). The lower surface 185c of the socket 185 is shaped to be concave from the periphery toward the center, and the power supply rod 83 abuts against the center of the socket 185. When this structure is adopted, the same effect as the above-mentioned embodiment can be obtained. It should be noted that when the elastic support part 185d can elastically support the power supply terminal 82 even without the external spring 185f, the external spring 185f can be omitted. The structure of the power supply terminals 62, 72, 92 and their surroundings can also adopt the same Figure 7 Same structure.

[0079] In the above embodiment, the structure in which the power supply rod 83 is in elastic contact with the lower surface 85c of the socket 85 is illustrated. Fig. 9 As shown, a plug insertion port 85d may be provided on the side opposite to the bottomed hole 85a of the socket 85, and a power supply plug (eg, a banana plug) may be inserted into the plug insertion port 85d as an external contact member.

[0080] In the above embodiment, an example is shown in which the wafer adsorption electrode 25, the central heater electrode 26, the FR adsorption electrode 27, and the peripheral heater electrode 28 are built into the ceramic substrate 20, but the invention is not particularly limited thereto, and at least one of these electrodes may be built into the ceramic substrate 20. In addition, an RF electrode may be built into the ceramic substrate 20. In this case, the power supply terminal, the power supply rod, etc. connected to the RF electrode are similar to the structure of Figure 3 The same structure will do.

[0081] The wafer stage 10 of the above embodiment may have lift pin holes for inserting lift pins (not shown) for vertically moving the wafer W relative to the wafer placement surface 22a. The lift pin holes are holes that penetrate the wafer stage 10 in the vertical direction.

[0082] In the above embodiment, the ceramic substrate 20 and the cooling substrate 30 are bonded by the metal bonding layer 40, but a resin bonding layer may be used instead of the metal bonding layer 40. In this case, the upper portion of the stepped insulating tubes 64, 74, 84, 94 may be inserted into the hole of the resin bonding layer or may not be inserted into the hole of the resin bonding layer. However, in consideration of thermal conductivity, the metal bonding layer 40 is more preferable than the resin bonding layer.

[0083] In the above embodiment, the lower end of the power supply terminal 82 may be flat, and a pair of flat springs may be provided in the socket 85 instead of the louver 86 , so that the lower end of the power supply terminal 82 can be clamped by the flat springs.

Claims

1. A wafer loading platform, wherein: have: A ceramic substrate having a wafer placement surface on an upper surface and having electrodes built therein; A cooling substrate having a refrigerant flow path formed therein; a bonding layer bonding the lower surface of the ceramic substrate and the upper surface of the cooling substrate; a hole with a step, the hole penetrating the bonding layer and the cooling substrate in the up-down direction, and having a hole upper portion with a small diameter, a hole lower portion with a large diameter, and a hole step portion between the hole upper portion and the hole lower portion, the hole upper portion passing through the region where the coolant flow path is formed; an insulating tube with a step, the insulating tube being inserted into the hole with the step and having a tube upper portion with a small diameter, a tube lower portion with a large diameter, and a tube step portion between the tube upper portion and the tube lower portion; a connecting terminal, the connecting terminal being inserted into the insulating tube with the step and the upper end of which is connected to the electrode; as well as a socket, which is arranged in the lower part of the insulating tube with the step and has an elastic support portion that elastically supports the outer peripheral surface of the connecting terminal without contacting the lower end surface of the connecting terminal, The elastic support portion includes a plurality of plate members erected at intervals in a circumferential direction, and an elastic member fastening the plurality of plate members from outside.

2. A wafer loading platform, wherein: have: A ceramic substrate having a wafer placement surface on an upper surface and having electrodes built therein; A cooling substrate having a refrigerant flow path formed therein; a bonding layer bonding the lower surface of the ceramic substrate and the upper surface of the cooling substrate; a hole with a step, the hole penetrating the bonding layer and the cooling substrate in the up-down direction, and having a hole upper portion with a small diameter, a hole lower portion with a large diameter, and a hole step portion between the hole upper portion and the hole lower portion, the hole upper portion passing through the region where the coolant flow path is formed; an insulating tube with a step, the insulating tube being inserted into the hole with the step and having a tube upper portion with a small diameter, a tube lower portion with a large diameter, and a tube step portion between the tube upper portion and the tube lower portion; a connecting terminal, the connecting terminal being inserted into the insulating tube with the step and the upper end of which is connected to the electrode; as well as a socket, which is arranged in the lower part of the insulating tube with the step and has an elastic support portion that elastically supports the outer peripheral surface of the connecting terminal without contacting the lower end surface of the connecting terminal, The lower surface of the socket is in a shape that is concave toward the center.

3. The wafer stage according to claim 2, wherein: The elastic support portion includes a plurality of plate members erected at intervals in a circumferential direction, and an elastic member fastening the plurality of plate members from outside.

4. The wafer stage according to any one of claims 1 to 3, wherein: The length of the upper portion of the hole is longer than the length of the lower portion of the hole.

5. The wafer stage according to any one of claims 1 to 3, wherein: The socket is in contact with the pipe step portion.

6. The wafer stage according to any one of claims 1 to 3, wherein: The elastic support portion has a plurality of leaf springs.

7. The wafer stage according to claim 6, wherein: The plurality of leaf springs are vertically arranged at intervals along the circumferential direction.

8. The wafer stage according to any one of claims 1 to 3, wherein: The diameter of the joining terminal is less than or equal to half of the diameter of the lower surface of the socket.

9. The wafer stage according to any one of claims 1 to 3, wherein: The socket has a plug insertion port into which a plug can be inserted.

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