Joint body and member for semiconductor manufacturing apparatus

Abstract

This joint body 20 is used by being fastened to a base member 30, and comprises: a ceramic plate 21 that has a wafer placement surface 21a; a rear surface plate 23 that is joined to a rear surface of the ceramic plate 21; an arrangement space 24 that is provided to the rear surface plate 23 and has a through hole 25 at the bottom, nuts 40 being arranged in the arrangement space at the time of fastening; and a moving lane 26 that reaches the arrangement space 24 from a port 27 that is open to the lower surface or a side surface of the rear surface plate 23, and is used for insertion and removal of the nuts 40. A wafer placement table 10 comprises the joint body 20, the base member 30, the nuts 40, and bolts 50.

Description

Bonded body and member for semiconductor manufacturing equipment

[0001] The present invention relates to a bonded body and a member for a semiconductor manufacturing apparatus.

[0002] Conventionally, as a member for a semiconductor manufacturing apparatus, a wafer mounting table including a bonded body in which a ceramic base material and a first cooling base material having a screw hole opened on the lower surface are bonded is known (for example, see Patent Document 1). In this wafer mounting table, a screw member inserted into a through hole of a second cooling base material is screwed into a screw hole opened on the lower surface of the first cooling base material, and a bonded body of the ceramic base material and the first cooling base material is fastened to the second cooling base material. Further, there is known an electrostatic chuck assembly including a bonded body in which a ceramic plate and a cooling plate in which a fixing member having an internal female screw portion is housed in an internal space are bonded (for example, see Patent Document 2). In this electrostatic chuck assembly, a through hole is provided so that the female screw portion is exposed at the bottom of the cooling plate, and a bolt for fixing the chamber is inserted through this through hole and screwed into the female screw portion of the fixing member to be fixed to the chamber.

[0003] International Publication No. 2024 / 004040 pamphlet International Publication No. 2024 / 069816 pamphlet

[0004] However, in Patent Document 1, when a defect occurs in the screw hole of the first cooling base material, the bonded body of the ceramic base material and the first cooling base material may become unusable due to inability to fasten. In Patent Document 2, a plurality of sets of female screw portions are provided in the fixing member, and when the fixing member is rotated with respect to the central axis of the cooling plate, another set of female screw portions is exposed at the bottom of the cooling plate. When a defect occurs in the female screw portion, it can be fastened by exposing another set of female screw portions. However, when defects occur in all sets of female screw portions of the fixing member, the electrostatic chuck assembly, which is a bonded body of the ceramic plate and the cooling plate, may become unusable due to inability to fasten.

[0005] The present invention has been made to solve such problems, and a main object thereof is to suppress the bonded body from becoming unusable due to a defect in the fastening portion.

[0006] [1] The joint of the present invention is a joint used by fastening to a base member, comprising: a ceramic plate having a wafer mounting surface on its upper surface and containing electrodes; a back plate bonded to the back surface of the ceramic plate; an arrangement space provided in the back plate and having a through hole at the bottom, in which a joint-side fastening member is placed when fastening; and a moving lane that extends from a port opening on the lower surface or side surface of the back plate to the arrangement space, whose position in plan view is different from that of the port, and is used for inserting and removing the joint-side fastening member.

[0007] This joint includes not only an arrangement space for the joint-side fastening members, but also a moving lane used for inserting and removing the joint-side fastening members. Therefore, the joint-side fastening members can be replaced, and even if a problem occurs with a joint-side fastening member, it can be replaced with a new one, allowing the joint to be fastened again, and the joint will not become unusable due to a problem with the joint-side fastening member.

[0008] In this specification, the present invention may be described using terms such as up and down, left and right, front and back, but up and down, left and right, and front and back are merely relative positional relationships. Therefore, if the orientation of the wafer mounting stage is changed, up and down may become left and right, or left and right may become up and down, but such cases are also included within the technical scope of the present invention.

[0009] [2] In the above-described joint (the joint described in [1]), a slit extending vertically through the bottom of the moving lane may be provided along the moving lane. By inserting a jig or the like through this slit and using it to move the fastening member on the joint side within the moving lane, the fastening member on the joint side can be easily replaced.

[0010] [3] In the above-described joint (the joint described in [1] or [2]), the joint-side fastening member may be a nut and the width of the slit may be wide enough to allow the leg of the bolt screwed into the joint-side fastening member to pass through, or the joint-side fastening member may be a bolt and the width of the slit may be wide enough to allow the leg of the bolt of the joint-side fastening member to pass through. In this case, if the joint-side fastening member is a nut, the joint-side fastening member can be replaced using a bolt used to fasten the base member without having to prepare a special jig. Also, if the joint-side fastening member is a bolt, the joint-side fastening member can be replaced by gripping the leg of the bolt.

[0011] [4] In the above-described joint (the joint described in any of [1] to [3] above), the side wall of the arrangement space may be configured to restrict the rotation of the joint-side fastening member around its axis. This allows fastening and unfastening, which involve rotation such as screwing, to be easily performed without the need for any measures to prevent the rotation of the joint-side fastening member.

[0012] [5] In the above-described joint (the joint described in any of [1] to [4] above), the moving lane may extend from one port to multiple arrangement spaces. This allows for the insertion and removal of multiple joint-side fastening members from one port, making it easy to replace the joint-side fastening members.

[0013] [6] In the above-described joint (the joint described in any of [1] to [5] above), the back plate may be made of ceramic and directly bonded to the back surface of the ceramic plate. Since the difference in thermal expansion coefficient between the ceramic back plate and the ceramic plate is small, warping and delamination due to the difference in thermal expansion coefficient are less likely to occur in the joint, and direct bonding is possible. Direct bonding is preferable because the heat resistance of the joint is high. Furthermore, direct bonding is often performed at high temperatures, such as above the melting point of the ceramic, and direct bonding with the joint-side fastening member embedded in the back plate may be practically impossible considering the deterioration of the joint-side fastening member. For this reason, there is great significance in adopting the present invention, in which the joint-side fastening member can be inserted into the back plate after bonding.

[0014] [7] In the above-described joint (the joint described in any of [1] to [5] above), the back plate may be made of a composite material of metal and ceramic, ceramic, or a low thermal expansion metal, and may be joined to the back surface of the ceramic plate by metal bonding. Back plates made of a composite material of metal and ceramic or a low thermal expansion metal have a relatively small difference in thermal expansion coefficient with the ceramic plate, and ceramic back plates have an even smaller difference in thermal expansion coefficient with the ceramic plate, so warping and delamination due to the difference in thermal expansion coefficient is less likely to occur in the joint, and bonding by metal bonding is possible. Metal bonding is also suitable for joining dissimilar materials and has relatively high heat resistance, so it is preferable. Furthermore, although metal bonding is not performed at high temperatures as direct bonding, it is often performed at high temperatures such as above the melting point of the metal, and there is great significance in adopting the present invention, in which the fastening member on the joint side can be inserted into the back plate after bonding, as in the case of direct bonding.

[0015] [8] The semiconductor manufacturing apparatus component of the present invention is a semiconductor manufacturing apparatus component comprising the above-described joint (the joint described in any of [1] to [7] above), and further comprising: the base member; the joint-side fastening member; and the base-side fastening member used in combination with the joint-side fastening member.

[0016] Because this semiconductor manufacturing equipment component includes the aforementioned joint, the joint will not become unusable due to a malfunction in the fastening member on the joint side.

[0017] [9] In the semiconductor manufacturing equipment component described above (the semiconductor manufacturing equipment component described in [8] above), the space between the back surface of the joint and the upper surface of the base member may be filled with gas. In this way, the heat transfer between the joint and the base member can be adjusted by the gas.

[0018]

[10] In the semiconductor manufacturing apparatus component described above (the semiconductor manufacturing apparatus component described in [8] or [9] above), a heat insulating member may be placed around at least one of the joint-side fastening member and the base-side fastening member. This suppresses heat transfer between the joint and the base member via the joint-side fastening member and the base-side fastening member (hereinafter collectively referred to as the fastening member), thereby preventing extreme temperature differences from occurring between the area directly above or around the fastening member on the wafer mounting surface and other areas.

[0019] A longitudinal cross-sectional view of the wafer mounting table 10 installed in the chamber 94. A plan view of the wafer mounting table 10. A plan view of Figure 2 with the ceramic plate 21 removed. A diagram of the manufacturing process of the wafer mounting table 10 (manufacturing process of the bonded body 20). A diagram of the manufacturing process of the wafer mounting table 10 (placement process of the nut 40). A diagram of the manufacturing process of the wafer mounting table 10 (assembly process of the wafer mounting table 10). An explanatory diagram showing another example of the moving lane 26. An explanatory diagram showing another example of the moving lane 26. An enlarged view of the A-view portion of Figure 8. A longitudinal cross-sectional view of the wafer mounting table 110 installed in the chamber 94.

[0020] As a preferred embodiment of the semiconductor manufacturing apparatus of the present invention, a wafer mounting table 10 used as an electrostatic chuck heater will be described below with reference to the drawings. Figure 1 is a longitudinal cross-sectional view of the wafer mounting table 10 installed in the chamber 94 (a cross-sectional view when cut by a plane including the central axis of the wafer mounting table 10), Figure 2 is a plan view of the wafer mounting table 10, and Figure 3 is a plan view of Figure 2 with the ceramic plate 21 removed. In this specification, the "~" indicating a numerical range is used to mean that the numerical values ​​written before and after it are included as the lower limit and upper limit.

[0021] The wafer mounting stage 10 is used to perform CVD, etching, and other processes on a wafer W using plasma, and is fixed to a mounting plate 96 provided inside a semiconductor process chamber 94. The wafer mounting stage 10 comprises a jointed body 20 in which a ceramic plate 21 and a back plate 23 are joined, a base member 30, a nut 40 as a fastening member on the jointed body side, and a bolt 50 as a fastening member on the base side.

[0022] The assembled body 20 comprises a ceramic plate 21, a back plate 23, a placement space 24, and a moving lane 26. The ceramic plate 21 and the back plate 23 are joined by a metal bonding layer 29.

[0023] The ceramic plate 21 is, for example, a disc-shaped member with a diameter of about 300 mm, and has a circular wafer mounting surface 21a on its upper surface. A wafer W is placed on the wafer mounting surface 21a. The ceramic plate 21 is made of a ceramic material such as aluminum nitride or alumina. The ceramic plate 21 incorporates internal electrodes 22, with a wafer adsorption electrode 22a on the side closer to the wafer mounting surface 21a and a heater electrode 22b on the side further away from the wafer mounting surface 21a. The wafer adsorption electrode 22a is made of a material containing one or more of W, Mo, WC, and MoC. The wafer adsorption electrode 22a is a disc-shaped or mesh-shaped unipolar electrostatic electrode. The layer of the ceramic plate 21 above the wafer adsorption electrode 22a functions as a dielectric layer. A DC power supply, the wafer adsorption power supply 52a, is connected to the wafer adsorption electrode 22a via a power supply terminal 54a. The power supply terminal 54a is provided so as to reach the wafer adsorption electrode 22a from the lower surface of the ceramic plate 21, passing through an insulating tube 55a located in a through-hole that penetrates the base member 30, the back plate 23, and the metal bonding layer 29 in the vertical direction. The heater electrode 22b is formed of a material containing one or more of WC, W, MoC, and Mo, for example. The heater electrode 22b may also be made of a material to which the ceramic plate 21 has added ceramics. The heater electrode 22b is formed, for example, of a strip-shaped (flat and elongated ribbon-shaped) or coil-shaped resistance heating element formed on a surface parallel to the wafer mounting surface 21a. The heater electrode 22b is wired so as not to cross over the entire ceramic plate 21 in a single continuous line from one end of the pair of resistance heating elements to the other. The heater power supply 52b, which is an AC power supply, is connected to the heater electrode 22b via the power supply terminal 54b. The power supply terminal 54b is provided so as to pass through an insulating tube 55b located in a through-hole that penetrates the base member 30, the back plate 23, and the metal bonding layer 29 in the vertical direction, and reach the heater electrode 22b from the lower surface of the ceramic plate 21.

[0024] The back plate 23 is a disc slightly larger than the ceramic plate 21 and is made of a composite material of metal and ceramic (hereinafter also referred to as a metal-ceramic composite material), ceramic, or a low thermal expansion metal. Examples of metal-ceramic composite materials include metal matrix composites (MMCs) and ceramic matrix composites (CMCs). Specific examples of such metal-ceramic composite materials include materials containing Si, SiC, and Ti, and materials in which Al and / or Si are impregnated into a porous SiC body. Materials containing Si, SiC, and Ti are called SiSiCTi, materials in which Al is impregnated into a porous SiC body are called AlSiC, and materials in which Si is impregnated into a porous SiC body are called SiSiC. Specific examples of ceramic materials include aluminum nitride and alumina. The ceramic material may be, for example, the same type as the ceramic plate 21, or it may be the same type as the ceramic plate 21 but with lower purity. Specific examples of low thermal expansion metal materials include Mo. The material used for the back plate 23 has an absolute difference of 1.5 × 10⁻¹⁰ in the coefficient of linear thermal expansion between 40 and 400°C compared to the ceramic material used for the ceramic plate 21. -6 It is preferable that the value is less than or equal to / K, and 1.0 × 10 -6 It is more preferable that it be less than or equal to / K, and 0.5 × 10 -6 It is even more preferable that the temperature is less than or equal to / K. The thickness of the back plate 23 may be, for example, 5 mm or more from the viewpoint of strength and rigidity. Also, the thickness of the back plate 23 may be 25 mm or less from the viewpoint of shortening the heat transfer distance between the lower surface of the ceramic plate 21 and the upper surface of the base member 30.

[0025] The placement space 24 is a space provided in the back plate 23, where the nut 40 is placed when fastening the joint 20 to the base member 30. Multiple placement spaces 24 are provided at equal intervals along the circumference of the back plate 23 (six in this case). The placement space 24 is provided, for example, in a region inside half the diameter of the ceramic plate 21 (for example, a region with a diameter of 150 mm or less) centered on the axis of the back plate 23. The placement space 24 is a space formed when the upper opening of a bottomed hole 24a provided on the upper surface of the back plate 23 is closed by the ceramic plate 21. The bottom of the placement space 24 is lower than the bottom of the moving lane 26. The placement space 24 is formed in an oval shape, with a width in the narrow direction that is greater than the distance between opposite sides (width across flats) of the nut 40 and smaller than the diagonal distance of the nut 40, and the side walls of the placement space 24 restrict the rotation of the nut 40 around its axis. The height of the placement space 24 (the length from the bottom surface of the ceramic plate 21 to the bottom of the placement space 24) should be greater than the thickness of the nut 40, but may be 1.05 times or more the thickness of the nut 40, taking into consideration the protrusion of the bolt legs 50. Also, the height of the placement space 24 may be 3 times or less the thickness of the nut 40, from the viewpoint of reducing the thickness of the back plate 23. The thickness of the bottom of the placement space 24 may be 3 mm or more, from the viewpoint of strength and rigidity. Also, the thickness of the bottom of the placement space 24 may be 20 mm or less, from the viewpoint of reducing the thickness of the back plate. A through hole 25 is provided at the bottom of the placement space 24, connecting the bottom surface of the back plate 23 and the placement space 24. The through hole 25 is formed so that the legs of the bolt 50 can be inserted through it, and the bolt 50 can be inserted from the bottom surface of the back plate 23 through the through hole 25 and screwed into the nut 40. The through hole 25 is formed to be narrower (or smaller in diameter) than the distance between the opposite sides of the nut 40, so that the nut 40 does not fall out.

[0026] The moving lane 26 is used for inserting and removing the nut 40, and is formed so that it extends from a port 27 opening on the lower surface of the back plate 23 to a placement space 24 whose position in plan view is different from that of the port 27. The moving lane 26 is tunnel-shaped when the upper opening of a bottomed groove 26a provided on the upper surface of the back plate 23 is closed by a ceramic plate 21. The moving lane 26 is formed radially in a horizontal direction (in the plane of the back plate) from a single substantially circular port 27 opening in the center of the lower surface of the back plate 23 to multiple (six in this case) placement spaces 24. The port 27 penetrates the back plate 23 in the vertical direction. The moving lane 26 is formed with a width greater than the distance between opposite sides of the nut 40 and less than the diagonal distance of the nut 40, and the side walls of the moving lane 26 restrict the rotation of the nut 40 around its axis. The height of the moving lane 26, excluding port 27 (the length from the bottom surface of the ceramic plate 21 to the bottom of the moving lane 26), should be greater than the thickness of the nut 40, and may be 1.05 times or more the thickness of the nut 40. Also, from the viewpoint of reducing the thickness of the back plate 23, the height of the moving lane 26 may be 3 times or less the thickness of the nut 40. The thickness of the bottom of the moving lane 26 may be, for example, 3 mm or more from the viewpoint of strength and rigidity. Also, from the viewpoint of reducing the thickness of the back plate 23, the thickness of the bottom of the moving lane 26 may be 10 mm or less. A slit 28 is provided at the bottom of the moving lane 26, penetrating vertically along the moving lane 26. The slit 28 is formed to a width that allows the legs of the bolt 50 to be inserted, enabling the nut 40 to be moved along the moving lane 26 using the bolt 50. The slit 28 is formed to be narrower than the distance between opposite sides of the nut 40, preventing the nut 40 from falling out. The internal space of the moving lane 26 is integrated with the arrangement space 24. Furthermore, the slit 28 provided at the bottom of the moving lane 26 is integrated with the through hole 25 provided at the bottom of the arrangement space 24.

[0027] The metal bonding layer 29 joins the lower surface of the ceramic plate 21 to the upper surface of the back plate 23. The metal bonding layer 29 has through holes 29b that have the same planar shape as the arrangement space 24 and the moving lane 26 (including the port 27), and the metal bonding layer 29 is not placed on the arrangement space 24 and the moving lane 26. The metal bonding layer 29 may be a layer formed of, for example, solder or metal brazing material. The metal bonding layer 29 is formed by, for example, TCB (Thermal Compression Bonding). TCB is a known method in which a metal bonding material is sandwiched between two members to be joined, and the two members are pressurized and bonded together while heated to a temperature below the solidus temperature of the metal bonding material.

[0028] The base member 30 is a metal disc member, typically made of aluminum, aluminum alloy, or stainless steel (SUS material). The outer diameter of the base member 30 is the same as the outer diameter of the back plate 23. A refrigerant flow path 35 is provided inside the base member 30. The refrigerant flow path 35 is arranged in a spiral shape from the inlet 35a to the outlet 35b in a single continuous line, so as to reach the entire area where the ceramic plate 21 is located. The inlet 35a and outlet 35b of the refrigerant flow path 35 penetrate the lower surface of the base member 30 and the bottom surface of the refrigerant flow path 35. The inlet 35a and outlet 35b of the refrigerant flow path 35 are connected to a refrigerant cooling device (not shown), and the refrigerant discharged from the outlet 35b is temperature-adjusted by the refrigerant cooling device and then returned to the inlet 35a and supplied back into the refrigerant flow path 35. The refrigerant flowing through the refrigerant flow path 35 is preferably a liquid and preferably electrically insulating. Examples of electrically insulating liquids include fluorine-based inert liquids. The base member 30 is connected to the RF power supply 62 via a power supply terminal 64. Therefore, the base member 30 also functions as a high-frequency (RF) electrode for plasma generation. The base member 30 has a plurality of through holes 36. The through holes 36 are located opposite the arrangement space 24 and penetrate the base member 30 in the vertical direction. The through holes 36 have a counterbore on the lower side, and the heads of the bolts 50 are housed in these counterbores.

[0029] A sealing member 70 is positioned between the joint 20 and the base member 30. Specifically, an outer sealing member 70a is positioned slightly inward along the outer edge of the base member 30, and an inner sealing member 70b is positioned inside the outer sealing member 70a, surrounding the terminal holes 30b and 30c that penetrate the base member 30 vertically. As a result, a gap is formed between the joint 20 and the base member 30 (including the arrangement space 24, through hole 25, movement lane 26, port 27, and slit 28), and the portion of this gap inside the outer sealing member 70a and outside the inner sealing member 70b is filled with a gas such as He gas. In addition, a sealing member 71 is positioned between the head of the bolt 50 and the bottom of the counterbore of the through hole 36. The sealing members 70 and 71 are elastically deformable annular members, and by being compressed vertically, they prevent the gas filled between the joint 20 and the base member 30 from leaking to the outside. O-rings, packings, and the like can be used as sealing members 70 and 71. The sealing members 70 and 71 may be made of insulating material or conductive material. The sealing members 70 and 71 may be made of resin, rubber or metal.

[0030] The nut 40 is a hexagonal nut made of metal such as stainless steel. The nut 40 is inserted into the back plate 23 from the port 27 and moves laterally along the movement lane 26 to be positioned in the placement space 24. The nominal diameter of the nut 40 may be, for example, 3 mm or more and 10 mm or less.

[0031] The bolt 50 is a hexagonal bolt made of metal such as stainless steel. The bolt 50 is inserted into the through hole 36 from the lower surface of the base member 30 and screwed onto the nut 40 located in the arrangement space 24 of the back plate 23. The head of the bolt 50 is housed in the counterbore so as not to protrude below the lower surface of the base member 30. By screwing the bolt 50 onto the nut 40, the joint 20 and the base member 30 are fastened together with the sealing member 70 sandwiched in between. As a result, the sealing member 70 is compressed in the vertical direction. The nominal diameter of the bolt 50 may be, for example, 3 mm or more and 10 mm or less.

[0032] The joint 20 and the base member 30 are fastened together with nuts 40 and bolts 50 at the inner circumference where the ceramic plate 21 is placed, and further fastened together with bolts 75 at the outer circumference where the back plate 23 protrudes from the ceramic plate 21. The bolts 75 are hexagonal bolts made of metal such as stainless steel. The bolts 75 are inserted from the upper surface of the back plate 23 into through holes 23d provided on the outer circumference of the back plate 23 and screwed into threaded holes 30d formed on the upper surface of the base member 30. The heads of the bolts 75 are housed in a counterbore provided above the through holes 23d so as not to protrude above the upper surface of the back plate 23.

[0033] Annular heat insulating members 76 are placed around bolts 50 and 75. Specifically, for example, the heat insulating member 76 is placed around the portion of the bolt 50's leg that is positioned in the gap between the joint 20 and the base member 30. Also, for example, the heat insulating member 76 is placed around the portion of the bolt 75's leg that is positioned in the gap between the joint 20 and the base member 30, and around the portion that is positioned in the counterbore of the through hole 23d (between the bottom of the counterbore and the head of the bolt 75). Examples of materials for the heat insulating member 76 include pentamethylene diisocyanate (PDI: PDI is a registered trademark) and zirconia.

[0034] Next, an example of the manufacturing of the wafer mounting table 10 will be explained using Figures 4 to 6. Figures 4 to 6 are manufacturing process diagrams for the wafer mounting table 10. Figure 4 shows the manufacturing process for the bonded body 20, Figure 5 shows the placement process for the nuts 40, and Figure 6 shows the assembly process for the wafer mounting table 10.

[0035] The bonded body 20 is manufactured, for example, as follows. First, a ceramic plate 21 is manufactured by hot-press firing a molded body of ceramic powder (Figure 4A). The ceramic plate 21 incorporates a wafer adsorption electrode 22a and a heater electrode 22b. Next, a hole 21b is drilled from the bottom surface of the ceramic plate 21 to the wafer adsorption electrode 22a, and a hole 21c is drilled from the bottom surface of the ceramic plate 21 to the heater electrode 22b (Figure 4B). Then, a power supply terminal 54a is inserted into the hole 21b to bond the power supply terminal 54a to the wafer adsorption electrode 22a, and a power supply terminal 54b is inserted into the hole 21c to bond the power supply terminal 54b to the heater electrode 22b (Figure 4C).

[0036] In parallel with this, a disc-shaped back plate 23 is manufactured (Figure 4D), and through holes 23b to 23d that penetrate vertically are formed in the back plate 23, as well as a bottomed hole 24a opening on the upper surface of the back plate 23, a through hole 25 that penetrates vertically through the bottom of the bottomed hole 24a, a bottomed groove 26a opening on the upper surface of the back plate 23, a slit 28 that penetrates vertically through the bottom of the bottomed groove 26a, and a through hole 27a that penetrates vertically through the back plate 23 (Figure 4E). When the ceramic plate 21 is made of alumina, the back plate 23 is preferably made of SiSiCTi or AlSiC. This is because the thermal expansion coefficient of SiSiCTi or AlSiC can be made to be approximately the same as that of alumina. A SiSiCTi back plate 23 can be manufactured, for example, as follows. First, silicon carbide, metallic Si, and metallic Ti are mixed to produce a powder mixture. Next, the obtained powder mixture is molded into a disc shape by uniaxial pressure molding, and the molded body is hot-press sintered in an inert atmosphere to obtain a SiSiCTi backing plate 23. If the ceramic plate 21 is made of aluminum nitride, it is desirable that the backing plate 23 be made of the same material (aluminum nitride) or molybdenum. This is because if it is made of the same material or molybdenum, the coefficient of thermal expansion with the ceramic plate 21 will be approximately or exactly the same.

[0037] Next, a metal bonding material is placed on the upper surface of the back plate 23. The metal bonding material has through holes that communicate with the through holes 23b of the back plate 23, and through holes that communicate with the bottomed holes 24a, bottomed grooves 26a, and through holes 27a of the back plate 23. Then, the ceramic plate 21 is placed on top of the metal bonding material while inserting the power supply terminals 54a and 54b of the ceramic plate 21 into the through holes 23b and 23c of the back plate 23. This creates a laminate in which the back plate 23, the metal bonding material, and the ceramic plate 21 are stacked in this order from bottom to top. By heating and pressurizing this laminate (TCB), a bonded body 20 is obtained (Figure 4F). The bonded body 20 is formed by bonding the ceramic plate 21 to the upper surface of the back plate 23 via the metal bonding layer 29. This bonding blocks the bottomed hole 24a with the ceramic plate 21, forming a placement space 24. Furthermore, the joining process blocks the bottomed groove 26a and through hole 27a with the ceramic plate 21, forming a tunnel-shaped moving lane 26 (with a port 27).

[0038] TCB is performed as follows, for example: The laminate is pressed and bonded at a temperature below the solidus temperature of the metal bonding material (for example, between a temperature 20°C below the solidus temperature and the solidus temperature), and then returned to room temperature. As a result, the metal bonding material becomes a metal bonding layer (or conductive bonding layer). As the metal bonding material, Al-Mg-based bonding materials or Al-Si-Mg-based bonding materials can be used. For example, when performing TCB using an Al-Si-Mg-based bonding material, the laminate is pressed while heated in a vacuum atmosphere. It is preferable to use a metal bonding material with a thickness of around 100 μm.

[0039] In the resulting joint 20, the nut 40 is positioned as follows: First, the nut 40 is screwed onto the tip of the leg of the bolt 50, and the bolt 50 is gripped and the nut 40 is inserted into the port 27 from the lower side of the back plate 23 (Figure 5A). Once the lower surface of the nut 40 exceeds the height of the bottom of the movement lane 26, the bolt 50 is moved laterally along the slit 28, thereby moving the nut 40 laterally along the movement lane 26 (Figure 5B). When the nut 40 reaches the positioning space 24, it is lowered to the bottom of the positioning space 24, which is one level lower than the bottom of the movement lane 26 (Figure 5C). Then, the bolt 50 used for movement is rotated around its axis and removed from the nut 40, thereby positioning the nut 40 in the positioning space 24 (Figure 5D). At this time, the width of the positioning space 24 in the narrow direction is smaller than the diagonal distance of the nut 40, and the rotation of the nut 40 around its axis is restricted, so the bolt 50 can be easily removed by simply rotating it.

[0040] The wafer mounting table 10 is manufactured by fastening a joint 20, which is made as described above and has a nut 40 placed inside, and a base member 30 with bolts 50. The base member 30 is made of a metal such as aluminum, aluminum alloy, or stainless steel, has a refrigerant flow path 35 inside, and is equipped with terminal holes 30b and 30c that penetrate the base member vertically, a screw hole 30d that opens on the upper surface of the base member 30, and a through hole 36 that penetrates the base member vertically. An annular outer sealing member 70a with a diameter slightly smaller than the outer circumference of the back plate 23 and an annular inner sealing member 70b with a diameter slightly larger than the openings of the terminal holes 30b and 30c that open on the upper surface of the base member 30 are placed on the upper surface of the base member 30. In addition, heat insulating members 76 with a diameter slightly larger than the openings of the screw holes 30d and the through hole 36 are placed on the upper surface of the base member 30 (Figure 6A). Next, the power supply terminal 54a of the joint 20 is inserted into the terminal hole 30b, and the power supply terminal 54b of the joint 20 is inserted into the terminal hole 30c, while the joint 20 is placed on top of the sealing members 70a, 70b and the heat insulating member 76 arranged on the upper surface of the base member 30 (Figure 6B). Next, the annular sealing member 71 is passed through the legs of the bolts 50, and the bolts 50 are inserted into each through hole 36 from the lower surface of the base member 30 and screwed into the nuts 40 arranged in the arrangement space 24 of the back plate 23. At this time, the width of the arrangement space 24 in the narrow direction is smaller than the diagonal distance of the nuts 40, and the rotation of the nuts 40 around the axis is restricted, so the bolts 50 can be easily screwed in by simply rotating the bolts 50. Also, the annular heat insulating member 76 is passed through the legs of the bolts 75, and the bolts 75 are inserted into each through hole 23d from the upper surface of the back plate 23 and screwed into the screw holes 30d that open on the upper surface of the base member 30. By screwing the bolts 50 and 75 in this manner, the sealing members 70 and 71 are compressed and perform their sealing function. Subsequently, insulating tubes 55a and 55b are inserted through the terminal holes 30b and 30c, through which the power supply terminals 54a and 54b are inserted. In this way, the wafer mounting table 10 can be obtained (Figure 6C).Even if a problem occurs with the nut 40 in this wafer mounting stage 10, the defective nut 40 can be removed in the reverse procedure to FIGS. 5 and 6, and a new nut 40 can be placed in the placement space 24 in the procedure of FIG. 5, so that the joining body 20 and the base member 30 shown in FIG. 6 can be fastened again.

[0041] Next, a usage example of the wafer mounting stage 10 will be described using FIG. 1. First, the wafer mounting stage 10 is fixed to the installation plate 96 of the chamber 94 using bolts 80. A disk-shaped wafer W is placed on the wafer mounting surface 21a of the wafer mounting stage 10 installed on the installation plate 96. In this state, a DC voltage of the wafer adsorption power supply 52a is applied to the wafer adsorption electrode 22a to adsorb the wafer W to the wafer mounting surface 21a. Further, the temperature of the wafer mounting surface 21a is adjusted by flowing temperature-controlled refrigerant through the refrigerant flow path 35 or applying an AC voltage of the heater power supply 52b to the heater electrode 22b. Then, the inside of the chamber 94 is set to a predetermined vacuum atmosphere (or reduced pressure atmosphere), and an RF voltage from the RF power supply 62 is applied to the base member 30 while supplying a process gas from the shower head 98. Then, plasma is generated between the wafer W and the shower head 98. Then, CVD film formation or etching is performed on the wafer W using the plasma.

[0042] In the wafer mounting stage 10 described above, in addition to the placement space 24 where the nut 40 is placed, the joining body 20 is provided with a moving lane 26 used for inserting and removing the nut 40. Therefore, the nut 40 can be replaced. Even if a problem occurs with the nut 40, it can be replaced with a new nut 40 and fastened again, and the joining body 20 will not become unusable due to a problem with the nut 40.

[0043] In addition, since a slit 28 penetrating vertically along the moving lane 26 is provided at the bottom of the moving lane 26, the nut 40 can be easily replaced by inserting a jig or the like through the slit 28 and using it for the movement of the nut 40 in the moving lane 26.

[0044] Further, since the width of the slit 28 is such that the legs of the bolts 50 screwed into the nut 40 can be inserted, the nut 40 can be replaced using bolts 50 or the like used for fastening the base member 30 without specially preparing a jig.

[0045] Furthermore, since the side wall of the placement space 24 is configured to restrict the rotation of the nut 40 around its axis, fastening and releasing with rotation such as screwing can be easily performed without taking measures such as preventing rotation of the joint-side fastening member.

[0046] And since the moving lane 26 reaches from one port 27 to a plurality of placement spaces 24, the insertion and removal of a plurality of nuts 40 can be performed from one port 27, and the replacement of the nut 40 can be easily performed.

[0047] Also, the back plate 23 is made of a composite material of metal and ceramic, ceramic, or low thermal expansion metal, and since the difference in thermal expansion coefficient from the ceramic plate 21 is small, warping or peeling due to the difference in thermal expansion coefficient in the joined body is unlikely to occur. Therefore, the back plate 23 can be joined to the back surface of the ceramic plate 21 by metal bonding. Metal bonding is suitable for joining different materials and has relatively high heat resistance, so it is preferable. Also, metal bonding is often performed at a high temperature such as above the melting point of the metal. Metal bonding with the nut 40 built into the back plate 23 may be substantially impossible considering the alteration of the nut 40. Therefore, it is highly significant to adopt the present invention in which the nut 40 can be inserted into the back plate 23 after joining.

[0048] Further, since the space between the back surface of the joined body 20 and the upper surface of the base member 30 is filled with gas, the heat transfer between the joined body 20 and the base member 30 can be adjusted by the gas.

[0049] Furthermore, since heat insulating members 76 are arranged around the bolts 50 and bolts 75, heat transfer through the bolts

[0050] It goes without saying that the present invention is not limited in any way to the embodiments described above, and can be implemented in various forms as long as they fall within the technical scope of the present invention.

[0051] For example, in the embodiment described above, the back plate 23 is slightly larger than the ceramic plate 21, but it may be the same diameter as the ceramic plate 21. In this case, it is preferable that the metal bonding layer 29 is also the same diameter as the ceramic plate 21. Also, the base member 30 is the same diameter as the back plate 23, but it may be larger in diameter than the back plate 23.

[0052] In the embodiment described above, the bottom of the arrangement space 24 was set to be one level lower than the bottom of the moving lane 26, but for example, it may be set to be the same height as the bottom of the moving lane 26.

[0053] In the embodiment described above, the moving lane 26 is formed radially from one port 27 to multiple placement spaces 24, but it is not limited to this and may be formed as shown in Figure 7, for example. Figure 7 is a partially enlarged view of the plan view of the wafer mounting table 10 excluding the ceramic plate 21 (an enlarged view of the quadrant of the portion where the ceramic plate 21 is placed). The moving lane 26 may be formed, for example as shown in Figure 7A, so as to reach multiple placement spaces 24 that are located at the same distance from the axis of the joint 20, centered on one port 27 (multiple placements within the same diameter). Alternatively, the moving lane 26 may be formed, for example as shown in Figure 7B, so as to reach multiple placement spaces 24 that are located on a predetermined radius of the joint 20, centered on one port 27 (multiple placements within the same angle). Alternatively, the moving lane 26 may be formed so as to reach one placement space 24 from one port 27, for example as shown in Figure 7C (single placement). In Figure 7, the same reference numerals are used for the same components as in the embodiment described above.

[0054] In the embodiments described above and in another example of the moving lane 26 shown in Figure 7, the port 27 is assumed to open on the lower surface of the back plate 23. However, the invention is not limited to this, and may open on the side surface of the back plate 23, for example, as shown in Figures 8-9. Figure 8 is a partially enlarged view of the plan view of the wafer mounting table 10 excluding the ceramic plate 21 (an enlarged view of the quadrant of the portion where the ceramic plate 21 is placed). Figure 9 is a partially enlarged view of the A view of Figure 8. In Figure 9, the ceramic plate 21 not shown in Figure 8 is indicated by a dashed line. When the port 27 opens on the side surface, the moving lane 26 may be formed to branch from one port 27 and reach multiple placement spaces 24 that are located at the same distance from the axis of the joint 20, for example, as shown in Figure 8A (multiple placements within the same diameter). Alternatively, the moving lane 26 may be formed to reach multiple placement spaces 24 that are located on a predetermined radius of the joint 20 without branching from one port 27, for example, as shown in Figure 8B (multiple placements within the same angle). Furthermore, the moving lane 26 may be formed to extend from one port 27 to one arrangement space 24, as shown in Figure 8C (single arrangement). When the port 27 opens on the side surface of the back plate 23, it is preferable that the diameters of the ceramic plate 21 and the back plate 23 are the same. This prevents the moving lane 26 from being exposed on the upper surface of the back plate 23. In Figures 8-9, the same reference numerals are used for the same components as in the embodiments described above.

[0055] In the above-described embodiment, the wafer mounting base 10, in which the joint 20 and the base member 30 are fastened together with bolts 50, is installed on the mounting plate 96 of the chamber 94, but the invention is not limited to this. For example, as shown in Figure 10, the base member 30 may also be used as the mounting plate 96 of the chamber 94. In Figure 10, the same reference numerals are used for the same components as in the above-described embodiment.

[0056] In the above-described embodiment, a nut 40 was used as the fastening member on the joint side, but a bolt similar to the bolt 50 may be used instead of the nut 40. In that case, a nut formed in the same way as the nut 40 may be used as the fastening member on the base side. Alternatively, a screw hole provided to open on the upper surface of the base member 30 may be used as the fastening member on the base side. Note that although the nut 40 is a hexagonal nut, it is not limited to this, and for example, a square nut or an octagonal nut may be used. The same applies to the bolt 50.

[0057] In the embodiment described above, a slit 28 is provided at the bottom of the moving lane 26, but the slit 28 may be omitted. However, if a bolt is used as the fastening member on the joint side, the slit 28 should not be omitted.

[0058] In the embodiment described above, the nut 40 was replaced using a bolt 50, but a jig or other tool may be used instead of a bolt. In that case, it is preferable that the slit 28 is wide enough to allow the jig to pass through.

[0059] In the embodiments described above, the ceramic plate 21 and the back plate 23 are metal-bonded, but they may also be directly bonded. In that case, the ceramic plate 21 and the back plate 23 are directly bonded without the metal bonding layer 29. In the case of direct bonding, the back plate 23 is made of ceramic, preferably of the same type of ceramic as the ceramic plate 21. Direct bonding can be achieved by directly contacting the lower surface of the ceramic plate 21 and the upper surface of the back plate 23, but it is preferable to heat them to a temperature above the melting point of the ceramic and then pressurize them to bond them. For direct bonding, the ceramic plate 21 and back plate 23 may be used before firing, but it is preferable to use the ceramic plate 21 and back plate 23 after firing (preferably after hot pressing). The ceramic plate 21 and the back plate 23 may be bonded together with a resin adhesive. In direct bonding, a diffusion layer may be formed around the boundary between the ceramic plate 21 and the back plate 23, where the components of each material are diffused.

[0060] In the embodiment described above, the ceramic plate 21 incorporates a wafer adsorption electrode 22a and a heater electrode 22b, but either one may be omitted, or an RF electrode for plasma generation may be incorporated in place of or in addition to at least one of them. When an RF electrode is incorporated, the high-frequency power supply is connected to the RF electrode rather than the base member 30.

[0061] In the embodiment described above, one heater electrode 22b is provided, but multiple heater electrodes 22b may be provided. For example, a heater electrode 22b may be provided for each zone, such as an inner zone and an outer zone.

[0062] In the embodiment described above, the refrigerant flow path 35 is provided in a spiral shape from the inlet 35a to the outlet 35b, but the shape of the refrigerant flow path 35 is not particularly limited. Also, in the embodiment described above, one refrigerant flow path 35 is provided, but multiple refrigerant flow paths 35 may be provided. For example, refrigerant flow paths 35 may be provided for each zone, such as an inner circumferential zone and an outer circumferential zone.

[0063] In the embodiment described above, the ceramic plate 21 was manufactured by hot-press firing a molded body of ceramic powder. However, the molded body may be manufactured by stacking multiple tape molded bodies, by mold casting, or by compressing ceramic powder.

[0064] In the embodiment described above, a hole may be provided that penetrates the wafer mounting base 10 from the lower surface of the base member 30 to the wafer mounting surface 21a. Examples of such holes include a gas supply hole for supplying a heat-conducting gas (e.g., He gas) to the back surface of the wafer W, and a lift pin hole for inserting a lift pin to move the wafer W up and down relative to the wafer mounting surface 21a. The heat-conducting gas is supplied to the space formed by the wafer W and a number of small protrusions (supporting the wafer W) provided on the wafer mounting surface 21a (not shown).

[0065] This application is based on the priority claim of Japanese Patent Application No. 2024-230939, filed on 26 December 2024, the entire contents of which are incorporated herein by reference.

[0066] This invention can be used, for example, in wafer mounting equipment used for performing CVD, etching, or other processes on wafers.

[0067] 10 Wafer mounting stage, 20 Bonding body, 21 Ceramic plate, 21a Wafer mounting surface, 21b Hole, 21c Hole, 22 Internal electrode, 22a Wafer adsorption electrode, 22b Heater electrode, 23 Back plate, 23b Through hole, 23c Through hole, 23d Through hole, 24 Placement space, 24a Bottomed hole, 25 Through hole, 26 Movement lane, 26a Bottomed groove, 27 Port, 27a Through hole, 28 Slit, 29 Metal bonding layer, 29b Through hole, 30 Base member, 30b Terminal hole, 30c Terminal hole, 30d Screw hole, 35 Refrigerant flow path, 35a Inlet, 35b Outlet, 36 Through hole, 38 Screw hole, 40 Nut, 50 Bolt, 52a Wafer adsorption power supply, 52b Heater power supply, 54a Power supply terminal, 54b Power supply terminal, 55a Insulating tube, 55b Insulating tube, 62 RF power supply, 64 Power supply terminal, 70 Sealing member, 70a Outer sealing member, 70b Inner sealing member, 71 Sealing member, 75 Bolt, 76 Heat insulation member, 80 Bolt, 94 Chamber, 96 Mounting plate, 98 Shower head, 110 Wafer mounting stand.

Claims

1. A joint used by fastening to a base member, comprising: a ceramic plate having a wafer mounting surface on its upper surface and containing electrodes; a back plate bonded to the back surface of the ceramic plate; an arrangement space provided in the back plate with a through hole at its bottom for positioning the joint-side fastening member during fastening; and a moving lane that extends from a port opening on the lower surface or side of the back plate to the arrangement space, whose position in plan view is different from the port, and is used for inserting and removing the joint-side fastening member.

2. The joint according to claim 1, wherein a slit is provided at the bottom of the moving lane, penetrating vertically along the moving lane.

3. The joint according to claim 2, wherein the fastening member on the joint side is a nut and the width of the slit is wide enough to allow the leg of a bolt screwed into the fastening member on the joint side to pass through, or the fastening member on the joint side is a bolt and the width of the slit is wide enough to allow the leg of the bolt of the fastening member on the joint side to pass through.

4. The joint according to any one of claims 1 to 3, wherein the side wall of the arrangement space restricts the rotation of the fastening member on the joint side about its axis.

5. The joint according to any one of claims 1 to 3, wherein the moving lane extends from one port to a plurality of the arrangement spaces.

6. The joint according to any one of claims 1 to 3, wherein the back plate is made of ceramic and is directly bonded to the back surface of the ceramic plate.

7. The joint according to any one of claims 1 to 3, wherein the back plate is made of a composite material of metal and ceramic, is made of ceramic, or is made of a low thermal expansion metal, and is joined to the back surface of the ceramic plate by metal bonding.

8. A semiconductor manufacturing apparatus component comprising a joint according to any one of claims 1 to 3, the component comprising: a base member; a joint-side fastening member; and a base-side fastening member used in combination with the joint-side fastening member.

9. The space between the back surface of the joint and the upper surface of the base member is filled with gas, as described in claim 8.

10. A thermal insulation member is provided around at least one of the fastening member on the joint side and the fastening member on the base side, as described in claim 8.

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