Holding device

Abstract

To provide a technique capable of improving at least any one of a cooling speed of a side surface where an object is mounted and a uniformity of an in-surface temperature distribution of the side surface where the object is mounted in a retainer holding the object.SOLUTION: A retainer comprises: a plate-like part that is formed in a plate-like shape having a first surface on the side where an object is mounted and a second surface as a back surface of the first surface; a base part that is arranged onto the second surface side of the plate-like part, supports the plate-like part, includes a cooling function, and is formed in the plate-like shape; and a joint part that is arranged between the plate-like part and the base part, and joints the plate-like part and the base part. A heat resistance of the joint part is 1.1×10-3 (m2K / W) or less at the time of -60°C.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to a holding device. [Background technology]

[0002] Conventionally, as a holding device for holding objects, for example, when manufacturing semiconductors, a holding device for wafers etc. Electrostatic chucks are known for holding objects. Generally, electrostatic chucks are used when the object is placed on them. A plate-shaped portion, a base portion in which a refrigerant flow path is formed, and a joint portion that connects the plate-shaped portion and the base portion. It includes the following. For example, Patent Documents 1 and 2 describe silicon as the material for the adhesive layer (joint). A thermally conductive compound such as aluminum oxide or aluminum nitride in a resin or silicone resin. The document states that an adhesive made of a composite resin with added filler should be used. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 4-287344 [Patent Document 2] Japanese Patent Publication No. 2014-207374 [Overview of the project] [Problems that the invention aims to solve]

[0004] In environments where the electrostatic chuck is exposed to strong plasma energy, or when the electrostatic chuck is subjected to high power When used in an environment where such inputs are present, the wafer mounting surface tends to become hot. (See the above-mentioned patent document.) When the electrostatic chucks described in 1 and 2 are used in such environments, the heat transfer of the adhesive layer Because the conductivity is relatively low, there is a risk that the cooling rate of the wafer mounting surface may not be sufficient. In order to increase the cooling rate of the wafer mounting surface, it is desired to improve heat sinking at the joint .

[0005] Furthermore, when the wafer mounting surface tends to reach a high temperature as described above, the base side is used at an extremely low temperature for cooling the wafer mounting surface, so a large temperature difference occurs between the upper and lower sides of the joint and within the in-plane direction of the joint. The silicone resins described in Patent Documents 1 and 2 have a temperature range in which thermal conductivity changes greatly in a low temperature region due to the presence of said temperature range, temperature distribution occurs at the joint, and when the heat conduction characteristics of the joint change , there is a risk that the non-uniformity of the in-plane temperature distribution of the wafer mounting surface of the electrostatic chuck will increase. Therefore , there is a need for a joint whose thermal conductivity has a small degree of change depending on temperature. Note that these problems are not limited to electrostatic chucks, and also apply to semiconductors such as plasma etching apparatuses they are problems common to various holding devices such as manufacturing apparatuses.

[0006] The present disclosure has been made to solve at least part of the above-mentioned problems, and an object of the present disclosure is to provide, in a holding device that holds an object, a technology that improves at least one of the cooling rate of the surface on which the object is mounted and the uniformity of the in-plane temperature distribution of the surface on which the object is mounted that improves at least one of the cooling rate of the surface on which the object is mounted and the uniformity of the in-plane temperature distribution of the surface on which the object is mounted . [MEANS FOR SOLVING THE PROBLEM]

[0007] The present disclosure can be implemented in the following modes. (1) According to one aspect of the present disclosure, there is provided a holding device that holds an object. This holding device comprises: a plate-shaped plate portion having a first surface on the side where the object is mounted and a second surface that is the back surface of the first surface; and a base member that is arranged on the second surface side of the plate-shaped portion, supports the plate-shaped portion, formed in a plate shape, and arranged on the second surface side of the plate-shaped portion, supports the plate-shaped portion, A base portion formed in the shape of a plate and having a cooling function, and a portion disposed between the plate-shaped portion and the base portion. The device comprises a joint that connects the plate-like portion and the base portion, and the thermal resistance of the joint is , at -60℃ 1.1 × 10 -3 (m 2 It is less than or equal to kW.

[0008] According to this type of retaining device, the thermal resistance of the joint is 1.1 × 10⁻¹⁰ at -60°C. -3 (m 2 (K / W) is below this value, and because the thermal resistance is low, for example, the plate-shaped part of the holding device becomes hot, When the base part is used at an extremely low temperature of around -60°C, the plate-shaped part can be rapidly cooled. Therefore, the cooling rate of the surface on which the object is placed can be improved.

[0009] (2) In the above-described holding device, the joint portion has a thermal conductivity of λ1 at -60°C Furthermore, when the thermal conductivity at 25°C is denoted as λ², λ1 / λ² must be 1.18 or less. And when the thermal resistance at -60°C is θ1 and the thermal resistance at 25°C is θ2, θ It is possible to satisfy at least one of the following conditions: 1 / θ² is 0.85 or greater. With this configuration, the change in thermal conductivity due to temperature changes at the joint is small, so the temperature of the plate-like part This can improve the uniformity of the distribution.

[0010] (3) In the above-described holding device, the joint has a thermal resistance of 1.2 × 1 at 25°C. 0 -3 (m 2 It may be less than or equal to (K / W). With this configuration, the operating temperature of the holding device Even at room temperature (25°C), the joint has good thermal conductivity, allowing the plate-like portion to cool rapidly. It can be rejected.

[0011] (4) In the above-described holding device, the joint is heat conduction at 25°C and -60°C. The conductivity may be 0.7 (W / mK) or higher. With this configuration, extremely low temperatures (for example) However, sufficient thermal conductivity can be obtained even at room temperature (-60°C).

[0012] (5) In the above-described holding device, the joint contains aluminum nitride (AlN). This is also acceptable. Doing so results in good flexibility, stress relaxation performance, and good thermal conductivity. This can provide a suitable joint.

[0013] (6) In the holding device of the above form, the amount of strain at the maximum shear stress of the joint is 0.5 (mm) or more is also acceptable. This configuration allows for flexibility and stress relaxation of the joint. This makes it possible to ensure sufficient performance. Therefore, when shear force is applied to the joint... This can reduce damage to the joint.

[0014] (7) In the above-described holding device, a hole that penetrates the base portion and the inner wall of the hole An insulating portion that covers, an end face of the plate-shaped portion in the insulating portion that faces the second surface, and the plate-shaped portion It has a joint for a hole that joins a part, and the joint for a hole is made of the material that constitutes the joint. It may be formed from the same material and may be thinner than the joint. In the holding device, there is a hole that penetrates the base portion, so the plate-shaped portion corresponds to the hole. The area is difficult to cool. Therefore, with this configuration, a hole joint with good thermal conductivity is achieved. Because heat can be dissipated from the part corresponding to the hole in the plate-shaped part via the part, the temperature of the plate-shaped part Non-uniformity can be suppressed.

[0015] This disclosure can be implemented in various forms other than those described above, for example, a semiconductor-made device including a holding device. This can be realized in the form of a manufacturing device, a method for manufacturing a holding device, or a method for forming a joint. [Brief explanation of the drawing]

[0016] [Figure 1] This is an explanatory diagram illustrating the configuration of the electrostatic chuck in the first embodiment. [Figure 2] This is an explanatory diagram illustrating the cross-sectional structure of an electrostatic chuck. [Figure 3] This is an explanatory diagram that summarizes the evaluation results for each sample. [Figure 4] This is an explanatory diagram showing the composition of each sample. [Figure 5] This figure shows the particle size distribution of 10 μm alumina. [Figure 6] This figure shows an SEM image and particle size distribution of 15 μm aluminum nitride. [Figure 7] This figure shows an SEM image and particle size distribution of 5 μm aluminum nitride. [Figure 8] This figure shows an SEM image and particle size distribution of 2 μm aluminum nitride. [Figure 9] This is an explanatory diagram showing the temperature dependence of the thermal conductivity of each sample. [Figure 10] This is an explanatory diagram showing the temperature dependence of the thermal resistance of each sample. [Figure 11] This is an explanatory diagram showing the temperature dependence of the thermal resistance of each sample. [Figure 12] This is a schematic diagram illustrating the method for calculating maximum shear stress and strain. [Figure 13] This figure shows the composition and thermal conductivity of a sample using the first silicone resin. [Figure 14] This figure shows the composition and thermal conductivity of a sample using the first silicone resin. [Figure 15] The triangular diagram of the thermal conductivity of the sample using the first silicone resin is shown. [Figure 16]This figure shows the composition and thermal conductivity of a sample using the second silicone resin. [Figure 17] This figure shows the composition and thermal conductivity of a sample using the second silicone resin. [Figure 18] The triangular diagram of the thermal conductivity of the sample using the second silicone resin is shown. [Figure 19] This is a schematic cross-sectional view showing the configuration of the electrostatic chuck of the second embodiment. [Figure 20] This is an enlarged view of section X in Figure 19. [Modes for carrying out the invention]

[0017] A. First Embodiment: (A-1) Overall configuration of the electrostatic chuck: Figure 1 is an explanatory diagram illustrating the configuration of the electrostatic chuck 10 in the first embodiment. Figure 2 is an explanatory diagram schematically showing the cross-sectional configuration of the electrostatic chuck 10. In Figure 1, the electrostatic chuck A portion of the block 10 is shown broken off. Also, in the figure, to determine the direction, the parts are perpendicular to each other. The intersecting X, Y, and Z axes are shown. For convenience, in this specification, the positive Z-axis direction is referred to as the upward direction. Although the negative Z-axis direction is defined as downward, the electrostatic chuck 10 is actually oriented in such a way. They may be installed in different orientations. The X, Y, and Z axes shown in each figure are in the same orientation. This represents the arrangement of each part. Note that the above diagrams schematically represent the arrangement of each part, and the ratio of the dimensions of each part is not accurate. It does not accurately represent anything.

[0018] The electrostatic chuck 10 is a device that attracts and holds an object by electrostatic attraction, for example, a semi-electrostatic chuck. Used to fix the wafer W (Figure 2), which is the object to be manufactured, inside the vacuum chamber of a conductor manufacturing apparatus. The electrostatic chuck 10 comprises a plate-shaped portion 20, a base portion 30, and a joint portion 40. These are the plate-shaped part 20, the joint part 40, and the base part 3, oriented in the -Z axis direction (vertically downward). They are stacked in order of 0. The electrostatic chuck 10 in this embodiment is also called a "holding device". Bu.

[0019] The plate-like portion 20 has a first surface 24 on which the object is placed, and a second surface which is the back surface of the first surface 24. A substantially circular plate-shaped member having 26, and made of ceramic (for example, aluminum oxide or nitride). Formed primarily from aluminum, etc. In this specification, a specific component is "main "It is an ingredient" or "it is the main forming material" means that the content of the specific ingredient is 50% This means that it is greater than or equal to a certain volume percentage. The diameter of the plate-like portion 20 is, for example, 50 mm to 500 mm. It should be approximately 200mm to 350mm. The thickness of the plate-like part 20 is, for example, For example, it should be about 1 mm to 10 mm. In other embodiments, the plate-like portion 20 is, for example, It may be formed primarily from materials other than ceramics, such as resins like liimide.

[0020] As shown in Figure 2, an adsorption electrode 22 is arranged inside the plate-shaped portion 20. 22 is formed from a conductive material such as tungsten or molybdenum. When a voltage is applied to the electrode 22 from a power source (not shown), an electrostatic attraction is generated, and this static The wafer W is adsorbed and fixed to the first surface 24 of the plate-shaped portion 20 by electroattraction. The adsorption electrode 22 is It may be a bipolar type or a unipolar type. Also, a conductive material is placed inside the plate-shaped part 20. It is composed of a resistance heating element made of a material (for example, tungsten or molybdenum), A heater electrode (not shown) is provided for heating the wafer W adsorbed and fixed to the first surface 24. That's good too.

[0021] The base portion 30 is positioned on the second surface 26 side of the plate-shaped portion 20, supporting the plate-shaped portion 20 and the cooling unit. It is a plate-shaped member that has the function of being formed in a substantially circular shape. The base portion 30 is, for example, aluminum. at least one of magnesium, molybdenum, titanium, tungsten, and nickel It may contain the following metals: Molybdenum, titanium, and tungsten are as described above. Because it has a relatively small coefficient of thermal expansion among metals, at least one of these metals is used. When constructing the base portion 30, the difference in thermal expansion coefficient between the base portion 30 and the plate-shaped portion 20 is suppressed. It is desirable to be able to obtain this. Note that in this specification, "thermal expansion coefficient" is referred to as "linear expansion coefficient". This refers to... Also, because magnesium has a relatively small Young's modulus, magnesium is used in... When constructing the base portion 30, it is desirable to reduce the thermal stress generated in the base portion 30. Furthermore, aluminum has relatively high thermal conductivity, is easy to process, and is inexpensive. Therefore, when aluminum is used to construct the base portion 30, This improves the cooling efficiency of the plate-shaped part 20 and the wafer W, and reduces the manufacturing cost of the electrostatic chuck 10. It is desirable to be able to suppress the cost. The cooling efficiency of the base part 30 is improved while reducing manufacturing costs. From the perspective of suppressing, it is desirable for the metal content in the base part 30 to be high, 30 should preferably be primarily composed of metal. For example, aluminum, which is highly versatile, should be 90 It must contain at least % by mass (for example, aluminum alloys such as A6061 and A5052). It is desirable that the base portion 30 be made of a material other than metal, such as ceramic. It may include minutes. The diameter of the base part 30 is, for example, about 220mm to 550mm. This is sufficient, and is usually 220mm to 350mm. The thickness of the base part 30 is, for example, 2 A size of approximately 0mm to 40mm is appropriate.

[0022] Multiple refrigerant flow paths 32 are formed inside the base portion 30 so as to follow the XY plane. By flowing a refrigerant such as a fluorine-based inert liquid, water, or liquid nitrogen through the refrigerant flow path 32, The base portion 30 is cooled. Then, the base portion 30 and the plate-shaped portion 20 are connected via the joint portion 40. The heat transfer between them cools the plate-shaped portion 20, and the wafer W held on the first surface 24 of the plate-shaped portion 20 is cooled. The wafer W is cooled. This enables temperature control of the wafer W. In addition to the configuration having a medium flow path 32, the base portion 30 is cooled from the outside. Alternatively, the base portion 30 may be provided with a cooling function.

[0023] The joint portion 40 is positioned between the plate-shaped portion 20 and the base portion 30, and the plate-shaped portion 20 and the base portion 30 is joined together. The joint 40 contains an adhesive formed from a resin material. Joint 4 Furthermore, 0 adjusts the properties of the joint 40 and the properties of the paste used to form the joint 40. It may contain various fillers (inorganic fillers) for this purpose. That is, the joint 40 is It can be made of a composite material containing an adhesive and an inorganic filler. However, the joint 40 The joint 40 may not contain inorganic fillers, provided that it satisfies the properties described later. The thickness of the joint 40 is, for example, 1.00 mm or less, from the viewpoint of reducing the thermal resistance of the joint 40. This is sufficient, and a size of 0.60 mm or less is preferable, a size of 0.50 mm or less is more preferable, and 0.3 A thickness of 5 mm or less is even more desirable. The thickness of the joint 40 is, for example, related to the flexibility of the joint 40 and From the viewpoint of ensuring strength, the thickness may be 0.05 mm or more. The junction 40 will be described in detail later .

[0024] The electrostatic chuck 10 is further formed with a plurality of gas supply paths 50. The gas supply path 50 is provided to penetrate through the plate-like portion 20, the junction 40, and the base portion 30 in the Z direction and opens at a gas discharge port 52 formed on the first surface 24 (see FIG. 1). The gas sup ply path 50 is supplied with an inert gas such as helium gas from a gas supply device (not shown) and supplies the inert gas from the gas discharge port 52 into the space between the first surface 24 and the wafer W . This improves heat transfer between the plate-like portion 20 and the wafer W, further improving the controllability of the temperature distribution of the wafer W. Note that the gas supply path 50 is not essential, and the gas supply path 50 may not be provided in the electrostatic chuck 10.

[0025] (A-2) Configuration of Junction: The thermal resistance of the junction 40 included in the electrostatic chuck 10 of the present embodiment is 1.1 ×10 -3 (m 2 K / W) or less. When the thermal resistance of the junction 40 is represented as R(m 2 K / W), the thickness of the junction 40 is t(m), and the thermal conductivity of the junction 40 is λ(W / mK), the thermal resist ance R of the junction 40 is obtained by the following formula (1).

[0026] R(m 2 K / W)=t(m)÷λ(W / mK) …(1)

[0027] In an environment where the electrostatic chuck 10 is exposed to high plasma energy, or when the electrostatic chuck 10 is used in an environment where high power is input thereto, the first surface 24 of the plate-like portion 20 tends to become high temperature For example, under usage conditions where the first surface 24 of the plate-like portion 20 reaches 120°C, the plate-like portion To cool section 20, the temperature of the refrigerant supplied to the base section 30 is set to, for example, about -60°C. It may be set to -60 degrees. When the base part 30 becomes cold, the joint part 40 also becomes cold, so By setting the thermal resistance of the joint 40 at °C to the above value, the temperature of the base 30 can be reduced to an extremely low value. When heated to a temperature (for example, -60°C), the base portion 30 and the plate-shaped portion 20 are connected via the joint portion 40. Heat transfer between them, that is, heat transfer from the plate-shaped part 20 to the base part 30, becomes easier, and electrostatic discharge occurs. The cooling efficiency in the chuck 10 can be improved. As described above, the joint 40 is made of resin The adhesive is composed of a material whose thermal conductivity generally decreases as the temperature rises. In other words, if the thickness of the joint 40 is kept constant, the thermal resistance increases as the temperature rises. It tends to become so. If the thermal resistance of the joint 40 at -60℃ is set to the above value, the joint 4 Sufficient cooling performance can be obtained even when the temperature of 0 rises above -60°C. Therefore, The cooling rate of the surface on which the object is placed (first surface 24) can be improved.

[0028] The thermal conductivity of the joint 40 is not particularly limited, but the thermal conductivity at -60°C is taken as λ1. When the thermal conductivity at 25°C is λ2, it is preferable that λ1 / λ2 is 1.18 or less. Here, 25°C is the room temperature (normal temperature) when using the electrostatic chuck 10. As shown above, adhesives generally have lower thermal conductivity as the temperature rises. Thermal conductivity of joint 40 When the ratio is set as described above, the change in thermal conductivity of the joint 40 due to temperature changes is small. If the change in thermal conductivity due to temperature changes is large, the lower temperature area will be cooled more, and the high temperature area will be cooled more. Because the cooling of the hot portion is slow, there is a risk that the temperature difference between the top and bottom and within the plane of the joint 40 will become large. In contrast, if the thermal conductivity of the joint 40 is as described above, the temperature change of the joint 40 will Because the change in thermal conductivity is small, the temperature difference between the upper and lower parts and within the plane of the joint 40 is suppressed. This can be achieved. In other words, the uniformity of the temperature distribution of the plate-like portion 20 can be improved. λ1 / λ2 is usually greater than or equal to 1.00.

[0029] Regarding the thermal resistance of the joint 40, let θ1 be the thermal resistance at -60°C, and the thermal resistance at 25°C When the resistance is θ2, it is preferable that θ1 / θ2 is 0.85 or greater. As a result, the change in thermal resistance due to temperature changes in the joint 40 is small, and the upper and lower parts of the joint 40 and In other words, the uniformity of the temperature distribution of the plate-like portion 20 can be suppressed. It can be improved. Note that θ1 / θ2 is usually less than or equal to 1.00.

[0030] The thermal resistance of the joint 40 at 25°C is not particularly limited, but is 1.2 × 10⁻⁶. -3 (m 2 K / W) or less is preferable. In this way, the operating temperature of the electrostatic chuck 10 is room temperature (25℃). Even in this case, since the joint 40 has good thermal conductivity, the plate-shaped portion 20 is rapidly cooled. It is possible.

[0031] The amount of strain at maximum shear stress in the joint 40 is not particularly limited, but is preferably 0.5 mm or more. It is more desirable for the thickness to be 1.0 mm or more, and even more desirable for it to be 1.1 mm or more. It is so. Furthermore, the strain at the maximum shear stress of the joint 40 is usually 5.0 mm or less. The strain at maximum shear stress is an indicator of the flexibility and stress relaxation performance of the joint 40. This value represents the maximum shear stress generated at the joint 40 when a shear force is applied to the joint 40. When it becomes large, that is, when the maximum shear stress occurs at the joint 40, This refers to the magnitude of the strain that occurs (the amount of displacement in the direction of the shear force). The amount of strain at maximum shear stress is large. The larger the value, the higher the flexibility of the joint 40. The amount of strain at maximum shear stress is measured. The specific measurement method using a tensile testing machine will be explained in detail later. Joint 4 If the strain amount at maximum shear stress is set to the above value, the flexibility and stress relaxation of the joint 40 will be improved. This makes it possible to ensure sufficient performance. Therefore, when a shear force is applied to the joint 40 This can reduce damage to the joint 40 at that time.

[0032] The lower limit of the thermal resistance of the joint 40 is, for example, 0.6 × 10 -4 (m 2 (K / W) This is possible. In order to reduce the thermal resistance of the joint 40, an inorganic filler is constructed as described above. One possible approach is to appropriately select the materials and increase the proportion of inorganic fillers. However, if the proportion of inorganic filler is increased excessively, the flexibility of the joint 40 will be impaired. Therefore, it may become difficult to sufficiently secure the magnitude of the strain amount at the time of maximum shear stress in the joint 40, as described later. It is possible. Also, in order to reduce the thermal resistance of the joint 40, one method is to make the joint 40 thinner. That is possible. However, if the joint 40 is made excessively thin, the strength of the joint 40 will decrease. At the same time, it becomes difficult to ensure the flexibility of the joint 40, and the strain amount at maximum shear stress becomes a desired number. It may become difficult to keep the value within a certain range. Therefore, the thermal resistance of the joint 40 is as described above. ta 0.6 × 10 -4 (m 2 It is desirable to set it to kW or higher.

[0033] The amount of strain at maximum shear stress in the joint 40 is determined by the adhesive (resin) contained in the joint 40. It can be changed. For example, the maximum shear resistance can be changed depending on the type of resin that makes up the joint 40. In addition to being able to change the amount of strain under force, even when using the same type of resin, the polymer material is resin By controlling the distance between crosslinking points in the resin, the amount of strain at maximum shear stress in the joint 40 can be controlled. It can be changed. Specifically, the content of functional groups that form crosslinking points in the above resin (functional group equivalent). Reducing the crosslinking point increases the distance between crosslinking points, improving the flexibility of the resin, thus reducing the maximum shear The amount of strain under stress can be increased. Also, the content of reactive functional groups in the resin Even in equivalent cases, the distance between crosslinking points can vary depending on curing conditions such as the curing temperature and curing time of the resin. This allows for control over curing temperature, or lengthening the curing time. In this case, the resin hardening progresses further, the crosslinking density increases, and the distance between crosslinking points shortens. Yes.

[0034] Furthermore, the amount of strain at maximum shear stress in the joint 40 can be increased by increasing the thickness of the joint 40. Therefore, it can be made larger.

[0035] Furthermore, the higher the proportion of inorganic filler in the joint 40, the greater the maximum radius of the joint 40. The amount of strain under sectional stress tends to decrease. This is because the amount of strain decreases as the proportion of inorganic filler increases. As a result, the degree to which the inorganic filler restrains the surrounding resin (resin composition) increases, and the flexibility of the joint 40 increases. This is thought to be because the flexibility decreases, making the joint 40 less susceptible to deformation.

[0036] Examples of adhesives that make up the joint 40 include silicone resin, acrylic resin, and Epoxy resins and the like can be used. Silicone resins, in particular, have relatively good heat resistance and It is desirable because of its excellent flexibility. Among these resins, silicone resin has a relatively high elastic modulus. Because it is low, it has a high function of mitigating thermal stress generated at the joint 40, and the heat resistance temperature is relatively low. Because it is expensive, it is desirable.

[0037] Inorganic fillers include ceramics, metal oxides, metals, or other inorganic compounds. Various inorganic materials can be used, in granular or powder form, etc. Specifically Examples of inorganic fillers include aluminum nitride (AlN), aluminum oxide (A Lumina (Al2O3), Zirconium oxide (Zirconia: ZrO2), Yttrium oxide ( Yttria (Y2O3), yttrium fluoride (YF3), silicon carbide (SiC), crystalline nitride Ion (Si3N4), silicon dioxide (silica: SiO2), iron oxide, barium sulfate, carbonate Calcium and the like can be used. The inorganic materials that make up the inorganic filler are generally Furthermore, because it has a higher thermal conductivity than the resin used as an adhesive, an inorganic filler is added to the joint 40. This makes it possible to improve the thermal conductivity at the joint 40. In particular, the thermal conductivity is relatively From the perspective of making it easier to reduce the thermal resistance of the joint 40, the materials constituting the inorganic filler are For this, aluminum nitride, aluminum oxide, and silicon carbide are preferred, and aluminum nitride Aluminum and aluminum oxide are particularly preferred.

[0038] Furthermore, the joint 40 is further equipped with a catalyst to promote the curing reaction and to promote curing and adhesion. Silane coupling agents, crosslinking agents, and reaction agents for adjusting the curing speed of adhesives to impart properties. It may contain a reaction inhibitor or viscosity modifier, etc. The catalyst contained in the joint 40 is: Various conventionally known catalysts can be used, such as platinum catalysts, rhodium catalysts, and titanium catalysts. A catalyst such as a bismuth catalyst can be used. In particular, a highly reactive platinum catalyst can be used. This is desirable. There are no particular restrictions on the silane coupling agent contained in the joint 40, for example, As organic reactive groups, vinyl groups, epoxy groups, methacrylic groups, amino groups, mercapto groups, Among conventionally known silane coupling agents, those having any of the isocyanate groups. You can choose from these as appropriate. Alternatively, instead of the silane coupling agent mentioned above, titane A t-type coupling agent or an aluminate-type coupling agent may be used. The joint 40 includes As a crosslinking agent, organohydrates having at least three hydrosilyl groups in one molecule Polymethyl Hydrogensiloxane and poly(dimethylsiloxane-methylhydrogen) At least one of the following can be used: (roxane)

[0039] Various conventionally known reaction inhibitors can be used as the reaction inhibitor contained in the joint 40. For example, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotet Lasiloxane, 1,1,3,3-tetramethyl-1,3-divinyldisiloxane, Tri Lyl isocyanurate and the like can be used. The viscosity modifier contained in the joint 40 is: Various conventionally known viscosity modifiers can be used, for example, fumed silica, fumed silica Lica, colloidal silica, fumed alumina, colloidal alumina, etc. The above-mentioned catalyst, silane coupling agent, crosslinking agent, reaction inhibitor, and The type and amount of viscosity modifiers, etc., depend, for example, on the type of resin that makes up the joint 40. You can choose as appropriate.

[0040] The thermal resistance of the joint 40 can be reduced by reducing the thickness of the joint 40, according to equation (1). This can be done. For example, by making the thickness of the joint 40 0.5 mm or less, the joint 4 The thermal resistance of 0 at -60°C is 1.1 × 10⁻⁶ -3 (m 2 It is easy to reduce the power consumption to below kW. Furthermore, by increasing the thermal conductivity of the joint 40 to, for example, 0.7 W / mK or higher, the joint Even if the thickness of the joint 40 is greater than 0.5 mm, the thermal resistance of the joint 40 at -60°C remains the same. 1.1 × 10 -3 (m 2 It becomes relatively easy to reduce the heat conduction of the joint 40 to below K / W. To increase the efficiency, for example, inorganic fillers made of materials with higher thermal conductivity can be used, as will be discussed later. This can be achieved by using [a specific material] or by increasing the proportion of inorganic fillers.

[0041] Furthermore, the thermal resistance of the joint 40 is determined by, for example, the material of the inorganic filler contained in the joint 40, and the joint The amount of inorganic filler in the joint 40 and the type of resin contained in the joint 40 can be changed. This is possible by using inorganic fillers composed of materials with higher thermal conductivity. Furthermore, by increasing the content of inorganic fillers, and by increasing the thermal conductivity of the resin By using grease, the thermal conductivity of the joint 40 is increased, and the thermal resistance of the joint 40 is reduced. It is possible.

[0042] Furthermore, the thermal resistance of the joint 40 depends on the shape of the inorganic filler particles contained in the joint 40. It can be changed.

[0043] Inorganic fillers are formed from homogeneous materials, or, for example, the particle bodies of the inorganic fillers are composed of... A coating layer made of a different material may be provided on the surface. By selecting the appropriate type, the water resistance of the inorganic filler can be improved, and the compatibility between the inorganic filler and the resin can be enhanced. This improves the flexibility of the joint 40. For example, an inorganic filler and When using aluminum nitride powder, the aluminum nitride particles that constitute the inorganic filler On its surface, silicon dioxide (SiO2), aluminum oxide (Al2O3), or phosphoric acid. A coating layer containing aluminum (AlPO4) may also be provided.

[0044] In the electrostatic chuck 10, generally, the base portion 30 has a higher coefficient of thermal expansion than the plate-shaped portion 20. It has a high viscosity and expands and contracts significantly with temperature changes. Therefore, depending on the temperature conditions, the base In some cases, the degree to which part 30 expands due to heat may be greater than the degree to which the plate-shaped part 20 expands due to heat. Thus, because the degree of expansion and contraction differs between the plate-like portion 20 and the base portion 30, At the joint 40, a shear force in the X-axis direction is applied, generating shear stress. As described above, the amount of strain at the time of maximum shear stress in the joint 40 is increased. Therefore, even when a large shear force is applied to the joint 40, the shear force generated at the joint 40 This reduces stress and minimizes damage to the joint 40.

[0045] As described above, according to the electrostatic chuck 10 of this embodiment, the electrostatic chuck 10 is equipped The thermal resistance of the joint 40 is 1.1 × 10 at -60°C. -3 (m 2 It is less than or equal to kW. Therefore, when the heat input to the plate-shaped portion 20 is greater, and the base portion 30 is very low Even when the temperature is high (for example, -60°C), the cooling performance of the electrostatic chuck 10 is improved. This is possible. As a result, excessive temperature rise in the plate-like portion 20 is suppressed, and the temperature rise is not a problem. This suppresses the decrease in wafer processing accuracy and also reduces contact due to the temperature difference between the plate-shaped part 20 and the base part 30. This makes it possible to suppress the shear stress generated at the joint 40.

[0046] Furthermore, for the joint 40, the thermal conductivity at -60°C is λ1, and the heat at 25°C is... When conductivity is λ², the ratio λ1 / λ² is 1.18 or less, or the thermal resistance at -60°C is defined as follows: Let θ1 be the temperature and θ2 be the thermal resistance at 25°C. Then, θ1 / θ2 must be 0.85 or greater. Therefore, the change in thermal conductivity of the joint 40 due to temperature changes can be reduced, This can suppress temperature differences between the top and bottom, and within the plane, of the 40.

[0047] Furthermore, the thermal resistance of the joint 40 at 25°C is 1.2 × 10 -3 (m 2 (K / W) or less As a result, even when the electrostatic chuck 10 is used at room temperature (25°C), the joint 40 maintains good heat. Because it is conductive, the plate-shaped portion 20 can be rapidly cooled.

[0048] Furthermore, the greater the strain at maximum shear stress in the joint 40, the greater the stress relaxation in the joint 40. To improve performance, the strain amount at maximum shear stress in the joint 40 should be 0.5 mm or more. Therefore, even if shear stress occurs at the joint 40, the joint caused by shear stress Damage to the joint 40 can be minimized.

[0049] Such effects are particularly pronounced when the electrostatic chuck 10 is exposed to higher-power plasma. As shown above, this is particularly noticeable when the heat input to the plate-like portion is large. For example, the plate-like portion 20 Even without a heater electrode for heating, the electrostatic pulse is produced along with high plasma power. When using the jack 10, the temperature difference between the mounting surface of the plate-shaped part 20 and the base part 30 is large. Because it is easily activated, the effects of this embodiment are significantly obtained. [Examples]

[0050] The holding device of this disclosure will be described below based on examples. Here, heat conduction In various joints where at least one of the ratio, thermal resistance, and strain at maximum shear stress differs As corresponding samples, sheet-like samples, Samples 1 through 11, were prepared. , a sample in the form of an electrostatic chuck having a joint with the same composition as each sheet-like sample 1 to 11 A wire was fabricated. Below, the electrostatic chuck-type sample is also described using the same composition as the joint. It is referred to by the same sample number as the sheet-shaped sample.

[0051] Figure 3 shows the thickness of the joint, thermal conductivity (-60°C, 25°C), and ratio of thermal conductivity for each sample. (-60℃ / 25℃), thermal resistance, thermal resistance ratio (-60℃ / 25℃), strain at maximum shear stress Along with the values ​​of the amount of heat, the evaluation results of the temperature distribution of the plate-like part in the electrostatic chuck and the cooling rate were also obtained. This is an explanatory diagram showing the overall composition. Figure 4 is an explanatory diagram showing the composition of each sample. Figure 5 is a diagram showing the composition of each sample. This figure shows the particle size distribution of 10 μm alumina used in the sample. Figure 6 shows the particle size distribution of the sample used This figure shows the SEM image and particle size distribution of 15 μm aluminum nitride. Figure 7 shows This figure shows the SEM image and particle size distribution of 5 μm aluminum nitride used as a sample. Figure 8 shows the SEM image and particle size distribution of 2 μm aluminum nitride used in the sample. Figure 9 is an explanatory diagram showing the temperature dependence of the thermal conductivity of each sample. Figures 10 and 11 are explanatory diagrams showing the temperature dependence of the thermal resistance of each sample. 1 shows the results for samples with a thickness of 0.5 mm (Samples 1, 3, 4, 6, 8, 10). Figure 11 shows samples 1, 3, 4, and 6, magnified (the maximum value on the vertical axis is smaller than in Figure 10). (It is shown by)

[0052] <Preparation of each sample> [Preparation of sheet-like samples] In each sample, silicone resin was used as the adhesive. Specifically, the bonding was performed before curing. The agent material (resin material) contains polydimethylsiloxane and 5 mol% phenyl groups. One of the polydimethylsiloxanes was used. Specifically, samples 1-3 were ferrosiloxane. Using polydimethylsiloxane containing 5 mol% of nyl groups, samples 4-11 were polydimethylsiloxane. Lusiloxane was used, as shown in Figure 4. Samples 1 and 2, Samples 4 and 5, Sample Samples 6 and 7, 8 and 9, and 10 and 11 each have the same composition, as shown in Figure 3. As shown, one has a thickness of 0.5 mm and the other has a thickness of 1 mm. The composition is as shown in Figure 4.

[0053] The filler shown in Figure 4, "Alumina 10μm", has an average particle size of 10μm. These are alumina particles, and their BET specific surface area is 1.3 m². 2 The particle size distribution is shown in Figure 5. As stated above, the average particle size was determined using the particle size distribution by the following method. The shape of the 10 μm mina is approximately spherical (Figure 4). Here, when the filler is viewed in cross-section... When the radius of the tangent circle is R1 and the radius of the circumscribed circle is R2, what is the average value of "R2 / R1"? A value close to 1.0 (for example, less than 1.05) is considered a "perfect sphere". The average particle size can be measured using a known particle size distribution analyzer. After distributing the data, the cumulative frequency is measured using, for example, a Microtrac MT3000II. The diameter at which 50% of the particles are found was defined as the average particle diameter. The method for determining the average particle diameter is as follows for aluminum nitride. The same applies to the latter.

[0054] "Aluminum nitride 15μm" refers to aluminum nitride particles with an average particle size of 15μm. The BET specific surface area is 0.9m². 2 The particle size distribution is as shown in Figure 6. "Aluminum nitride 5μm" refers to aluminum nitride particles with an average particle diameter of 5μm, and BE The specific surface area is 1.3 m². 2 The particle size distribution is as shown in Figure 7. "Minium 2μm" refers to aluminum nitride particles with an average particle diameter of 2μm, and has a BET surface ratio. The volume is 2.8m 2 The particle size distribution is as shown in Figure 8. The shape is angular granular. Here, "angular granular" refers to the SEM (scanning electron microscope) shown in Figures 6-8. As shown in the image, it is an angular, amorphous particle, not a rectangular prism, perfect sphere, rod-shaped, or plate-shaped. Yes. If the particle shape of the filler is not a perfect sphere and has corners, the number of contact points between particles increases. This makes it easier for heat conduction paths to form within the joint 40, and reduces the thermal resistance of the joint 40.

[0055] The method for preparing the sheet-like sample is as follows: A paste-like adhesive was prepared by mixing a filler and silicone resin. The mixing method was carefully controlled. There are no limits, including mixing with known stirring blades, three-roll mixers, kneaders, self-rotating / revolving mixers, and p A laminar mixer or the like can be used. The paste-like adhesive prepared is publicly known The coating device spreads the material onto a release-type film and allows it to harden, creating a sheet-like sample. A coating can be obtained. Coating equipment includes, for example, a roll coater, a bar coater, and a die coater. A painter, knife coater, etc. can be used. For release films, for example, Polyethylene terephthalate (PET) film can be used to improve release properties. A PET film coated with a mold release agent may also be used. To obtain a thick, block-shaped hardened material, the adhesive is placed in a container of a predetermined size. It may harden after being placed inside. Use a container made of polytetrafluoroethylene (PTFE). This makes it easier to remove and more suitable. Heating may be used as needed for hardening.

[0056] [Preparation of electrostatic chuck-type samples] The electrostatic chucks of Samples 1 to 12 are all electrostatic chucks of the first embodiment shown in Figure 2. It has the same configuration as chuck 10. A sample of the electrostatic chuck 10 is the semi-rigid described above. The prepared adhesive paste is placed between the plate-shaped part 20 and the base part 30, and then the adhesive paste It was manufactured by hardening the starch. The plate-like portion 20 was made of aluminum oxide. A plate-like section (with a thermal expansion coefficient of 7 ppm / K) is used, and the base section 30 is made of aluminum. A base portion made of nium (thermal expansion coefficient 23 ppm / K) was used. Plate-shaped portion 20 The diameter of the joint was set at 350 mm.

[0057] <Evaluation Method> • Thermal conductivity Thermal conductivity is measured using a known thermal conductivity meter (Agne thermal conductivity meter) on a block-shaped sample. The rate was measured using the ARC-TC-1000 rate measuring device and the hot-wire method (probe method). Furthermore, instead of block-shaped samples, the target is the joint incorporated into the electrostatic chuck. When measuring thermal conductivity, the plate-shaped part of the electrostatic chuck is ground off using a surface grinder or the like, and the joint part After exposing the material, the joint can be peeled away using a knife or similar tool, and the thermal conductivity can then be measured. .

[0058] ·Thermal resistance The thermal resistance R is calculated using the measured thermal conductivity values ​​of each sample as described above, as follows: This was obtained using equation (1). In equation (1), t is the thickness of the joint and λ is the heat of the joint. Conductivity, that is, the thermal conductivity of each sample measured as described above.

[0059] R(m 2 K / W) = t(m) ÷ λ(W / mK) …(1)

[0060] • Maximum shear stress and strain The strain amount at maximum shear stress is measured using a known tensile testing machine (Shimadzu Autograph AGS-). Measurements were taken using a 5kNX (5kNX) tensile test.

[0061] Figure 12 is a schematic diagram illustrating the method for calculating the maximum shear stress and strain. Figure 12(A) shows the tensile test viewed from the front, and Figures 12(B) and 12(C) are Figures 12(A) and 12(B) show the view from the side. Figure 12(C) shows the child, and the situation after the start of the test. The 70 test pieces of samples 1 to 12 are Two semi-cured adhesive sheets for each sample, measuring 25mm wide x 100mm long x 1mm thick. A 25mm x 12.5mm section of aluminum plate 80, 12.5mm from the edge. They are attached to each other, and the two aluminum plates 80 can be pulled in opposite directions. The above-mentioned semi-cured adhesive sheet was produced by bonding the two pieces together in the same orientation and then curing it. The thickness t of the test specimen 70 at the start of the test was the thickness of the joint shown in Figures 8 to 11. Next, Two aluminum plates 80 were used as fixtures for a tensile test so that a shear force would act on the above test specimen. They were gripped and moved relative to each other. Here, a tensile testing machine was used to connect one of the aluminum plates. While moving in one direction parallel to the contact surface at a tensile speed of 2 mm / min, the load and the distance moved are measured. The amount of strain δ was measured (see Figure 12(C)). The tensile testing machine and fixtures were sufficiently rigid. Using a high-strength material, the distance traveled by the jig and fixture of the tensile testing machine was defined as the strain amount δ. In Figure 12(B), The relative direction of movement of the two aluminum plates is indicated by white arrows. Load transfer The shear stress is calculated by dividing it by the bonding area of ​​the previous test specimen (25 mm × 12.5 mm). This relative movement of the two aluminum plates was continued until the test piece 70 fractured. The shear stress at which the shear stress reaches its maximum is defined as the maximum shear stress (in MPa). The strain at maximum shear stress (in mm) was obtained in the tensile test shown in Figure 12. The strain amount δ was defined as the amount when the tensile stress was at its maximum. Note that it was already incorporated into the electrostatic chuck. When measuring the maximum shear stress strain at a joined joint, for example, as follows: First, the joint is formed by a processing method such as laser cutting on the adherend (plate-shaped part and base). Cut out section by section. The shape of the cut-out test piece can be held by the jig of the tensile testing machine. Furthermore, the two joined adherends are pulled in opposite directions, as shown in Figure 12. Any shape that allows for this is acceptable. Before performing the tensile test, the joints in the cut test piece Measure the area and the thickness of the joint. Then, perform a tensile test in the same manner as described above. The process should be carried out, and the amount of strain at maximum shear stress should be measured.

[0062] • Temperature distribution of the plate-like portion For each of the electrostatic chuck samples 1 to 11, the temperature distribution of the plate-like portion was evaluated. Specifically The average surface temperature of the plate-like portion of each sample is kept constant at approximately 100°C over time. The plate-shaped part was heated, and at the same time, a refrigerant at -60°C was supplied to the refrigerant flow path of the base part to cool it. At that time, a temperature difference of less than 2°C between the maximum and minimum surface temperature of the plate-like part is marked "◎", and a temperature difference of 2°C or more but less than 5°C is marked "◎". A perfect temperature was rated as "○", and a temperature of 5°C or higher was rated as "×". The surface temperature of the plate-like portion and its change over time are shown in red. Measurements were taken using an external radiation thermometer. The plate-shaped part was heated by irradiating it with plasma. It can be done. Also, if a heater electrode is provided on the plate-shaped part, heating can be done by passing current through the heater electrode. It may also be used in combination with heating by plasma irradiation.

[0063] • Cooling rate of the plate-shaped portion For each of the electrostatic chuck samples 1 to 11, the same method as described above for evaluating the temperature distribution of the plate-like portion applies. The plate-like part is heated so that the average surface temperature of the plate-like part remains constant at approximately 100°C over time. At the same time, -60°C refrigerant is supplied to the refrigerant flow path of the base section to cool it, and then the plate-shaped section is heated. The heating of the plate-shaped part was stopped, and the cooling of the base part was continued. The time when the heating of the plate-shaped part was stopped was used as the starting point for the plate-shaped part. The change in the average surface temperature over time was measured. The average temperature of the plate-like portion cooled to below 0°C. Measure the time required and evaluate it as "○" if it is 15 seconds or less, and "×" if it exceeds 15 seconds. Ta.

[0064] Samples 1-7 meet the requirements of [1] below. [1] The thermal resistance of the joint is 1.1 × 10 at -60°C. -3 (m 2 It is less than or equal to kW.

[0065] Samples 1-3 satisfy the requirements of [1] above, as well as the requirements of [2] and [3] below. It is doing so. [2] The joint has a thermal conductivity of λ1 at -60°C and a thermal conductivity of λ2 at 25°C. In this case, λ1 / λ2 is less than or equal to 1.18. [3] The joint is defined as having a thermal resistance of θ1 at -60°C and a thermal resistance of θ2 at 25°C. In this case, θ1 / θ2 is 0.85 or greater.

[0066] Samples 1-6 meet the requirements of [1] above, as well as the requirements of [4] below. ru. [4] The joint has a thermal resistance of 1.2 × 10 at 25°C. -3 (m 2 It is less than or equal to kW.

[0067] Samples 1-7 also meet the requirements of [5] below. [5] The joint shall have a thermal conductivity of 0.7 (W / mK) or higher at 25°C and -60°C. ru.

[0068] Samples 1, 2, 4, and 5 also meet the requirements of [6] below. [6] The joint contains aluminum nitride (AlN).

[0069] Samples 1-7 also meet the requirements of [7] below. [7] The strain at the joint under maximum shear stress shall be 0.5 mm or more.

[0070] Thus, samples 8 to 11 satisfy at least all of the requirements in [1] above. There were no such findings, and the evaluation of the temperature distribution and cooling rate of the plate-like portion was marked as "×" (Figure 3).

[0071] As shown in Figure 3, Sample 1~ 7 The temperature distribution and cooling rate were evaluated as "○" or "◎", indicating good performance. In other words, by satisfying the above requirement [1], it can be said that good heat transfer from the plate-like portion to the base portion was achieved.

[0072] Furthermore, Samples 1-3 satisfy the requirements of [2] and [3] above, as shown in Figures 9 and 11. As shown, there is no temperature range in which thermal conductivity and thermal resistance change rapidly. Samples 4-7 are Compared to samples 8-11, it has lower thermal resistance and can rapidly cool the plate-like portion. The thermal conductivity and thermal resistance change rapidly in the range of -20°C to -40°C (Figure 9, Figure 1). 1) As a result, the parts of the plate-like section that are at a lower temperature are cooled more, thus improving temperature uniformity. There is a risk that the thermal conductivity and thermal resistance will decrease. In contrast, as mentioned above, samples 1-3 have thermal conductivity and thermal resistance Because there is no temperature range in which the resistance changes rapidly, the temperature uniformity of the plate-like portion is better than that of samples 4-7. That is the case.

[0073] Samples 1-7 meet the requirements of [5] above, and their temperature distribution and cooling rate can be evaluated. The performance is good. The thermal conductivity of the joint is 0.7 (W / mK) at 25°C and -60°C. With these specifications, sufficient thermal conductivity can be obtained across a range from extremely low temperatures to room temperature.

[0074] Samples 1, 2, 4, and 5 contain aluminum nitride (AlN) as a filler. Samples 3, 6, and 7 contain alumina as a filler (Figure 4). Therefore, Samples 1, 2, 4, and 5 have higher thermal conductivity than samples 3, 6, and 7, and thermal resistance The resistance is low (Figures 3, 9-11), and the cooling rate of the plate-like portion is faster than that of 3, 6, and 7.

[0075] Samples 1, 3, 4, and 6 have a strain of 0.5 mm or more at maximum shear stress. Shear stress strain is a value that represents flexibility and stress relaxation performance, and is 0.5m If m or more, sufficient flexibility and stress relaxation performance of the electrostatic chuck joint must be ensured. This becomes possible.

[0076] <Investigation of methods for adjusting thermal conductivity> In order to create a material capable of forming the joint 40 of the above embodiment, the thermal conductivity of the forming material is adjusted. We considered the methods. Specifically, the type of silicone resin (silicone adhesive) and the filler. Multiple samples with different types and proportions were prepared, and their thermal conductivity was measured. For details, see Section 1. 1. As a silicone resin, the main component is polydimethylsiloxane containing 5 mol% phenyl groups. Using a silicone resin, polydimethylsiloxane is mainly used as the second silicone resin. A silicone resin was used. As a filler, aluminum nitride with different particle sizes was used. Three types (15 μm, 5 μm, 2 μm) were used. First silicone resin, second silicone resin Silicone resin that hardens and bonds when heated together (silicone adhesive) It is a chemical agent, and in addition to its main component, it contains known silane coupling agents and polydimethylsiloxane structures. It also contains a crosslinking agent with functional groups necessary for curing, a silicone curing catalyst, and the like.

[0077] Figures 13 and 14 show the composition and thermal conductivity of the sample using the first silicone resin. Yes. Figure 15 shows a triangular diagram of the thermal conductivity of a sample using the first silicone resin. Figure 1 6. Figure 17 shows the composition and thermal conductivity of a sample using the second silicone resin. Figure 18 shows a triangular diagram of the thermal conductivity of a sample using the second silicone resin. (Figure 15, Figure 18) In figure 18, the axis represents the weight ratio, and conductivity is illustrated next to the point. Figures 13 and 1 4. The thermal conductivity values ​​in Figures 16 and 17 were measured using a thermal conductivity measuring device manufactured by C-THERM. The measurements were taken using TCi. Note that the thermal conductivity shown in Figure 3 above is from Agne's thermal conductivity measurement system. The measurement was performed using the ARC-TC-1000 instrument and the hot-wire method (probe method). Although the relative magnitudes of the measurement results do not change due to the different mechanisms, the values ​​themselves are not necessarily They don't match.

[0078] The composition of sample S1 shown in Figure 13 is consistent with the compositions of samples 1 and 2 shown in Figure 4. 13. In Figure 14, the thermal conductivity of sample S1 is set as the baseline ("1"), and the heat of the remaining samples is calculated. The conductivity is shown as the "ratio of thermal conductivity". Also, the composition of sample S18 shown in Figure 16. This matches the composition of samples 4 and 5 shown in Figure 4. In Figures 16 and 17, sample S18 The thermal conductivity of one sample is set as the baseline ("1"), and the thermal conductivity of the remaining samples is set as the "ratio of thermal conductivity". It is showing.

[0079] Figure 15 shows a box around the thermal conductivity of 1.35 W / mK or higher. Also, in Figure 18... Figures 15 and 18 show a box around the thermal conductivity of 1.30 W / mK or higher. As shown, whether using the first silicone resin or the second silicone resin, A higher proportion of 15µm particles resulted in higher thermal conductivity. However, The thermal conductivity is higher when 5µm and 2µm particles are added compared to when only particles are used. This result was obtained. This is thought to be because smaller particles were placed between larger particles, resulting in closer proximity between the particles. .

[0080] Adhesives whose thermal conductivity does not change significantly have phase transition temperatures such as glass transition temperature and crystallization temperature. This adhesive does not have a temperature range within which it can be used. Such adhesives are silicone-based adhesives. Among them, this is a silicone adhesive containing 5 mol% phenyl groups. Phenyl groups are stereochemical Due to the significant damage, it is presumed that the material does not crystallize even at low temperatures, remains flexible, and exhibits minimal changes in thermal conductivity. .

[0081] High thermal conductivity in silicone adhesives can be achieved by incorporating inorganic fillers. For derivation, a large amount of filler needs to be incorporated, but the shape of the filler that can be incorporated in large quantities is true They are spherical or granular. Rod-shaped, plate-shaped, or needle-shaped ingredients reduce fluidity, so they should not be used in large quantities. This is difficult, and even a small amount increases the hardness of the adhesive, so thermal expansion is a problem, unlike with electrostatic chucks. It cannot be used for joining materials with different ratios.

[0082] To further increase the thermal conductivity of adhesives containing fillers, the shape of the fillers should be more spherical than a perfect sphere. Granular form is more preferable. There are many places where the filler particles are in contact with each other or as close together as possible. It is preferable to do so. In the case of granular form, there are protrusions and depressions in some parts, so the adjacent granules This is thought to be because it increases contact with children.

[0083] From the viewpoint of increasing the thermal conductivity of the adhesive, it is preferable to have aromatic functional groups. Aromatic functional groups The one containing the aromatic functional group has a higher density, and when blended in the same weight ratio, the one containing the aromatic functional group has a higher volume ratio. The reason for the lower content is thought to be that the resin content decreases and the filler content increases. Another reason is that polypolymer Pi bonds, like those in aromatic groups, have better thermal conductivity than sigma bonds, like those in tylsiloxane. It is thought that the price is high. Also, aromatic groups are found in alumina and aluminum nitride. It can coordinate to metal atoms such as 'mu' and to phosphorus atoms contained in surface treatment agents. Therefore, it contributes to lowering the thermal resistance at the interface between the filler and the adhesive, thereby increasing the overall thermal conductivity. That is also a possibility.

[0084] B. Second Embodiment: Figure 19 is a schematic cross-sectional view showing the configuration of the electrostatic chuck 10A of the second embodiment. 20 is an enlarged view of section X in Figure 19. The electrostatic chuck 10A of the second embodiment is In addition to the electrostatic chuck 10 of the first embodiment, it is equipped with a terminal through hole 60 (Figure 19). Second embodiment In the electrostatic chuck 10A of the embodiment, the part common to the electrostatic chuck 10 of the first embodiment The same reference number is assigned. The terminal through-hole 60 is also simply called the "hole."

[0085] As shown in Figure 19, the terminal through-hole 60 penetrates the base portion 30A and the joint portion 40A. Furthermore, the plate-shaped portion 20A extends to below the adsorption electrode 22. Within the terminal through hole 60 The electrode terminal 62 is positioned and is electrically connected to the adsorption electrode 22 via via 72.

[0086] For more details, as shown in Figure 20, vias 72 are connected to the adsorption electrode 22 in the plate-shaped portion 20A. A conductive electrode pad 74 is positioned. In this embodiment, the electrode pad is viewed in the Z-axis direction. The shape of 74 is approximately circular. The electrode pad 74 and via 72 are made of a conductive material (for example, It is formed from materials such as tungsten and molybdenum.

[0087] Within the terminal through-hole 60 formed in the base portion 30A, there is a columnar electrode end extending in the Z-axis direction. Child 62 is positioned. In this embodiment, the cross-section of the electrode terminal 62 (cross-section parallel to the plane direction) It is circular. The upper end of the electrode terminal 62 reaches the electrode pad 74, and the electrode terminal 62 It is joined to the electrode pad 74, for example, by a joint made of metal brazing material.

[0088] The electrode terminal 62 located in the terminal through hole 60 of the base part 30A and the base part 30A To provide insulation between them, an insulating part 64 is placed inside the terminal through-hole 60 of the base part 30A. The insulating portion 64 is interposed between the electrode terminal 62 and the surface of the terminal through hole 60. The pole terminal 62 is continuously surrounded. The insulating part 64 is made of, for example, resin or ceramics. It is made of insulating material. In this embodiment, the thermal conductivity of the insulating part 64 is the same as that of the plate-shaped part 20 The thermal conductivity of A is lower than that of the insulating part 64 (i.e., the thermal conductivity of the plate-shaped part 20A is lower than that of the insulating part 64). (High). Furthermore, around the insulating part 64, specifically between the insulating part 64 and the electrode terminal 62, Between the insulating part 64 and the plate-shaped part 20A, and between the insulating part 64 and the base part 30A, there is a joint for holes. 66 is positioned. The hole joint 66 is made of the same material as the material that constitutes the joint 40A. It is formed from the above, and the insulating part 64 is joined to the electrode terminal 62, the plate-shaped part 20A, and the base part 30A. In detail, the hole joint 66 is located opposite the second surface 26 of the plate-shaped portion 20A in the insulating portion 64. The facing end face 64S and the plate-like portion 20A are joined. In addition, the hole-joint portion 66 is joined to the joint portion 40 It is thinner than A. The terminal through-hole 60 has low thermal conductivity within the base part 30A. Therefore, this can easily cause temperature differences in the temperature distribution of the plate-like portion 20A. The thermal conductivity of the material used and the material constituting the base portion 30A is different from that of the material constituting the joint portion 40A. Because the material is lower, the joint portion 66 for the hole is made thinner than the joint portion 40A, which reduces the thermal conductivity. This suppresses the occurrence of temperature differences and reduces the possibility of temperature variations.

[0089] The configuration for supplying power to the adsorption electrode 22 is as described above. When using the electrostatic chuck 10 The adsorption electrode 22 is connected to an electrode terminal 62, an electrode pad 74, and vias from a power source (not shown). A voltage is applied through the conductive path from 72 to the adsorption electrode 22. This allows An electrostatic attraction force is generated to fix EHA W to the adsorption surface S1.

[0090] In the terminal through hole 60, an insulating part is used using a resin adhesive such as a general silicone adhesive. When 64 and the electrostatic chuck 10A are joined, the thermal conductivity of the adhesive is poor, so the plate-shaped part 2 At 0A, the heat dissipation of the portion corresponding to the terminal through hole 60 decreases, and the first of the plate-shaped portion 20A There is a risk that the temperature non-uniformity on surface 24 will increase. In contrast to this, the electrostatic chip of this embodiment According to the jack 10A, it is a hole formed from the same material as the joint 40A and has good thermal conductivity. The portion of the plate-shaped part 20A corresponding to the terminal through-hole 60 is used to dissipate heat via the joint portion 66. This makes it possible to further suppress temperature non-uniformity in the plate-like portion 20A.

[0091] This disclosure is not limited to the embodiments described above, but may extend to the extent that it does not depart from the spirit thereof. It can be realized in various configurations. For example, in each of the embodiments described in the section on the summary of the invention... The technical features in the embodiments corresponding to the technical features solve some or all of the above-mentioned problems. For this purpose, or to achieve some or all of the effects described above, substitutions or combinations may be made as appropriate. Combination can be performed. In addition, if the technical feature is not described as being essential in this specification , it can be deleted as appropriate.

[0092] The present disclosure can also be implemented as the following application examples. [Application Example 1] A holding device for holding an object, comprising: a plate-shaped portion formed in a plate shape having a first surface on the side where the object is placed and a second surface that is the back surface of the first surface; ; a base portion arranged on the second surface side of the plate-shaped portion, supporting the plate-shaped portion, having a cooling function, and formed in a plate shape; ; a joint portion arranged between the plate-shaped portion and the base portion and joining the plate-shaped portion and the base portion; , wherein the thermal resistance of the joint portion is 1.1×10 -3 (m 2 K / W) or less at -60°C , holding device. [Application Example 2] The holding device according to Application Example 1, wherein the joint portion satisfies: when λ1 is the thermal conductivity at -60°C and λ2 is the thermal conductivity at 25°C, λ 1 / λ2 is 1.18 or less, and when θ1 is the thermal resistance at -60°C and θ2 is the thermal resistance at 25°C, θ1 / θ2 is 0.85 or more, at least one of which is satisfied , holding device. [Application Example 3] The holding device according to Application Example 1 or 2, wherein the joint portion has a thermal resistance of 1.2×10 -3 (m 2 K / W) or less at 25°C , characterized in that holding device. [Application Example 4] A holding device according to any one of Application Examples 1 to 3, The aforementioned joint has a thermal conductivity of 0.7 (W / mK) or higher at 25°C and -60°C. Characterized by, holding device. [Application Example 5] A holding device according to any one of Application Examples 1 to 4, The aforementioned joint is characterized by containing aluminum nitride (AlN). holding device. [Application Example 6] A holding device according to any one of Application Examples 1 to 5, The aforementioned joint is characterized by having a maximum shear stress strain of 0.5 mm or more. ru, holding device. [Application Example 7] A holding device according to any one of Application Examples 1 to 6, The hole that penetrates the base portion, An insulating portion covering the inner wall of the aforementioned hole, The end face of the plate-shaped portion in the insulating portion that faces the second surface of the plate-shaped portion is joined to the plate-shaped portion. A joint for a hole, It has, The aforementioned hole joint is formed from the same material as the material constituting the joint, Furthermore, it is characterized by being thinner than the aforementioned joint portion. holding device. [Explanation of Symbols]

[0093] 10, 10A... Electrostatic chuck 20, 20A...plate-shaped part 22...Adsorption electrode 24...Side 1 26…Second side 30, 30A... Base section 32… Refrigerant flow path 40, 40A...joint 50…Gas supply lines 52...Gas outlet 60...Through hole for terminal 62...Electrode terminal 64...Insulation 64S…end face 66...Joint part for hole 70…Test piece 72... Beer 74… Electrode pads 80…Aluminum plate W...wafer

Claims

1. A holding device for holding an object, A plate-like portion formed in a plate shape having a first surface on which the object is placed and a second surface which is the back surface of the first surface, A base portion is positioned on the second surface side of the plate-shaped portion, supports the plate-shaped portion, has a cooling function, and is formed in the shape of a plate, A joint portion is positioned between the plate-like portion and the base portion and joins the plate-like portion and the base portion, Equipped with, The aforementioned joint includes an adhesive formed from a resin material. The thermal resistance of the aforementioned joint is 1.1 × 10 at -60°C. -3 (m 2 It is less than or equal to kW, The thermal conductivity of the aforementioned joint is 0.92 (W / mK) or higher at -60°C. The thermal resistance of the aforementioned joint is characterized by being 4.59 × 10⁻⁴ (m² K / W) or more at -60°C. holding device.

2. A holding device according to claim 1, The aforementioned joint is When the thermal conductivity at -60°C is λ1 and the thermal conductivity at 25°C is λ2, then λ1 / λ2 must be 1.18 or less, and When the thermal resistance at -60°C is θ1 and the thermal resistance at 25°C is θ2, the ratio θ1 / θ2 must be 0.85 or greater. Characterized by satisfying at least one of the following conditions: holding device.

3. A holding device according to claim 1, The aforementioned joint has a thermal resistance of 1.2 × 10 at 25°C. -3 (m 2 Characterized by being less than or equal to kW, holding device.

4. A holding device according to claim 3, The aforementioned joint is characterized in that its thermal resistance at 25°C is 5.05 × 10⁻⁴ (m² K / W) or more. holding device.

5. A holding device according to any one of claims 1 to 4, The aforementioned joint is characterized in that its thermal conductivity at 25°C and -60°C is 0.7 (W / mK) or higher. holding device.

6. A holding device according to any one of claims 1 to 4, The aforementioned joint is characterized by containing aluminum nitride (AlN). holding device.

7. A holding device according to any one of claims 1 to 4, The maximum shear stress strain at the joint is characterized by being 0.5 mm or more. holding device.

8. A holding device according to any one of claims 1 to 4, The hole that penetrates the base portion, An insulating portion covering the inner wall of the aforementioned hole, The insulating portion has an end face facing the second surface of the plate-shaped portion and a hole-joining portion that joins the plate-shaped portion, It has, The aforementioned hole joint is formed from the same material as the material constituting the joint, and is characterized by being thinner than the joint. Holding device.

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