wafer boat

Abstract

A wafer mounting table is provided which ensures the joining strength with an electrode even if a joining terminal is thin, and which suppresses the generation of cracks in a ceramic base material. A wafer mounting table (10) is provided with a ceramic base material (20), an electrode (FR adsorption electrode (27)), a joining terminal (power supply terminal (82)), and an electrode extraction portion (272). The ceramic base material (20) has a wafer mounting surface (22a) on an upper surface. The FR adsorption electrode (27) is implanted in the ceramic base material (20). The power supply terminal (82) is inserted into the ceramic base material (20) from a lower surface of the ceramic base material (20) and penetrates a through-hole (271) provided in the FR adsorption electrode (27). The electrode extraction portion (272) is provided in two or more along the periphery of the through-hole (271) at intervals, is thicker than the FR adsorption electrode (27), and an inner peripheral surface (272a) is joined to a side surface of the power supply terminal (82).

Description

TECHNICAL FIELD

[0001] The present application relates to a wafer boat. BACKGROUND

[0002] In the past, as a wafer boat, a wafer boat has been known which is provided with a ceramic base material having a wafer loading surface on an upper surface, an electrode implanted in the ceramic base material, and a bonding terminal inserted into the ceramic base material from a lower surface of the ceramic base material to be bonded to the electrode. For example, in the wafer boat described in Patent Literature 1, a circular plate-shaped electrode extraction portion integrated with the electrode is exposed to a bottom surface of a recessed portion which is opened in the lower surface of the ceramic base material, and the electrode extraction portion and the bonding terminal are bonded by a bonding layer. The bonding layer is also present between the bonding terminal and a side surface of the recessed portion.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Laid-Open No. 2012-216786 SUMMARY

[0006] However, in the wafer boat described in Patent Literature 1, particularly in the case where the recessed portion is shallow, the bonding strength of the electrode extraction portion and the bonding terminal is sometimes not sufficient. On the other hand, in order to ensure the bonding strength, it is considered to make the bonding terminal thick, but this sometimes deteriorates the uniform heating of the wafer.

[0007] The present application has been made to solve the above-described problems, and its main object is to ensure the bonding strength to the electrode even if the bonding terminal is thin.

[0008] The wafer boat of the present application is provided with:

[0009] a ceramic base material having a wafer loading surface on an upper surface;

[0010] an electrode implanted in the ceramic base material;

[0011] a bonding terminal inserted into the ceramic base material from a lower surface of the ceramic base material and penetrating a through-hole provided in the electrode; and

[0012] an electrode extraction portion provided at a periphery of the through-hole in a manner thicker than the electrode, and an inner peripheral surface of which is bonded to a side surface of the bonding terminal.

[0013] In the wafer mounting table, the joining terminal penetrates the through-hole provided in the electrode, and thus, compared with the case where the joining terminal hits the electrode, the length of the joining terminal inserted into the ceramic base material is longer. In addition, the electrode extraction portion is formed to be thicker than the electrode, and thus, the joining area of the side surface of the joining terminal and the inner peripheral surface of the electrode extraction portion is increased. Therefore, even if the power supply member is thin, the joining strength with the electrode can be ensured.

[0014] Note that, in the present specification, the present application is sometimes explained using up and down, left and right, front and back, and the like, but up and down, left and right, and front and back are merely relative positional relationships. Thus, in the case where the orientation of the wafer mounting table is changed, up and down become left and right, and left and right become up and down, and such cases are also included in the technical scope of the present application.

[0015] In the wafer mounting table of the present application, the electrode extraction portion can be provided at two or more along the peripheral edge of the through-hole. According to this, compared with the case where the electrode extraction portion is provided along the entire periphery of the through-hole, a crack is less likely to occur in the ceramic base material.

[0016] In the wafer mounting table of the present application, the joining terminal can be inserted into a terminal hole provided so as to penetrate the electrode from the lower surface of the ceramic base material, and the electrode extraction portion can be a shape obtained by cutting off a portion of a conductive material in a spherical segment shape or a cylindrical shape having a diameter smaller than the diameter of the terminal hole with the terminal hole. According to this, the electrode extraction portion can be easily manufactured.

[0017] In the wafer mounting table of the present application, the joining terminal can be joined to the side surface of the terminal hole including the inner peripheral surface of the through-hole and the inner peripheral surface of the electrode extraction portion, and the bottom surface of the terminal hole, with a metal filler layer, and the metal filler layer can be provided so as not to reach the lower surface of the ceramic base material. According to this, the joining strength is further improved.

[0018] In the wafer mounting table of the present application, the inner peripheral surface of the electrode extraction portion can be a surface perpendicular to the wafer mounting surface. According to this, compared with the case where the inner peripheral surface of the electrode extraction portion is inclined, the work of mounting the joining terminal to the electrode extraction portion can be smoothly performed.

[0019] In the wafer mounting table of the present application, the thickness of the inner peripheral surface side of the electrode extraction portion can be 0.1 mm or more and 1 mm or less. If the thickness is 0.1 mm or more, heat generation is sufficiently suppressed, and if the thickness is 1 mm or less, a crack is less likely to occur in the ceramic base material.

[0020] In the wafer boat of the present application, the electrode extraction portion can be convex downward with respect to the electrode. According to this, even if a terminal hole provided in the lower surface of the ceramic substrate for the purpose of inserting the bonding terminal is not deep, the electrode extraction portion and the bonding terminal can be bonded. In addition, since it is not necessary to make the terminal hole deep, it is also possible to suppress the influence of the terminal hole on the heat uniformity. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a longitudinal sectional view of the wafer boat 10 provided in the chamber 100.

[0022] Figure 2 is a plan view of the wafer boat 10.

[0023] Figure 3 is a partial enlarged view of Figure 1

[0024] Figure 4 is a perspective view of the electrode extraction portion 272.

[0025] Figure 5 is an A-A sectional view of Figure 3

[0026] Figure 6 is a perspective view of the louvers 86.

[0027] Figure 7 is a manufacturing process view of the wafer boat 10.

[0028] Figure 8 is a manufacturing process view of the wafer boat 10.

[0029] Figure 9 is a manufacturing process view of the wafer boat 10.

[0030] Figure 10 is a partial enlarged view of the electrode extraction portion 372 and its periphery.

[0031] Figure 11 is a perspective view of the electrode extraction portion 372.

[0032] Figure 12 is a partial longitudinal sectional view of another embodiment.

[0033] Figure 13 is a partial longitudinal sectional view of another embodiment.

[0034] SYMBOL EXPLANATION

[0035] ​​10...wafer boat, 20...ceramic base material, 22...central portion, 22a...wafer loading surface, 24...peripheral portion, 24a...focus ring loading surface, 25...wafer chucking electrode, 26...central heater electrode, 27...FR chucking electrode, 28...peripheral heater electrode, 30...cooling base material, 30a...lower member, 30b...upper member, 30c...conductive bonding layer, 31...coolant flow path, 32...coolant supply path, 33...coolant discharge path, 34...coolant circulator, 36...high-frequency power source, 37...region where coolant flow path is formed, 40...metal bonding layer, 42...BS gas passage, 42a...hole with step, 42b...through hole, 43...BS gas supply source, 45, 50...ceramic base material, 46, 51, 52...electrode, 47, 53...terminal hole, 48, 55...bonding terminal, 49, 54, 56...electrode extraction portion, 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...louver, 78...focus ring, 81a...hole upper portion, 81b...hole lower portion, 81c...hole step portion, 84a...tube upper portion, 84b...tube lower portion, 84c...tube step portion, 85a...bottomed hole, 85b...upper surface, 85c...lower surface, 86a...ring portion, 86b...thin plate portion, 88...adhesive layer, 100...chamber, 100a...shower head, 101...mounting plate, 110...bonded body, 120...ceramic sintered body, 121-124...first to fourth ceramic formed bodies, 125...laminated body, 130c, 140...metallic bonding material, 131...flow path groove, 261, 271, 281...through hole, 252, 262, 272, 282...electrode extraction portion, 253, 263, 273, 283...hole, 254...wafer chucking electrode precursor, 264...central heater electrode precursor, 272a...inner peripheral surface, 272b...lower surface, 274...FR chucking electrode precursor, 284...peripheral heater electrode precursor, 372...electrode extraction portion, 621, 721, 821, 921...terminal hole, 621a, 721a, 821a, 921a...shaft. DETAILED DESCRIPTION

[0036] Hereinafter, a preferred embodiment of the present application will be described with reference to the accompanying drawings. Figure 1 is a longitudinal sectional view of the wafer boat 10 provided in the chamber 100 (a sectional view when a surface including the central axis of the wafer boat 10 is cut), Figure 2 is a plan view of the wafer boat 10, Figure 3 is Figure 1a partial enlarged view (a cross-sectional view of the power terminal 82 and its periphery) of Figure 4 is a perspective view of the electrode extraction portion 272, Figure 5 is Figure 3 is an A-A cross-sectional view of Figure 6 is a perspective view of the louvers 86. Note that Figure 4 In the figure, for convenience, only one of the three electrode extraction portions 272 present is shown.

[0037] The wafer boat 10 is a member used when performing CVD, etching, etc. on a wafer W using plasma, and is fixed to a setting plate 101 provided inside a chamber 100 used for semiconductor processing. The wafer boat 10 is provided with a ceramic base material 20, a cooling base material 30, and a metal joint layer 40.

[0038] The ceramic base material 20 is provided with an outer peripheral portion 24 having a ring-shaped focus ring seating surface 24a on the outer periphery of a central portion 22 having a circular wafer seating surface 22a. Hereinafter, the focus ring is sometimes referred to simply as "FR". The wafer seating surface 22a is for seating a wafer W, and the FR seating surface 24a is for seating a focus ring 78. The ceramic base material 20 is formed of a ceramic material represented by alumina, aluminum nitride, etc. The FR seating surface 24a is lower than the wafer seating surface 22a.

[0039] The central portion 22 of the ceramic base material 20 has built therein, in order from the side closer to the wafer seating surface 22a, a wafer suction electrode 25 and a central heater electrode 26. The above-mentioned electrodes 25, 26 are formed of a material containing, for example, W, Mo, Ru, WC, MoC, etc.

[0040] The wafer-adsorbing electrode 25 is a single-pole electrostatic electrode in a circular plate shape or a circular mesh shape. The layer of the ceramic substrate 20 above the wafer-adsorbing electrode 25 functions as a dielectric layer. The thickness of the wafer-adsorbing electrode 25 from the upper surface thereof to the wafer placement surface 22a is 1 mm or less. The wafer-adsorbing electrode 25 is connected to a not-shown direct-current power source for wafer adsorption by way of a power supply terminal 62 and a power supply rod 63. The power supply terminal 62 is disposed so as not to contact the central heater electrode 26. The power supply terminal 62 is inserted through an insulating pipe 64 with a step. The upper surface of the power supply terminal 62 is engaged with the lower surface of the wafer-adsorbing electrode 25 by way of an electrode extraction portion 252 in a spherical-taillike shape (the shape of the center of a sphere when the sphere is cut by two parallel planes). The electrode extraction portion 252 is formed of the same material as the wafer-adsorbing electrode 25 in a manner substantially coaxial with the power supply terminal 62. The insulating pipe 64 with a step is inserted through a hole with a step that penetrates the cooling substrate 30 and the bonding layer 40. A socket 65 is disposed at the pipe lower portion of the insulating pipe 64 with a step that has been expanded in diameter. The lower portion of the power supply terminal 62 is inserted through a louver 66 disposed at a bottomed hole provided at 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 urged upward by a spring 63a.

[0041] The central heater electrode 26 is provided with an elongated flat plate-shaped (strip-shaped) electric resistance heating element in a stroke from one end to the other end in a manner of extending over the entire surface of the wafer mounting surface 22a in plan view. At one end of the central heater electrode 26, a central heater power source, not shown, is connected via a power supply terminal 72 and a power supply rod 73. The upper portion of the power supply terminal 72 penetrates a through-hole 261 provided in a flat plate portion forming the one end of the central heater electrode 26. An electrode extraction portion 262 is provided in a convex manner downward at the periphery of the through-hole 261. The electrode extraction portion 262 is formed of the same material as the central heater electrode 26 in a manner of being thicker than the central heater electrode 26 at the periphery of the through-hole 261. The electrode extraction portion 262 is provided at two or more positions spaced apart along the periphery of the through-hole 261. The side surface of the upper portion of the power supply terminal 72 is engaged with the inner peripheral surface of the through-hole 261 and the inner peripheral surface of the electrode extraction portion 262. The power supply terminal 72 is inserted through an insulating pipe 74 having a step. The insulating pipe 74 having a step is inserted into a stepped hole penetrating the cooling base material 30 and the joint layer 40. A socket 75 is provided at the pipe lower portion of the insulating pipe 74 having a step. The lower portion of the power supply terminal 72 is inserted into a louver 76 provided in a bottomed hole provided in 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 which is forced upward by a spring 73a. Although not shown, a flat plate portion forming the other end of the central heater electrode 26 is connected to the central heater power source via a power supply terminal and a power supply rod in the same manner as the flat plate portion forming the one end of the central heater electrode 26.

[0042] The outer peripheral portion 24 of the ceramic base material 20 is provided with an FR adsorption electrode 27 and an outer peripheral heater electrode 28 in this order from the side close to the FR mounting surface 24a. The electrodes 27 and 28 are formed of a material containing, for example, W, Mo, Ru, WC, MoC, or the like.

[0043] The FR adsorption electrode 27 is a single-pole electrostatic electrode in a circular ring plate shape or a circular ring mesh shape. The layer of the ceramic substrate 20 above the FR adsorption electrode 27 functions as a dielectric layer. The FR adsorption electrode 27 is connected to an unillustrated FR adsorption DC power source via a power supply terminal 82 and a power supply rod 83. The upper portion of the power supply terminal 82 penetrates a through-hole 271 provided in the FR adsorption electrode 27. An electrode extraction portion 272 is provided on the periphery of the through-hole 271 in a convex shape downward. The electrode extraction portion 272 is formed of the same material as the FR adsorption electrode 27 in a manner thicker than the FR adsorption electrode 27 on the periphery of the through-hole 271. Two or more electrode extraction portions 272 are provided at intervals along the periphery of the through-hole 271. The side surface of the upper portion of the power supply terminal 82 is engaged with the inner peripheral surface of the through-hole 271 and the inner peripheral surface of the electrode extraction portion 272. The power supply terminal 82 is inserted through an insulating pipe 84 with a step. The insulating pipe 84 with a step is inserted into a stepped hole that penetrates the cooling substrate 30 and the joint layer 40. A socket 85 is disposed on the pipe lower portion of the insulating pipe 84 with a step that has been expanded in diameter. The lower portion of the power supply terminal 82 is inserted into a louver 86 disposed on 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 is in contact with the upper surface of the power supply rod 83 that is forced upward by a spring 83a.

[0044] The outer peripheral heater electrode 28 is provided with an elongated flat plate-shaped (strip-shaped) electric resistance heating element in one stroke from one end to the other end in a manner of being spread over the entire surface of the FR mounting surface 24a in plan view. At one end of the outer peripheral heater electrode 28, an outer peripheral heater power source, not shown, is connected via a power supply terminal 92 and a power supply rod 93. The upper portion of the power supply terminal 92 penetrates a through-hole 281 provided in a flat plate portion that forms one end of the outer peripheral heater electrode 28. An electrode extraction portion 282 is provided in a convex manner downward around the periphery of the through-hole 281. The electrode extraction portion 282 is formed of the same material as the outer peripheral heater electrode 28 in a manner of being thicker than the outer peripheral heater electrode 28 around the periphery of the through-hole 271. The electrode extraction portion 282 is provided with two or more than two at intervals along the periphery of the through-hole 281. The side surface of the upper portion of the power supply terminal 92 is engaged with the inner peripheral surface of the through-hole 281 and the inner peripheral surface of the electrode extraction portion 282. The power supply terminal 92 is inserted through a stepped insulating tube 94. The stepped insulating tube 94 is inserted into a stepped hole that penetrates the cooling base material 30 and the joint layer 40. A socket 95 is provided at the tube lower portion of the stepped insulating tube 94 that has been expanded in diameter. The lower portion of the power supply terminal 92 is inserted into a louver 96 provided at a bottomed hole provided at 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 forced upward by the spring 93a. Although not shown, a flat plate portion that forms the other end of the outer peripheral heater electrode 28 is connected to the outer peripheral heater power source via a power supply terminal and a power supply rod in the same manner as the flat plate portion that forms one end of the outer peripheral heater electrode 28.

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

[0046] The cooling base 30 is a circular plate member that is electrically conductive, and is obtained by joining a lower member 30a and an upper member 30b with an electrically conductive joining layer 30c. The electrically conductive joining layer 30c can be formed of the same material as the metal joining layer 40 described later. The cooling base 30 has, inside, a coolant flow path 31 in which a coolant can circulate. The coolant flow path 31 is formed in one stroke from one end to the other end in a manner that traverses the entire surface of the ceramic base 20 in plan view. The coolant flow path 31 is formed of a flow path groove formed in the lower surface of the upper member 30b and the electrically conductive joining layer 30c that covers the flow path groove from below. One end of the coolant flow path 31 is connected to a coolant supply path 32, and the other end is connected to a coolant discharge path 33. A coolant circulator 34 is a circulation pump that has a temperature adjustment function, and introduces a coolant adjusted to a desired temperature into the coolant supply path 32, and adjusts the coolant discharged from the coolant discharge path 33 of the coolant flow path 31 to a desired temperature and then introduces it again into the coolant supply path 32. The cooling base 30 is made of an electrically conductive material that contains metal. As the electrically conductive material, for example, a composite material, a metal, or the like can be given. As the composite material, a metal matrix composite (also referred to as Metal Matrix Composite (MMC)), or the like can be given, and as the MMC, a material containing Si, SiC, and Ti, a material obtained by impregnating Al and / or Si into a SiC porous body, or the like can be given. The material containing Si, SiC, and Ti is referred to as SiSiCTi, the material obtained by impregnating Al into a SiC porous body is referred to as AlSiC, and the material obtained by impregnating Si into a SiC porous body is referred to as SiSiC. As the metal, Mo can be given. The cooling base 30 is connected to a high-frequency power source 36 for generating plasma, and functions as a high-frequency electrode.

[0047] The metal joining layer 40 joins the lower surface of the ceramic base 20 and the upper surface of the cooling base 30. The metal joining layer 40 can be, for example, a layer formed of solder or metal brazing material. The metal joining layer 40 is formed by, for example, TCB (Thermal compression bonding). TCB refers to a known method in which a metal joining material is interposed between two members to be joined, and the two members are joined by pressure bonding in a state in which the temperature is heated to a temperature below the solidus temperature of the metal joining material.

[0048] The wafer boat 10 has a BS gas passage 42 for supplying a backside gas (BS gas) to the back surface of the wafer W. The BS gas passage 42 is composed of a stepped hole 42a that penetrates the cooling base 30 and the metal joining layer 40 in the up-and-down direction, and a through hole 42b that communicates with the stepped hole 42a and penetrates the ceramic base 20 in the up-and-down direction. The BS gas passage 42 is connected to a BS gas supply source 43. As the BS gas, a heat-conducting gas (for example, He gas) can be given.

[0049] Next, the structure of the power supply terminal 62, 72, 82, 92 of the wafer boat 10 and its periphery will be described. Since these structures are common, the following description will be given using the power supply terminal 82 as an example. Figures 3 to 6 The structure of the power supply terminal 82 and its periphery will be described.

[0050] The stepped hole 81 is a cross-sectional circular hole that penetrates the metal bonding layer 40 and the cooling base material 30 in the up-and-down direction, and has a hole upper portion 81a of a small diameter, a hole lower portion 81b of a large diameter, and a hole step portion 81c between the hole upper portion 81a and the hole lower portion 81b. The hole upper portion 81a penetrates the metal bonding layer 40, the upper member 30b and the conductive bonding layer 30c of the cooling base material 30, and reaches the lower member 30a. The hole upper portion 81a passes through the formation region 37 of the refrigerant flow paths 31 (the portions of the walls of the cooling base material 30 that separate the refrigerant flow paths 31 from each other) in the cooling base material 30 in the up-and-down direction. The hole lower portion 81b is formed so as to reach the lower surface of the lower member 30a from the outer peripheral position of the hole step portion 81c. The length of the hole upper portion 81a is longer than that of the hole lower portion 81b. Accordingly, the height (length in the up-and-down direction) of the refrigerant flow paths 31 can be sufficiently obtained, and thus the heat removal capacity of the refrigerant flow paths 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 by means of the silicone adhesive layer 88. The stepped insulating tube 84 has an outer shape that coincides with the shape of the stepped hole 81. The stepped insulating tube 84 has a tube upper portion 84a of a small diameter, a tube lower portion 84b of a large diameter, and a tube step portion 84c between the tube upper portion 84a and the tube lower portion 84b in the inside thereof. The tube upper portion 84a is positioned at the hole upper portion 81a, and the tube lower portion 84b is positioned at the hole lower portion 81b. The outer surface of the tube step portion 84c is bonded to the hole step portion 81c by means of the adhesive layer 88.

[0052] A bottomed cylindrical terminal hole 821 is provided in the ceramic base material 20 from the lower surface of the FR adsorption electrode 27 to the lower surface of the ceramic base material 20. The terminal hole 821 is substantially coaxial with the tube upper portion 84a of the stepped insulating tube 84.

[0053] The upper portion of the power supply terminal 82 is inserted into the terminal hole 821, and penetrates the cylindrical through hole 271 provided in the FR adsorption electrode 27. The through hole 271 forms a part of the terminal hole 821. A plurality of electrode extraction portions 272 (here, three electrode extraction portions 272 are provided at equal intervals as shown in FIG. 8) are provided at intervals along the periphery of the through hole 271. Figure 5 The electrode extraction portion 272 is a shape obtained by cutting a part of a spherical segment shape (a shape obtained by cutting a sphere with a horizontal plane) with the through hole 271. Figure 4The thickness t2 of the inner circumferential surface 272a side at the section where the electrode removal part 272 is cut with a vertical plane is thicker than the thickness t1 of the FR adsorption electrode 27. Figure 3 Thickness t2 is preferably 0.1 mm or more and 1 mm or less. Thickness t1 is preferably 0.005 mm or more and 0.03 mm or less. Thickness t2 is preferably 20 times or more than thickness t1. The lower surface 272b of the electrode extraction portion 272 is convex and protruding downwards. The power supply terminal 82 is joined to the FR adsorption electrode 27 by means of the metal solder layer BR. Specifically, the metal solder layer BR is provided in the gap between the bottom surface of the terminal hole 821 and the upper surface of the power supply terminal 82, and in the gap between the side surface of the terminal hole 821 and the side surface of the power supply terminal 82. The lower end of the metal solder layer BR is located above the lower opening of the terminal hole 821, so that it does not reach the lower surface of the ceramic substrate 20. The inner peripheral surface of the through hole 271 provided in the FR adsorption electrode 27 and the inner peripheral surface 272a of the electrode extraction portion 272 are joined to the side surface of the power supply terminal 82 by means of the metal solder layer BR. The inner peripheral surface 272a is perpendicular to the wafer mounting surface 22a. The metal solder layer BR is formed of, for example, Au-Ge, Al, Ag, Ag-Cu-Ti, etc. The lower part of the power supply terminal 82 reaches the interior of the lower part 84b of the insulating tube 84 with steps attached.

[0054] The socket 85 is a cylindrical component made of metal (e.g., Cu), which is embedded in the lower part 84b of the stepped insulating tube 84. The socket 85 has a bottom hole 85a at the center of its upper surface. The annular upper surface 85b of the socket 85 abuts against the stepped portion 84c of the stepped insulating tube 84. The diameter of the circular lower surface 85c of the socket 85... The inner diameter of the lower part 84b of the insulating tube 84 with the attached steps is approximately the same. The lower surface 85c is a concave surface that slopes from the outer periphery toward the center. The cone angle θ of the concave surface is preferably 90° or more and less than 180°. A metal (e.g., beryllium copper) louver 86 is disposed in the bottom hole 85a of the socket 85. The louver 86 has an upper and lower ring portion 86a respectively, and has a plurality of thin plate portions 86b that are vertically arranged at intervals along the circumferential direction of the ring portion 86a. Figure 6The ring portion 86a contacts the inner peripheral wall of the bottom 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 curved towards the central axis of the louver plate 86. The lower part of the power supply terminal 82 is inserted into the louver plate 86. The outer peripheral surface of the power supply terminal 82 contacts the multiple thin plate portions 86b, and the lower end surface of the power supply terminal 82 is separated from the bottom surface of the bottom hole 85a. The thin plate portion 86b is in a state of elastic deformation when pressed towards the outer radius of the power supply terminal 82. That is, the louver plate 86 elastically supports the lower outer peripheral surface of the power supply terminal 82 in a state where the lower end surface of the power supply terminal 82 does not abut against the bottom surface of the bottom hole 85a of the socket 85. The diameter of the lower surface of the socket 85 The preferred relationship between the diameter ψ of the power supply terminal 82 and the actual diameter ψ is as follows:

[0055] Next, adopt Figures 7 to 9 A manufacturing example of the chip carrier stage 10 will be described. Figures 7 to 9 This is a manufacturing process diagram of the chip carrier stage 10.

[0056] First, using a casting method, first to fourth ceramic molded bodies 121 to 124 in the shape of circular plates are made as molded bodies of ceramic powder. Spherical cap-shaped holes 253, 263, 273, and 283 are formed on the upper surface of the first to third ceramic molded bodies 121 to 123. Figure 7 (A) Specifically, on the upper surface of the first ceramic molded body 121, at a position offset from the axis 921a of the subsequently formed terminal hole 921, a spherical cap-shaped hole 283 is formed by cutting. On the upper surface of the second ceramic molded body 122, at a position offset from the axis 721a of the subsequently formed terminal hole 721, a spherical cap-shaped hole 263 is formed by cutting, and at a position offset from the axis 821a of the subsequently formed terminal hole 821, a spherical cap-shaped hole 273 is formed by cutting. On the upper surface of the third ceramic molded body 123, a spherical cap-shaped hole 253 is formed by cutting, with its center aligned with the center of the axis 621a of the subsequently formed terminal hole 621.

[0057] Next, conductive paste is printed on the upper surfaces of the first to third ceramic molded bodies 121 to 123 according to a specified pattern. Figure 7(B)). Specifically, the outer periphery heater electrode precursor 284 which becomes the outer periphery heater electrode 28 is formed on the upper surface of the first ceramic formed body 121. At this time, the hole 283 is filled with the conductive paste. The central heater electrode precursor 264 which becomes the central heater electrode 26 and the FR adsorption electrode precursor 274 which becomes the FR adsorption electrode 27 are formed on the upper surface of the second ceramic formed body 122. At this time, the holes 263, 273 are filled with the conductive paste. The wafer adsorption electrode precursor 254 which becomes the wafer adsorption electrode 25 is formed on the upper surface of the third ceramic formed body 123. At this time, the hole 253 is filled with the conductive paste.

[0058] Next, the first to fourth ceramic formed bodies 121 to 124 are stacked in order from the lower side to obtain a laminate 125 Figure 7 (C)). After the laminate 125 is subjected to heat press sintering, the through hole 42b which becomes a part of the BS gas passage 42, the terminal holes 621, 721, 821, 921 are formed by cutting processing, and outer shape processing, thickness processing are performed, thereby obtaining a ceramic sintered body 120 Figure 7 (D)) in a round plate shape which becomes the basis of the ceramic substrate 20. Each of the electrode precursors 254, 264, 274, 284 becomes the electrodes 25, 26, 27, 28, respectively, after heat press sintering. In forming the terminal hole 621, the lower end of the conductive material filled in the hole 253 in a spherical segment shape is cut to become an electrode extraction portion 252 in a spherical platform shape. In forming the terminal holes 721, 821, 921, a part of the conductive material filled in the holes 263, 273, 283 in a spherical segment shape is cut to become electrode extraction portions 262, 272, 282, and through holes are formed in the electrodes 26, 27, 28. For example, the through hole 271 is formed in the FR adsorption electrode 27.

[0059] At the same time as the ceramic sintered body 120 is produced, the lower member 30a and the upper member 30b Figure 8(A)). In the lower member 30a, the refrigerant supply path 32, the refrigerant discharge path 33, and holes that constitute part of the stepped holes 42a, 61, 71, 81, 91 are formed by cutting. In the upper member 30b, the flow path groove 131 that becomes the basis of the refrigerant flow path 31, and holes that constitute part of the stepped holes 42a, 61, 71, 81, 91 are formed by cutting. In the case where the ceramic sintered body 120 is made of alumina, the lower member 30a and the upper member 30b are preferably made of SiSiC or AlSiC. This is because the thermal expansion coefficient of alumina is approximately 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 member 30a and the upper member 30b are preferably made of Mo. This is because the thermal expansion coefficient of AlN is approximately the same as the thermal expansion coefficient of Mo.

[0060] A circular plate member made of SiSiC can be produced, for example, as follows. First, silicon carbide, metal Si, and metal Ti are mixed to produce a powder mixture. Next, the obtained powder mixture is used to produce a circular plate-shaped molded body by uniaxial press molding, and the molded body is subjected to hot-press sintering in an inactive atmosphere, thereby obtaining a circular plate member made of SiSiC.

[0061] A metal joining material 130c provided with through holes at necessary sites is arranged between the lower member 30a and the upper member 30b, and a metal joining material 140 provided with through holes at necessary sites is arranged between the upper member 30b and the ceramic sintered body 120. Figure 8 (A)). Then, they are laminated to obtain a laminate.

[0062] Next, the laminate is subjected to pressing while being heated (TCB), thereby obtaining a joined body 110 Figure 8 (B)). The joined body 110 is obtained by joining the ceramic sintered body 120 to the upper surface of the cooling base material 30 obtained by joining the lower member 30a and the upper member 30b with the conductive joining layer 30c, with the metal joining layer 40. In the inside of the cooling base material 30, the opening of the flow path groove 131 of the upper member 30b is covered by the conductive joining layer 30c and the lower member 30a, thereby forming the refrigerant flow path 31. The metal joining layer 40 and the cooling base material 30 are formed with the stepped holes 42a, 61, 71, 81, 91.

[0063] For example, TCB is performed as follows: the laminate is bonded by pressure at a temperature below the solidus temperature of the metal bonding material (e.g., a temperature above but below the solidus temperature, obtained by subtracting 20°C from 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 in this case. 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 is a material with a thickness of approximately 100 μm.

[0064] Next, the outer periphery of the ceramic sintered body 120 is cut to form steps, thereby producing a ceramic substrate 20 having a central portion 22 and an outer peripheral portion 24. Figure 8 (C)).

[0065] Next, the necessary components are installed in the stepped holes 61, 71, 81, and 91, thereby obtaining the wafer stage 10. Here, the case of installing the necessary components in the stepped hole 81 is described as an example. It should be noted that the necessary components are also installed in the other stepped holes 61 and 91 in the same way. The necessary components are installed in the stepped hole 71 according to this standard.

[0066] First, using a metal solder, the power supply terminal 82 is joined to the terminal hole 821 of the FR adsorption electrode 27 penetrating from the lower surface of the ceramic substrate 20, thereby joining the power supply terminal 82 and the FR adsorption electrode 27 with the aid of the metal solder layer BR. Figure 9 (A) and (B)). For example, a Mo power supply terminal 82 is bonded to a WC or Mo FR adsorption electrode 27 using a metal solder (e.g., Au-Ge, Al, Ag, etc.). Accordingly, the inner peripheral surface of the through hole 271 provided in the FR adsorption electrode 27 and the inner peripheral surface 272a of the electrode extraction portion 272 are bonded to the side surface of the power supply terminal 82 by means of the metal solder layer BR.

[0067] Next, an adhesive made of silicone is applied to the outer peripheral surface of the stepped insulating tube 84 and the inner peripheral surface of the narrow-diameter upper part 84a. Then, the power supply terminal 82 is inserted into the interior of the stepped insulating tube 84, and the stepped insulating tube 84 is simultaneously inserted into the stepped hole 81, allowing the adhesive to cure, thus obtaining adhesive layers 88 and 89. Figure 9 (B) and (C)). The lower end of the power supply terminal 82 protrudes into the interior of the lower part 84b of the larger diameter tube.

[0068] Next, the socket 85 with the shutter 86 is prepared, the power supply terminal 82 is inserted into the shutter 86, and the socket 85 is assembled to the thick tube lower portion 84b of the thick diameter of the insulating tube 84 with the step Figure 9 (C) and (D)). At this time, even if a force in the direction toward the FR adsorption electrode 27 is applied to the socket 85, 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 shutter 86 of the socket 85 elastically supports the outer peripheral surface of the power supply terminal 82 without abutting against the lower end surface of the power supply terminal 82. Therefore, the load at the time of connecting the power supply terminal 82 and the shutter 86 of the socket 85 is not applied to the joint portion of the power supply terminal 82 and the FR adsorption electrode 27, that is, the metal brazing layer BR.

[0069] The other holes 61, 71, 91 with the step are also similarly installed with necessary components. Accordingly, the wafer boat 10 is obtained.

[0070] Next, the wafer boat 10 is used. Figure 1 An example of use of the wafer boat 10 will be described. As described above, the wafer boat 10 is provided to the setting plate 101 of the chamber 100. A shower head 100a that releases process gas from a plurality of gas injection holes to the inside of the chamber 100 is disposed on the top surface of the chamber 100.

[0071] The focus ring 78 is placed on the FR placement surface 24a of the wafer boat 10, and the disc-shaped wafer W is placed on the wafer placement surface 22a. The focus ring 78 has a step along the inner periphery of the upper end portion so as not to interfere with the wafer W. In this state, a direct current voltage is applied to the wafer adsorption electrode 25 to adsorb the wafer W to the wafer placement surface 22a, and a direct current 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 gas) is supplied to the back surface of the wafer W from the BS gas passage 42, and the central heater electrode 26 and the outer peripheral heater electrode 28 are energized to control the wafer W to a high temperature. Then, the inside of the chamber 100 is set to a predetermined vacuum atmosphere (or a reduced pressure atmosphere), and a process gas is supplied from the shower head 100a while a high frequency voltage from the high frequency power source 36 is applied to the cooling base 30. As a result, plasma is generated between the cooling base 30 and the shower head 100a. Then, the wafer W is processed by the plasma. In addition, the coolant is circulated in the coolant flow path 31 as necessary to adjust the temperature of the wafer W.

[0072] Here, the correspondence between the constituent elements of this embodiment and the constituent elements of the present invention is clarified. The ceramic substrate 20 of this embodiment corresponds to the ceramic substrate of the present invention, the central heater electrode 26, the FR adsorption electrode 27 and the peripheral heater electrode 28 correspond to electrodes, the power supply terminals 72, 82 and 92 correspond to connection terminals, and the electrode removal portions 272, 282 and 292 correspond to electrode removal portions.

[0073] In the wafer stage 10 of this embodiment described in detail above, the power supply terminal 82 penetrates through the through hole 271 provided in the FR adsorption electrode 27. Therefore, compared to the case where the power supply terminal 82 touches the lower surface of the FR adsorption electrode 27, the length of the power supply terminal 82 inserted into the ceramic substrate 20 is longer. In addition, the electrode extraction portion 272 is formed to be thicker than the FR adsorption electrode 27, thus increasing the contact area between the side of the power supply terminal 82 and the inner peripheral surface 272a of the electrode extraction portion 272. Therefore, even if the power supply terminal 82 is relatively thin, the contact strength with the FR adsorption electrode 27 can be ensured. Furthermore, three electrode extraction portions 272 are provided along the periphery of the through hole 271, thus reducing the likelihood of cracks forming in the ceramic substrate 20 compared to the case where they are provided around the entire periphery of the through hole 271. The same applies to the power supply terminals 72 and 92, and the electrode extraction portions 262 and 282.

[0074] Furthermore, three electrode extraction portions 272 are provided at equal intervals along the periphery of the through hole 271. Because the electrode extraction portions 272 are not provided around the entire periphery of the through hole 271, but are distributed at equal intervals, it is easier to suppress cracking in the ceramic substrate 20. The same applies to electrode extraction portions 262 and 282.

[0075] Furthermore, the electrode removal section 272 is a shape obtained by cutting away a portion of conductive material in the shape of a ball-shaped cap with a diameter smaller than that of the terminal hole 821, including the through hole 271, through the terminal hole 821. Figure 4 Therefore, it is relatively easy to manufacture the electrode extraction part 272. Figure 7 (C) and Figure 7 (D)). The same applies to electrode removal sections 262 and 282.

[0076] Furthermore, the power supply terminal 82 is brazed to a portion of the side surface and the bottom surface of the terminal hole 821. Therefore, the bonding strength is further improved. The same applies to power supply terminals 72 and 92.

[0077] Further, the inner peripheral surface 272a of the electrode extraction portion 272 is a surface perpendicular to the wafer placement surface 22a, and thus, compared to a case where the inner peripheral surface 272a of the electrode extraction portion 272 is inclined, the work of mounting the power supply terminal 82 to the electrode extraction portion 272 can be smoothly performed. This is also the same for the electrode extraction portions 262 and 282.

[0078] Further, the distance between the upper surface of the wafer suction electrode 25 in the ceramic substrate 20 and the wafer placement surface 22a is as low as 1 mm or less, and thus, if the power supply terminal 62 is provided so as to penetrate the wafer suction electrode 25, a dielectric layer cannot be ensured. Therefore, a through-hole through which the power supply terminal 62 penetrates is not provided in the wafer suction electrode 25, and the upper surface of the power supply terminal 62 is brazed and joined to the electrode extraction portion 252 provided on the lower surface of the wafer suction electrode 25.

[0079] Further, the thickness t2 of the inner peripheral surface 272a side of the electrode extraction portion 272 is preferably 0.1 mm or more and 1 mm or less. If the thickness is 0.1 mm or more, heat generation is sufficiently suppressed, and if the thickness is 1 mm or less, cracks are less likely to occur in the ceramic substrate 20. This is also the same for the electrode extraction portions 262 and 282.

[0080] Further, the electrode extraction portion 272 is convex downward with respect to the FR suction electrode 27. According to this, even if the terminal hole 821 is not deep, the electrode extraction portion 272 and the power supply terminal 82 can be joined. Further, since it is not necessary to make the terminal hole 821 deep, it is also possible to suppress the influence of the terminal hole 821 on the heat uniformity. This is also the same for the electrode extraction portions 262 and 282.

[0081] Note that the present application is not limited to the above-described embodiments, and can be implemented in various forms as long as it belongs to the technical scope of the present application.

[0082] In the above-described embodiments, the electrode extraction portion 272 is in a shape obtained by cutting a portion of a conductive material in a spherical segment shape having a diameter smaller than that of the terminal hole 821 with the terminal hole 821, but is not particularly limited thereto. For example, it can be in a shape obtained by cutting a portion of a conductive material in a cylindrical shape having a diameter smaller than that of the terminal hole 821 with the terminal hole 821, like the electrode extraction portion 372 shown in Figs. 37 and 38. Figure 10 Figure 11 Note that the same components as those in the above-described embodiments are denoted by the same reference numerals. Figure 10 Figure 11 Note that the same components as those in the above-described embodiments are denoted by the same reference numerals.

[0083] ​​The above embodiments illustrate an example where a wafer adsorption electrode 25, a central heater electrode 26, an FR adsorption electrode 27, and a peripheral heater electrode 28 are integrated into the ceramic substrate 20. However, this is not a limitation, and at least one of these electrodes may be integrated into the ceramic substrate 20. Additionally, an RF electrode may be integrated into the ceramic substrate 20. In this case, the power supply terminal, power supply rod, or other structures connected to the RF electrode are... Figure 3 The same structure will suffice.

[0084] In the above embodiments, such as Figure 5 As shown, three electrode extraction sections 272 are provided along the periphery of the through hole 271; however, the number is not particularly limited to three, and there can be two or more. Furthermore, the electrode extraction sections 272 are provided at equal intervals along the periphery of the through hole 271, but they can be provided at unequal intervals. Additionally, the electrode extraction sections 272 can be provided around the entire circumference of the through hole 271. This also applies to the electrode extraction sections 262 and 282.

[0085] In the above embodiments, as a configuration for connecting the power supply terminal 82 to a heater power source (not shown), an example is provided with a socket 85 equipped with a louvered plate 86 disposed at the lower part 84b of the stepped insulating tube 84 inserted into the stepped hole 81, but this is not particularly limited. For example, a structure can be adopted in which the stepped hole 81 is replaced with a straight hole, and the stepped insulating tube 84 is replaced with a straight insulating tube, and the socket 85 is removed so that the lower end of the power supply terminal 82 reaches the lower surface of the cooling substrate 30.

[0086] In the above embodiments, the first to fourth ceramic molded bodies 121 to 124 were produced by casting molding, but it is not particularly limited to this method. For example, they can be produced by casting molding or by pressing ceramic powder.

[0087] The wafer stage 10 of the above embodiment may have a lifting pin hole (not shown) through which a lifting pin for moving the wafer W up and down relative to the wafer placement surface 22a is inserted. The lifting pin hole is a hole that passes through the wafer stage 10 in the up-down direction.

[0088] In the above embodiment, the ceramic substrate 20 and the cooling substrate 30 are joined using a metal bonding layer 40. However, a resin bonding layer can be used instead of the metal bonding layer 40. In this case, the upper part of the stepped insulating tubes 64, 74, 84, and 94 can be inserted into the hole of the resin bonding layer or not. However, considering thermal conductivity, the metal bonding layer 40 is more ideal than the resin bonding layer.

[0089] In the above-described embodiments, the cases where the power supply terminals 62, 72, 82, 92 are insulated from the cooling substrate 30 are exemplified, but at least one of the power supply terminals 62, 72, 82, 92 can be connected to the cooling substrate 30 to be the same potential as the cooling substrate 30, and can be grounded as a whole through the cooling substrate 30, according to the situation.

[0090] In addition to the above-described embodiments, the embodiments of Figure 12 , Figure 13 may be employed. Figure 12 In the embodiment, the ceramic substrate 45 is implanted with a plurality of (two in this case) electrodes 46 in layers of different heights. The terminal holes 47 penetrate the plurality of electrodes 46. The bonding terminals 48 are inserted into the terminal holes 47. The electrode extraction portions 49 are formed around the through holes of the electrodes 46 in a manner thicker than the electrodes 46, and the inner peripheral surfaces thereof are bonded to the side surfaces of the bonding terminals 48 with the metal brazing layer BR. Figure 13 In the embodiment, the ceramic substrate 50 is implanted with a plurality of (two in this case) electrodes 51, 52 in layers of different heights. The terminal holes 53 penetrate the electrodes 52 except for the uppermost electrode 51, and the lower surfaces of the electrode extraction portions 54 of the electrode 51 are exposed to the bottom surfaces of the terminal holes 53. The bonding terminals 55 are inserted into the terminal holes 53. The electrode 52 is provided with the electrode extraction portion 56. The electrode extraction portion 56 is formed around the through hole of the electrode 52 in a manner thicker than the electrode 52, and the inner peripheral surface thereof is bonded to the side surface of the bonding terminal 55 with the metal brazing layer BR. The top surface of the bonding terminal 55 is bonded to the lower surface of the electrode extraction portion 54 of the electrode 51 with the metal brazing layer BR.

Claims

1. A wafer boat, comprising: Possessing: a ceramic substrate having a wafer mounting surface on an upper surface; an electrode embedded in the ceramic substrate; a bonding terminal inserted into the ceramic substrate from a lower surface of the ceramic substrate and penetrating a through-hole provided in the electrode; and an electrode extraction portion provided at a periphery of the through-hole in a manner thicker than the electrode and having an inner peripheral surface in contact with a side surface of the bonding terminal, the bonding terminal being inserted into a terminal hole provided to penetrate the electrode from the lower surface of the ceramic substrate, the electrode extraction portion not being provided at a position opposed to an upper surface of the bonding terminal but being provided at a position opposed to the side surface of the bonding terminal.

2. The wafer mounting table according to claim 1, wherein the electrode extraction portion is provided at two or more along a periphery of the through-hole.

3. The wafer mounting table according to claim 1, wherein the electrode extraction portion is a shape obtained by cutting off the terminal hole from a portion of a conductive material in a spherical segment shape or a cylindrical shape having a diameter smaller than a diameter of the terminal hole.

4. The wafer mounting table according to claim 3, wherein the bonding terminal is in contact with a side surface of the terminal hole including an inner peripheral surface of the through-hole and an inner peripheral surface of the electrode extraction portion and a bottom surface of the terminal hole by a metal filler layer, the metal filler layer is provided so as not to reach a lower surface of the ceramic substrate.

5. The wafer mounting table according to any one of claims 1 to 4, wherein the inner peripheral surface of the electrode extraction portion is a surface perpendicular to the wafer mounting surface.

6. The wafer mounting table according to any one of claims 1 to 4, wherein a thickness of the inner peripheral surface side of the electrode extraction portion is 0.1 mm or more and 1 mm or less.

7. The wafer mounting table according to any one of claims 1 to 4, wherein the electrode extraction portion is convex downward with respect to the electrode. ​

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