Electrostatic chuck device and method for manufacturing electrostatic chuck device

Abstract

The present invention employs an electrostatic chuck device including an electrostatic chuck member having an electrode therein, a temperature adjustment base member, and a bonding layer for bonding the electrostatic chuck member and the temperature adjustment base member, wherein: the bonding layer includes a spherical filler and a resin; the filler includes a first filler and a second filler; the thermal conductivity of the first filler is 180 W / (m·K) or more; the thermal conductivity of the second filler is 180 W / (m·K) or more; the primary particle diameter of the first filler is 2 μm to 15 μm (exclusive of 15 μm); the primary particle diameter of the second filler is 15 μm to 50 μm; the total content of the first filler and the second filler in the bonding layer is 50 volume% to 90 volume%; and the content of the first filler with respect to the total of the first filler and the second filler is 10 volume% to 50 volume%.

Description

Electrostatic chuck device and method for manufacturing an electrostatic chuck device

[0001] The present invention relates to an electrostatic chuck device and a method for manufacturing an electrostatic chuck device. This application claims priority based on Japanese Patent Application No. 2025-056512, filed on March 28, 2025, the contents of which are incorporated herein by reference.

[0002] Conventionally, in semiconductor manufacturing processes for producing semiconductor devices such as ICs, LSIs, and VLSIs, plate-shaped samples such as silicon wafers are fixed to an electrostatic chuck member equipped with an electrostatic chuck function by electrostatic adsorption and subjected to predetermined processing. However, when, for example, etching is performed on this plate-shaped sample under a plasma atmosphere, the surface of the plate-shaped sample becomes hot due to the heat of the plasma, and problems such as the resist film on the surface cracking (bursting) can occur. Therefore, an electrostatic chuck device is used to maintain the temperature of this plate-shaped sample at a desired constant temperature. The electrostatic chuck device is a device in which a temperature-regulating base member, which has a flow channel formed inside a metal member for circulating a temperature-controlling cooling medium, is joined and integrated to the lower surface of the electrostatic chuck member described above via a resin-based adhesive. In such an electrostatic chuck device, heat exchange is performed by circulating a temperature-regulating cooling medium through the flow channel of the temperature-regulating base member. By performing the aforementioned heat exchange, the temperature of the plate-shaped sample fixed to the upper surface of the electrostatic chuck member is maintained at a desired constant temperature, the plate-shaped sample is electrostatically adsorbed, and various plasma treatments are applied to the plate-shaped sample.

[0003] Incidentally, in such electrostatic chuck devices, in order to maintain the temperature of the plate-shaped sample at a desired constant temperature, it is required that the temperature variation of the adsorption surface for the plate-shaped sample on the electrostatic chuck member be small. To achieve this, it is necessary to increase the heat exchange efficiency between the electrostatic chuck member and the temperature-regulating base member. Furthermore, it is necessary to improve the thermal conductivity of the bonding layer that joins the electrostatic chuck member and the temperature-regulating base member. In order to improve the thermal conductivity of the resin-based adhesive, various high thermal conductivity fillers, such as alumina (Al), are added to the resin-based adhesive. ２ O ３ ), silicon dioxide (SiO ２), ceramic powders such as aluminum nitride (AlN) or metal powders such as aluminum (Al) are sometimes mixed in (see, for example, Patent Documents 1 and 2).

[0004] Japanese Patent Publication No. 2011-222979 Japanese Patent Publication No. 2019-165184

[0005] In semiconductor manufacturing, the power of the plasma used for etching is increasing dramatically. Therefore, further improvements in thermal conductivity of the bonding layer are required for heat dissipation control. However, increasing the filler content in the bonding layer to achieve higher thermal conductivity has resulted in a problem of weakened adhesive strength.

[0006] The present invention has been made in view of the above problems, and the object of the present invention is to provide an electrostatic chuck device having a bonding layer that achieves both high thermal conductivity and high adhesive strength.

[0007] To solve the above problems, a first aspect of the present invention provides the configuration of (1) below. (1) An electrostatic chuck device comprising: an electrostatic chuck member having electrodes inside; a temperature-regulating base member; and a bonding layer that bonds the electrostatic chuck member and the temperature-regulating base member, wherein the bonding layer comprises a spherical filler and a resin, the filler comprises a first filler and a second filler, the thermal conductivity of the first filler is 180 W / (m·K) or more, the thermal conductivity of the second filler is 180 W / (m·K) or more, the primary particle diameter of the first filler is 2 μm or more and less than 15 μm, the primary particle diameter of the second filler is 15 μm or more and 50 μm or less, the content of the filler in the bonding layer is 50 volume% or more and 90 volume% or less, and the content of the first filler relative to the sum of the first and second fillers is 10 volume% or more and 50 volume% or less. The apparatus of the first embodiment of the present invention preferably has the following features. It is also preferable to combine two or more of the following features. (2) The electrostatic chuck apparatus according to (1), wherein the thermal conductivity of the bonding layer is 3.0 W / (m·K) or more. (3) The electrostatic chuck apparatus according to (1) or (2), wherein the filler further comprises a spherical third filler, the primary particle diameter of the third filler is 0.05 μm or more and less than 2 μm, the thermal conductivity of the third filler is 30 W / (m·K) or more, the content of the first filler relative to the total of the first filler, the second filler and the third filler is 5 volume% or more and 45 volume% or less, the content of the second filler is 50 volume% or more and 90 volume% or less, and the content of the third filler is 1 volume% or more and 25 volume% or less. (4) The electrostatic chuck device according to any one of (1) to (3), wherein the thermal conductivity of the bonding layer is 4.0 W / (m·K) or more, the difference between the minimum and maximum values ​​of the thermal conductivity of the bonding layer measured at three arbitrary points on the bonding layer is 0.3 W / (m·K) or less, and the resin is at least one selected from the group consisting of silicone resin, acrylic resin, epoxy resin, and polyimide resin.(5) The electrostatic chuck device according to any one of (1) to (4), wherein the bonding layer comprises a first layer containing the filler and a pair of second layers formed only from a resin without the filler and sandwiching the first layer. (6) The electrostatic chuck device according to any one of (1) to (5), wherein the first filler and the second filler are formed from the same material or from different materials, and the first filler and the second filler are each aluminum oxide particles or aluminum nitride particles. (7) The electrostatic chuck device according to any one of (3) to (5), wherein the first filler, the second filler and the third filler are formed from the same material, or at least one of these fillers is formed from a different material, and the first filler, the second filler and the third filler are each aluminum oxide particles or aluminum nitride particles. A second aspect of the present invention provides the following manufacturing method (8). (8) A method for manufacturing an electrostatic chuck device according to any one of (5) to (7), comprising: a step of forming a first coating film containing a precursor of the resin before curing on one surface of the electrostatic chuck member; a step of forming a second coating film containing a precursor of the resin before curing on the surface of the temperature-regulating base member facing the electrostatic chuck member; a step of forming a laminate by laminating the electrostatic chuck member, the sheet adhesive and the temperature-regulating base member such that a sheet adhesive containing at least the filler and the resin is sandwiched between the first coating film and the second coating film; and a step of pressing and heating the electrostatic chuck device including the obtained laminate to bond the laminate. The method of the second aspect of the present invention preferably has the following features. It is also preferable to combine two or more of the following features.(9) A method for manufacturing an electrostatic chuck device according to (8), comprising the step of preparing the sheet adhesive, the step of mixing an organic solvent, the resin precursor, and the filler so that the amount of the filler is 50% by volume or more and 90% by volume or less relative to the total content of the resin precursor and the filler, to form a mixed liquid; the step of applying the mixed liquid to a release substrate to form a coating film and drying the coating film to semi-cure it; and the step of peeling the coating film from the release substrate to obtain the sheet adhesive. (10) A method for manufacturing an electrostatic chuck device according to (8) or (9), comprising the step of mixing the resin precursor before curing with an organic solvent to prepare a mixed liquid, the step of forming the first coating film comprising the step of applying the mixed liquid to one surface of the electrostatic chuck member to form the first coating film, and the step of forming the second coating film comprising the step of applying the mixed liquid to the opposing surface of the temperature adjustment base member to form the second coating film.

[0008] According to the present invention, it is possible to provide an electrostatic chuck device having a bonding layer that achieves both high thermal conductivity and high adhesive strength.

[0009] Figure 1 is a schematic cross-sectional view showing one embodiment. Figure 2 is an enlarged schematic cross-sectional view showing a portion of Figure 1.

[0010] Hereinafter, preferred examples of an electrostatic chuck device and a method for manufacturing an electrostatic chuck device according to this embodiment will be described with reference to Figures 1 and 2. In the following drawings, the dimensions and proportions of each component may be changed as appropriate for the sake of clarity. Furthermore, the following description is intended to provide a concrete explanation to better understand the spirit of the invention and does not limit the present invention unless otherwise specified. For example, unless otherwise specified, conditions such as material, quantity, type, number, size, shape, position, and proportion may be changed, added, or omitted as necessary. The embodiments and modifications shown below may share preferred conditions and limitations with each other unless there is a particular problem.

[0011] The electrostatic chuck device of this embodiment is an electrostatic chuck device having an electrostatic chuck member having electrodes inside, a temperature-regulating base member, and a bonding layer that bonds the electrostatic chuck member and the temperature-regulating base member, wherein the bonding layer contains a spherical filler and a resin, the filler contains a first filler (filler A) and a second filler (filler B), the thermal conductivity of the first filler is 180 W / (m·K) or more, the thermal conductivity of the second filler is 180 W / (m·K) or more, the primary particle diameter of the first filler is 2 μm or more and less than 15 μm, the primary particle diameter of the second filler is 15 μm or more and 50 μm or less, the filler content in the bonding layer is 50 volume% or more and 90 volume% or less, and the content of the first filler relative to the filler is 10 volume% or more and 50 volume% or less.

[0012] Conventional adhesives had a problem in that while increasing the particle filling density improved thermal conductivity, it tended to worsen adhesive performance. Therefore, the inventors diligently investigated the preparation conditions, such as the shape and content of the filler contained in the bonding layer. As a result, they found that an excellent electrostatic chuck device could be obtained that had a bonding layer that achieved both high thermal conductivity and good adhesive performance. Preferred examples of embodiments of the electrostatic chuck device and its manufacturing method of the present invention will now be described.

[0013] <Electrostatic Chuck Device> A preferred example of the electrostatic chuck device in this embodiment will be described below with reference to Figure 1.

[0014] Figure 1 is a schematic cross-sectional view showing an electrostatic chuck device according to one embodiment of the present invention. As shown in Figure 1, the electrostatic chuck device 1 has a disc-shaped electrostatic chuck member 2 in plan view, a disc-shaped temperature-adjusting base member 3 for adjusting the electrostatic chuck member 2 to a desired temperature, and a bonding layer 4 for joining and integrating the electrostatic chuck member 2 and the temperature-adjusting base member 3. In the following description, the mounting surface 11a side of the mounting plate 11 may be referred to as "upper" and the temperature-adjusting base member 3 side as "lower" to indicate the relative positions of each component.

[0015] [Electrostatic Chuck Member] The electrostatic chuck member 2 comprises at least a mounting plate 11, an electrostatic adsorption electrode 13, an insulating material 14, and a support plate 12. The mounting plate 11 is made of ceramics, with its upper surface being a mounting surface 11a on which a plate-shaped sample such as a semiconductor wafer is placed. The support plate 12 is provided on the side of the mounting plate 11 opposite to the mounting surface 11a. The electrostatic adsorption electrode 13 is sandwiched between the mounting plate 11 and the support plate 12. An annular insulating material 14 is provided so as to surround the electrostatic adsorption electrode 13, which is sandwiched between the mounting plate 11 and the support plate 12. The electrostatic chuck member 2 also has a power supply terminal 16 provided in a fixing hole 15 of the support plate 12 so as to be in contact with the electrostatic adsorption electrode 13.

[0016] These mounting plate 11, support plate 12, and electrostatic adsorption electrode 13 are provided with a number and position of cooling gas introduction holes 17 that continuously penetrate in the thickness direction. In this embodiment, multiple holes, for example, a total of four, are formed at positions that are rotationally symmetric with respect to the central axis. The cooling gas introduced through the cooling gas introduction holes 17 is used to cool the plate-shaped sample, as will be described later.

[0017] [Mounting Plate] Preferably, the mounting surface 11a of the mounting plate 11 has numerous protrusions (not shown) erected on it for supporting plate-shaped samples such as semiconductor wafers. The height, number, and position of the protrusions can be arbitrarily selected. Furthermore, preferably, a peripheral wall (not shown) is formed around the periphery of the mounting surface 11a of the mounting plate 11, with a width of, for example, 1 mm or more and 5 mm or less, and a height equal to that of the above-mentioned protrusions, to prevent leakage of cooling gas such as helium (He). The inside of this peripheral wall is an adsorption region for electrostatically adsorbing the plate-shaped sample. Cooling gas is supplied to the gap between the mounting surface 11a of the mounting plate 11 and the plate-shaped sample placed on the top surface of the protrusions via the above-mentioned cooling gas introduction hole 17. The mounting plate 11 may be circular in plan view, for example.

[0018] The ceramic material constituting the mounting plate 11 has a volume resistivity of 10 １３ Ω·cm or more and 10 １５It is not particularly limited as long as it has a resistivity of about Ω·cm or less, has mechanical strength, and has durability against corrosive gas and plasma thereof. As such ceramics, for example, aluminum oxide (Al ２ O ３ ) sintered bodies, aluminum nitride (AlN) sintered bodies, aluminum oxide (Al ２ O ３ )-silicon carbide (SiC) composite sintered bodies and the like are suitably used. The volume resistivity value is, for example, 10 １３ Ω·cm or more and 10 １４ Ω·cm or less, or 10 １４ Ω·cm or more and 10 １５ Ω·cm or less may be used.

[0019] The thickness of the mounting plate 11 can be arbitrarily selected, but is preferably 0.3 mm or more and 3.0 mm or less, and more preferably 0.5 mm or more and 1.5 mm or less. It may be 0.7 mm or more and 2.3 mm or less, 1.0 mm or more and 2.0 mm or less, 1.2 mm or more and 1.8 mm or less, or the like. When the thickness of the mounting plate 11 is 0.3 mm or more, the voltage resistance is excellent. On the other hand, when the thickness of the mounting plate 11 is 3.0 mm or less, the electrostatic adsorption force of the electrostatic chuck member 2 does not decrease, and the thermal conductivity between the plate-shaped sample mounted on the mounting surface 11a of the mounting plate 11 and the temperature adjustment base member 3 does not decrease, so that the temperature of the plate-shaped sample during processing can be maintained at a preferable constant temperature.

[0020] [Support Plate] The support plate 12 supports the mounting plate 11 and the electrostatic chuck electrode 13 from below.

[0021] The support plate 12 is made of the same material as the ceramics that make up the mounting plate 11. The support plate 12 and the mounting plate 11 may be made of exactly the same material. The support plate 12 may be circular in plan view, for example. The thickness of the support plate 12 can be arbitrarily selected, but it is preferably 0.3 mm or more and 3.0 mm or less, and more preferably 0.5 mm or more and 1.5 mm or less. It may also be 0.7 mm or more and 2.3 mm or less, 1.0 mm or more and 2.0 mm or less, or 1.2 mm or more and 1.8 mm or less. If the thickness of the support plate 12 is 0.3 mm or more, sufficient dielectric strength can be ensured. On the other hand, if the thickness of the support plate 12 is 3.0 mm or less, the electrostatic adsorption force of the electrostatic chuck member 2 will not decrease, the thermal conductivity between the plate-shaped sample placed on the mounting surface 11a of the mounting plate 11 and the temperature adjustment base member 3 will not decrease, and the temperature of the plate-shaped sample during processing can be maintained at a preferred constant temperature. The mounting plate 11 and the support plate 12 may be of the same thickness, or they may be of different thicknesses.

[0022] [Electrostatic Adsorption Electrode] The electrostatic adsorption electrode 13 is located between the mounting plate 11 and the support plate 12 and is not exposed to the outside. By applying a voltage to the electrostatic adsorption electrode 13, an electrostatic adsorption force is generated to hold the plate-shaped sample on the mounting surface 11a of the mounting plate 11.

[0023] The materials constituting the electrostatic adsorption electrode 13 can be arbitrarily selected, but high-melting-point metals such as titanium, tungsten, molybdenum, and platinum, carbon materials such as graphite and carbon, and conductive ceramics such as silicon carbide, titanium nitride, and titanium carbide are preferably used. It is desirable that the thermal expansion coefficients of these materials approximate the thermal expansion coefficient of the mounting plate 11 as closely as possible.

[0024] Although the thickness of the electrostatic chuck electrode 13 can be arbitrarily selected, for example, it is preferably 5 µm or more and 200 µm or less, and more preferably 10 µm or more and 100 µm or less. It may also be 20 µm or more and 150 µm or less, or 30 µm or more and 60 µm or less. If the thickness of the electrostatic chuck electrode 13 is 5 µm or more, sufficient conductivity can be ensured. On the other hand, if the thickness of the electrostatic chuck electrode 13 is 200 µm or less, the thermal conductivity between the plate-shaped sample placed on the placement surface 11a of the placement plate 11 and the temperature adjustment base member 3 will not decrease, and the temperature of the plate-shaped sample during processing can be maintained at a desired constant temperature. In addition, plasma permeability does not decrease, and plasma can be stably generated.

[0025] The electrostatic chuck electrode 13 can be formed by any method, and for example, can be easily formed by a film formation method such as sputtering or vapor deposition, or a coating method such as screen printing.

[0026] [Insulating Material] The insulating material 14 surrounds the electrostatic chuck electrode 13 and is for protecting the electrostatic chuck electrode 13 from corrosive gas and plasma thereof. The insulating material 14 is composed of an insulating material having the same composition as the mounting plate 11 and the support plate 12, or the same main component. By means of the insulating material 14, the mounting plate 11 and the support plate 12 are joined and integrated via the electrostatic chuck electrode 13.

[0027] [Power Feed Terminal] The power feed terminal 16 is for applying a voltage to the electrostatic chuck electrode 13. The number, shape, and the like of the power feed terminals 16 can be determined depending on the form of the electrostatic chuck electrode 13, for example, whether it is a unipolar electrode or a bipolar electrode.

[0028] The material of the power feed terminal 16 is not particularly limited as long as it is a conductive material excellent in heat resistance. As the material of the power feed terminal 16, it is preferable that the coefficient of thermal expansion approximates the coefficients of thermal expansion of the electrostatic chuck electrode 13 and the support plate 12. As the material of the power feed terminal 16, for example, metal materials such as Kovar alloy and niobium (Nb), and various conductive ceramics are suitably used.

[0029] [Temperature Control Base Member] The temperature control base member 3 is preferably a thick, disc-shaped member made of at least one of metal and ceramics. The body of the temperature control base member 3 is configured to also serve as an internal electrode for plasma generation. The temperature control base member 3 is, for example, circular in plan view. Inside the body of the temperature control base member 3 are water, He gas, N ２ A flow path 21 is formed for circulating a cooling medium of any choice, such as a gas. In addition, cooling gas introduction holes 17 and fixing holes 15 are formed inside the body of the temperature adjustment base member 3, similar to the electrostatic chuck member 2.

[0030] The body of the temperature control base member 3 is connected to an external high-frequency power supply 22. A power supply terminal 16, whose outer circumference is surrounded by an insulating material 23, is fixed inside the fixing hole 15 of the temperature control base member 3 via the insulating material 23. The power supply terminal 16 is connected to an external DC power supply 24.

[0031] The material constituting the temperature control base member 3 can be arbitrarily selected and is not particularly limited as long as it is a metal with excellent thermal conductivity and electrical conductivity, a ceramic with high thermal conductivity, or a composite material containing these. Suitable materials for the temperature control base member 3 include, for example, metal members such as aluminum (Al), copper (Cu), stainless steel (SUS), and titanium (Ti), and conductive ceramic members. It is preferable that at least the surface of the temperature control base member 3 exposed to the plasma is anodized or coated with a polyimide resin. It is even more preferable that the entire surface of the temperature control base member 3 is anodized or coated with the aforementioned resin.

[0032] By applying anodizing or resin coating to the temperature control base member 3, the plasma resistance of the temperature control base member 3 is improved, and abnormal discharge is prevented. Therefore, the plasma resistance stability of the temperature control base member 3 is improved, and surface scratches on the temperature control base member 3 can also be prevented.

[0033] [Bonding Layer] Bonding layer 4 contains resin and filler. The filler includes a first spherical filler and a second spherical filler, each having a different primary particle size. Preferably, bonding layer 4 has a thermal conductivity of 3.0 W / (m·K) or higher. A thermal conductivity of 3.0 W / (m·K) or higher makes it easier to transfer heat from the temperature control base member to the electrostatic chuck device, allowing the temperature of the sample on the electrostatic chuck device to be kept constant. More preferably, the thermal conductivity of the bonding layer is 3.5 W / (m·K) or higher, even more preferably 3.7 W / (m·K) or higher, and particularly preferably 4.0 W / (m·K) or higher. The thermal conductivity of the bonding layer may also be 4.5 W / (m·K) or higher, or 5.0 W / (m·K) or higher.

[0034] The thermal conductivity of a bonding layer can be obtained using methods such as the laser flash method. The laser flash method involves applying pulsed laser light to the surface of a flat sample to heat it, and obtaining the thermal diffusivity from the temperature behavior on the opposite side of the sample. The thermal conductivity can also be calculated using the following formula: (Thermal conductivity = Thermal diffusivity × Specific heat capacity × Density) Specifically, for example, the thermal diffusivity of a bonding layer can be measured using the laser flash method at room temperature (25°C) and atmospheric pressure (0.1 MPa) using a thermal diffusivity measuring device or similar equipment. The density of a bonding layer can be measured, for example, at room temperature (25°C) using the liquid weighing method with an electronic balance or similar equipment. Purified water can be used as a standard sample. The specific heat and specific heat capacity of a bonding layer can be measured using differential scanning calorimetry (DSC) or similar equipment such as a differential scanning calorimeter. The measurement conditions can be, for example, room temperature (25°C) and an argon gas flow rate of 20 mL / min, with a heating rate of, for example, 10°C / min.

[0035] The bonding layer 4 preferably has a uniform thickness and low variation in thermal conductivity. Specifically, it is preferable that the difference between the minimum and maximum values ​​of the thermal conductivity of the bonding layer 4 measured at three arbitrary points on the bonding layer 4 is 0.3 W / (m·K) or less. However, the difference between the minimum and maximum values ​​may be 0.2 W / (m·K) or less, or 0.1 W / (m·K) or less. As a method for sampling the bonding layer, for example, the electrostatic chuck member body may be cut and samples may be taken directly from the cross-section.

[0036] The bonding layer 4 will be explained in more detail below. Note that in the following explanation, the resin in its uncured state may be referred to as "resin composition" or "resin precursor."

[0037] (Resin) The resin used for the bonding layer 4 can be arbitrarily selected, but for example, at least one selected from the group consisting of silicone resin, acrylic resin, epoxy resin, and polyimide resin can be used. It is also preferable to use the resin described in the manufacturing method described later. These resins are preferred because the curing reaction is easy to control. From the viewpoint of easily adjusting the thickness of the bonding layer uniformly, it is particularly preferable to use acrylic resin.

[0038] (First filler, second filler) The bonding layer 4 further includes fillers in addition to the resin. The fillers include at least a first filler and a second filler. The materials of the first filler and the second filler included in the filler are not particularly limited as long as they have high thermal conductivity and a thermal conductivity of 180 W / (m·K) or more. If the material has a thermal conductivity of less than 180 W / (m·K), it will be difficult to achieve high thermal conductivity when mixed with the resin composition to form a bonding layer. Examples of materials for the highly thermally conductive fillers that form the first filler and the second filler include aluminum nitride (AlN) and alumina (Al ２ O ３ ) and silicon dioxide (SiO ２Ceramic powders such as ) and metal powders such as aluminum (Al) are preferred examples. In other words, fillers made of alumina and fillers made of aluminum nitride are preferred examples of the first and second fillers. The first and second fillers may be formed from the same material or from different materials.

[0039] Furthermore, in addition to the filler being formed from a homogeneous material, i.e., each particle being made from a single material, a surface-coated filler may also be used, for example, in which a coating layer made of a material different from the material constituting the filler particle body is provided on its surface. By appropriately selecting the material constituting the coating layer, it is possible to improve the water resistance of the filler, improve the compatibility between the filler and the resin, and increase the flexibility of the joint (joint layer 4). As the coating layer, for example, silicon dioxide (SiO₂) ２ ) Coating layer, aluminum oxide (Al ２ O ３ ) coating layer, or aluminum phosphate (AlPO ４ Examples include coating layers. Specifically, for example, when using aluminum nitride powder as a filler, silicon dioxide (SiO₂) is applied to the surface of the aluminum nitride particles that make up the filler. ２ ), aluminum oxide (Al ２ O ３ ), or aluminum phosphate (AlPO ４ A coating layer including the first filler may be provided. Both the first and second fillers may have a coating layer, or they may not, or only one of them may have a coating layer.

[0040] On the surface of aluminum nitride (AlN) particles, silicon dioxide (SiO ２ Surface-coated aluminum nitride (AlN) particles, which have a coating layer formed on them, have superior water resistance compared to simple aluminum nitride (AlN) particles without a surface coating. Therefore, the durability of the bonding layer 4 can be ensured, and the durability of the electrostatic chuck device 1 can be dramatically improved.

[0041] Aluminum nitride (AlN) particles without a surface coating undergo hydrolysis of their surface by, for example, water in the atmosphere, as shown in the chemical reaction equation (a) below, to form aluminum hydroxide (Al(OH)₂ ３ ) and ammonia (NH ３ This can produce aluminum hydroxide (Al(OH) ３ This can reduce the thermal conductivity of aluminum nitride (AlN). AlN + 3H ２ O → Al(OH) ３ +NH ３ ... (a)

[0042] On the other hand, surface-coated aluminum nitride (AlN) particles have a surface coated with silicon dioxide (SiO₂), which has excellent water resistance. ２ It is covered with a coating layer made of ). Therefore, aluminum nitride (AlN) is not hydrolyzed by water in the atmosphere, and the thermal conductivity of aluminum nitride (AlN) does not decrease. Thus, the durability of the bonding layer 4 is improved. In addition, aluminum hydroxide (Al(OH) ３ ) and ammonia (NH ３ Since these are less likely to occur, they do not become a source of contamination for plate-shaped samples such as semiconductor wafers.

[0043] Silicon dioxide (SiO ２ Surface-coated aluminum nitride (AlN) particles, which have a coating layer formed on them, can form a strong bond between the silicon (Si) in the coating layer and the resin in the bonding layer. This makes it possible to improve the elongation of the bonding layer 4. As a result, thermal stress caused by the difference between the thermal expansion coefficient of the support plate 12 of the electrostatic chuck member 2 and the thermal expansion coefficient of the temperature-regulating base member 3 can be alleviated. As a result, the electrostatic chuck member 2 and the temperature-regulating base member 3 can be joined precisely and firmly. In addition, the resistance to thermal cycle loads during use becomes sufficient, improving the durability of the electrostatic chuck device.

[0044] The thickness of the coating layer of the surface coating filler, for example, the thickness of the coating layer of surface-coated aluminum nitride (AlN) particles, can be arbitrarily selected, but is preferably 0.005 μm or more and 0.05 μm or less, and more preferably 0.005 μm or more and 0.03 μm or less. It may also be 0.007 μm or more and 0.04 μm or less, or 0.010 μm or more and 0.02 μm or less. If the thickness of the coating layer is 0.005 μm or more, the water resistance (moisture resistance) of the surface coating filler, for example aluminum nitride (AlN), can be sufficiently exhibited. On the other hand, if the thickness of the coating layer is 0.05 μm or less, the thermal conductivity of the surface coating filler, for example surface-coated aluminum nitride (AlN) particles, will not decrease, and consequently, the thermal conductivity between the plate-shaped sample placed on the mounting surface 11a of the mounting plate 11 and the temperature-adjusting base member 3 will not decrease. Therefore, the temperature of the plate-shaped sample during processing can be maintained at a preferred constant temperature.

[0045] The primary particle diameter of the first filler is 2 μm or more and less than 15 μm, and the primary particle diameter of the second filler is 15 μm or more and 50 μm or less. Having these particle diameters for the first and second fillers makes it easier for the smaller first fillers to fill the gaps between the larger second filler particles when mixed with the resin. This makes it easier to achieve a high particle filling rate while maintaining adhesive performance as a bonding layer, and to impart high thermal conductivity to the bonding layer. The lower limit of the primary particle diameter of the first filler may be 2 μm or more, 3 μm or more, 5 μm or more, 10 μm or more, etc., as needed. The upper limit of the primary particle diameter of the first filler may be less than 15 μm, 13 μm or less, 10 μm or less, 8 μm or less, 5 μm or less, etc. The lower limit of the primary particle diameter of the second filler may be 15 μm or more, 20 μm or more, 25 μm or more, 30 μm or more, 40 μm or more, etc., as needed. The upper limit of the primary particle diameter of the second filler may be 50 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, 20 μm or less, etc. The difference between the average primary particle diameter of the first filler and the average primary particle diameter of the second filler may be, for example, 1 to 48 μm, preferably 10 to 40 μm, and more preferably 20 to 30 μm.

[0046] In this embodiment, with respect to the filler contained in the bonding layer 4, "primary particle diameter of the filler" means the diameter of the spherical particles. If the spherical particles are not perfectly spherical, it means the diameter of the circumscribed circle of the filler with the largest diameter. The primary particle diameter of the filler can be measured using a scanning electron microscope (SEM) or the like. The primary particle diameter of the filler may mean the size of each individual particle, or it may mean the average value of multiple particles. If the primary particle diameter of the filler means the average value (average primary particle diameter), for example, the filler as a raw material for forming the bonding layer may be observed from an image of a scanning electron microscope (SEM), and the average value (diameter of the circumscribed circle) obtained from 200 or 100 particles may be used.

[0047] Regarding the shape of the filler contained in the bonding layer 4, from the viewpoint of improving the thermal conductivity of the bonding layer 4 by high-density filling of the filler, it is preferable that the filler be perfectly spherical. However, the sphericity of the filler only needs to be spherical to the extent that the objective of the present invention is achieved. For example, the sphericity of the filler may be 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, or 0.9 or more. In this embodiment, the sphericity of the filler is the value obtained by dividing the circumference of a circle with the same area as the projected area of ​​the particle image by the perimeter of the particle image. In the case of a perfect circle, the sphericity is 1, and it decreases as it deviates from a sphere. The average sphericity of the filler is preferably 0.7 or more, and more preferably 0.8 or more. The upper limit is 1.0 or less, and may be 0.98 or less, or 0.95 or less. The average sphericity of the filler is obtained by measuring the sphericity of a predetermined number of fillers, for example, 200 or 100, and taking a weighted average of these measured values. Furthermore, if the objective of the present invention is achieved, non-spherical fillers may be included.

[0048] The filler content in the bonding layer 4 is preferably 50 volume% or more. A filler content of 50 volume% or more makes it easier to impart high thermal conductivity to the bonding layer 4. Consequently, the thermal conductivity between the plate-shaped sample placed on the mounting surface 11a of the mounting plate 11 and the temperature-adjusting base member 3 does not decrease, and the temperature of the plate-shaped sample during processing can be maintained at a preferred constant temperature. The filler content is more preferably 55 volume% or more, even more preferably 60 volume% or more, even more preferably 65 volume% or more, and particularly preferably 70 volume% or more. On the other hand, the filler content is preferably 90 volume% or less, more preferably 85 volume% or less, and even more preferably 80 volume% or less. If the filler content is 90 volume% or less, sufficient adhesive performance can be ensured. The filler content in the bonding layer 4 may be obtained, for example, from the ratio of filler and resin precursor used as materials. To obtain the density of the bonding layer itself, for example, the electrostatic chuck member can be removed from the electrostatic chuck device, the electrostatic chuck member can be cut, and a sample of the bonding layer obtained from the cross-section can be measured for density. The density of the sampled material can be measured using methods such as liquid weighing.

[0049] The content of the first filler must be between 10% and 50% by volume relative to the total volume of the first and second fillers. The content of the second filler must be between 50% and 90% by volume relative to the total volume of the first and second fillers. If the content of the first filler is less than 10% by volume, i.e., the amount of the first filler is extremely small compared to the second filler, the amount of the first filler that can enter the gaps between the second fillers will be small, making it difficult to achieve a high particle packing density. If the content of the first filler exceeds 50% by volume, i.e., the amount of the first filler is extremely large compared to the second filler, the first filler will not be able to enter the gaps between the second fillers, making it difficult to maintain a good dispersion state within the bonding layer 4.

[0050] (Dispersant) A dispersant may be included in the bonding layer 4 for the purpose of improving the dispersibility of the filler within the bonding layer 4. The inclusion of a dispersant can suppress localized non-uniformity of the filler within the bonding layer 4. This makes it easier to make the thickness of the bonding layer 4 uniform and suppresses variations in thermal conductivity. The dispersant can be arbitrarily selected, but for example, at least one of phosphonic acid, carboxylic acid, polycarboxylic acid, phosphoric acid, polyphosphoric acid or their salts, or silane coupling agents or polyvinylpyrrolidone can be used. It is preferable to add the dispersant to the entire bonding layer 4 in a mass ratio of more than 0.0% and 5.0% or less. It may also be 0.1% to 0.5%, 0.5% to 1.0%, 1.0% to 3.0%, or 3.0% to 5.0%, etc.

[0051] (Composition of the bonding layer) The thickness of the bonding layer 4 can be arbitrarily selected, but it is preferably 50 μm or more and 300 μm or less, more preferably 55 μm or more and 250 μm or less, and even more preferably 60 μm or more and 200 μm or less. It may also be 70 μm or more and 150 μm or less, or 100 μm or more and 180 μm or less. If the thickness of the bonding layer 4 is 50 μm or more, the thermal conductivity between the electrostatic chuck member 2 and the temperature control base member 3 will be good and thermal stress will be sufficiently relieved. On the other hand, if the thickness of the bonding layer 4 is 300 μm or less, sufficient thermal conductivity between the electrostatic chuck member 2 and the temperature control base member 3 can be ensured and plasma permeability will also be improved.

[0052] In the bonding layer 4, the variation in thickness in the direction perpendicular to the bonding surfaces within the bonding surface with the electrostatic chuck member 2 and within the bonding surface with the temperature-regulating base member 3 is expressed as the difference between the maximum and minimum values ​​of the thickness. Preferably, the difference between the maximum and minimum values ​​of the thickness in the direction perpendicular to the bonding surface within the bonding surface with the electrostatic chuck member 2 and within the bonding surface with the temperature-regulating base member 3 is 10 μm or less. Furthermore, the smaller the difference between the maximum and minimum values, the better; 5 μm or less is more preferable, 1 μm or less is even more preferable, 0.7 μm or less is particularly preferable, and ideally, 0 μm is preferable. The thickness of the bonding layer 4 can be measured using, for example, a micrometer before bonding, or measured using, for example, an optical microscope while observing the cross-section after bonding.

[0053] Figure 2 is a schematic cross-sectional view of the bonding layer 4 of the electrostatic chuck device 1 in this embodiment. In this embodiment, the bonding layer 4 is preferably formed from a first layer 31 containing a filler and a pair of second layers 32 that sandwich the first layer 31, as shown in Figure 2. With this configuration, the first layer 31 has high thermal conductivity, and the second layers 32 that do not contain a filler have adhesive properties, so that the entire bonding layer 4 can exhibit high thermal conductivity and good adhesion. The total thickness of the pair of second layers 32 is preferably 5% to 30%, more preferably 7% to 25%, and even more preferably 10% to 20% of the thickness of the bonding layer 4. Within this thickness range, it is possible to maintain adhesion while suppressing a decrease in thermal conductivity. The sum of the thicknesses of the pair of second layers 32 can be arbitrarily selected. For example, it may be 2 μm to 60 μm, 4 μm to 40 μm, 6 μm to 30 μm, or 8 μm to 20 μm. It may also be 3 μm to 15 μm, or 15 μm to 25 μm, etc. The pair of second layers 32 may both have the same thickness or different thicknesses. For example, the ratio of the thickness of one second layer 32 to the thickness of the other second layer 32 can be arbitrarily selected, but may be 1:1 to 2:1, or 1:1 to 1:1.5, etc. The thickness of the first layer 31 can be arbitrarily selected. For example, it may be 50 μm to 270 μm, 70 μm to 200 μm, or 80 μm to 150 μm. It may also be 60 μm to 130 μm, or 130 μm to 170 μm, etc.

[0054] (Third Filler) The filler included in the bonding layer 4 of the electrostatic chuck device in this embodiment may further include a spherical third filler (filler C). The primary particle diameter of the third filler is preferably 0.05 μm or more and less than 2 μm. The lower limit of the primary particle diameter may be 0.10 μm or more, 0.20 μm or more, 0.30 μm or more, 0.50 μm or more, 1.0 μm or more, 1.3 μm or more, etc. The upper limit of the primary particle diameter may be less than 1.80 μm, less than 1.50 μm, less than 1.20 μm, less than 1.0 μm, less than 0.80 μm, etc. Being within this range of primary particle diameter indicates that the particle diameter of the third filler is smaller than that of the first filler and the second filler. This size makes it easier for the third filler to fill the gaps between the second fillers, thereby increasing the particle filling rate of the bonding layer. The difference between the average primary particle diameter of the first filler and the average primary particle diameter of the third filler may be, for example, 1.0 to 14.0 μm, preferably 2.0 to 10.0 μm, and more preferably 3.0 to 7.0 μm. The third filler is preferably spherical, and more preferably perfectly spherical. Examples of materials constituting the third filler include the materials listed for the first and second fillers. The material constituting the third filler may be the same as, or different from, the material constituting the first and second fillers.

[0055] The third filler is not particularly limited, but is preferably a filler with a thermal conductivity of 30 W / (m·K) or higher. The thermal conductivity may be 40 W / (m·K) or higher, or 50 W / (m·K) or higher. By having a thermal conductivity of 30 W / (m·K) or higher for the third filler, it is possible to prevent a decrease in the thermal conductivity of the bonding layer. Examples of third fillers include Al ２ O ３ Examples include AlN. The third filler, like the first and second fillers, may have a coating layer on its surface made of a material different from the material that constitutes the particle body of the third filler.

[0056] The third filler is preferably 10% to 50% by volume relative to the total volume of the first and third fillers. It may also be 10% to 20% by volume, 20% to 35% by volume, or 35% to 50% by volume. For example, it is preferable to replace a portion of the first filler with a third filler having a smaller particle size than the first filler. For example, when the filler contains a third filler, it is preferable that the content of the first filler relative to the total volume of the first, second, and third fillers is 5% to 45% by volume, the content of the second filler is 50% to 90% by volume, and the content of the third filler is 1% to 25% by volume. The content of the second filler relative to the total volume of the first, second, and third fillers may be 60% to 85% by volume, or 70% to 80% by volume. Such a content makes it easier to achieve good adhesion and high thermal conductivity in the bonding layer. Examples of materials constituting the third filler include those listed for the first and second fillers. The material constituting the third filler may be the same as, or different from, the material constituting the first and second fillers.

[0057] The above describes a preferred example of the configuration of the electrostatic chuck device in this embodiment. Below, a preferred example of a method for manufacturing the electrostatic chuck device will be described.

[0058] [Method for Manufacturing an Electrostatic Chuck Device] The method for manufacturing an electrostatic chuck device in this embodiment comprises the steps of: forming a first coating film containing a resin precursor on one surface of the electrostatic chuck member 2; forming a second coating film containing a resin precursor on the surface of the temperature-regulating base member 3 facing the electrostatic chuck member 2; forming a laminate by stacking the electrostatic chuck member 2, the sheet adhesive 3x, and the temperature-regulating base member 3 in a position where a sheet adhesive 3x containing at least the filler and the resin precursor is sandwiched between the first coating film and the second coating film; and joining the obtained laminate by applying pressure and heating. The first and second coating films formed in the coating film forming step do not contain a filler. To manufacture the electrostatic chuck device, first, the electrostatic chuck member 2 and the temperature-regulating base member 3 are manufactured. These can be formed by any method selected, for example, by a known method. The electrostatic chuck device of this embodiment can be manufactured by integrating the fabricated electrostatic chuck member 2, the temperature control base member 3, and the bonding layer 4, which is manufactured by the manufacturing method described later. The manufacturing method of the bonding layer 4 will be described in detail below.

[0059] [Method for Manufacturing Bonding Layer 4] (Preparation of Mixture α containing Filler for Forming Sheet Adhesive 3x) Prepare a mixture α for forming sheet adhesive 3x. Mixture α is obtained by mixing a resin precursor, an organic solvent, and a filler. The resin precursor refers to a resin in its pre-curing state. In other words, it may refer to an uncured resin. The resin precursor may be a thermosetting resin before curing. The form of the resin precursor is not particularly limited, but it is preferably in a monomer state. The resin precursor can be a precursor of the same material as those already described in the description of the bonding layer, such as silicone resin, acrylic resin, epoxy resin, or polyimide resin. The filler can also be the same material as those already described in the description of the bonding layer. The organic solvent can be arbitrarily selected, and any organic solvent that can be mixed with the resin precursor and does not cause the filler to aggregate is acceptable, such as toluene, xylene, ethyl acetate, or methyl ethyl ketone. The filler is preferably prepared by combining a first filler having an average primary particle diameter of 2 μm or more and less than 15 μm, a second filler having an average primary particle diameter of 15 μm or more and 50 μm or less, and a third filler having an average primary particle diameter of 0.05 μm or more and 0.7 μm or less, and mixing them in a predetermined volume ratio. The filler may also be prepared by pre-mixing the first filler and the second filler, or the first filler, the second filler, and the third filler, and then mixing the mixture with the resin precursor and organic solvent. The average primary particle diameter of the filler is calculated by measuring the primary particle diameter of 200 or 100 fillers and taking a weighted average of these measurements. In the mixed solution α, the filler content is preferably 50% to 90% by volume, more preferably 60% to 90% by volume, and even more preferably 65% ​​to 85% by volume, relative to the total content of the resin precursor and filler. The amount of organic solvent in the mixed solution α can be adjusted as appropriate to ensure that it is sufficient to form a coating film. For example, the viscosity of the mixed solution α may be adjusted to be between 50 Pa·s and 300 Pa·s.Alternatively, the content of the organic solvent may be 5% by mass or more and 70% by mass or less, 10% by mass or more and 60% by mass or less, or 15% by mass or more and 50% by mass or less. It may also be 10% by mass or more and 30% by mass or 15% by mass or more and 40% by mass or less.

[0060] (Preparation of a filler-free mixed solution β for forming the first and second coating films) A mixed solution β is prepared to form the first and second coating films. Mixed solution β is obtained by mixing a resin precursor with an organic solvent. The resin precursor and organic solvent used in mixed solution α are preferably the same as those used in mixed solution β, but are not limited to this example. The mixed solution β used to form the first coating film and the mixed solution β used to form the second coating film are preferably the same, but are not limited to this example. The content of the resin precursor in mixed solution β is not particularly limited as long as it can be adjusted to a viscosity sufficient to form the first and second coating films. For example, it may be 5% by mass or more and 90% by mass or less, 10% by mass or more and 70% by mass or less, 15% by mass or more and 50% by mass or less, or 20% by mass or more and 40% by mass or less. The organic solvent is not particularly limited as long as it can be mixed with the resin precursor, and organic solvents such as ethyl acetate, toluene, methyl ethyl ketone, toluene, and xylene can be used.

[0061] (Formation of sheet adhesive 3x) The prepared mixed solution α is applied to a release substrate such as a release film or release sheet, such as a polyethylene film with a release agent, so that the cured film thickness is 50 μm or more and 270 μm or less, to form a coating film. This is then dried, for example in a drying oven, to partially cure it. Here, partial curing means that only the surface of the mixed solution α is cured to the extent that when the coated surface of the mixed solution α is lightly rubbed, no scratches are left on the coated surface. Partial curing can also be thought of as partial curing of only the surface. Thus, partial curing may mean a state in which only the surface is cured. At this time, the inside of the mixed solution α is not cured. By controlling the drying temperature and drying time, a state in which the surface is cured and the inside is not cured can be formed. Next, the partially cured film is peeled off from the polyethylene film to obtain the sheet adhesive 3x.

[0062] (Formation of Laminated Structure) After obtaining the above-mentioned mixed liquid β and sheet adhesive 3x, a laminate is formed. That is, the bonding surface of the electrostatic chuck member 2 is then degreased and cleaned, for example, using acetone, and the mixed liquid β is applied to this bonding surface so that the cured film thickness is predetermined, for example, 1 μm to 30 μm. After that, it is dried, for example, in a drying oven for 2 minutes to reach a semi-cured state. In this way, a first coating film containing a resin precursor is formed. The cured film thickness can be arbitrarily selected and may be 1 μm to 5 μm, 5 μm to 10 μm, 10 μm to 20 μm, 20 μm to 30 μm, etc.

[0063] Next, the bonding surface of the temperature-regulating base member 3 is degreased and cleaned, for example, using acetone, in the same manner as the electrostatic chuck member 2. Then, the mixed solution β is applied to the bonding surface with the electrostatic chuck member 2 so that the cured film thickness is predetermined, for example, 1 μm to 30 μm, and dried, for example, dried in a dryer for 2 minutes to reach a semi-cured state, forming a second coating film containing a resin precursor. The conditions for the first coating film can be used as examples of the cured film thickness, temperature, and time.

[0064] The application method for mixture α and / or mixture β can be arbitrarily selected. For example, it can be applied manually using a spatula, or by using a bar coating method, screen printing method, or applicator.

[0065] Next, the obtained sheet adhesive 3x is sandwiched between the first coating film and the second coating film so that the electrostatic chuck member 2 and the temperature control base member 3 are joined via the bonding layer 4.

[0066] Subsequently, the laminated sheet adhesive 3x, the first coating film, and the second coating film are cured at a predetermined temperature and other conditions selected as needed. The curing conditions should follow the optimal curing conditions for the resin used. Pressurization may also be applied during curing as needed. For example, heating to 100°C to 150°C for about two hours is one example, during which pressurization of 0.5 MPa to 5 MPa may be applied. Pressurization of 1.0 MPa to 2 MPa or 2 MPa to 4 MPa may also be applied. For example, the laminated electrostatic chuck member 2 and the temperature control base member 3 may be pressed and heated from both the top and bottom sides.

[0067] In this way, the support plate 12 of the electrostatic chuck member 2 and the temperature-regulating base member 3 can be joined. Preferably, the average value of the thermal conductivity of the bonding layer 4 formed between the support plate 12 and the temperature-regulating base member 3 is 3.0 W / (m·K) or higher. Such a bonding layer 4 has excellent thermal conductivity. Furthermore, it also has sufficient bonding strength.

[0068] It should be noted that the plate-shaped sample that can be held by the electrostatic chuck device in this embodiment is not limited to semiconductor wafers. For example, it may be a glass substrate for flat panel displays (FPDs) such as liquid crystal displays (LCDs), plasma displays (PDPs), and organic EL displays. Furthermore, the electrostatic chuck device of this embodiment can be designed to suit the shape and size of the substrate.

[0069] The present invention will be described below using examples, but the present invention is not limited to these examples.

[0070] (Preparation of Mixture A containing Filler) Using a glass apparatus commonly used for polymerization, Mixture A was prepared by mixing 6.9 parts by mass of acrylic resin precursor, 20.7 parts by mass of organic solvent, and 71.7 parts by mass of filler in the apparatus. The filler was a mixture of spherical aluminum nitride particles with an average primary particle diameter of 5 μm (first filler) and spherical aluminum nitride particles with an average primary particle diameter of 30 μm (second filler). The ratio of aluminum nitride particles was such that the volume ratio of aluminum nitride particles with an average primary particle diameter of 5 μm (first filler) to aluminum nitride particles with an average primary particle diameter of 30 μm (second filler) was 3:7.

[0071] (Preparation of Mixture B containing Filler) Mixture B was prepared by mixing 6.9 parts by mass of acrylic resin precursor, 20.7 parts by mass of organic solvent, and 71.7 parts by mass of filler. The filler is a mixture of spherical aluminum oxide particles (third filler) with an average primary particle diameter of 0.3 μm, spherical aluminum nitride particles (first filler) with an average primary particle diameter of 5 μm, and aluminum nitride particles (second filler) with an average primary particle diameter of 30 μm. The acrylic resin precursor, organic solvent, first filler, and second filler used are the same as those used in Mixture A. The filler is a mixture of aluminum oxide particles (third filler), aluminum nitride particles (first filler) with an average primary particle diameter of 5 μm, and aluminum nitride particles (second filler) with an average primary particle diameter of 30 μm, in a volume ratio of 1:2:7.

[0072] (Preparation of Mixture C containing Filler) Mixture C was prepared by mixing 6.9 parts by mass of acrylic resin precursor, 20.7 parts by mass of organic solvent, and 71.7 parts by mass of spherical aluminum nitride particles (second filler) with an average primary particle diameter of 5 μm. The acrylic resin precursor, organic solvent, and second filler used were the same as those used in Mixture A. (Preparation of Mixture D containing Filler) Mixture D was prepared by mixing 6.9 parts by mass of acrylic resin precursor, 20.7 parts by mass of organic solvent, and 71.7 parts by mass of spherical aluminum nitride particles (first filler) with an average primary particle diameter of 5 μm. The acrylic resin precursor, organic solvent, and first filler used were the same as those used in Mixture A.

[0073] (Preparation of Mixture E containing Filler) Mixture E was prepared by mixing 6.9 parts by mass of acrylic resin precursor, 20.7 parts by mass of organic solvent, and 71.7 parts by mass of spherical aluminum nitride particles (second filler) with an average primary particle diameter of 30 μm. The acrylic resin precursor, organic solvent, and second filler used were the same as those used in Mixture A.

[0074] (Preparation of Mixture F without Filler) Mixture F was prepared by dissolving 25 parts by mass of acrylic resin precursor and 75 parts by mass of solvent in a glass apparatus commonly used for polymerization, while stirring with a stirring device. The acrylic resin precursor and organic solvent used were the same as those used in Mixture A.

[0075] [Evaluation of Thermal Conductivity] (Preparation of Cured Body (Evaluation Sample) for Thermal Conductivity Measurement) ・Example 1 A cured body for thermal conductivity measurement was formed as follows. A mixed liquid F without filler was applied to a polyethylene film with a release agent using an applicator to form a coating film C with a cured film thickness of 10 μm. This coating film was dried in a 70°C dryer for 2 minutes to bring the coating film C to a semi-cured state. Next, a mixed liquid A containing filler was applied to the coating surface of the semi-cured coating film C using an applicator to form a coating film with a cured film thickness of 90 μm. This coating film was dried in a 70°C dryer for 2 minutes to bring it to a semi-cured state, and was designated as coating film C1-1. Next, a mixed liquid F without filler was applied to the coating surface of coating film C1-1 using an applicator to form a coating film with a cured film thickness of 10 μm. This coating film was dried in a 70°C dryer for 2 minutes to bring it to a semi-cured state, and was designated as coating film C2. Next, the laminate of coating film C, coating film C1-1, and coating film C2 was hot-pressed at 2 MPa and 130°C for 2 hours to harden the semi-cured film and obtain a cured film a (three-layer laminate). The obtained cured film was peeled off the polyethylene film to obtain a cured body a (bonding layer) for measurement. For ease of evaluation, the order of layer formation in the cured body for measurement (evaluation sample) was changed from that used in the manufacturing method of the electrostatic chuck device.

[0076] Example 2 A polyethylene film coated with a release agent was coated with a filler-free mixed solution F using an applicator to form a coating film with a cured film thickness of 10 μm. This coating film was dried in a 70°C dryer for 2 minutes to a semi-cured state, which was designated as coating film C. Next, a filler-containing mixed solution B was applied to the coating surface of coating film C using an applicator to form a coating film with a cured film thickness of 90 μm. This coating film was dried in a 70°C dryer for 2 minutes to a semi-cured state, which was designated as coating film C1-2. Next, a filler-free mixed solution F was applied to the coating surface of coating film C1-2 using an applicator to form a coating film with a cured film thickness of 10 μm. This coating film was dried in a 70°C dryer for 2 minutes to a semi-cured state, which was designated as coating film C2. Next, the laminate of coating film C, coating films C1-2, and coating film C2 was hot-pressed at 2 MPa and 130°C for 2 hours to cure the semi-cured film and obtain a cured film b. The obtained cured film b was peeled off from the polyethylene film to obtain a cured body b (bonding layer) for measurement.

[0077] ・Example 3 Mixture A1 containing filler was prepared by adding polycarboxylic acid as a dispersant at a mass ratio of 2% relative to the filler to mixture A containing filler. Mixture F without filler was applied to a polyethylene film with a release agent using an applicator to form a coating film with a cured film thickness of 10 μm. This coating film was dried in a 70°C dryer for 2 minutes to a semi-cured state, and was designated as coating film C. Next, mixture A1 containing polycarboxylic acid and filler was applied to the coating surface of coating film C using an applicator to form a coating film with a cured film thickness of 90 μm. This coating film was dried in a 70°C dryer for 2 minutes to a semi-cured state, and was designated as coating film C1-3. Next, mixture F without filler was applied to the coating surface of coating film C1-3 using an applicator to form a coating film with a cured film thickness of 10 μm. This coating film was dried in a 70°C dryer for 2 minutes to a semi-cured state, and was designated as coating film C2. Next, a laminate of coating film C, coating films C1-3, and coating film C2 was hot-pressed at 2 MPa and 130°C for 2 hours to cure the semi-cured film and obtain a cured film c. The obtained cured film was peeled off the polyethylene film to obtain a cured body c (bonding layer) for measurement.

[0078] ・Example 4 A polycarboxylic acid was added as a dispersant to a filler-containing mixture B at a mass ratio of 2% relative to the filler to prepare a filler-containing mixture B1. The same polycarboxylic acid used in Example 3 was used. A filler-free mixture F was applied to a polyethylene film with a release agent using an applicator to form a coating film with a cured film thickness of 10 μm. This coating film was dried in a 70°C dryer for 2 minutes to a semi-cured state, which became coating film C. Next, a polycarboxylic acid and filler-containing mixture B1 was applied to the coating surface of coating film C using an applicator to form a coating film with a cured film thickness of 90 μm. This coating film was dried in a 70°C dryer for 2 minutes to a semi-cured state, which became coating film C1-4. Next, a filler-free mixture F was applied to the coating surface of coating film C1-4 using an applicator to form a coating film with a cured film thickness of 10 μm. This coating was dried in a 70°C dryer for 2 minutes to a semi-cured state, which was then designated as coating film C2. Next, coating films C, C1-4, and C2 were hot-pressed at 2 MPa and 130°C for 2 hours to cure the semi-cured films and obtain a cured film d. The obtained cured film was peeled off the polyethylene film to obtain a cured body d (bonding layer) for measurement.

[0079] Comparative Example 1 A polycarboxylic acid was added as a dispersant to a filler-containing mixture C at a mass ratio of 2% relative to the filler to prepare a filler-containing mixture C1. The same polycarboxylic acid used in Example 3 was used. Instead of the filler-containing mixture A of Example 1, a mixture C1 containing polycarboxylic acid and one type of filler was used, and a cured body e (bonding layer) was obtained in the same manner as in Example 1.

[0080] Comparative Example 2 A filler-containing mixture E1 was prepared by adding polycarboxylic acid as a dispersant at a mass ratio of 2% relative to the filler to a filler-containing mixture E. The same polycarboxylic acid used in Example 3 was used. Instead of the filler-containing mixture A of Example 1, a mixture E1 containing polycarboxylic acid and one type of filler was used, and a cured body f (bonding layer) was obtained in the same manner as in Example 1.

[0081] (Thermal Conductivity of the Hardened Material) The hardened material was measured to obtain its thermal diffusivity, density, and specific heat. From the obtained thermal diffusivity, density, and specific heat, the thermal conductivity was calculated. Note that this method for determining thermal conductivity is not exactly the same as the method for determining the thermal conductivity of the bonding layer of the chuck member, as it uses a formed evaluation sample. However, it is possible to judge the trend and make comparisons. Specifically, the thermal conductivity of the hardened material was calculated from the product of thermal diffusivity, density, and specific heat based on the following formula (X): Thermal conductivity of hardened material (W / (m·K)) = Thermal diffusivity (mm ２ / s) x density (g / cm ３ ) × Specific heat (J / (K・g)) ... (X) ・Thermal diffusivity The thermal diffusivity of the hardened material was measured by laser flash method at room temperature (25°C) and atmospheric pressure (0.1 MPa) using a thermal diffusivity measuring device (NETZSCH: LFA 467 HyperFlash). ・Density The density of the hardened material was measured at room temperature (25°C) using an electronic balance (Sartorius: CPA225D) by liquid weighing method. Purified water equivalent to JIS K 0557 A3 standard was used as the standard sample. ・Specific heat The specific heat of the hardened material was measured by differential scanning calorimetry (DSC method) using a differential scanning calorimeter (NETZSCH: DSC3500 Sirius type). The measurements were performed under room temperature (25°C) and an argon gas flow rate of 20 mL / min, with a heating rate of 10°C / min. The evaluation results are shown in Table 1.

[0082]

[0083] As shown in Table 1, Example 1 yielded a bonding layer with high thermal conductivity. Furthermore, it can be seen that the difference in thermal conductivity depending on the location was small, and the filling density of the filler was nearly uniform. In addition, Example 2, in which a filler was added to Example 1, showed even greater improvement in thermal conductivity. Moreover, as in Examples 3 and 4, when a dispersant was added, the thermal conductivity was further improved. In Example 4, the difference between the maximum and minimum values ​​of thermal conductivity depending on the measurement location was 0.1 W / (m·K) or less, indicating that a bonding layer even further improved from Example 2 was obtained.

[0084] [Peel Test] ・Example 1A Two aluminum substrates (1 cm thick) were coated with a filler-free mixed solution F using an applicator to form two precursor coating films C, with a cured film thickness of 10 μm. These two coating films C were dried in a 70°C dryer for 2 minutes to a semi-cured state. A polyethylene film with a release agent was coated with a mixed solution A1, which contains the filler (including the first and second fillers) and dispersant formed in Example 3, using an applicator to form a coating film with a cured film thickness of 90 μm. This coating film was dried in a 70°C dryer for 2 minutes to a semi-cured state. Next, the semi-cured film was peeled off the polyethylene film to obtain a sheet adhesive 1x. The obtained sheet adhesive 1x was sandwiched between the two coating films C and hot-pressed at 2 MPa and 130°C for 2 hours. In this way, the semi-cured film (laminated structure) was cured to obtain a cured film (bonding layer) sandwiched and bonded between two aluminum substrates. In this way, a test sample containing five layers, including the aluminum substrates, was obtained. The aluminum substrate bonded to the bonding layer was pulled using a tensile testing machine (Instron 5582 universal material testing machine) until it peeled off in the vertical direction (axial direction perpendicular to the bonding surface). As a result, it did not break even when the strain was 200% or more and the stress was 2.0 MPa or more. Subsequently, when the strain was 600% or more and the stress was 7.0 MPa or more, fracture occurred. Furthermore, the fracture occurred in the first layer containing the filler. It can be concluded that the adhesive strength was excellent. Example 2B A peel test was performed in the same manner as in Example 1A, except that instead of the filler-containing mixture A1, a mixture B1 containing the filler formed in Example 4 (including the first, second, and third fillers) and a dispersant was used. As a result, similar to Example 1A, fracture did not occur even when the strain was 200% or more and the stress was 2.0 MPa or more. Fracture occurred when the strain was 600% or more and the stress was 7.0 MPa or more. Furthermore, the fracture occurred in the first layer containing the filler. It can be concluded that the adhesive strength was excellent.

[0085] ・Reference Example 1A The test was carried out in the same manner as in Example 1A, except that a three-layer structure of the coating film was formed and then sandwiched between two aluminum substrates. Specifically, a filler-free mixed solution F was applied to a polyethylene film with a release agent using an applicator to form a precursor coating film C with a cured film thickness of 10 μm. This coating film was dried in a 70°C dryer for 2 minutes to bring coating film C to a semi-cured state. Next, a filler-free mixed solution A1 was applied to the coating surface of coating film C using an applicator to form a coating film C1-1 with a cured film thickness of 90 μm. This coating film C1-1 was dried in a 70°C dryer for 2 minutes to bring coating film C1-1 to a semi-cured state. Next, a filler-free mixed solution F was applied to the coating surface of coating film C1-1 using an applicator to form a coating film C2 with a cured film thickness of 10 μm. This coating was dried in a 70°C dryer for 2 minutes to obtain a semi-cured film C2. The resulting laminate of coating C, coating C1-1, and coating C2 was peeled off the polyethylene film. Next, the laminate was sandwiched between two aluminum substrates and hot-pressed at 2 MPa and 130°C for 2 hours to cure the laminate, obtaining a cured film (bonding layer), which was a test sample sandwiched between two aluminum substrates and bonded to the substrates. The aluminum substrate bonded to the bonding layer was subjected to a tensile test using a tensile testing machine until delamination occurred, in the same manner as in Example 1A. As a result, although delamination did not occur at stresses of 2.0 MPa or higher, fracture occurred at a stress of approximately 4 MPa with a strain of 200%. Furthermore, the fracture occurred between the first layer containing the filler and the second layer without the filler. From this, it was confirmed that the bonding layer produced by the method of Reference Example 1A has weaker adhesive strength than the bonding layer bonded by the method of Example 1A.

[0086] From the above results, it has been found that the present invention can provide an excellent electrostatic chuck device. It has been confirmed that an electrostatic chuck device having an excellent bonding layer can be obtained according to the manufacturing method of the present invention.

[0087] 1 Electrostatic chuck device 2 Electrostatic chuck member 3 Temperature control base member 4 Bonding layer 11 Mounting plate 11a Mounting surface 12 Support plate 13 Electrostatic adsorption electrode 14 Insulating material 15 Fixing hole 16 Power supply terminal 17 Cooling gas introduction hole 21 Flow path 22 High-frequency power supply 23 Insulating material 24 DC power supply 31 First layer including filler 32 Second layer without filler

Claims

An electrostatic chuck member having electrodes inside, A base component for temperature control, A bonding layer that joins the electrostatic chuck member and the temperature control base member, An electrostatic chuck device having, The bonding layer comprises a spherical filler and a resin. The filler includes a first filler and a second filler, The thermal conductivity of the first filler is 180 W / (m·K) or higher. The thermal conductivity of the second filler is 180 W / (m·K) or higher. The primary particle size of the first filler is 2 μm or more and less than 15 μm. The primary particle size of the second filler is 15 μm or more and 50 μm or less. The content of the filler in the bonding layer is 50% by volume or more and 90% by volume or less. An electrostatic chuck device in which the content of the first filler relative to the total of the first and second fillers is 10% by volume or more and 50% by volume or less. 　 The electrostatic chuck device according to claim 1, wherein the thermal conductivity of the bonding layer is 3.0 W / (m·K) or more. 　 The filler further comprises a spherical third filler, The primary particle size of the third filler is 0.05 μm or more and less than 2 μm. The thermal conductivity of the third filler is 30 W / (m·K) or higher. The electrostatic chuck device according to claim 1, wherein the content of the first filler relative to the total of the first filler, the second filler, and the third filler is 5% by volume or more and 45% by volume or less, the content of the second filler is 50% by volume or more and 90% by volume or less, and the content of the third filler is 1% by volume or more and 25% by volume or less. 　 The thermal conductivity of the bonding layer is 4.0 W / (m·K) or higher. The difference between the minimum and maximum values ​​of the thermal conductivity of the bonding layer, measured at three arbitrary points in the bonding layer, is 0.3 W / (m·K) or less. The electrostatic chuck device according to claim 1, wherein the resin is at least one selected from the group consisting of silicone resin, acrylic resin, epoxy resin, and polyimide resin. 　 The aforementioned bonding layer is A first layer containing the aforementioned filler, An electrostatic chuck device according to any one of claims 1 to 4, comprising a pair of second layers formed solely from a resin that does not contain the aforementioned filler, and which sandwich the first layer. 　 The first filler and the second filler may be formed from the same material or from different materials. The first filler and the second filler are, respectively, aluminum oxide particles or aluminum nitride particles. The electrostatic chuck device according to claim 1. 　 The first filler, the second filler, and the third filler are formed from the same material, or at least one of these fillers is formed from a different material. The first filler, the second filler, and the third filler are, each, aluminum oxide particles or aluminum nitride particles. The electrostatic chuck device according to claim 3. 　 A method for manufacturing an electrostatic chuck device according to claim 5, A step of forming a first coating film containing a precursor of the resin before curing on one surface of the electrostatic chuck member, A step of forming a second coating film containing a precursor of the resin before curing on the surface of the temperature-regulating base member facing the electrostatic chuck member, The process involves stacking the electrostatic chuck member, the sheet adhesive, and the temperature-regulating base member so that a sheet adhesive containing at least the filler and the resin is sandwiched between the first coating film and the second coating film, thereby forming a laminate. A method for manufacturing an electrostatic chuck, comprising the steps of: pressing and heating the electrostatic chuck device containing the obtained laminate to bond the laminate. 　 This includes the step of preparing the aforementioned sheet adhesive, This process, A sub-step involves mixing an organic solvent, the resin precursor, and the filler so that the amount of the filler is 50% by volume or more and 90% by volume or less relative to the total content of the resin precursor and the filler, to form a mixed solution. The aforementioned mixture is applied to a release substrate to form a coating film, and the coating film is dried to partially harden it. The process includes a sub-step of peeling the coating film from the release substrate to obtain the sheet adhesive. A method for manufacturing an electrostatic chuck device according to claim 8. 　 The process includes a step of mixing the resin precursor before curing with an organic solvent to prepare a mixed solution. The step of forming the first coating film is, The sub-step includes applying the mixed liquid to one surface of the electrostatic chuck member to form the first coating film, The step of forming the second coating film is, The sub-step includes applying the mixed liquid to the opposing surface of the temperature-regulating base member to form the second coating film, A method for manufacturing an electrostatic chuck device according to claim 8.

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