Wafer mounting table and member for semiconductor manufacturing apparatus using the same

Abstract

To reduce the cost of a wafer placement table.SOLUTION: A wafer placement table 10 includes a ceramic base material 20 having a wafer placement surface 22a on an upper surface and incorporating an electrode (wafer suction electrode 26), a cooling base material 30 provided to a lower surface of the ceramic base material 20, and a coolant passage groove 32 provided to the cooling base material 30 so as to open at a lower surface of the cooling base material 30.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a wafer stage and a member for a semiconductor manufacturing apparatus using the same.

Background Art

[0002] Conventionally, a wafer stage in which a ceramic base material embedded with an electrostatic electrode and a cooling base material having a refrigerant flow path inside are joined by a metal bonding layer is known (for example, Patent Documents 1 and 2). The cooling base material is manufactured, for example, as follows. First, first to third substrates formed of a metal matrix composite material are prepared. The first and third substrates are disks. The second substrate is a disk provided with a punched portion by punching from one surface to the other surface of the disk so as to have the same shape as the refrigerant flow path. Subsequently, the second substrate is sandwiched between the first substrate and the third substrate to form a laminate. At this time, a metal bonding material is placed between the second substrate and the first substrate and between the second substrate and the third substrate. Then, by thermocompression bonding this laminate, the punched portion becomes the refrigerant flow path, a metal bonding layer is formed between the first substrate and the second substrate, and a metal bonding layer is formed between the second substrate and the third substrate, thereby obtaining a cooling base material.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described wafer stage, since a large amount of material is required for the cooling base material, the material cost increases, and as a result, the cost of the wafer stage becomes high.

[0005] The present invention has been made to solve the above problems, and has as its main object to reduce the cost of the wafer mounting table. [Means for solving the problem]

[0006] [1] The wafer mounting table of the present invention comprises: a ceramic substrate having a wafer mounting surface on its upper surface and incorporating an electrode; a cooling substrate provided on the lower surface side of the ceramic substrate; a refrigerant flow channel provided in the cooling base material so as to open to a lower surface of the cooling base material; It is equipped with the following.

[0007] When this wafer mounting table is in use, the underside of the cooling substrate is attached to a mounting plate separate from the wafer mounting table via a seal member that surrounds the coolant flow channel. In this case, the opening of the coolant flow channel is closed by the seal member and the mounting plate to form a coolant flow channel. The cooling substrate has a coolant flow channel groove, but the coolant flow channel groove opens to the underside of the cooling substrate. Therefore, less material is required for the cooling substrate compared to conventional cooling substrates with built-in coolant flow channels. This allows for lower costs for the wafer mounting table.

[0008] Although the present invention is sometimes described using terms such as up / down, left / right, front / back, etc., these terms merely refer to relative positional relationships. Therefore, when the orientation of the wafer table is changed, up / down may become left / right, or left / right may become up / down, and such cases are also within the technical scope of the present invention.

[0009] [2] In the wafer stage described above (the wafer stage described in [1] above), the cooling substrate may be formed of a composite material of metal and ceramic. Such a composite material can reduce the difference in coefficient of linear thermal expansion (CTE) between the ceramic material constituting the ceramic substrate and the cooling substrate. This can prevent the bond between the ceramic substrate and the cooling substrate from being damaged by thermal stress. Furthermore, since such a composite material is relatively expensive, it is very important to reduce the cost.

[0010] [3] In the wafer mounting table (the wafer mounting table described in [1] or [2] above), the cooling substrate may be bonded to the lower surface of the ceramic substrate via a metal bonding layer. This allows heat from the wafer mounting surface to be dissipated to the cooling substrate more efficiently than when the cooling substrate is bonded to the lower surface of the ceramic substrate via a resin (organic) bonding layer.

[0011] [4] In the above-described wafer mounting table (the wafer mounting table described in any one of [1] to [3] above), the distance from the ceiling surface of the refrigerant flow channel to the wafer mounting surface at the most upstream and most downstream portions of the region of the refrigerant flow channel that overlaps with the wafer mounting surface in a plan view may be shorter at the most downstream portion than at the most upstream portion. When the wafer mounting table is in use, the opening of the refrigerant flow channel is closed with a member separate from the wafer mounting table to form a refrigerant flow channel, and a refrigerant is then passed through the refrigerant flow channel. Because the refrigerant flows from the most upstream portion to the most downstream portion of the refrigerant flow channel while removing heat from a high-temperature wafer, the temperature of the refrigerant flowing through the refrigerant flow channel is higher at the most downstream portion than at the most upstream portion. Meanwhile, because the distance from the ceiling surface of the refrigerant flow channel to the wafer mounting surface is shorter at the most downstream portion than at the most upstream portion of the refrigerant flow channel, the thermal resistance from the ceiling surface of the refrigerant flow channel to the wafer mounting surface is lower at the most downstream portion than at the most upstream portion. Therefore, the temperature difference between the position on the wafer mounting surface facing the most upstream portion of the coolant flow path and the position facing the most downstream portion of the coolant flow path can be reduced overall, thereby improving the temperature uniformity of the wafer.

[0012] [5] In the above-described wafer mounting table (the wafer mounting table according to any one of [1] to [4] above), the cross-sectional areas of the refrigerant flow path grooves at the most upstream portion and the most downstream portion in the region overlapping the wafer mounting surface in plan view among the refrigerant flow path grooves may be such that the cross-sectional area of the most downstream portion is smaller than that of the most upstream portion. When the wafer mounting table is in use, the opening of the refrigerant flow path groove is closed with a member different from the wafer mounting table to form a refrigerant flow path, and then refrigerant is caused to flow through the refrigerant flow path. Since the refrigerant flows while taking heat from the high-temperature wafer from the most upstream portion to the most downstream portion of the refrigerant flow path, the temperature of the refrigerant flowing through the refrigerant flow path is higher at the most downstream portion than at the most upstream portion. On the other hand, since the cross-sectional area of the refrigerant flow path is smaller at the most downstream portion than at the most upstream portion of the refrigerant flow path, the pressure loss is larger at the most downstream portion than at the most upstream portion, and the heat exchange between the refrigerant and the wafer is promoted more at the most downstream portion than at the most upstream portion. Therefore, overall, the temperature difference between the position facing the most upstream portion of the refrigerant flow path and the position facing the most downstream portion on the wafer mounting surface can be reduced. Accordingly, the isothermal property of the wafer is improved.

[0013] [6] In the above-described wafer mounting table (the wafer mounting table according to any one of [1] to [5] above), the cooling base material may have a hole penetrating the cooling base material in the vertical direction, and a heat exchange promoting portion for promoting heat exchange between the refrigerant flowing through the refrigerant flow path when using the refrigerant flow path groove as the refrigerant flow path and the wafer placed on the wafer mounting surface may be provided in the peripheral region of the hole. Generally, the area directly above such a hole in the wafer tends to become a hot spot, but here, since a heat exchange promoting portion is provided in the peripheral region of such a hole, heat removal from the peripheral region of the hole is promoted. Therefore, the occurrence of hot spots on the wafer can be suppressed.

[0014] [7] In the above-described wafer mounting table (the wafer mounting table according to any one of [1] to [6] above), the lower surface of the cooling base material may be attached to an installation plate different from the wafer mounting table via a seal member surrounding the refrigerant flow path groove during use.

[0015] [8] In the wafer stage described in [7] above, the cooling substrate may have a central fastening member that fastens the central portion of the cooling substrate to the mounting plate. Note that the "central portion of the cooling substrate" may be the center of the cooling substrate or the circumference of a circle that is smaller than the diameter of the cooling substrate.

[0016] [9] In the wafer mounting table described above (the wafer mounting table described in any one of [1] to [8] above), the cross-sectional shape of the refrigerant flow channel (the shape that appears on a cross section when the wafer mounting table is cut in a direction perpendicular to the wafer mounting surface) may be such that the width of the ceiling portion of the refrigerant flow channel is wider than the width of the opening portion of the refrigerant flow channel, and the distance between adjacent opening portions of the refrigerant flow channel may be wider than the distance between adjacent ceiling portions of the refrigerant flow channel. In this way, the wide distance between adjacent opening portions of the refrigerant flow channel can prevent the refrigerant from mixing between the opening portions. Furthermore, the narrow distance between adjacent ceiling portions of the refrigerant flow channel can increase the cooling area by the refrigerant, thereby improving cooling efficiency. Furthermore, the total area of the opening portions of the refrigerant flow channel is narrower than the total area of the ceiling portion, so the force due to the pressure of the refrigerant acting between the cooling substrate and the mounting plate on the chamber side can be reduced.

[0017]

[10] In the wafer stage described in [9] above, the openings of the coolant flow channel grooves do not have to be sealed with a seal ring. Even if they are not sealed with a seal ring, the openings of the coolant flow channel grooves are spaced relatively wide apart, so that mixing of the coolants at the openings can be prevented.

[0018]

[11] In the above-described wafer mounting table (the wafer mounting table described in [9] above), the opening of the refrigerant flow path groove may be sealed by a seal ring. By doing so, since the seal ring suppresses the mixing of the refrigerant between the adjacent openings of the refrigerant flow path grooves, the interval between the adjacent openings of the refrigerant flow path grooves can be made relatively narrow, and thus the refrigerant flow path grooves can be provided densely. Along with this, since the interval between the adjacent ceiling portions of the refrigerant flow path grooves can be made even narrower, the cooling area by the refrigerant becomes wider and the cooling efficiency becomes higher.

[0019]

[12] The member for a semiconductor manufacturing apparatus of the present invention includes the wafer mounting table described in any one of [1] to

[11] above, a mounting plate on which the lower surface of the cooling base material is installed via a seal member surrounding the refrigerant flow path groove, and an outer peripheral portion fastening member for fastening the outer peripheral portion of the wafer mounting table to the mounting plate. In this member for a semiconductor manufacturing apparatus, by attaching the lower surface of the cooling base material to the mounting plate via a seal member surrounding the refrigerant flow path groove, the opening of the refrigerant flow path groove is closed and a refrigerant flow path is formed. In such a member for a semiconductor manufacturing apparatus, when it has a central portion fastening member for fastening the central portion of the cooling base material to the mounting plate, since the wafer mounting table is fixed to the mounting plate not only at the outer peripheral portion but also at the central portion, it is possible to prevent the wafer mounting table from warping during use. As a result, the sealing performance by the seal member can be maintained over a long period. Further, since the seal member is below the cooling base material (the refrigerant flow path groove is above the seal member), even if the ceramic base material becomes hot, it is hardly affected by the heat. Therefore, it is not necessary to use a seal member having high heat resistance.

[0020]

[13] In the above-described member for a semiconductor manufacturing apparatus (the member for a semiconductor manufacturing apparatus described in

[12] above), the absolute value of the CTE difference between 40 and 400 °C of the cooling base material and the mounting plate may be 1.5×10 -6 / K or more. Since the lower surface of the cooling base material and the upper surface of the mounting plate are assembled with a seal member interposed therebetween, the influence due to the difference in CTE between the cooling base material and the mounting plate is absorbed by the seal member. Therefore, the absolute value of the CTE difference between 40 and 400 °C of the mounting plate and the cooling base material is 1.5×10 -6Even when it is above / K, cracks can be prevented.

Brief Description of the Drawings

[0021] [Figure 1] Vertical sectional view of the wafer stage 10 installed in the chamber 94. [Diagram 2] Plan view of the wafer stage 10. [Figure 3] Bottom view of the cooling base material 30 provided with the seal members 16a to 16d. [Figure 4] Manufacturing process diagram of the wafer stage 10. [Figure 5] Bottom view of the cooling base material 30 provided with the seal members 16a, 16c to e. [Figure 6] Vertical sectional view of the wafer stage having the cooling base material 30 provided with the seal members 16a, 16c to e. [Figure 7] Partial vertical sectional view showing another example of the seal member 16e. [Figure 8] Vertical sectional view of the wafer stage 10 provided with a central fastening member. [Figure 9] Plan view of the wafer stage 10 in FIG. 8. [Figure 10] Vertical sectional view showing another example of the central fastening member. [Figure 11] Vertical sectional view showing another example of the refrigerant flow path groove 32. [Figure 12] Vertical sectional view showing another example of the refrigerant flow path groove 32. [Figure 13] Explanatory drawing showing another example of the outer peripheral fastening member. [Figure 14] Vertical sectional view of the wafer stage provided with the refrigerant flow path groove 432. [Figure 15] Vertical sectional view of the wafer stage in which the opening 432p of the refrigerant flow path groove 432 is sealed with the seal ring 483. [Figure 16] Vertical sectional view (partial enlarged view) of the wafer stage in which the opening 432p of the refrigerant flow path groove 432 is sealed with the seal ring 583. [Figure 17] Vertical sectional view showing a reference example.

Embodiments for Carrying Out the Invention

[0022] A preferred embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a vertical cross-sectional view of a wafer mounting table 10 installed in a chamber 94 (a cross-sectional view taken along a plane including the central axis of the wafer mounting table 10), Fig. 2 is a plan view of the wafer mounting table 10, and Fig. 3 is a bottom view of a cooling substrate 30 on which sealing members 16a to 16d are arranged.

[0023] The wafer mounting table 10 is used to perform CVD, etching, etc. on a wafer W using plasma, and is fixed to a mounting plate 96 provided inside a semiconductor process chamber 94. The wafer mounting table 10 includes a ceramic base 20, a cooling base 30, and a metal bonding layer 40.

[0024] The ceramic base 20 has a central portion 22 having a circular wafer mounting surface 22a, and an outer peripheral portion 24 having an annular focus ring mounting surface 24a at the outer periphery thereof. Hereinafter, focus ring may be abbreviated as "FR." A wafer W is mounted on the wafer mounting surface 22a, and a focus ring 78 is mounted on the FR mounting surface 24a. The ceramic base 20 is formed of a ceramic material such as alumina or aluminum nitride. The FR mounting surface 24a is one step lower than the wafer mounting surface 22a.

[0025] In the central portion 22 of the ceramic substrate 20, an electrode 26 for wafer adsorption is built in on the side closer to the wafer mounting surface 22a. The electrode 26 for wafer adsorption is formed of a material containing, for example, W, Mo, WC, MoC, etc. The electrode 26 for wafer adsorption is a disk-shaped or mesh-shaped single-pole type electrostatic adsorption electrode. The layer above the electrode 26 for wafer adsorption in the ceramic substrate 20 functions as a dielectric layer. A DC power supply 52 for wafer adsorption is connected to the electrode 26 for wafer adsorption via a power supply terminal 54. The power supply terminal 54 is inserted into a terminal hole 51 provided between the lower surface of the electrode 26 for wafer adsorption and the lower surface of the cooling substrate 30 in the wafer mounting table 10. The power supply terminal 54 passes through an insulating tube 55 disposed in a through hole that vertically penetrates the cooling substrate 30 and the metal bonding layer 40 in the terminal hole 51, and is provided so as to reach the electrode 26 for wafer adsorption from the lower surface of the ceramic substrate 20. A low-pass filter (LPF) 53 is provided between the DC power supply 52 for wafer adsorption and the electrode 26 for wafer adsorption.

[0026] The cooling substrate 30 is a disk member. A preferred material for the cooling substrate 30 is a composite material of metal and ceramic. Examples of such composite materials include metal matrix composites (MMCs) and ceramic matrix composites (CMCs). Specific examples of such composite materials include materials containing Si, SiC, and Ti, porous SiC impregnated with Al and / or Si, and composites of Al2O3 and TiC. A material containing Si, SiC, and Ti is called SiSiCTi, a porous SiC impregnated with Al is called AlSiC, and a porous SiC impregnated with Si is called SiSiC. When the ceramic substrate 20 is an alumina substrate, composite materials such as AlSiC and SiSiCTi, which have a CTE similar to that of alumina, are preferred for the cooling substrate 30. The cooling substrate 30 has refrigerant flow channel grooves 32. The refrigerant flow path groove 32 is formed in a spiral shape in a single stroke from an inlet 32a provided near the center to an outlet 32b provided on the outer periphery, and is provided in the cooling substrate 30 so as to open on the lower surface of the cooling substrate 30. The opening of the refrigerant flow path groove 32 is closed by the upper surface of the installation plate 96 of the chamber 94, thereby forming a refrigerant flow path 82. Therefore, the refrigerant flow path groove 32 constitutes the side wall and ceiling surface of the refrigerant flow path 82. Coolant flow path 82 The coolant flowing through the cooling substrate 30 is preferably a liquid and is preferably electrically insulating. Examples of electrically insulating liquids include fluorine-based inert liquids. The thickness of the cooling substrate 30 above the coolant flow channel groove 32 is preferably 5 mm or less, more preferably 3 mm or less. The upper corners of the coolant flow channel groove 32 (corners where the sidewall and ceiling surface intersect) are preferably rounded, with a curvature radius of 0.5 to 2 mm, for example. The cooling substrate 30 is connected to an RF power source 62 via a power supply terminal 64. A high-pass filter (HPF) 63 is disposed between the cooling substrate 30 and the RF power source 62. The cooling substrate 30 has a flange 34 used to clamp the outer periphery of the wafer stage 10 to a mounting plate 96. The mounting plate 96 has a single-layer structure and is made of an insulating material such as alumina.

[0027] The metallic bonding layer 40 bonds the lower surface of the ceramic substrate 20 and the upper surface of the cooling substrate 30. The metallic bonding layer 40 may be, for example, a layer formed of solder or a metal brazing material. The metallic bonding layer 40 is formed, for example, by thermal compression bonding (TCB). TCB is a known method in which a metallic bonding material is sandwiched between two members to be joined and the two members are pressure-bonded while heated to a temperature below the solidus temperature of the metallic bonding material.

[0028] The side surface of the outer periphery 24 of the ceramic substrate 20, the outer periphery of the metal bonding layer 40, and the top surface and side surface of the flange portion 34 of the cooling substrate 30 are covered with an insulating film 42. Examples of the insulating film 42 include a thermally sprayed film of alumina, yttria, or the like.

[0029] The wafer stage 10 is attached to a mounting plate 96 provided inside the chamber 94 using a clamp member 70. The clamp member 70 is an annular member with a substantially inverted L-shaped cross section and has an inner peripheral stepped surface 70a. The wafer stage 10 and the mounting plate 96 are integrated by the clamp member 70. With the inner peripheral stepped surface 70a of the clamp member 70 placed on the flange portion 34 of the cooling substrate 30 of the wafer stage 10, bolts 72 are inserted from the upper surface of the clamp member 70 and screwed into screw holes 97 provided on the upper surface of the mounting plate 96. The bolts 72 are attached at multiple locations (e.g., 8 or 12 locations) equally spaced around the circumference of the clamp member 70. The clamp member 70 and the bolts 72 may be made of an insulating material or a conductive material (such as metal). Seal members 16a to 16d are arranged at predetermined positions between the lower surface of the cooling substrate 30 and the upper surface of the mounting plate 96. These sealing members 16a to 16d exhibit sealing properties when they are compressed in the vertical direction by threading bolts 72 into threaded holes 97. The clamp members 70, bolts 72, and threaded holes 97 of the installation plate 96 correspond to outer periphery fastening members.

[0030] The sealing member 16a is an O-ring having a diameter slightly smaller than that of the cooling substrate 30. The sealing member 16b is an O-ring having a diameter slightly smaller than that of the sealing member 16a, and surrounds the refrigerant flow groove 32 when the wafer mounting table 10 is in use. The sealing member 16c is disposed on the lower surface of the cooling substrate 30 at a location where the refrigerant flow groove 32 is not provided, so as to surround the power supply terminal 64. The sealing member 16d is disposed on the lower surface of the cooling substrate 30 at a location where the refrigerant flow groove 32 is not provided, so as to surround the power supply terminal 54. The sealing members 16a to 16d may be O-rings, packings, or the like. The sealing members 16a to 16d may be made of an insulating material (for example, a resin such as PTFE) or a conductive material (for example, a metal).

[0031] A refrigerant supply port 96a is provided in the mounting plate 96 so as to penetrate vertically at a position facing the inlet 32a of the refrigerant flow channel groove 32, and a refrigerant discharge port 96b is provided in the mounting plate 96 so as to penetrate vertically at a position facing the outlet 32b. A refrigerant supply / discharge device (not shown) is connected to the refrigerant supply port 96a and the refrigerant discharge port 96b. The refrigerant flow channel 82 is formed by closing the opening of the refrigerant flow channel groove 32 with the mounting plate 96. In this embodiment, a small gap surrounded by the lower surface of the cooling base material 30, the upper surface of the mounting plate 96, and the seal member 16b (excluding the insides of the seal members 16c and 16d) also forms part of the refrigerant flow channel 82. When refrigerant is supplied from the refrigerant supply / discharge device to the refrigerant supply port 96a, the refrigerant passes from the inlet 82a of the refrigerant flow path 82 (inlet 32a of the refrigerant flow path groove 32) through the refrigerant flow path 82 (refrigerant flow path groove 32) to the outlet 82b (outlet 32b of the refrigerant flow path groove), and then returns to the refrigerant supply / discharge device via the refrigerant discharge port 96b. The refrigerant supply / discharge device adjusts the temperature of the returned refrigerant and then supplies the refrigerant again to the refrigerant supply port 96a.

[0032] Next, a manufacturing example of the wafer stage 10 will be described with reference to FIG. 4. FIG. 4 is a manufacturing process diagram of the wafer stage 10. First, a disk-shaped ceramic sintered body 120 that serves as the ceramic base material 20 is produced by hot press sintering a molded body of ceramic powder (FIG. 4A). The ceramic sintered body 120 incorporates an electrode 26 for wafer adsorption. Next, a terminal hole upper portion 151a is formed between the lower surface of the ceramic sintered body 120 and the electrode 26 for wafer adsorption (FIG. 4B). Then, a power supply terminal 54 is inserted into the terminal hole upper portion 151a, and the power supply terminal 54 and the electrode 26 for wafer adsorption are joined (FIG. 4C).

[0033] In parallel with this, a disk member 130 is produced (FIG. 4D). When the ceramic sintered body 120 is made of alumina, the disk member 130 is preferably made of SiSiC-Ti or AlSiC. This is because the CTE of alumina and the CTE of SiSiC-Ti or AlSiC can be made substantially the same.

[0034] The SiSiC-Ti disk member can be produced, 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 uniaxially press-molded to produce a disk-shaped molded body, and the molded body is hot press-sintered in an inert atmosphere to obtain a SiSiC-Ti disk member.

[0035] Next, a terminal hole lower portion 151c that penetrates the disk member 130 in the vertical direction is drilled, and a coolant flow path groove 32 is formed on the lower surface of the disk member 130 by machining to obtain a cooling base material 30 (FIG. 4E).

[0036] Next, a metal bonding material 140 is placed on the upper surface of the cooling substrate 30 (FIG. 4F). A terminal hole intermediate portion 151b is provided in the metal bonding material 140 at a position facing the terminal hole upper portion 151a and the terminal hole lower portion 151c. Then, the ceramic sintered body 120 is placed on the metal bonding material 140 placed on the upper surface of the cooling substrate 30 while inserting the power supply terminal 54 of the ceramic sintered body 120 into the terminal hole intermediate portion 151b and the terminal hole lower portion 151c. This results in a stacked body in which the cooling substrate 30, the metal bonding material 140, and the ceramic sintered body 120 are stacked in this order from bottom to top. This stacked body is heated and pressurized (TCB) to obtain the bonded body 110 (FIG. 4G). The bonded body 110 is formed by bonding the ceramic sintered body 120 to the upper surface of the cooling substrate 30 via the metal bonding layer 40. The terminal hole 51 is a hole in which the terminal hole upper portion 151a, the terminal hole intermediate portion 151b, and the terminal hole lower portion 151c are connected.

[0037] TCB is performed, for example, as follows: The laminate is pressed and bonded at a temperature below the solidus temperature of the metal bonding material (for example, a temperature equal to or higher than the solidus temperature minus 20°C and lower than the solidus temperature), and then returned to room temperature. This causes the metal bonding material to become a metal bonding layer. An Al-Mg based bonding material or an Al-Si-Mg based bonding material can be used as the metal bonding material in this case. For example, when TCB is performed 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 about 100 μm.

[0038] Next, the outer periphery of the ceramic sintered body 120 is cut to form a step, thereby forming the ceramic substrate 20 having a central portion 22 and an outer periphery 24. An insulating tube 55 is placed in the terminal hole 51, from the underside of the ceramic substrate 20 to the underside of the cooling substrate 30, through which the power supply terminal 54 is inserted. Furthermore, an insulating film 42 is formed by thermally spraying ceramic powder on the side surface of the outer periphery 24 of the ceramic substrate 20, the periphery of the metal bonding layer 40, and the upper surface (exposed surface) and side surface of the cooling substrate 30 (FIG. 4H). In this way, the wafer mounting table 10 is obtained.

[0039] Next, an example of how the wafer stage 10 is used will be described with reference to Figure 1. As described above, the wafer stage 10 is fixed to the mounting plate 96 of the chamber 94 with the clamp members 70. A shower head 95 is disposed on the ceiling surface of the chamber 94, and discharges process gas into the chamber 94 from a number of gas injection holes.

[0040] A focus ring 78 is placed on the FR mounting surface 24a of the wafer mounting table 10, and a disk-shaped wafer W is placed on the wafer mounting surface 22a. The focus ring 78 has a step along the inner periphery of its upper end to prevent interference with the wafer W. In this state, a DC voltage from the wafer suction DC power supply 52 is applied to the wafer suction electrode 26 to suction the wafer W onto the wafer mounting surface 22a. The interior of the chamber 94 is then set to a predetermined vacuum atmosphere (or reduced-pressure atmosphere), and an RF voltage from the RF power supply 62 is applied to the cooling substrate 30 while a process gas is supplied from the shower head 95. This generates plasma between the wafer W and the shower head 95. The plasma is then used to perform CVD film formation or etching on the wafer W.

[0041] In the embodiment described above, when the wafer mounting table 10 is in use, the lower surface of the cooling substrate 30 is attached to a mounting plate 96 separate from the wafer mounting table 10 via the seal member 16b that surrounds the refrigerant flow channel 32. The cooling substrate 30 has the refrigerant flow channel 32, but the refrigerant flow channel 32 opens to the lower surface of the cooling substrate 30. Therefore, compared to conventional cooling substrates with built-in refrigerant channels, a circular plate that covers the lower surface is not required, and less material is required for the cooling substrate 30. This allows the cost of the wafer mounting table 10 to be kept low.

[0042] Furthermore, since the lower surface of the cooling substrate 30 and the upper surface of the installation plate 96 are assembled with sealing members 16a-d such as O-rings sandwiched therebetween, the influence of the difference in CTE between the cooling substrate 30 and the installation plate 96 is absorbed by the sealing members 16a-d. As a result, cracks in the cooling substrate 30 can be prevented. Furthermore, the absolute value of the difference in CTE between the installation plate 96 and the cooling substrate 30 at 40 to 400°C is 1.5 × 10 -6Even when the temperature is higher than / K, cracks can be prevented. Therefore, even when MMC is used for the cooling base material 30 and aluminum is used for the installation plate 96, the CTE difference can be absorbed.

[0043] Further, the cooling base material 30 is preferably formed of a composite material of metal and ceramic. Such a composite material can reduce the CTE difference from the ceramic material constituting the ceramic base material 20. Therefore, it is possible to prevent the joint between the ceramic base material 20 and the cooling base material 30 from being damaged by thermal stress. Also, since such a composite material is relatively expensive, the significance of cost reduction is great.

[0044] Furthermore, the cooling base material 30 is joined to the lower surface of the ceramic base material 20 via the metal joining layer 40. Therefore, compared with the case where the cooling base material 30 is joined to the lower surface of the ceramic base material 20 via a resin (organic) joining layer, the heat of the wafer mounting surface 22a can be efficiently released to the cooling base material 30.

[0045] Moreover, since the seal members 16a to 16d are located below the cooling base material 30 (the refrigerant flow path grooves 32 are above the seal members 16a to 16d), even if the ceramic base material 20 becomes hot, it is not easily affected by the heat. Therefore, it is not necessary to use seal members 16a to 16d with high heat resistance.

[0046] It should be noted that the present invention is not limited to the above-described embodiments at all, and it goes without saying that the present invention can be implemented in various modes as long as it belongs to the technical scope of the present invention.

[0047] In the above-described embodiment, the seal member 16b is in a ring shape surrounding the entire spiral refrigerant flow path groove 32, but it is not particularly limited thereto. For example, instead of the seal member 16b, the seal member 16e shown in FIGS. 5 and 6 may be employed. In FIGS. 5 and 6, the same components as those in the above-described embodiment are denoted by the same reference numerals. The seal member 16e is formed along the edge of the spiral refrigerant flow path groove 32 provided on the lower surface of the cooling base material 30 (parallel seal member). When the seal member 16e is used, the flow of the refrigerant through the gap between the lower surface of the cooling base material 30 and the upper surface of the installation plate 96 is suppressed. The seal member 16e is crushed between the lower surface of the cooling base material 30 and the upper surface of the installation plate 96 to exhibit sealing performance. In this case, since the reaction force of the seal member 16e is generated in the vertical direction, it is necessary to increase the force for fixing with the bolt 72. On the other hand, the seal member 16e may be arranged as shown in FIG. 7. In FIG. 7, a protrusion 99 is provided along the refrigerant flow path groove 32 on the upper surface of the installation plate 96. The width of the protrusion 99 is narrower than the width of the refrigerant flow path groove 32, and the seal member 16e is arranged between the side surface of the protrusion 99 and the wall surface of the refrigerant flow path groove 32. The seal member 16e is crushed laterally by the side surface of the protrusion 99 and the wall surface of the refrigerant flow path groove 32 to exhibit sealing performance. In this case, since the reaction force of the seal member 16e is generated in the lateral direction, the side surface of the protrusion 99 and the wall surface of the refrigerant flow path groove 32 receive the reaction force. Therefore, the force for fixing with the bolt 72 can be small. In the above-described embodiment as well, the gap between the lower surface of the cooling base material 30 and the upper surface of the installation plate 96 is small, and the flow of the refrigerant through this gap is small, so the influence on the heat uniformity due to the flow of the refrigerant through the gap is almost negligible. Also, the seal member 16b is easier to arrange than the seal member 16e.

[0048] In the above-described embodiment, as shown in FIGS. 8 and 9, the cooling substrate 30 may include a central fastening member (a bolt 79 and a nut 80). In FIGS. 8 and 9, the same components as those in the above-described embodiment are denoted by the same reference numerals. The cooling substrate 30 has a plurality of nuts 80 (e.g., six nuts in FIG. 9) evenly spaced along the circumference of a circle 30a that is smaller than the diameter of the cooling substrate 30. The nuts 80 are housed in a storage hole 35 (e.g., a hexagonal hole) provided in the upper surface of the cooling substrate 30 in a state in which their rotation is restricted. The cooling substrate 30 has an insertion hole 36 that extends from the storage hole 35 to the lower surface of the cooling substrate 30. The bolt 79 is housed in a stepped hole 98 that penetrates an installation plate 96. The lower portion of the stepped hole 98 has a large diameter portion 98a that houses the head portion 79a of the bolt 79, and the upper portion has a small diameter portion 98b that houses the foot portion 79b of the bolt 79. The head 79a of the bolt 79 is engaged with the step between the large-diameter portion 98a and the small-diameter portion 98b. The foot 79b of the bolt 79 is inserted through the small-diameter portion 98b of the stepped hole 98 and further through the insertion hole 36 of the cooling base material 30 and is screwed onto the nut 80. Cooling base material 30 and the underside of Installation board 96 A seal member 16f is arranged around the foot portion 79b that passes through the gap with the upper surface of the cooling substrate 30. By screwing the bolt 79 into the nut 80, the center portion of the cooling substrate 30 (the portion where the storage hole 35 is provided) is pressed against the installation plate 96. Also, the outer periphery of the cooling substrate 30 is pressed against the installation plate 96 by the clamp member 70 as described above. In other words, the center fastening members (bolt 79 and nut 80) and the outer periphery fastening members (clamp member 70 and bolt 72) of the cooling substrate 30 are screw The outer periphery and center of the wafer stage 10 are fixed to the mounting plate 96 through the holes 97 so that the sealing members 16a-d are pressed from above and below. This prevents the wafer stage 10 from warping as it is used. As a result, the sealing performance of the sealing members 16a-d, f can be maintained for a long period of time.

[0049] In addition, in FIG. 9, a plurality of bolts 79 and nuts 80 are provided at equal intervals along the circle 30a. In addition to this, a plurality of bolts and nuts may be provided at equal intervals along a circle having a diameter smaller than that of the circle 30a. Further, instead of the central fastening members (bolts 79 and nuts 80) in FIG. 8, the central fastening members (bolts 84 and nuts 86) shown in FIG. 10 may be employed. In FIG. 10, the head of the bolt 84 is stored in the storage hole 35 in a state where rotation is restricted, the foot of the bolt 84 is inserted through the insertion hole 36 and protrudes downward from the lower surface of the cooling base material 30, and further reaches the large-diameter portion 98a through the small-diameter portion 98b. The foot of the bolt 84 is screwed with the nut 86 stored in the large-diameter portion 98a of the stepped hole 98.

[0050] In the above-described embodiment, when the refrigerant flow path groove 32 having the inlet 32a and the outlet 32b defines the most upstream portion 32U and the most downstream portion 32L in the region overlapping the wafer mounting surface 22a in a plan view as shown in FIG. 11, the distance d from the ceiling surface of the refrigerant flow path groove 32 to the wafer mounting surface 22a may be shorter at the most downstream portion 32L than at the most upstream portion 32U. Note that the width of the refrigerant flow path groove 32 may be constant throughout. Since the refrigerant flows from the most upstream portion 82U to the most downstream portion 82L of the refrigerant flow path 82 while taking heat from the high-temperature wafer, the temperature of the refrigerant flowing through the refrigerant flow path 82 is higher at the most downstream portion 82L than at the most upstream portion 82U. On the other hand, since the distance d from the ceiling surface of the refrigerant flow path 82 to the wafer mounting surface 22a is shorter at the most downstream portion 82L than at the most upstream portion 82U of the refrigerant flow path 82, the thermal resistance from the ceiling surface of the refrigerant flow path 82 to the wafer mounting surface 22a is lower at the most downstream portion 82L than at the most upstream portion 82U. Therefore, overall, the temperature difference between the position facing the most upstream portion 82U of the refrigerant flow path 82 and the position facing the most downstream portion 82L on the wafer mounting surface 22a can be reduced. Accordingly, the heat uniformity of the wafer is improved. It is preferable that this distance d gradually decreases from the most upstream portion 32U to the most downstream portion 32L. The distance d at the most downstream portion 32L is preferably 50 to 90% of the distance d at the most upstream portion 32U.

[0051] In the above-described embodiment, when the refrigerant flow path groove 32 having the inlet 32a and the outlet 32b defines the most upstream portion 32U and the most downstream portion 32L in the region overlapping the wafer mounting surface 22a in plan view as shown in FIG. 12, the cross-sectional area of the refrigerant flow path groove 32 may be made smaller in the most downstream portion 32L than in the most upstream portion 32U. Here, the height of the refrigerant flow path groove 32 and the distance from the ceiling surface of the refrigerant flow path groove 32 to the wafer mounting surface 22a are constant throughout, and the cross-sectional area of the refrigerant flow path groove 32 is changed by changing the width w of the refrigerant flow path groove 32. Since the refrigerant flows while taking heat from the high-temperature wafer from the most upstream portion 82U to the most downstream portion 82L of the refrigerant flow path 82, the temperature of the refrigerant flowing through the refrigerant flow path 82 is higher in the most downstream portion 82L than in the most upstream portion 82U. On the other hand, since the cross-sectional area of the refrigerant flow path 82 is smaller in the most downstream portion 82L than in the most upstream portion 82U of the refrigerant flow path 82, the pressure loss is larger in the most downstream portion 82L than in the most upstream portion 82U, and the heat exchange between the refrigerant and the wafer is promoted more in the most downstream portion 82L than in the most upstream portion 82U. Therefore, overall, the temperature difference between the position facing the most upstream portion 82U of the refrigerant flow path 82 and the position facing the most downstream portion 82L on the wafer mounting surface 22a can be reduced. Accordingly, the isothermal property of the wafer is improved. It is preferable that the cross-sectional area of the refrigerant flow path groove 32 gradually decreases from the most upstream portion 32U to the most downstream portion 32L of the refrigerant flow path groove 32. The cross-sectional area at the most downstream portion 32L is preferably 60 to 90% of the cross-sectional area at the most upstream portion 32U. The cross-sectional area of the refrigerant flow path groove 32 may be adjusted by at least one of the number of convex protrusions (for example, fins) provided on the inner wall of the refrigerant flow path groove 32, the thickness of the convex protrusions, and the length of the convex protrusions. The convex protrusions may be provided continuously or intermittently. Further, the convex protrusions may be provided at positions on the mounting plate 96 that face the refrigerant flow path groove 32.

[0052] In the above-described embodiment, the clamp member 70, the bolt 72, and the screw hole 97 are used as the outer peripheral fastening members of the wafer mounting table 10, but the present invention is not particularly limited thereto. For example, as shown in FIG. 13, a bolt insertion hole 39 is provided in the flange portion 34 of the cooling base material 30, and the outer peripheral portion of the wafer mounting table 10 may be attached to the installation plate 96 by passing the bolt 72 through the bolt insertion hole 39 and screwing it into the screw hole 97 of the installation plate 96. The bolt 72 is preferably inserted into the bolt insertion hole 39 with play. In FIG. 13, instead of bolt fastening from above, bolt fastening may be performed from below.

[0053] In the above-described embodiment, a heat exchange promoting portion for promoting heat exchange between the refrigerant flowing through the refrigerant flow path 82 and the wafer W placed on the wafer placement surface 22a may be provided in the peripheral region of the terminal hole 51 penetrating the cooling base material 30 when the refrigerant flow path groove 32 is used as the refrigerant flow path 82. Generally, the area immediately above the terminal hole 51 in the wafer W tends to become a hot spot. However, since the heat exchange promoting portion is provided in the peripheral region of the terminal hole 51 here, heat removal from the peripheral region of the terminal hole 51 is promoted. Therefore, the generation of hot spots in the wafer W can be suppressed. In such a heat exchange promoting portion, the refrigerant flow path groove 32 may be narrower than the region outside the peripheral region of the terminal hole 51. For example, the width of the refrigerant flow path groove 32 within the dashed-dotted line frame shown in FIG. 3 may be made narrower. The refrigerant flowing through the portion where the refrigerant flow path 82 is narrower has a higher flow velocity than when it flows through the portion where the refrigerant flow path 82 is not narrower. Therefore, heat removal from the peripheral region of the terminal hole 51 is promoted. The cross-sectional area of the flow path of the portion where the refrigerant flow path groove 32 is narrower is preferably 60 to 90% of the cross-sectional area of the flow path of the portion where it is not narrower. Alternatively, in the heat exchange promoting portion, convex projections (for example, fins) may be provided on the inner surface of the refrigerant flow path groove 32. For example, fins may be provided in the refrigerant flow path groove 32 within the dashed-dotted line frame shown in FIG. 3. The refrigerant flowing through the portion where fins are provided in the refrigerant flow path 82 is more likely to become turbulent than when it flows through the portion where fins are not provided. Therefore, heat removal from the peripheral region of the terminal hole 51 is promoted. The cross-sectional area of the flow path of the portion where fins are provided in the refrigerant flow path groove 32 is preferably 60 to 90% of the cross-sectional area of the flow path of the portion where fins are not provided. Alternatively, in the heat exchange promoting portion, the distance from the wafer placement surface 22a to the ceiling surface of the refrigerant flow path groove 32 may be shorter than the region outside the peripheral region of the terminal hole 51. For example, the distance between the ceiling surface of the refrigerant flow path groove 32 within the dashed-dotted line frame shown in FIG. 3 and the wafer placement surface 22a may be made shorter than other regions. The refrigerant flowing through the portion where the distance from the wafer placement surface 22a to the ceiling surface of the refrigerant flow path groove 32 is short has a smaller thermal resistance between the refrigerant and the wafer W than when it flows through the portion where the distance from the wafer placement surface 22a to the ceiling surface of the refrigerant flow path groove 32 is not short. Therefore, heat removal from the peripheral region of the terminal hole 51 is promoted.The distance from the wafer placement surface 22a to the ceiling surface of the refrigerant flow path groove 32 in the heat exchange promotion part is preferably 50 to 90% of the distance from the wafer placement surface 22a outside the heat exchange promotion part to the ceiling surface of the refrigerant flow path groove 32. Note that a heat exchange promotion part may be provided in the peripheral region of the gas supply hole and the lift pin hole, which will be described later, in the cooling base material 30.

[0054] In the above-described embodiment, the installation plate 96 of the chamber 94 is configured as a single layer, but the installation plate 96 may be configured as a plurality of layers. In that case, at least one of the plurality of layers may be made of an insulating material. For example, all of the plurality of layers may be made of an insulating material, or some of the plurality of layers (for example, the outermost layer) may be made of an insulating material and the remaining layers may be made of a conductive material.

[0055] In the above-described embodiment, a composite material of metal and ceramic is exemplified as the material constituting the cooling base material 30, but it is not particularly limited thereto. For example, the cooling base material 30 may be made of a metal material such as aluminum or an aluminum alloy. However, considering reducing the CTE difference from the ceramic base material 20, a composite material of metal and ceramic is preferable.

[0056] In the above-described embodiment, the wafer adsorption electrode 26 is built in the central part 22 of the ceramic base material 20, but instead of or in addition to this, an RF electrode for plasma generation may be built in. In this case, a high-frequency power supply is connected to the RF electrode instead of the cooling base material 30. Further, a focus ring (FR) adsorption electrode may be built in the outer peripheral part 24 of the ceramic base material 20. In this case, a DC power supply is connected to the FR adsorption electrode. Further, the ceramic base material 20 may have a built-in heater electrode (resistance heating element). In this case, a heater power supply is connected to the heater electrode. The ceramic base material 20 may have one layer of built-in electrode or two or more layers of built-in electrodes.

[0057] The wafer mounting table 10 of the above-described embodiment may have holes penetrating the wafer mounting table 10 from the lower surface of the cooling substrate 30 to the wafer mounting surface 22a. Examples of such holes include gas supply holes for supplying a thermally conductive gas (e.g., He gas) to the backside of the wafer W and lift pin holes for inserting lift pins that move the wafer W up and down relative to the wafer mounting surface 22a. The thermally conductive gas is supplied to a space formed by the wafer W and a number of small protrusions (not shown) on the wafer mounting surface 22a that support the wafer W. When the wafer W is supported by, for example, three lift pins, three lift pin holes are provided. When such through holes are provided, a seal member is disposed around the through holes as well as around the insulating tube 55 in the space between the lower surface of the ceramic substrate 20 and the upper surface of the cooling substrate 30.

[0058] In the above-described embodiment, the seal member 16a is provided on the outermost periphery, but the seal member 16a may be omitted.

[0059] In the above-described embodiment, the refrigerant flow channel groove 32 is provided in a spiral shape from the inlet 32a to the outlet 32b, but there are no particular limitations on the shape of the refrigerant flow channel groove 32. For example, the refrigerant flow channel groove 32 may be provided in a zigzag shape in a plan view.

[0060] In the above-described embodiment, the ceramic sintered body 120 in FIG. 4A was produced by hot-pressing and firing a ceramic powder compact. However, the compact may be produced by stacking multiple tape compacts, by a mold casting method, or by compressing ceramic powder.

[0061] In the above-described embodiment, grooves into which the seal members 16a to 16d are fitted may be provided at positions on the upper surface of the installation plate 96 where the seal members 16a to 16d are to be arranged. Alternatively or additionally, grooves into which the seal members 16a to 16d are to be fitted may be provided at positions on the lower surface of the cooling substrate 30 where the seal members 16a to 16d are to be arranged.

[0062] In the above-described embodiment, the shape of the vertical cross-section of the refrigerant flow path groove 32 (the shape that appears on the cut surface when the wafer mounting table 10 is cut by a plane perpendicular to the wafer mounting surface 22a) is rectangular, but it is not particularly limited thereto. For example, as shown in FIG. 14, the shape of the vertical cross-section of the refrigerant flow path groove 432 may be such that the width w2 of the ceiling portion 432q of the refrigerant flow path groove 432 is wider than the width w1 of the opening portion 432p of the refrigerant flow path groove 432 (w2 > w1). In FIG. 14, the same reference numerals are given to the same components as those in the above-described embodiment. The refrigerant flow path groove 432 forms the refrigerant flow path 482 when the opening portion 432p is blocked by the upper surface of the installation plate 96 of the chamber 94. The inlet 432a and the outlet 432b of the refrigerant flow path groove 432 (the inlet 482a and the outlet 482b of the refrigerant flow path 482) are connected to the refrigerant supply port 96a and the refrigerant discharge port 96b provided in the installation plate 96, respectively. Here, the interval d1 between adjacent opening portions 432p of the refrigerant flow path groove 432 is wider than the interval d2 between adjacent ceiling portions 432q of the refrigerant flow path groove 432 (d1 > d2). In FIG. 14, since the interval d1 between adjacent opening portions 432p of the refrigerant flow path groove 432 is wide, it is possible to suppress the mixing of the refrigerant through the gap G between the opening portions 432p. Further, since the interval d2 between adjacent ceiling portions 432q of the refrigerant flow path groove 432 is narrow, the cooling area of the wafer W by the refrigerant becomes wide, and the cooling efficiency is increased. Furthermore, since the total area of the opening portions 432p of the refrigerant flow path groove 432 is narrower than the total area of the ceiling portions 432q, it is possible to reduce the force due to the pressure of the refrigerant applied between the cooling base material 30 and the installation plate 96 on the chamber 94 side. As a result, warping of the wafer mounting table itself can be suppressed. Furthermore, since the interval d1 between the opening portions 432p of the refrigerant flow path groove 432 is relatively wide, it is possible to suppress the mixing of the refrigerant through the gap G between the opening portions 432p without sealing the opening portions 432p with a seal ring or the like. Such a refrigerant flow path groove 432 can be formed using a grindstone having the same shape as the vertical cross-section of the refrigerant flow path groove 432. In that case, the inlet 432a and the outlet 432b of the refrigerant flow path groove 432 are round holes (cylindrical holes).

[0063] The opening 432p of the refrigerant flow path groove 432 may be sealed with a seal ring 483 as shown in FIG. 15. In FIG. 15, the same components as those in FIG. 14 are denoted by the same reference numerals. The seal ring 483 appears in the same shape as the refrigerant flow path groove 432 in a plan view. In this way, the seal ring 483 prevents the refrigerant from mixing in the gap G between adjacent openings 432p of the refrigerant flow path groove 432, so that the interval d1 between adjacent openings 432p of the refrigerant flow path groove 432 can be made narrower than that in FIG. 14, and consequently, the refrigerant flow path grooves 432 can be provided more densely. Accordingly, the interval d2 between adjacent ceiling portions 432q of the refrigerant flow path groove 432 can be made even narrower, so that the cooling area of the wafer W by the refrigerant becomes wider and the cooling efficiency becomes higher.

[0064] In FIG. 15, the longitudinal cross-sectional shape of the seal ring 483 is circular, but it is not particularly limited thereto. For example, as in the seal ring 583 shown in FIG. 16, the longitudinal cross-sectional shape is such that the left and right sides of a trapezoid (or rectangle) are recessed inward, the portion above the recess of the seal ring 583 is arranged to be in close contact with the wall surface in the refrigerant flow path groove 432, and the portion below the recess of the seal ring 583 is arranged outside the refrigerant flow path groove 432 (the gap between the cooling base material 30 and the installation plate 96). In this way, even if the cooling base material 30 is pressed toward the installation plate 96, the seal ring 583 can be prevented from being pushed into the refrigerant flow path groove 432.

[0065] Incidentally, as a structure for reducing the amount of material used for the cooling base material, as shown in FIG. 1714, a plate-shaped cooling base material 230 without a refrigerant flow path groove is joined to the lower surface of the ceramic base material 20 via a metal bonding layer 40, and on the lower surface of the cooling base material 230, a plate-shaped member 330 having a refrigerant flow path groove 332 that opens upward is attached via a seal member 216b. In this case, even if the cooling base material 230 is formed of an expensive material, if the plate-shaped member 330 is formed of an inexpensive material, the cost of the wafer mounting table can be kept low. However, in the structure of FIG. 1714, although heat exchange is performed between the refrigerant flow path 382 formed by closing the upper opening of the refrigerant flow path groove 332 with the cooling base material 230 and the ceramic base material 20 on the ceiling surface, sufficient heat exchange is not performed between the side surface and the ceramic base material 20. On the other hand, in the above-described embodiment, since sufficient heat exchange is performed between the ceiling surface and the side surface of the refrigerant flow path 82 and the ceramic base material 20, heat dissipation of the wafer W can be efficiently performed.

Description of reference numerals

[0066] 10 wafer mounting table, 16a-f seal member, 20 ceramic base material, 22 center portion, 22a wafer mounting surface, 24 outer periphery, 24a focus ring mounting surface, 26 wafer suction electrode, 30 cooling base material, 30a circle, 32 coolant flow groove, 32a inlet, 32b outlet, 32L most downstream portion, 32U most upstream portion, 34 flange portion, 35 storage hole, 36 insertion hole, 39 bolt insertion hole, 40 metal bonding layer, 42 insulating film, 51 terminal hole, 52 wafer suction DC power supply, 54 power supply terminal, 55 insulating tube, 62 RF power supply, 64 power supply terminal, 70 clamp member, 70a inner peripheral stepped surface, 72 bolt, 78 focus ring, 80 nut, 79 bolt, 79a head, 79b foot, 82 Refrigerant flow path, 82a inlet, 82b outlet, 82L most downstream portion, 82U most upstream portion, 84 bolt, 86 nut, 94 chamber, 95 shower head, 96 installation plate, 96a refrigerant supply port, 96b refrigerant discharge port, 97 screw hole, 98 stepped hole, 98a large diameter portion, 98b small diameter portion, 99 protrusion, 110 joint body, 120 ceramic sintered body, 130 disk member, 140 metal joint material, 151a upper terminal hole, 151b middle terminal hole portion, 151c lower terminal hole, 216b seal member, 230 cooling base material, 330 plate-shaped member, 332 refrigerant flow path groove, 382 refrigerant flow path, 432 refrigerant flow path groove, 432a inlet, 432b outlet, 432p opening, 432q ceiling portion, 482 Refrigerant flow path, 482a inlet, 482b outlet, 483,583 sealing ring.

Claims

1. A wafer mounting table having a wafer mounting surface on the upper surface and incorporating electrodes, a cooling base provided on the lower surface side of the ceramic base, a refrigerant flow path groove provided in the cooling base so as to open on the lower surface of the cooling base, comprising: The distance from the ceiling surface of the refrigerant flow path groove at the most upstream portion and the most downstream portion in the region overlapping the wafer mounting surface in plan view of the refrigerant flow path groove to the wafer mounting surface is shorter at the most downstream portion than at the most upstream portion, The distance gradually decreases from the most upstream portion toward the most downstream portion, Wafer mounting table.

2. The cooling base is formed of a composite material of metal and ceramic, The wafer mounting table according to claim 1.

3. The cooling base is joined to the lower surface of the ceramic base via a metal bonding layer, The wafer mounting table according to claim 1 or 2.

4. The cross-sectional area of the refrigerant flow path groove at the most upstream portion and the most downstream portion in the region overlapping the wafer mounting surface in plan view of the refrigerant flow path groove is smaller at the most downstream portion than at the most upstream portion, The wafer mounting table according to claim 1 or 2.

5. The cooling base has a hole penetrating the cooling base in the vertical direction, and in the peripheral region of the hole, a heat exchange promoting portion for promoting heat exchange between the refrigerant flowing through the refrigerant flow path when using the refrigerant flow path groove as the refrigerant flow path and the wafer placed on the wafer mounting surface is provided, The wafer mounting table according to claim 1 or 2.

6. The lower surface of the cooling base of the wafer mounting table is attached to an installation plate different from the wafer mounting table via a seal member surrounding the refrigerant flow path groove during use, The wafer mounting table according to claim 1 or 2.

7. The cooling base has a central portion fastening member for fastening the central portion of the cooling base to the installation plate, The wafer mounting table according to claim 6.

8. The shape of the longitudinal section of the refrigerant flow path groove is such that the width of the ceiling portion of the refrigerant flow path groove is wider than the width of the opening portion of the refrigerant flow path groove, and the interval between adjacent openings of the refrigerant flow path groove is wider than the interval between adjacent ceiling portions of the refrigerant flow path groove, The wafer mounting table according to claim 1 or 2.

9. The opening of the refrigerant flow path groove is not sealed by a seal ring, The wafer mounting table according to claim 8.

10. The opening of the refrigerant flow path groove is sealed by a seal ring, The wafer mounting table according to claim 8.

11. The wafer mounting table according to claim 1 or 2, An installation plate on which the lower surface of the cooling base material is installed via a seal member surrounding the refrigerant flow path groove, An outer peripheral fastening member that fastens the outer peripheral portion of the wafer mounting table to the installation plate, A member for a semiconductor manufacturing apparatus comprising the above.

12. The absolute value of the linear thermal expansion coefficient difference between the cooling base material and the installation plate is 1.5×10 -6 / K or more at 40 to 400 °C. The member for a semiconductor manufacturing apparatus according to claim 11.

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