Temperature regulation member and electrostatic chuck device

Abstract

This temperature regulation member for supporting an electrostatic chuck member comprises, in at least a portion thereof, an inner peripheral portion and an outer peripheral portion that have mutually different thermal conductivity, the temperature regulation member being such that: the inner peripheral portion is formed of a first electroconductive ceramic that includes a first highly thermoconductive material and a first electroconductive material; the outer peripheral portion is formed of a second electroconductive ceramic that includes a second highly thermoconductive material and a second electroconductive material, the outer peripheral portion surrounding the outside of the inner peripheral portion in a closed manner in plan view; and the outer peripheral portion has higher thermoconductivity than the inner peripheral portion.

Description

Temperature adjusting member and electrostatic chuck device

[0001] This application claims priority to Japanese Patent Application No. 2024-054289, filed March 28, 2024, the contents of which are incorporated herein by reference.

[0002] Conventionally, in semiconductor manufacturing processes for manufacturing semiconductors such as ICs, LSIs, and VLSIs, an electrostatic chuck device is used to electrostatically attract a plate-like sample such as a silicon wafer when performing plasma processing on the plate-like sample. The electrostatic chuck device includes a temperature adjustment member for controlling the temperature of the plate-like sample. The temperature adjustment member is a base that supports an electrostatic chuck member having an electrostatic attraction electrode and also has a function of dissipating heat from the plate-like sample placed on the electrostatic chuck member (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2024-022214

[0004] The electrostatic chuck device has different configurations at the center and the periphery of the mounting surface, and the state of contact with the plate-shaped sample differs between the center and the periphery of the mounting surface. Due to this difference in contact state, the periphery of the mounting surface on which the plate-shaped sample is placed is less likely to cool during plasma processing of the plate-shaped sample, and is more likely to be heated by the plasma and reach high temperatures. Therefore, the temperature of the periphery of the plate-shaped sample during plasma processing tends to be higher than that of the center. When plasma processing is performed in this state where the plate-shaped sample has different temperatures, the plasma processing becomes non-uniform between the center and the periphery of the plate-shaped sample, and an improvement has been sought.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a temperature adjustment member that can suitably adjust the temperature of the peripheral portion of a plate-like sample placed on an electrostatic chuck device. Another object of the present invention is to provide an electrostatic chuck device that has such a temperature adjustment member and can suitably adjust the temperature of the peripheral portion of the plate-like sample.

[0006] In order to solve the above-described problems, the present invention provides a temperature adjustment member for supporting an electrostatic chuck member, the temperature adjustment member including: an inner peripheral portion formed of a first conductive ceramic containing a first high thermal conductivity material and a first conductive material; and an outer peripheral portion formed of a second conductive ceramic containing a second high thermal conductivity material and a second conductive material, the outer peripheral portion surrounding the outside of the inner peripheral portion in a closed annular shape in a plan view, the outer peripheral portion having a higher thermal conductivity than the inner peripheral portion. More specifically, the temperature adjustment member includes the following aspects.

[0007] [1] A temperature adjustment member for supporting an electrostatic chuck member, the temperature adjustment member comprising: an inner peripheral portion and an outer peripheral portion having at least a portion different in thermal conductivity; the inner peripheral portion being formed of a first conductive ceramic containing a first high thermal conductive material and a first conductive material; and the outer peripheral portion being formed of a second conductive ceramic containing a second high thermal conductive material and a second conductive material, the temperature adjustment member surrounding the outside of the inner peripheral portion in a closed ring shape in a plan view; and the outer peripheral portion having a higher thermal conductivity than the inner peripheral portion.

[0008] [2] The temperature adjustment member according to [1], which has an intermediate portion that is provided between the inner peripheral portion and the outer peripheral portion in a plan view and contacts the inner peripheral portion and the outer peripheral portion, and the intermediate portion is formed of a third conductive ceramic that includes the first high thermal conductivity material, the second high thermal conductivity material, and the first conductive material and the second conductive material, and has a thermal conductivity higher than that of the inner peripheral portion and a thermal conductivity lower than that of the outer peripheral portion.

[0009] [3] The temperature adjustment member according to [1] or [2], wherein the area of ​​the inner peripheral portion in a plan view is 55% to 95% of the area of ​​the temperature adjustment member in a plan view.

[0010] [4] A temperature adjustment member described in any one of [1] to [3], wherein the difference between the thermal conductivity of the inner peripheral portion and the thermal conductivity of the outer peripheral portion is 15 W / m·K or more and 250 W / m·K or less.

[0011] [5] The temperature adjusting member according to any one of [1] to [4], wherein the difference between the thermal expansion coefficient of the inner peripheral portion and the thermal expansion coefficient of the outer peripheral portion is less than 2 ppm / K.

[0012] [6] An electrostatic chuck device comprising: the temperature adjustment member according to any one of [1] to [5]; and an electrostatic chuck member having a dielectric substrate and an electrostatic attraction electrode and supported by the temperature adjustment member, wherein the electrostatic chuck member overlaps with the outer periphery in a plan view. [7] The temperature adjustment member according to any one of [1] to [5], wherein the temperature adjustment member consists only of the inner periphery and the outer periphery. [8] The temperature adjustment member according to any one of [1] to [5], wherein the temperature adjustment member consists only of the inner periphery, the intermediate portion, and the outer periphery.

[0013] According to the present invention, it is possible to provide a temperature adjustment member that can suitably adjust the temperature at the peripheral portion of a plate-shaped sample in an electrostatic chuck device. Another object of the present invention is to provide an electrostatic chuck device that has such a temperature adjustment member and can suitably adjust the temperature at the peripheral portion of a plate-shaped sample.

[0014] FIG. 1 is a schematic cross-sectional view showing an example of an electrostatic chuck device 1 according to this embodiment. FIG. 2 is a schematic perspective view showing an example of an electrostatic chuck device 1. FIG. 3 is a schematic explanatory view showing an example of a method for manufacturing a base 3. FIG. 4 is a schematic explanatory view showing an example of a method for manufacturing a base 3. FIG. 5 is a schematic explanatory view showing an example of a method for manufacturing a base 3. FIG. 6 is a schematic explanatory view showing an example of a method for manufacturing a base 3. FIG. 7 is a schematic explanatory view showing an example of a method for manufacturing a base 3. FIG. 8 is a schematic plan view showing a modified example of a conductive ceramic plate and a base. FIG. 9 is a schematic plan view showing a modified example of a conductive ceramic plate and a base.

[0015] Hereinafter, preferred examples of the temperature adjustment member and electrostatic chuck device according to this embodiment will be described with reference to Figures 1 to 9. In all of the following drawings, the dimensions and ratios of the components have been appropriately changed to make the drawings easier to understand. The following explanation is provided for specific purposes to better understand the gist of the invention, and does not limit the present invention unless otherwise specified. For example, unless otherwise specified, conditions such as materials, amounts, types, numbers, sizes, shapes, positions, and ratios may be changed, added, or omitted as necessary.

[0016] 1 is a cross-sectional schematic view showing an example of an electrostatic chuck device 1 according to the present embodiment. The electrostatic chuck device 1 includes an electrostatic chuck member 2, a base 3, and a bonding layer 4. The electrostatic chuck member 2 and the base 3 are stacked on top of each other with the bonding layer 4 interposed therebetween. The base 3 corresponds to the temperature adjustment member of the present invention.

[0017] In this specification, the direction in which the electrostatic chuck member 2 and the base 3 are stacked is referred to as the stacking direction. Furthermore, the side on which the electrostatic chuck member 2 is disposed relative to the base 3 may be referred to as "one side in the stacking direction," and the opposite side, i.e., the side on which the electrostatic chuck member 2 is not disposed relative to the base 3, may be referred to as "the other side in the stacking direction." Furthermore, in the following description, each part of the electrostatic chuck device 1 will be described with the vertical direction as the stacking direction. However, the vertical direction here is used merely for the sake of simplicity of description and does not limit the position of the electrostatic chuck device 1 during use. The upper side corresponds to one side in the stacking direction, and the lower side corresponds to the other side in the stacking direction.

[0018] <Electrostatic Chuck Member> The electrostatic chuck member 2 has a dielectric substrate 11 and an attraction electrode 13 located inside the dielectric substrate 11. The electrostatic chuck member 2 has a first attraction portion 21 that attracts and holds the wafer W on its upper surface, and a second attraction portion 22 that attracts and holds the focus ring FR on its upper surface.

[0019] The first suction portion 21 is formed in a cylindrical shape, and has a plurality of protrusions 211 protruding upward on its upper surface. In addition, a closed annular protrusion 212 is provided on the peripheral portion of the upper surface of the first suction portion 21 along the edge of the upper surface of the first suction portion 21. In this specification, the term "plan view" refers to a field of view seen from the thickness direction of the electrostatic chuck member 2.

[0020] The electrostatic chuck device 1 supports the wafer W on the tip portions (upper surfaces) of the plurality of convex portions 211 and the upper surface of the annular convex portion 212. That is, in the electrostatic chuck device 1, an imaginary plane connecting the upper surface of the annular convex portion 212 and the upper surfaces of the plurality of convex portions 211 corresponds to the mounting surface 21 a of the wafer W.

[0021] When a wafer W is placed on the mounting surface 21 a, a space surrounded by the underside of the wafer W, the plurality of protrusions 211, and the annular protrusion 212 functions as a flow path 21 x for flowing a cooling gas. The electrostatic chuck device 1 is provided with a gas supply hole (not shown) that penetrates the electrostatic chuck device 1 in the thickness direction, and the cooling gas is supplied from the gas supply hole to the flow path 21 x. The cooling gas flowing through the flow path 21 x cools the wafer W that is heated during plasma processing.

[0022] The second suction portion 22 has a cylindrical shape concentric with the first suction portion 21 and has a larger radius than the first suction portion 21, and is formed integrally with the first suction portion 21. Specifically, the first suction portion 21 is formed at the center of the second suction portion 22. An upper surface 22a of the second suction portion 22 is exposed and surrounds the periphery of the first suction portion 21 in a plan view. The upper surface 22a corresponds to a mounting surface that suction-holds the focus ring FR.

[0023] The upper surface 22a is formed with a groove 22x that is annular in plan view. When a focus ring FR is placed on the upper surface 22a, the space surrounded by the lower surface of the focus ring FR and the groove 22x functions as a flow path for a cooling gas. The electrostatic chuck device 1 is provided with a gas supply hole (not shown) that penetrates the electrostatic chuck device 1 in the thickness direction, and a cooling gas is supplied from the gas supply hole to the flow path (groove 22x). The cooling gas flowing through the flow path cools the focus ring FR, which is heated during plasma processing.

[0024] (Dielectric Substrate) The dielectric substrate 11 of the electrostatic chuck member 2 is made of ceramics that contains an insulating material and a conductive material, has sufficient mechanical strength, and is durable against corrosive gases and their plasma.

[0025] The ceramics constituting the dielectric substrate 11 are mainly composed of insulating material, such as aluminum oxide (Al ２ O ３ The insulating material may be 60% or more by volume, 70% or more by volume, 80% or more by volume, or 90% or more by volume, as needed.

[0026] The conductive material is not particularly limited as long as it is a material that can be used for the dielectric substrate 11, and examples thereof include SiC and TiO ２ , TiN, TiC, W, WC, MoC, Mo ２ At least one selected from the group consisting of C, TaC, TaN, NbC, VC and C can be used.

[0027] The ceramics constituting the dielectric substrate 11 are aluminum oxide (Al ２ O ３ In particular, from the viewpoints of dielectric properties at high temperatures, high corrosion resistance, plasma resistance, and heat resistance, the material constituting the dielectric substrate 11 is preferably Al ２ O ３ A sintered SiC composite is preferred.

[0028] (Chuck Electrode) The chucking electrode 13 is disposed inside the dielectric substrate 11. The chucking electrode 13 extends along the mounting surface 21 a of the dielectric substrate 11. When a voltage is applied to the chucking electrode 13, the chucking electrode 13 generates an electrostatic chucking force that holds the wafer W on the mounting surface 21 a. The shape and number of the chucking electrode 13 in a plan view can be selected arbitrarily.

[0029] The chucking electrode 15 is disposed inside the dielectric substrate 11. The chucking electrode 15 extends in a circular ring shape in a plan view along the upper surface 22 a of the second chucking portion 22. When a voltage is applied to the chucking electrode 15, it generates an electrostatic chucking force that holds the wafer W on the upper surface 22 a.

[0030] The chucking electrodes 13 and 15 are connected to power supply terminals (not shown) for applying a DC voltage to the chucking electrodes 13 and 15, respectively.

[0031] The chucking electrodes 13 and 15 are made of a composite of an insulating material and a conductive material. The insulating material contained in the chucking electrodes 13 and 15 is not particularly limited, but may be, for example, aluminum oxide (Al ２ O ３ ), aluminum nitride (AlN), silicon nitride (Si ３ N ４ ), yttrium (III) oxide (Y ２ O ３), yttrium aluminum garnet (YAG) and SmAlO ３ It is preferable that the polymer is at least one selected from the group consisting of:

[0032] The conductive material contained in the attraction electrode 13 is not particularly limited, but may be, for example, molybdenum carbide (Mo ２ It is preferable that the material is at least one selected from the group consisting of molybdenum (Mo), tungsten carbide (WC), tungsten (W), tantalum carbide (TaC), tantalum (Ta), silicon carbide (SiC), carbon black, carbon nanotubes, and carbon nanofibers.

[0033] The thickness of the electrostatic chuck member 2 is preferably 0.5 mm or more and 5 mm or less. When the thickness of the electrostatic chuck member 2 is 0.5 mm or more, the withstand voltage of the electrostatic chuck member 2 is high. Furthermore, when the thickness of the electrostatic chuck member 2 is 5 mm or less, the heat capacity of the electrostatic chuck member 2 is small, making it easier to maintain a uniform temperature of the plate-shaped sample, which is the processing object, during plasma processing.

[0034] <Base (Temperature Adjusting Member)> The base (temperature adjusting member) 3 is a disc-shaped member in a plan view, and supports the electrostatic chuck member 2 from below (the other side in the stacking direction). An upper surface (supporting surface) 3a of the base 3 faces the lower surface 2a of the electrostatic chuck member 2 in the up-and-down direction (stacking direction) with the bonding layer 4 interposed therebetween. The base 3 supports the electrostatic chuck member 2 on the supporting surface 3a.

[0035] A flow path 3f for circulating a coolant may be provided inside the base 3. The coolant flowing through the flow path 3f can be selected arbitrarily, and may be a fluorine-based inert liquid, water, He gas, N ２ The flow path 3f extends along the support surface 3a. The coolant in the flow path 3f cools the entire base 3 and also cools the electrostatic chuck member 2 via the support surface 3a.

[0036] The base 3 is connected to an external high frequency power source 5 via a matching box (not shown), and may also serve as an internal electrode for generating plasma.

[0037] FIG. 2 is a schematic perspective view showing the electrostatic chuck device 1, and is an explanatory view mainly showing the base 3.

[0038] In the example shown in Figures 1 and 2, the base 3 has an inner peripheral portion 311 and an outer peripheral portion 312 that surrounds the outside of the inner peripheral portion 311 in a closed ring shape in a plan view. The base 3 may also have an intermediate portion 313 that is provided between the inner peripheral portion 311 and the outer peripheral portion 312 in a plan view and that contacts the inner peripheral portion 311 and the outer peripheral portion 312. It is preferable that the inner peripheral portion, the outer peripheral portion, and the intermediate portion have the same thickness. In the example shown in Figures 1 and 2, the base 3 is formed only from the inner peripheral portion, the intermediate portion, and the outer peripheral portion. The inner peripheral portion, the intermediate portion, and the outer peripheral portion have the same thickness and are joined in this order from the inside. The base 3 may also be formed only from the inner peripheral portion and the outer peripheral portion.

[0039] Comparing the thermal conductivity of each portion of the base 3, the thermal conductivity of the outer peripheral portion 312 is higher than that of the inner peripheral portion 311. The thermal conductivity of the intermediate portion 313 is higher than that of the inner peripheral portion 311 but lower than that of the outer peripheral portion 312. That is, the thermal conductivity of the base 3 increases in the order of the inner peripheral portion 311, the intermediate portion 313, and the outer peripheral portion 312, with the outer portions being relatively more susceptible to heat conduction. Therefore, heat dissipation can be more effectively achieved toward the outside. As described below, the base 3 may be formed by stacking and processing multiple, for example, three, conductive ceramic plates or green sheets. The multiple conductive ceramic plates or green sheets may have the same configuration and characteristics or different configurations and characteristics. It is sufficient for the base 3 as a whole to satisfy the characteristic that the thermal conductivity on the outer peripheral side is higher than that on the inner peripheral side. For example, at least one of the multiple stacked conductive ceramic plates or green sheets may be configured so that the thermal conductivity of its outer periphery is higher than that of its inner periphery, and the remaining conductive ceramic plates or green sheets may be configured to have a uniform composition.

[0040] 2 , the inner peripheral portion 311 is circular in plan view, and the outer peripheral portion 312 and the intermediate portion 313 are each annular (donut-shaped) and concentric with the inner peripheral portion 311 in plan view. The area of ​​the inner peripheral portion 311 in plan view is preferably 55% to 95% of the area of ​​the base 3 in plan view (total area in plan view). By having the area of ​​the inner peripheral portion 311 in the above range, the range of 5% to 45% of the area of ​​the base 3 in plan view has a higher thermal conductivity than the inner peripheral portion 311, and can effectively cool the peripheral portion of the wafer W. This makes it easier to maintain a uniform temperature between the center and peripheral portions of the wafer W during plasma processing.

[0041] A flow path 311f constituting a part of the flow path 3f is provided inside the inner peripheral portion 311. A flow path 312f constituting a part of the flow path 3f is provided inside the outer peripheral portion 312. The flow paths 311f and 312f may be continuous with each other or may be provided independently of each other.

[0042] Each portion of the base 3 (inner peripheral portion 311, outer peripheral portion 312, and intermediate portion 313) is made of conductive ceramics (hereinafter, sometimes abbreviated as "conductive ceramics") containing a high thermal conductivity material and a conductive material. The respective portions of the base 3 shown in FIG. 2 are made of different conductive ceramics. The inner peripheral portion 311 is made of a first conductive ceramic containing a first high thermal conductivity material and a first conductive material. The outer peripheral portion 312 is made of a second conductive ceramic containing a second high thermal conductivity material and a second conductive material. The intermediate portion 313 is made of a third conductive ceramic containing the first high thermal conductivity material, a second high thermal conductivity material, and the first conductive material and the second conductive material.

[0043] The first high thermal conductivity material and the second high thermal conductivity material may be the same material or different materials. The first conductive material and the second conductive material may be the same material or different materials. The thermal conductivity may be adjusted by changing the composition, etc.

[0044] When the entire volume of the base 3 is taken as 100 volume %, the material of the base 3 has a volume ratio of the highly thermally conductive material to the electrically conductive material of 30:70 to 70:30 in each portion of the base 3. The ratio may be 35:65 to 65:35, 40:60 to 60:40, 45:55 to 55:45, or the like.

[0045] By using a conductive ceramic material for the base 3, heat is easily transferred from the electrostatic chuck member 2, and an electrostatic chuck device can be obtained that facilitates temperature control of the wafer W supported by the electrostatic chuck member 2.

[0046] The material forming the base must have excellent thermal conductivity, electrical conductivity, and workability, so it has traditionally been made of metals such as aluminum. Meanwhile, the dielectric substrate that forms the electrostatic chuck member is made of ceramics. Generally, the thermal expansion coefficient of ceramics is significantly smaller than that of metals, so there is a large difference in the thermal expansion coefficient between the metal base and the electrostatic chuck member made of ceramics.

[0047] On the other hand, the base 3 employed in the electrostatic chuck device 1 of this embodiment is made of a conductive ceramic material. This reduces the difference in the thermal expansion coefficient between the two materials. Furthermore, since such a base 3 easily transfers heat from the electrostatic chuck member 2, an electrostatic chuck device that facilitates temperature control of the wafer W can be obtained. The ease with which the base 3 made of a conductive ceramic material transfers heat has been confirmed through simulations in which the base 3 has a uniform composition.

[0048] In the simulation, the dielectric substrate 11 is Al ２ O ３ The effect of heat transfer of the base 3 on plasma heat was confirmed for electrostatic chuck device A, which had an AlN--SiC composite sintered body and an aluminum base 3, and electrostatic chuck device B, which had an AlN--TiN composite sintered body, which is a conductive ceramic, as the base 3.

[0049] As a result, when the measured temperature of the bonding layer 4 in the electrostatic chuck device A was T°C, the measured temperature of the bonding layer 4 in the electrostatic chuck device B was T-50°C. Furthermore, the measured temperatures of the dielectric substrate 11, the wafer W, and the contact portion between the wafer W and the dielectric substrate 11 were also 50°C lower in the electrostatic chuck device B than in the electrostatic chuck device A. In other words, it was confirmed that by changing the material forming the base 3 from the conventional metal to a conductive ceramic, it is possible to effectively release (remove) plasma heat.

[0050] The conductive materials (first conductive material, second conductive material) are SiC and TiO ２ , TiN, TiC, W, WC, Mo, MoC, Mo ２ It is preferably at least one selected from the group consisting of C, TaC, TaN, Nb, NbC, VC and C. Among these, TiN is preferred because of its excellent plasma resistance.

[0051] The high thermal conductivity material (first high thermal conductivity material, second high thermal conductivity material) is AlN, SiC, GaN, Al ２ O ３ , SmAlO ３ , Si ３ N ４ , Al(OH) ３ , MgO, Mg(OH)2, BN, ZnO, BeO, B ４ Preferably, the material is at least one selected from the group consisting of C, carbon (C), W, Mo, Nb, aluminum, copper, silver, and gold. When SiC, W, Mo, or Nb is used as the high thermal conductivity material, the conductive material is selected from a material other than the material selected as the high thermal conductivity material. For example, when SiC is selected as the high thermal conductivity material, a material other than SiC is selected as the conductive material. When SiC is used as the high thermal conductivity material, TiN, for example, can be selected as the conductive material. High thermal conductivity means having high thermal conductivity, and may also mean having high heat dissipation properties.

[0052] Furthermore, the conductive ceramic may contain, as a third component, a material that serves as a base when forming a conductive ceramic body, in addition to the highly thermally conductive material and the conductive material, within the scope of the invention, without impairing the effects of the invention. Such a material can be SiO ２ Examples include:

[0053] (Thermal Conductivity of Base) The base 3 is preferably made of a material with a thermal conductivity of 40 W / m·K or more, and more preferably 50 W / m·K or more and 110 W / m·K or less. Having a thermal conductivity within the above range allows input heat to be effectively dissipated. The lower limit may be 60 W / m·K or more, 70 W / m·K or more, 80 W / m·K or more, or 90 W / m·K or more, as needed. The upper limit may be 100 W / m·K or less, 90 W / m·K or less, 80 W / m·K or less, 70 W / m·K or less, or 60 W / m·K or less, as needed. The thermal conductivity of the base 3 may represent an overall average value.

[0054] In the electrostatic chuck device 1, the outer peripheral portion 312 overlaps in plan with the peripheral edge portion of the electrostatic chuck member 2. This allows the outer peripheral side (periphery) of the wafer W, which tends to become relatively hot, to be effectively cooled via the peripheral edge portion of the electrostatic chuck member 2, thereby reducing the temperature difference within the surface of the wafer W. The inner peripheral portion 311 and the intermediate portion 313 are located inside the peripheral edge portion of the electrostatic chuck member 2 in a plan view.

[0055] The difference in thermal conductivity between the inner peripheral portion 311 and the outer peripheral portion 312 is preferably 15 W / m·K to 250 W / m·K, more preferably 20 W / m·K to 200 W / m·K. It may be 30 W / m·K to 150 W / m·K, 40 W / m·K to 100 W / m·K, or 60 W / m·K to 80 W / m·K. When the difference in thermal conductivity between the inner peripheral portion 311 and the outer peripheral portion 312 is within the above range, the outer peripheral side of the wafer W is relatively easier to cool than the inner peripheral side, and the outer peripheral side is not overcooled. Therefore, with this base 3, the outer peripheral side (peripheral edge) of the wafer W, which tends to become relatively hot, can be effectively cooled, thereby reducing the temperature difference within the wafer W. The thermal conductivity of the inner peripheral portion 311 is preferably, for example, 20 W / m·K to 80 W / m·K, and more preferably 40 W / m·K to 60 W / m·K, but is not limited to this example. The thermal conductivity of the outer peripheral portion 312 is preferably, for example, 40 W / m·K to 120 W / m·K, and more preferably 50 W / m·K to 100 W / m·K, but is not limited to this example.

[0056] The thermal conductivity of each part of the base 3 can be controlled by adjusting the volume ratio of the highly thermally conductive material in each part. The thermal conductivity of the base and each part can be determined as follows. For example, the thermal conductivity of the inner peripheral part can be measured using a thermal dilatometer. Any thermal dilatometer can be selected, and for example, a horizontal total expansion type thermal dilatometer (model number DIL402, manufactured by NETZSCH) can be used.

[0057] (Thermal Expansion Coefficient of Base) The base 3 is preferably formed using a material that can reduce the difference in thermal expansion coefficient from that of the dielectric substrate 11, taking into consideration the thermal expansion coefficient of the dielectric substrate 11.

[0058] For example, when the main component of the dielectric substrate 11 is aluminum oxide and is combined with silicon carbide, the thermal expansion coefficient of the dielectric substrate 11 is approximately equal to the thermal expansion coefficient of aluminum oxide (7.0 to 7.7 × 10 －６ / K) and the thermal expansion coefficient of silicon carbide (4.0 × 10 －６ / K). In this case, when a material having a thermal expansion coefficient larger than that of aluminum oxide is used as the conductive material contained in the base 3, it is advisable to combine a material having a thermal expansion coefficient relatively smaller than that of aluminum oxide as the highly thermally conductive material contained in the base 3. Such a material is, for example, AlN (thermal expansion coefficient 4.5×10 －６ / K) is preferred.

[0059] The overall thermal expansion coefficient of the base 3 is 6.0×10 －６ / K or more 9.0×10 －６ / K or less. －６ / K or more 8.5×10 －６ / K or less, 7.0 x 10 －６ / K or more 8.0×10 －６ When the thermal expansion coefficient of the base 3 is within the above range, the difference in thermal expansion with the dielectric substrate 11 containing mainly aluminum oxide can be easily reduced, and even when heated in the plasma process, internal stress is small, making it difficult for damage such as interfacial peeling to occur in the bonding layer.

[0060] The difference between the thermal expansion coefficient of the inner circumferential portion 311 and the thermal expansion coefficient of the outer circumferential portion 312 is preferably less than 2 ppm / K, more preferably less than 1.5 ppm / K, and even more preferably less than 1 ppm / K. The lower limit of the difference in thermal expansion coefficient between the inner circumferential portion 311 and the outer circumferential portion 312 is ideally 0 ppm / K. By keeping the difference in thermal expansion coefficient between the inner circumferential portion 311 and the outer circumferential portion 312 within the above range, damage at the interface between the inner circumferential portion 311 and the outer circumferential portion 312 can be suppressed. The thermal expansion coefficient of the inner circumferential portion 311 is, for example, 6.0×10 －６ / K ~ 9.0 x 10 －６ / K, and preferably 6.5×10 －６ / K~8.5 x 10 －６ / K, more preferably 7.0 × 10 －６ / K ~ 8.0 x 10 －６ The thermal expansion coefficient of the outer peripheral portion 312 is preferably, for example, 6.0×10 / K. －６ / K ~ 9.0 x 10 －６ / K, and preferably 6.5×10－６ / K~8.5 x 10 －６ / K, more preferably 7.0 × 10 －６ / K ~ 8.0 x 10 －６ / K is more preferable, but this is not the only example. The thermal expansion coefficient of each part can be determined, for example, as follows. For example, to determine the thermal expansion coefficient of the base and inner peripheral part, a test piece measuring 3 mm x 3 mm x 15 mm is obtained from the obtained conductive ceramic plate. Using this test piece, a thermal expansion measuring device, for example, a thermal expansion measuring device (TD5000SA, manufactured by NETZSCH), is used to measure the change in diameter length when the temperature is changed from 25°C to 800°C at a heating rate of 5°C / min, and the thermal expansion coefficient from 25°C to 800°C is determined. The determined thermal expansion coefficient is then divided by the temperature change width (ΔT = 800°C - 25°C = 775°C) to obtain the thermal expansion coefficient ( / K).

[0061] As an example, the base 3 may have an inner peripheral portion 311 made of an AlN-TiN composite sintered body and an outer peripheral portion 312 made of an AlN-Mo composite sintered body.

[0062] Intermediate portion 313 has physical properties, such as thermal conductivity and thermal expansion coefficient, that are between those of inner peripheral portion 311 and outer peripheral portion 312. Intermediate portion 313 includes a first high thermal conductivity material in inner peripheral portion 311 and a second high thermal conductivity material in outer peripheral portion 312. The volume fraction of the first high thermal conductivity material in intermediate portion 313 is smaller than that in inner peripheral portion 311. Furthermore, the volume fraction of the second high thermal conductivity material in intermediate portion 313 is smaller than that in outer peripheral portion 312.

[0063] Similarly, intermediate portion 313 includes a first conductive material in inner peripheral portion 311 and a second conductive material in outer peripheral portion 312. In intermediate portion 313, the volume fraction of the first conductive material is smaller than in inner peripheral portion 311. Also, in intermediate portion 313, the volume fraction of the second conductive material is smaller than in outer peripheral portion 312.

[0064] In the intermediate portion 313, the thermal conductivity may increase from the inner peripheral portion 311 side toward the outer peripheral portion 312 side, or may exhibit a uniform thermal conductivity. When the thermal conductivity increases from the inner peripheral portion 311 side toward the outer peripheral portion 312 side, the increase may be gradual, stepwise, or otherwise.

[0065] The base 3 may contain a sintering aid as long as it does not impair the effects of the present invention. The sintering aid is not particularly limited as long as it is a commonly added sintering aid, and examples thereof include Y ２ O ３ , MgO, SiO ２ , CaO, La ２ O ３ , Ce ２ O ３ Among these, at least one selected from Y ２ O ３ , MgO, SiO ２ is preferred.

[0066] The volume resistivity of the base 3 is 1.0×10 －６ Ω・cm or more 1.0×10 －３ It is preferable that the resistivity is 1.0×10 Ω cm or less. －５ Ω・cm or more 1.0×10 －４ When the volume resistivity of the base 3 is in the above range, sufficient conductivity can be obtained.

[0067] The thermal expansion coefficient of the base 3 as a whole is preferably equal to or nearly equal to that of the dielectric substrate 11. The absolute value of the difference between the thermal expansion coefficient of the base 3 and the thermal expansion coefficient of the dielectric substrate 11 is preferably 2.0 or less, more preferably 1.5 or less, even more preferably 1.3 or less, and even more preferably 1.0 or less.

[0068] The surface of the base 3 is preferably anodized to improve plasma resistance.

[0069] <Bonding Layer> In this embodiment, the bonding layer 4 is made of a metal material and bonds the electrostatic chuck member 2 and the base 3. The bonding layer 4 may be formed, for example, from an alloy containing 50% by volume to 99.98% by volume of Al or Ag and 0.02% by volume to 40% by volume of at least one metal selected from the group consisting of Ti, Zr, and Hf, assuming the entire bonding layer 4 to be 100% by volume. When the bonding layer 4 contains at least one metal selected from the group consisting of Ti, Zr, and Hf, the molten alloy formed by melting the material of the bonding layer 4 easily wets and spreads over the surface of the ceramic (electrostatic chuck member 2) during bonding between the electrostatic chuck member 2 and the base 3, facilitating bonding. Furthermore, when the bonding layer 4 contains the metal, the metal and the ceramic (electrostatic chuck member 2) are easily bonded to each other, preventing voids at the interface and enabling a strong bond.

[0070] The electrostatic chuck member 2 and the base 3 can be bonded to each other by any method, such as diffusion bonding of the members, or by applying a ceramic paste by printing or the like and bonding them by hot pressing or the like.

[0071] Furthermore, in order to suppress interfacial peeling between the electrostatic chuck member 2 and the bonding layer 4 due to a difference in thermal expansion between them, a stress relaxation layer may be provided therebetween using a material having a thermal expansion coefficient between the thermal expansion coefficients of the electrostatic chuck member 2 and the bonding layer 4. Based on the same technical concept, such a stress relaxation layer may also be provided between the base 3 and the bonding layer 4.

[0072] The thickness of the bonding layer 4 can be selected arbitrarily, but is preferably 0.005 mm or more and 0.5 mm or less.

[0073] When manufacturing the electrostatic chuck device 1, a metal foil or a metal paste obtained by adding a binder to metal powder may be used as the material for the bonding layer 4. These materials are placed between the electrostatic chuck member 2 and the base 3 and heated to a temperature equal to or higher than the melting point of the metal material that forms the bonding layer 4, and the molten metal material spreads between the electrostatic chuck member 2 and the base 3, thereby forming the bonding layer 4.

[0074] Such a bonding layer 4 is formed by brazing the electrostatic chuck member 2 and the base 3 using the material of the bonding layer 4. During brazing, the opposing surfaces of the electrostatic chuck member 2 and the base 3 are in contact with each other through molten brazing material, and are heated to the melting temperature of the brazing material (e.g., 800°C). Here, when the material of the base 3 is aluminum, the thermal expansion coefficient of the material of the base 3 is about 20×10 －６ On the other hand, the thermal expansion coefficient of the electrostatic chuck member 2 is 7.0 to 7.7×10 －６ / K).

[0075] Therefore, it is expected that a large tensile stress will be applied to the electrostatic chuck member 2 due to the difference in expansion coefficient between the opposing surfaces of the electrostatic chuck member 2 and the base 3, which are in contact with the molten brazing material. It is thought that this tensile stress may cause cracks to occur in the electrostatic chuck member 2.

[0076] In contrast, in the electrostatic chuck device 1, since the base 3 is made of the above material, cracks are less likely to occur in the electrostatic chuck member 2 when the electrostatic chuck member 2 and the base 3 are brazed together.

[0077] The bonding layer 4 may also have a laminated structure in which a pair of bonding layers sandwich a stress relaxation layer.

[0078] The stress relaxation layer is made of a material that is easily plastically deformed, and relieves thermal stress caused by the difference in thermal expansion coefficient between the electrostatic chuck member 2 and the base 3. The stress relaxation layer is made of a metal foil made of at least one metal selected from the group consisting of Cu, Al, and Ti, for example.

[0079] Alternatively, the Al constituting the electrostatic chuck member 2 may be used as the material for the stress relaxation layer. ２ O ３ Materials with a small difference in thermal expansion coefficient from Al can also be used. ２ O ３ Thermal expansion coefficient (7 to 7.7 × 10 －６ / K) and is used as a material for the stress relaxation layer. －６ / K), Nb (7.1 × 10 －６ / K), W (4.6 × 10 －６ / K).

[0080] The thickness of the stress relaxation layer can be selected arbitrarily, but is preferably 0.001 mm to 1 cm, and more preferably 1 mm to 1 cm. When the thickness of the stress relaxation layer falls within this range, thermal stress can be sufficiently relieved, and peeling between the electrostatic chuck member 2 and the base 3 can be suppressed.

[0081] The material of the pair of bonding layers has a lower melting point than the material of the stress relaxation layer. The pair of bonding layers may be made of the same material. The same material as the bonding layer 4 can be used for the pair of bonding layers.

[0082] The pair of bonding layers preferably have a thickness of 0.005 mm or more and 0.5 mm or less.

[0083] By providing the bonding layer 4 with the stress relaxation layer, the stress occurring at the interface between the base 3 and the electrostatic chuck member 2 is further relaxed, and peeling of the bonding layer 4 can be suppressed.

[0084] In addition, the electrostatic chuck device 1 can appropriately adopt any known configuration that is included in an electrostatic chuck device, as long as the effects of the invention are not impaired.

[0085] <Method of Manufacturing Base> FIGS. 3 to 7 are explanatory diagrams showing a method of manufacturing the base 3. FIG.

[0086] 3 to 5 show an example of a method for manufacturing a conductive ceramic plate, which is the material of the base 3. The conductive ceramic plate can be obtained by mixing a highly thermally conductive material and a conductive material in a predetermined range to obtain a raw material powder, and then using the obtained raw material powder to manufacture ceramics by a known method. For example, the conductive ceramic plate can be manufactured by the following steps: a step of mixing a highly thermally conductive material and a conductive material in a volume ratio of 30:70 to 60:40 to obtain a raw material powder (mixing step); a step of applying pressure to the obtained raw material powder to obtain a molded body (molding step); and a step of pressure-sintering the obtained molded body to obtain a conductive ceramic plate (pressure sintering step).

[0087] The average primary particle size of the highly thermally conductive material is not particularly limited as long as a conductive ceramic plate can be obtained. For example, a highly thermally conductive material of 0.5 μm to 5 μm can be used. The particle size may be 0.8 μm to 4.5 μm, 1.0 μm to 4.0 μm, 1.5 μm to 3.5 μm, or 2.0 μm to 3.0 μm. The average primary particle size of the conductive material is not particularly limited as long as a conductive ceramic plate can be obtained. For example, a conductive material of 0.5 μm to 5 μm can be used. The particle size may be 0.8 μm to 4.5 μm, 1.0 μm to 4.0 μm, 1.5 μm to 3.5 μm, or 2.0 μm to 3.0 μm. A preferred particle size can be selected depending on the required conditions.

[0088] (Mixing step) In the mixing step, the mixing method is not particularly limited as long as it is possible to mix the highly thermally conductive material and the electrically conductive material to obtain a raw material powder, but it is preferable to mix the highly thermally conductive material and the electrically conductive material with an appropriate dispersant or solvent to prevent them from agglomerating, and to mix them using a mixing device such as a disperser. The mixing device is not particularly limited, and general devices such as a ball mill, planetary mill, bead mill, atomizer, etc. can be used.

[0089] After mixing the raw material powders, a drying step may be carried out. The drying method may be natural drying, a dryer, or spray drying to form granules of 30 to 100 μm from the raw material powders.

[0090] After the mixing step or the drying step, the raw material powder may be heated in a non-oxidizing atmosphere at 300° C. or higher and 600° C. or lower to remove impurities such as moisture, solvents, and dispersants contained in the raw material powder.

[0091] The non-oxidizing atmosphere is preferably an inert gas atmosphere using nitrogen or argon. When the heating is performed under an inert gas atmosphere, it is preferable to perform the heating treatment under a gas flow, in which the atmospheric gas is made to flow, in order to efficiently discharge the generated impurities out of the system.

[0092] By the above method, the raw material powder for the inner peripheral portion 311 and the raw material powder for the outer peripheral portion 312 are prepared.

[0093] (Forming step) In the forming step, the obtained raw material powder is subjected to pressure by a mold forming method or the like according to the shape of the desired conductive ceramic plate, preferably uniaxial forming (uniaxial press forming) to obtain a molded body of the desired shape.

[0094] In this embodiment, as shown in FIG. 3 , a cylindrical inner frame F is placed inside the mold M, and then raw material powder 311A ​​of the inner peripheral portion 311 is filled inside the inner frame F, and raw material powder 312A of the outer peripheral portion 312 is filled outside the inner frame F.

[0095] The inner frame F has a shape and size corresponding to the shape and size of the inner peripheral portion 311 of the base 3. In the case of the base 3 shown in Figure 2, a cylindrical inner frame F having a diameter equal to or approximately equal to the diameter of the inner peripheral portion 311 is used.

[0096] Next, as shown in Fig. 4, inner frame F is removed from mold M. As a result, raw material powder 311A ​​and raw material powder 312A flow into the position where inner frame F was located and mix with each other to generate raw material powder 313A in intermediate portion 313. In raw material powder 313A, the composition (e.g., the volume fraction of the conductive material) may change continuously or discontinuously from the inside to the outside of mold M, or may be a uniform composition.

[0097] In this way, raw material powder 313A is a mixed powder obtained by mixing raw material powder 311A ​​and raw material powder 312A, and the volume ratio of the highly thermally conductive material to the electrically conductive material is the ratio between raw material powder 311A ​​and raw material powder 312A. Furthermore, the thickness of inner frame F correlates with the volume of middle portion 313; if inner frame F is thick, the width of middle portion 313 formed will be wide, and if inner frame F is thin, the width of middle portion 313 formed will be narrow.

[0098] Next, as shown in FIG. 5, the upper part of the mold M filled with the raw material powders 311A, 312A, and 313A is closed, and pressure P is applied to perform uniaxial press molding.

[0099] (Pressure Sintering Step) In the pressure sintering step, the compact obtained in the molding step is pressure-sintered by heating to a temperature of, for example, 1600°C or higher while compacting under a vacuum or a non-oxidizing atmosphere at a pressure of, for example, 5 MPa or higher. This procedure allows the highly thermally conductive material and electrically conductive material contained in the compact to be sintered, resulting in a dense sintered body with few pores. The temperature can be selected as needed, and may be 1600 to 1900°C or 1650 to 1800°C, for example. The heating time can be selected as needed, and may be, for example, 1 to 5 hours, 3 to 8 hours, or 6 to 12 hours.

[0100] As a result, raw material powders 311A, 312A, and 313A become inner peripheral portion 311, outer peripheral portion 312, and intermediate portion 313, respectively, to obtain conductive ceramic plates that are the material of base 3. It is preferable that each of the conductive ceramic plates has a constant thickness that can be selected arbitrarily.

[0101] (Method 1 for Manufacturing Base) In manufacturing method 1 of this embodiment, the base 3 is obtained by processing the conductive ceramic plate obtained by the above-mentioned method into the desired shape of the base 3. Figures 6 and 7 are explanatory views showing an example of a method for manufacturing the base 3. The base 3 may be composed of portions resulting from two conductive ceramic plates, or may be composed of portions resulting from three conductive ceramic plates, for example. It is preferable that at least one conductive ceramic plate has an inner peripheral portion, a middle portion, and an outer peripheral portion.

[0102] 6, two conductive ceramic plates are prepared, and a continuous groove portion 30x having a band shape in a plan view is formed on one surface 30a of at least one of the conductive ceramic plates 30 of the pair of conductive ceramic plates 30, 31. The groove portion 30x can be formed by any method selected, for example, by known die-sinking electrical discharge machining or copying machining.

[0103] The "pair of conductive ceramic plates" may have the same or different compositions and characteristics. In this embodiment, the pair of conductive ceramic plates have the same composition, shape in plan view, and arrangement of the inner peripheral portion 311, the outer peripheral portion 312, and the intermediate portion 313, but differ in thickness and the presence or absence of grooves. Note that only one of the pair of conductive ceramic plates 30, 31 may have an inner peripheral portion, an intermediate portion, and an outer peripheral portion, while the other conductive ceramic plate may have a uniform composition without an inner peripheral portion, an intermediate portion, and an outer peripheral portion. For example, the other conductive ceramic plate may be formed from the same material in the portions corresponding to the inner peripheral portion or the outer peripheral portion. For example, the other conductive ceramic plate may be formed from a material with high thermal conductivity or may be formed from the same material as the outer peripheral portion.

[0104] The grooves 30x may be uniformly of the same depth, or may have different depths.

[0105] Next, the pair of conductive ceramic plates 30, 31 are overlapped and diffusion bonded with the groove 30x facing the other conductive ceramic plate 31. The space surrounded by the groove 30x and the opposing surface 31a of the conductive ceramic plate 31 becomes a flow path 3f (see FIG. 1) through which a refrigerant flows. Note that diffusion bonding is a method in which the conductive ceramic plates are brought into close contact with each other, pressurized at a temperature below the melting point of the base material, and bonded using atomic diffusion between the bonding surfaces.

[0106] 7, three conductive ceramic plates are first prepared, and through-holes 35x that are continuous and strip-shaped in plan view are formed in one surface of one of the plates, substrate 35. The through-holes 35x can be formed using known wire electric discharge machining or the like.

[0107] Next, the substrate 35 is sandwiched and bonded between the remaining two conductive ceramic plates 36 and 37. The space surrounded by the through hole 35x and the opposing surfaces 36a and 37a of the conductive ceramic plates 36 and 37 becomes a flow path 3f (see FIG. 1) through which the refrigerant flows.

[0108] In this way, the base 3 can be manufactured. By using the same composition and structure for the conductive ceramic plates 30, 31, or the substrate 35 and the conductive ceramic plates 36, 37, the obtained base 3 has a single composition that does not contain other materials such as adhesives.

[0109] The obtained base 3 can be superimposed on and bonded to the electrostatic chuck member 2 via a bonding member (described later) to form the electrostatic chuck device 1. Note that, in this example, at least one of the substrate 35 and the conductive ceramic plates 36, 37 may have an inner periphery, an intermediate portion, and an outer periphery, while the remaining plates or substrates may have a uniform composition overall without having an inner periphery, an intermediate portion, and an outer periphery. For example, only one of the substrate 35 and the conductive ceramic plates 36 may have an inner periphery and an outer periphery, or an inner periphery, an intermediate portion, and an outer periphery. The remaining conductive ceramic plates may be formed, for example, from the same material in the portions corresponding to the inner periphery or the outer periphery. For example, at least one of the remaining conductive ceramic plates may be formed from a material with high thermal conductivity or from the same material as the outer periphery.

[0110] Although the method for manufacturing the base has been described above as a method for uniaxially pressing the powder material and sintering it at high pressure and high temperature, other methods can also be used. (Base Manufacturing Method 3) For example, the base can be manufactured by adding a resin or the like to the powder material to create green sheets (flexible sheets before sintering), stacking the green sheets, and firing them.

[0111] In this case, for example, green sheet 1 for the inner peripheral portion and green sheet 2 for the outer peripheral portion, each having a different composition, are prepared, and then green sheet 1 is processed into a circular shape in plan view and green sheet 2 into a ring shape in plan view. Then, the two are combined and fired to form a base. In this case, the peripheral portion of the circular member prepared from green sheet 1 and the inner peripheral portion of the ring-shaped member prepared from green sheet 2 can each be formed into any shape. For example, the peripheral portion and the inner peripheral portion can be processed into tapered surfaces with complementary inclinations, more specifically, complementary slopes. Using green sheets with such a configuration allows for a strong bond between the two. Furthermore, by forming them in this manner, it is possible to obtain green sheets having inner and outer peripheral portions, or green sheets having an inner peripheral portion, a middle portion, and an outer peripheral portion.

[0112] Furthermore, when using the above-described green sheets, the green sheets may be processed to form structures corresponding to the grooves 30x and through-holes 35x, and then processed and / or unprocessed green sheets may be selected as necessary, stacked, and fired to produce a base. In this case, the depth and position of the flow paths can be controlled by changing the number and positions of the through-holes that communicate with each other when the green sheets are stacked. The number of stacked green sheets can be selected arbitrarily, and one or more of the green sheets may be a green sheet having an inner peripheral portion and an outer peripheral portion, or a green sheet having an inner peripheral portion, a middle portion, and an outer peripheral portion.

[0113] 8 and 9 are plan views showing modified examples of the conductive ceramic plate and the base.

[0114] The conductive ceramic plate 38 of modified example 1 shown in Figure 8 has an inner peripheral portion 321, an outer peripheral portion 322 that surrounds the outside of the inner peripheral portion 321 in a closed ring shape in a planar view, and an intermediate portion 323 that is provided between the inner peripheral portion 321 and the outer peripheral portion 322 in a planar view and is in contact with the inner peripheral portion 321 and the outer peripheral portion 322.

[0115] Unlike the base 3 described above, the conductive ceramic plate 38 has an intermediate portion 323 that is not annular in plan view, but has multiple arc portions 323A (four equally spaced circumferentially in the figure) along an imaginary circle VC, and multiple protrusions 323B (four equally spaced circumferentially in the figure) provided between the arc portions 323A. The protrusions 323B protrude outward from the imaginary circle VC. The four protrusions 323B have the same shape in plan view. The center of the imaginary circle VC and the center of the base 3B coincide. The number of arc portions 323A and protrusions 323B can be selected arbitrarily, and may be, for example, 4 to 6, 7 to 12, or 13 to 20.

[0116] 6 and 7, the base 3B can be manufactured using such conductive ceramic plates 38. When manufacturing the base 3B, the conductive ceramic plates 38 are stacked in the vertical direction so that the convex portions 323B thereof completely overlap each other in a plan view, or so that the convex portions 323B partially overlap each other, or so that the convex portions 323B are shifted in the circumferential direction so as not to overlap each other.

[0117] Furthermore, the conductive ceramic plate 39 of variant example 2 shown in Figure 9, like the other examples, has an inner circumferential portion 331, an outer circumferential portion 332 surrounding the outside of the inner circumferential portion 331, and an intermediate portion 333 provided between the inner circumferential portion 331 and the outer circumferential portion 332 and in contact with the inner circumferential portion 331 and the outer circumferential portion 332.

[0118] In the conductive ceramic plate 39, the intermediate portion 333 has a wavy shape in plan view, with convex portions 333A and concave portions 333B periodically repeating in the circumferential direction. Here, assuming a maximum imaginary circle VC1 inscribed in the intermediate portion 333 in plan view and a minimum imaginary circle VC2 concentric with the imaginary circle VC1 and circumscribed around the intermediate portion 333, the imaginary circle at the midpoint between the imaginary circles VC1 and VC2 is defined as imaginary circle VC3. The radius D3 of the imaginary circle VC3 is the average value of the radius D1 of the imaginary circle VC1 and the radius D2 of the imaginary circle VC2. The convex portions 333A are portions that protrude outward from the imaginary circle VC3, and the concave portions 333B are portions that are recessed inward from the imaginary circle VC3. The number of alternating convex portions 333A and concave portions 333B can be selected arbitrarily, and may be, for example, 6 to 10, 11 to 16, or 17 to 24.

[0119] 6 and 7, the base 3C can be manufactured using such conductive ceramic plates 39. When manufacturing the base 3C, the conductive ceramic plates 39 are stacked in the vertical direction so that the convex portions 333A of the plates 39 completely overlap each other in a plan view, or so that the convex portions 333A partially overlap each other, or so that the convex portions 333A are shifted in the circumferential direction so as not to overlap each other.

[0120] The base (temperature adjustment member) 3 having the above-described configuration can suitably adjust the temperature at the peripheral portion of the wafer W placed on the electrostatic chuck device 1. Furthermore, the electrostatic chuck device 1 having the above-described configuration has the base 3 and can suitably adjust the temperature at the peripheral portion of the wafer W.

[0121] In the above embodiment, the base has the intermediate portion having the above-described shape, but the intermediate portion may not be present, or the presence of the intermediate portion may not be visible when the base is viewed from above. In this case, in each base of the above example, the shape of the boundary portion between the inner periphery and the outer periphery may be the same as the shape of the edge of the intermediate portion when the intermediate portion is present (for example, the shape of the boundary portion between the intermediate portion and the outer periphery).

[0122] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. The shapes and combinations of the components shown in the above examples are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0123] REFERENCE SIGNS LIST 1 Electrostatic chuck device 2 Electrostatic chuck member 2a Lower surface of electrostatic chuck member 3, 3B, 3C Base (temperature adjustment member) 3a Upper surface (support surface) of base 3f Flow path 4 Bonding layer 5 High frequency power supply 11 Dielectric substrate 13 Adsorption electrode 15 Adsorption electrode 21 First adsorption portion 21a Wafer mounting surface 21x Flow path 22 Second adsorption portion 22a Upper surface of second adsorption portion 22x Groove portion of second adsorption portion 30, 35, 36, 37, 38, 39 Conductive ceramic plate 30a One surface of conductive ceramic plate 30x Groove portion 31 Other conductive ceramic plate 31a, 36a, 37a Opposing surface of other conductive ceramic plate 35x Through hole 211 Convex portion 311, 321, 331 Inner peripheral portion 311A, 312A, 313A Raw material powder 311f Inner peripheral flow path 312, 322, 332 Outer peripheral portion 312f Outer peripheral flow path 313, 323, 333 Intermediate portion 323A Circular arc portion 323B Convex portion 333A Convex portion 333B Concave portion D1, D2, D3 Radius of virtual circle F Inner frame FR Focus ring M Mold Ma Inside P Pressure VC Virtual circle VC1 Maximum virtual circle VC2 Minimum virtual circle VC3 Virtual circle at intermediate position W Wafer

Claims

1. A temperature adjustment member for supporting an electrostatic chuck member, comprising, at least in part, an inner peripheral portion and an outer peripheral portion having different thermal conductivities, the inner peripheral portion being formed of a first conductive ceramic containing a first high thermal conductive material and a first conductive material, and the outer peripheral portion being formed of a second conductive ceramic containing a second high thermal conductive material and a second conductive material, and surrounding the outside of the inner peripheral portion in a closed ring shape in a plan view, and the outer peripheral portion having a higher thermal conductivity than the inner peripheral portion.

2. A temperature adjustment member as described in claim 1, which has an intermediate portion that is provided between the inner peripheral portion and the outer peripheral portion in a plan view and that contacts the inner peripheral portion and the outer peripheral portion, the intermediate portion being formed of a third conductive ceramic that includes the first high thermal conductivity material, the second high thermal conductivity material, and the first conductive material and the second conductive material, and has a thermal conductivity higher than that of the inner peripheral portion and lower than that of the outer peripheral portion.

3. A temperature adjustment member according to claim 1 or 2, wherein the area of ​​the inner peripheral portion in a plan view is 55% to 95% of the area of ​​the temperature adjustment member in a plan view.

4. A temperature adjusting member according to claim 1 or 2, wherein the difference in thermal conductivity between the inner peripheral portion and the outer peripheral portion is 15 W / m·K or more and 250 W / m·K or less.

5. A temperature adjusting member according to claim 1 or 2, wherein the difference between the thermal expansion coefficient of the inner peripheral portion and the thermal expansion coefficient of the outer peripheral portion is less than 2 ppm / K.

6. An electrostatic chuck device comprising: a temperature adjustment member according to claim 1 or 2; and an electrostatic chuck member having a dielectric substrate and an electrostatic attraction electrode and supported by said temperature adjustment member, wherein said electrostatic chuck member overlaps with said outer periphery in a plan view.

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