Electrostatic chuck device, method for manufacturing electrostatic chuck device, and method for manufacturing stack

Abstract

This electrostatic chuck device comprises: an electrostatic chuck member having a dielectric substrate and an internal electrode; a base formed of a conductive ceramic-containing material; and a joining layer made of a metal material and joining the electrostatic chuck member and the base. The joining layer is structured as a stack in which a first metal layer and a second metal layer are stacked. The first metal layer contains Ag or Al in a total amount of 50 vol.% or more with respect to the total volume of the first metal layer, the second metal layer is a layer containing at least one active metal selected from the group consisting of Ti, Zr, Hf, and Nb, and the second metal layer is sandwiched between the base and the first metal layer and / or between the electrostatic chuck member and the first metal layer.

Description

Electrostatic chuck device, method for manufacturing electrostatic chuck device, and method for manufacturing laminate

[0001] The present invention relates to an electrostatic chuck device, a method for manufacturing an electrostatic chuck device, and a method for manufacturing a laminate. This application claims priority to Japanese Patent Application No. 2024-108781, filed on July 5, 2024, the contents of which are incorporated herein by reference.

[0002] Conventionally, in semiconductor manufacturing processes for manufacturing semiconductors such as ICs, LSIs, and VLSIs, an electrostatic chuck device is used to electrostatically attract a plate-like sample such as a silicon wafer when performing plasma processing on the plate-like sample. In the electrostatic chuck device, an electrostatic chuck member and a metal base are stacked with a bonding layer interposed therebetween. This bonding layer is generally formed using a resin adhesive (see, for example, Patent Document 1).

[0003] In recent years, with the diversification of semiconductor processes, the temperature of plate-shaped samples being processed has come to be controlled over a wider temperature range than in the past. However, the above-mentioned resin adhesive has lower thermal conductivity than a metal base. Therefore, when controlling the temperature of a wafer over a wide temperature range, in an electrostatic chuck device in which the electrostatic chuck member and the base are bonded together with a resin adhesive, heat transfer between the electrostatic chuck member and the base is hindered, making stable temperature control difficult.

[0004] In order to solve such problems, Patent Document 2 proposes an electrostatic chuck device in which a bonding layer that bonds an electrostatic chuck member to a metal base is bonded (brazed) with an inorganic bonding material such as a metallic material. Note that brazing generally refers to a method of bonding base materials together by melting a material with a lower melting point than the base materials and then allowing the material to penetrate, diffuse, cool, and solidify due to capillary action.

[0005] JP 2022-133003 A JP 2023-1603 A

[0006] However, when the electrostatic chuck member made of ceramics and the base are brazed together using a metal material, there is a problem in that voids or streak-like defects may occur in the joint.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electrostatic chuck device in which an electrostatic chuck member made of a ceramic material and a base are brazed together, and a method for manufacturing an electrostatic chuck device and a laminated body in which an objective product is obtained by suitably brazing the electrostatic chuck member and the base together.

[0008] The inventors have conducted research and found that defects occur when an electrostatic chuck member and a base are joined using a brazing filler metal containing Ti. Based on this knowledge, the inventors have conducted extensive research and have completed the present invention.

[0009] [1] An electrostatic chuck device comprising: an electrostatic chuck member having a dielectric substrate and an internal electrode; a base formed of a conductive material containing ceramic; and a bonding layer made of a metal material bonding the electrostatic chuck member to the base, wherein the bonding layer has a laminated structure in which a first metal layer and a second metal layer are laminated; the first metal layer contains a total of 50 volume % or more of Ag or Al with respect to a total volume of the first metal layer; the second metal layer is a layer containing at least one active metal selected from the group consisting of Ti, Zr, Hf, and Nb; and the second metal layer is sandwiched between the base and the first metal layer and / or between the electrostatic chuck member and the first metal layer.

[0010] [2] The electrostatic chuck device according to [1], wherein the first metal layer does not contain the active metal.

[0011] [3] The electrostatic chuck device according to [1] or [2], wherein the base is made of a conductive ceramic or a metal-based composite material.

[0012] [4] The electrostatic chuck device according to [3], wherein the conductive ceramic is composed of a highly thermally conductive material and a conductive material, and the volume ratio of the highly thermally conductive material to the conductive material is 10:90 to 90:10.

[0013] [5] The high thermal conductivity material is AlN, SiC, GaN, Al ２ O ３ , SmAlO ３ , MgO, SiO ２, Si ３ N ４ , Al(OH) ３ , MgO, Mg(OH) ２ , BN, ZnO, BeO, B ４ At least one material selected from the group consisting of C, carbon, aluminum, copper, silver, and gold, and the conductive material is SiC, TiO ２ , TiN, TiC, W, WC, Mo, MoC, Mo ２ [4] The electrostatic chuck device according to [4], wherein the material is at least one selected from the group consisting of C, TaC, TaN, NbC, VC, and C.

[0014] [6] An electrostatic chuck device according to any one of [1] to [5], further comprising a support plate on the opposite side of the base from the electrostatic chuck member, the support plate being made of a material having a higher Young's modulus than the material of the base.

[0015] [7] A method for manufacturing an electrostatic chuck device, comprising: a step of forming a film of at least one active metal selected from the group consisting of Ti, Zr, Hf, and Nb on one or both of a main surface of an electrostatic chuck member having a dielectric substrate and an internal electrode and a main surface of a base; and a step of bringing the active metal film into contact with a metallic brazing material, brazing the electrostatic chuck member to the base by arranging the main surface of the electrostatic chuck member and the main surface of the base opposite each other, thereby obtaining an electrostatic chuck device, wherein the metallic brazing material contains a total of 50 volume % or more of Ag or Al relative to the entire metallic brazing material.

[0016] [8] The method for manufacturing an electrostatic chuck device according to [7], wherein the metal brazing material does not contain the active metal.

[0017] [9] A method for manufacturing a laminate, comprising: a step of forming a film of at least one active metal selected from the group consisting of Ti, Zr, Hf, and Nb on either or both of a main surface of a first substrate made of a ceramic and a main surface of a second substrate made of an inorganic material; a step of contacting the active metal film with a metallic brazing material, brazing the first substrate and the second substrate by opposing the main surface of the first substrate to the main surface of the second substrate, and obtaining a laminate of the first substrate and the second substrate, wherein the metallic brazing material contains a total of 50 volume % or more of Ag or Al relative to the entire metallic brazing material.

[0018]

[10] A method for manufacturing a laminate according to [9], wherein the metallic brazing material does not contain the active metal.

[11] A laminate comprising: a first substrate made of ceramic, a second substrate made of an inorganic material, and a bonding layer made of a metallic material bonding the first substrate and the second substrate, wherein the bonding layer has a laminate structure in which a first metal layer and a second metal layer are laminated, the first metal layer contains 50 volume % or more of Ag or Al relative to the total volume of the first metal layer, the second metal layer is a layer containing at least one active metal selected from the group consisting of Ti, Zr, Hf, and Nb, and the second metal layer is sandwiched between the second substrate and the first metal layer, or between the first substrate and the first metal layer, or both.

[0019] According to the present invention, it is possible to provide a novel electrostatic chuck device in which an electrostatic chuck member made of a ceramic material and a base are brazed together, thereby suppressing the occurrence of defects in the bonding layer. It is also possible to provide a method for manufacturing an electrostatic chuck device and a method for manufacturing a laminate in which an objective product is obtained by suitably brazing the electrostatic chuck member and the base.

[0020] FIG. 1 is a cross-sectional schematic diagram showing an example of an electrostatic chuck device 1A according to a first embodiment. FIG. 2 is a cross-sectional view (SEM photograph) of the example of the electrostatic chuck device 1A. FIG. 3 is an elemental map of Al in the field of view of FIG. 2. FIG. 4 is an elemental map of Ti in the field of view of FIG. 2. FIG. 5 is an elemental map of Si in the field of view of FIG. 2. FIG. 6 is a schematic explanatory diagram showing an example of a method for manufacturing an electrostatic chuck device and a method for manufacturing a laminate according to this embodiment. FIG. 7 is a schematic explanatory diagram showing an example of a method for manufacturing an electrostatic chuck device and a laminate according to this embodiment. FIG. 8 is a cross-sectional schematic diagram showing an example of an electrostatic chuck device 1B according to a second embodiment.

[0021] First Embodiment A preferred example of an electrostatic chuck device according to a first embodiment of the present invention will be described below with reference to FIGS. 1 to 7. In all of the following drawings, the dimensions and proportions of the components have been appropriately changed to make the drawings easier to understand. The following description is provided for specific purposes to facilitate a better understanding of the spirit of the invention, and does not limit the present invention unless otherwise specified. For example, unless otherwise specified, conditions such as shape, size, number, material, amount, type, position, and ratio may be changed, added, or omitted as necessary. The first and second embodiments may share preferred conditions.

[0022] 1 is a schematic cross-sectional view showing an example of an electrostatic chuck device 1A according to a first embodiment. The electrostatic chuck device 1A includes an electrostatic chuck member 2, a base 3, a bonding layer 4, a support plate 5, an insulator (insertion component) 23, and a power supply terminal 16. The electrostatic chuck member 2 and the base 3 are stacked on top of each other with the bonding layer 4 interposed therebetween.

[0023] In this specification, the direction in which the electrostatic chuck member 2 and the base 3 are stacked is referred to as the stacking direction. Furthermore, the side on which the electrostatic chuck member 2 is disposed with respect to the base 3 may be referred to as "one side of the stacking direction," and the opposite side may be referred to as "the other side of the stacking direction." In the following description, each part of the electrostatic chuck device 1A will be described assuming that the vertical direction is the stacking direction. However, the vertical direction here is used merely for the sake of simplicity of description and does not limit the position of the electrostatic chuck device 1A during use. The upper side corresponds to one side of the stacking direction, and the lower side corresponds to the other side of the stacking direction.

[0024] <Electrostatic Chuck Member> The electrostatic chuck member 2 has a dielectric substrate 11 and an attraction electrode 13 located inside the dielectric substrate 11. A mounting surface 2 a for attracting and holding a wafer W is provided on the upper surface of the electrostatic chuck member 2. A focus ring surrounding the wafer W may be disposed outside the mounting surface 2 a of the electrostatic chuck member 2.

[0025] (Dielectric Substrate) The dielectric substrate 11 is made of ceramics that has sufficient mechanical strength and is resistant to corrosive gases and their plasma.

[0026] The ceramics constituting the dielectric substrate 11 can be selected arbitrarily, but aluminum oxide (Al ２ O ３ The term "main component" refers to a component that accounts for 50% or more by volume of the entire component. If necessary, the component may account for 60% or more by volume, 70% or more by volume, 80% or more by volume, or 90% or more by volume of the entire component. Examples of the ceramic include aluminum oxide (Al ２ O ３ ) sintered body, aluminum oxide (Al ２ O ３ In particular, from the viewpoints of dielectric properties at high temperatures, high corrosion resistance, plasma resistance, and heat resistance, the material constituting the dielectric substrate 11 is preferably Al ２ O ３ A sintered SiC composite is preferred.

[0027] The dielectric substrate 11 has a circular plate shape in a plan view. The dielectric substrate 11 has a mounting surface 2a on which the wafer W is mounted and a back surface 2b facing the opposite side of the mounting surface 2a. The mounting surface 2a may have, for example, a plurality of protrusions (not shown) formed at predetermined intervals. In this case, the mounting surface 2a supports the wafer W at the tips of the plurality of protrusions. In this specification, the term "plan view" refers to a field of view seen from the thickness direction of the electrostatic chuck member 2.

[0028] (Attraction Electrode) The attraction electrode 13 is disposed inside the dielectric substrate 11. The attraction electrode 13 extends in a plate shape along the mounting surface 2 a of the dielectric substrate 11. When a voltage is applied to the attraction electrode 13, the attraction electrode 13 generates an electrostatic attraction force that holds the wafer W on the mounting surface 2 a of the dielectric substrate 11. A power supply terminal 16 for applying a DC voltage to the attraction electrode 13 is connected to the attraction electrode 13.

[0029] The chucking electrode 13 is preferably made of a composite of an insulating material and a conductive material. The insulating material contained in the chucking electrode 13 is not particularly limited, but may be, for example, aluminum oxide (Al ２ O ３ ), aluminum nitride (AlN), silicon nitride (Si ３ N４ ), yttrium (III) oxide (Y ２ O ３ ), yttrium aluminum garnet (YAG) and SmAlO ３ It is preferable that the polymer is at least one selected from the group consisting of:

[0030] The conductive material contained in the attraction electrode 13 can be selected arbitrarily, but molybdenum carbide (Mo ２ It is preferable that the material is at least one selected from the group consisting of molybdenum (Mo), tungsten carbide (WC), tungsten (W), tantalum carbide (TaC), tantalum (Ta), silicon carbide (SiC), carbon black, carbon nanotubes, and carbon nanofibers.

[0031] The thickness of the electrostatic chuck member 2 can be selected arbitrarily, but is preferably 0.5 mm or more and 5 mm or less. It may also be 1.0 mm or more and 4.0 mm or less, or 2.0 mm or more and 3.0 mm or less. When the thickness of the electrostatic chuck member 2 is 0.5 mm or more, the withstand voltage of the electrostatic chuck member 2 is high. Furthermore, when the thickness of the electrostatic chuck member 2 is 5 mm or less, the heat capacity of the electrostatic chuck member 2 is small, making it easier to maintain a uniform temperature of the plate-shaped sample, which is the processing target, during plasma processing.

[0032] <Base> The base 3 is a disk-shaped member in a plan view, and supports the electrostatic chuck member 2 from its underside (the other side in the stacking direction). The base 3 is provided with a support surface 3a facing upward (one side in the stacking direction) and a lower surface 3b facing downward (the other side in the stacking direction). The support surface 3a faces the back surface 2b of the dielectric substrate 11 in the vertical direction (stacking direction) via the bonding layer 4. The base 3 supports the electrostatic chuck member 2 on the support surface 3a.

[0033] A flow path 3f for circulating a coolant is preferably provided inside the base 3. The coolant flowing through the flow path 3f may be water, He gas, N ２A gas or the like is employed. The flow path 3f extends along the support surface 3a. The refrigerant in the flow path 3f cools the entire base 3 and also cools the electrostatic chuck member 2 via the support surface 3a. The base 3 is connected to an external high-frequency power supply 22 via a matching box (not shown), and also serves as an internal electrode for generating plasma.

[0034] The material forming the base 3 is an inorganic material, and further, a material that is conductive and contains ceramics. Examples of materials that are preferable as the material for the base 3 will be described below.

[0035] (Base Material 1) The base 3 can be formed using conductive ceramics (hereinafter sometimes abbreviated as "conductive ceramics") that contain a highly thermally conductive material and a conductive material as a material that is conductive and contains ceramics. That is, the conductive ceramics can be used as the material for forming the base. The base may be made only of conductive ceramics. A method for manufacturing conductive ceramics will be described later.

[0036] Specifically, when the entire base 3 is taken as 100% by volume, the material forming the base 3 has a volume ratio of the highly thermally conductive material to the electrically conductive material (volume of the highly thermally conductive material:volume of the electrically conductive material) of 10:90 to 90:10, preferably 20:80 to 80:20, more preferably 25:75 to 70:30, and even more preferably 30:70 to 60:40. If necessary, the ratio may be 15:85 to 35:65, 35:55 ​​to 55:45, 55:45 to 75:25, or the like.

[0037] The conductive material can be selected arbitrarily, but SiC, TiO ２ , TiN, TiC, W, WC, Mo, MoC, Mo ２ Preferably, the conductive material is at least one selected from the group consisting of C, TaC, TaN, NbC, VC, and C. Among these, TiN is preferred because of its excellent plasma resistance. Mo and W are preferred because of their high thermal conductivity. As the conductive material, TiN and Mo may be used alone or in combination.

[0038] The high thermal conductivity material can be selected arbitrarily, but examples include AlN, SiC, GaN, and SiO２ , Al ２ O ３ , SmAlO ３ , MgO, SiO ２ , Si ３ N ４ , Al(OH) ３ , MgO, Mg(OH) ２ , BN, ZnO, BeO, B ４ It is preferably at least one selected from the group consisting of C, carbon (C), aluminum, copper, silver, and gold. Among these, AlN is preferred because of its high thermal conductivity and ease of handling.

[0039] When SiC is used as the highly thermally conductive material, a conductive material other than SiC is selected. When SiC is used as the highly thermally conductive material, TiN, for example, can be selected as the conductive material. Similarly, when C is used as the highly thermally conductive material, a conductive material other than C is selected.

[0040] Furthermore, when combining the above-mentioned materials with a conductive material and a highly thermally conductive material, the resulting material preferably contains one or more materials selected from the group consisting of inorganic oxides, inorganic carbides, inorganic nitrides, and inorganic carbonitrides, which belong to either the conductive material or the highly thermally conductive material. Among these, it is preferable to contain either or both of inorganic oxides and inorganic nitrides. By including these, the resulting material can be said to be preferable as a "conductive ceramic."

[0041] (Base Material 2) The base 3 may be formed from a metal matrix composite (MMC), which is a composite material of metal and ceramic, as a material that is conductive and contains ceramics. The base may also be formed from a metal matrix composite only. MMCs are generally prepared by preparing a porous ceramic substrate and then introducing molten metal such as Mg, Al, or Si into the pores of the ceramic substrate (metal infiltration method, forging method).

[0042] The MMC preferably contains SiC as a material. Specifically, when the entire base 3 is taken as 100 volume %, the MMC preferably contains 75 volume % or more but less than 100 volume %, and more preferably 75 volume % or more but 99 volume % or less of SiC. If necessary, the SiC content may be 78 volume % or more but 95 volume % or less, or 80 volume % or more but 90 volume % or less.

[0043] The MMC contains one or more elements selected from the group consisting of aluminum (Al), silicon (Si), and magnesium (Mg) as the metal introduced into the pores. The inclusion of these elements in SiC improves the thermal conductivity of the base 3, facilitating heat dissipation through the base 3. In an MMC containing 75% or more by volume of SiC, the thermal expansion coefficient can be reduced to 2.8 × 10 by adjusting the mating material contained in the material. －６ / K ~ 6.8 x 10 －６ / K range.

[0044] The absolute value of the difference in thermal expansion coefficient between the MMC and the ceramic material of the electrostatic chuck member 2 is 10 ppm / K or less, preferably 8.5 ppm / K or less, and more preferably 7.0 ppm / K or less. It may be 6.0 ppm / K or less, 4.0 ppm / K or less, etc. The relationship between the material of the base 3A and the material of the electrostatic chuck member 2 described above facilitates suppression of internal stress due to thermal deformation during heating.

[0045] The MMC is preferably a material containing 75% by volume or more and 99% by volume or less of SiC and 1% by volume or more and 25% by volume or less of Al, Si, or Mg when the entire MMC is taken as 100% by volume. The base 3 formed from an MMC of such a composition has a thermal expansion coefficient that is equal to or less than that of Al constituting the electrostatic chuck member 2. ２ O ３ -It becomes very close to SiC, and the difference in the amount of thermal expansion between it and the electrostatic chuck member 2 when heated becomes small.

[0046] Examples of MMCs that can be used include Mg—SiC (7.0 ppm / K), Al—SiC (6.8 ppm / K), and Si—SiC (2.8 ppm / K). The amount of metal contained in each MMC can be adjusted appropriately within the above-mentioned content range depending on the desired thermal expansion coefficient.

[0047] Using the conductive ceramics or MMC described above as the material for forming the base 3 provides the following effects. When the heat medium flows through the flow path 3f, frictional charging is expected to occur between the heat medium and the base 3. Since the charge generated in this manner can have adverse effects on the process and the device, it is preferable to quickly remove the charge. By forming the base 3 from the conductive ceramics or MMC described above, the charge generated by frictional charging can be easily removed.

[0048] The thermal expansion coefficient of the material of the base 3 at 800°C is 10×10 －６ / K (10 ppm / K) or less, preferably 9 × 10 －６ / K or less, more preferably 8×10 －６ / K or less. By setting the thermal expansion coefficient of the base 3 to such a value, it is possible to suppress a change in the volume of the base 3 that accompanies a change in the temperature of the base 3 when a heat medium is flowed through the base 3. As a result, distortion is less likely to occur at the interface between the base 3 and the structure in contact with it (the bonding layer 4 in the case of the electrostatic chuck device 1A), and damage to the device can be suppressed. Note that the lower limit of the thermal expansion coefficient of the base 3 at 800°C can be selected arbitrarily, but may be set to, for example, 5 × 10 as needed. －６ / K or more, and may be 6×10 －６ / K or more, and may be 6.8 × 10 －６ / K or more.

[0049] The thermal expansion coefficient of the material of the base 3 at 800°C can be determined by the average coefficient of linear expansion (CTE) when the material of the base 3 is subjected to a temperature change from 25°C to 800°C.

[0050] The average linear expansion coefficient when the material of the base 3 is changed in temperature from 25°C to 800°C can be measured using any measuring device, for example, a thermal expansion measuring device (TD5000SA, manufactured by NETZSCH). First, a measurement sample (test piece) made from the material of the base 3 is heated from 25°C to 800°C at a temperature increase rate of 5°C / min, and the length (L0) of the measurement sample at 25°C and the length (L1) at 800°C are measured to measure the change in length (ΔL) of the measurement sample. The thermal expansion coefficient can be calculated by dividing ΔL by the length (L0) of the measurement sample at 25°C, and then dividing the thermal expansion coefficient by the temperature change range (ΔT = 800°C - 25°C).

[0051] That is, the "coefficient of thermal expansion at 800° C." in this embodiment can be calculated by {(L1−L0) / L0} / ΔT=(ΔL / L0) / ΔT.

[0052] The base 3 is preferably made of a material with a thermal conductivity of 40 W / m·K or more, and more preferably 50 W / m·K to 110 W / m·K. The thermal conductivity may be 45 W / m·K to 100 W / m·K, 60 W / m·K to 90 W / m·K, or 70 W / m·K to 80 W / m·K, as needed. When the thermal conductivity is within the above range, input heat can be effectively dissipated.

[0053] The thermal expansion coefficient of the dielectric substrate 11 can be selected arbitrarily. When the main component of the dielectric substrate 11 is aluminum oxide and is combined with silicon carbide, the thermal expansion coefficient of the dielectric substrate 11 is the thermal expansion coefficient of aluminum oxide at 800° C. (7.8×10 －６ / K~8.5 x 10 －６ / K) and the thermal expansion coefficient of silicon carbide at 800°C (4.1 × 10 －６ / ℃).

[0054] The highly thermally conductive material contained in the base 3 should be selected taking into consideration the thermal expansion coefficient of the conductive material to be combined, and should be a material that can reduce the difference in the thermal expansion coefficient between the dielectric substrate 11 and the base 3. For example, when a material with a thermal expansion coefficient larger than that of aluminum oxide is used as the conductive material contained in the base 3, the highly thermally conductive material to be combined should preferably be a material with a relatively smaller thermal expansion coefficient than that of aluminum oxide, such as AlN. The thermal expansion coefficient of AlN at 40°C to 800°C is 5.2 × 10 －６ It is thought to be around / K.

[0055] The base 3 is made of AlN and TiN (thermal expansion coefficient at 900°C: 7.75 × 10 －６ / K), i.e., an AlN-TiN composite sintered body. Also, the base 3 is preferably made of conductive ceramics formed from SiC and TiN, i.e., an SiC-TiN composite sintered body.

[0056] The thermal expansion coefficient of the material of the base 3 at 800°C is 6.0 × 10 －６ / ℃ or more 9.0 x 10 －６ / °C or less. When the thermal expansion coefficient of base 3 is within the above range, it is easy to reduce the difference in thermal expansion between base 3 and dielectric substrate 11, which mainly contains aluminum oxide, and defects such as voids and cracks are less likely to occur in electrostatic chuck member 2 when electrostatic chuck member 2 and base 3 are brazed with a metal material. Furthermore, even when electrostatic chuck device 1A is used at high or low temperatures, distortion is less likely to occur at the interface between electrostatic chuck member 2 and base 3.

[0057] The thermal expansion coefficient of the material of the base 3 at 800°C is set to 6.5×10 －６ / K or more 8.5×10 －６ / K or less, 6.8 x 10 －６ / K or more 8.3×10 －６ / K or less or 7.0 x 10 －６ / K or more 8.0×10 －６ / K or less.

[0058] The base 3 may contain one or more sintering aids as needed, as long as the effects of the present invention are not impaired. The amount and type of sintering aid are not particularly limited as long as they are generally added. ２ O ３ , MgO, SiO ２ , CaO, La ２ O ３ , Ce ２ O ３ , Y.O.F., Y.F. ３ Among these, Y ２ O ３ , MgO, SiO ２ , Y.F. ３ is preferred.

[0059] The volume resistivity of the base 3 can be selected arbitrarily, but is preferably 1.0×10 －３ The volume resistivity of the base 3 is preferably in the above range, so that sufficient conductivity can be obtained. The lower the volume resistivity of the base 3, the better. However, the lower limit is, for example, 1.0×10 －１０ The volume resistivity of the base 3 may be 1.0×10 Ω·cm or more, if necessary. －８ Ω・cm or more 1.0×10 －４ It may be Ω cm or less, and may be 1.0 × 10 －６ Ω・cm or more 1.0×10 －５ The volume resistivity of the base 3 may be 1.0×10 －６ Ω・cm or more 1.0×10 －５ Ω・cm or less or 1.0×10 －５ Ω・cm or more 1.0×10 －４ Ω・cm or less or 1.0×10 －４ Ω・cm or more 1.0×10 －３ It may be Ω·cm or less.

[0060] The thermal expansion coefficient at 800°C of the material of the base 3 is preferably equal to or approximately equal to that of the dielectric substrate 11. The absolute value of the difference between the thermal expansion coefficient at 800°C of the material of the base 3 and the thermal expansion coefficient at 800°C of the material of the dielectric substrate 11 is 2.5×10 －６ / K or less, and preferably 1.5 × 10 －６ / K or less, and more preferably 1.3 × 10－６ / K or less, and more preferably 1.0 × 10 －６ It is even more preferable that the value is 0.1 / K or less.

[0061] It is preferable that an alumina sprayed film is provided on the surface of the base 3 as required in order to improve plasma resistance.

[0062] A hole 17 is provided in the base 3. The hole 17 extends in the vertical direction. The hole 17 penetrates the base 3 in the vertical direction and opens to the support surface 3a and the lower surface 3b of the base 3. The hole 17 has, for example, a circular or approximately circular shape in a plan view. An insulator 23, which will be described later, is preferably inserted into the hole 17. Although FIG. 1 shows the hole 17 as penetrating the base 3 in the vertical direction, the hole 17 does not necessarily have to penetrate the base 3 as long as it opens to at least the support surface 3a and an insulator 23 is inserted therein.

[0063] (Method for Manufacturing Conductive Ceramics) The conductive ceramics that are the material of the base 3 can be manufactured by any method. For example, they can be obtained by mixing a high thermal conductivity material and a conductive material in a predetermined range to obtain a raw material powder, and then using the obtained raw material powder to manufacture ceramics by a known method. Specific examples of manufacturing methods include, for example, mixing a high thermal conductivity material and a conductive material in a volume ratio of, for example, 10:90 to 90:10 or 30:70 to 60:40 to obtain a raw material powder, applying pressure to the obtained raw material powder to obtain a molded body, and pressure-sintering the obtained molded body to obtain a conductive ceramic. The obtained conductive ceramics can be manufactured by processing them into the shape of the base 3, thereby obtaining the base 3 of this embodiment.

[0064] The average primary particle size of the highly thermally conductive material is not particularly limited as long as a conductive ceramic can be obtained, and for example, a highly thermally conductive material having an average primary particle size of 0.5 μm to 5 μm can be used. The average primary particle size may be 1.0 μm to 5.0 μm, or 2.0 μm to 4.0 μm.

[0065] The average primary particle size of the conductive material is not particularly limited as long as a conductive ceramic can be obtained, and for example, a conductive material having an average primary particle size of 0.5 μm to 5 μm can be used. The average primary particle size may be 1.0 μm to 5.0 μm, or 2.0 μm to 4.0 μm.

[0066] In the mixing step, the highly thermally conductive material and the electrically conductive material may be mixed to obtain a raw material powder, and the mixing method is not particularly limited. To prevent the highly thermally conductive material and the electrically conductive material from agglomerating, it is preferable to mix them with a dispersant or solvent as needed, and then mix them using a mixing device such as a disperser. The mixing device is not particularly limited, and general devices such as a ball mill, planetary mill, bead mill, and atomizer can be used.

[0067] A drying step may be performed after the mixing step. The drying method may be natural drying, a dryer, or spray drying to form granules of 30 to 100 μm from the raw material powder.

[0068] After the mixing step or the drying step, the raw material powder may be placed in a non-oxidizing atmosphere. For example, the raw material powder may be heated in a non-oxidizing atmosphere at an arbitrarily selected temperature, for example, 300° C. or higher and 600° C. or lower, to remove impurities contained in the raw material powder, such as moisture, solvent, and dispersant.

[0069] The non-oxidizing atmosphere is preferably an inert gas atmosphere using nitrogen or argon. When the heating is performed under an inert gas atmosphere, it is preferable to perform the heating treatment under a gas flow, in other words, a gas flow, in order to efficiently discharge generated impurities out of the system.

[0070] In the molding step, the obtained raw material powder is subjected to pressure by a mold molding method or the like depending on the shape of the desired conductive ceramic, preferably uniaxial molding (uniaxial press molding) to obtain a molded body of the desired shape.

[0071] In the pressure sintering step, the compact obtained in the molding step is compressed under a vacuum or a non-oxidizing atmosphere at a pressure of 5 MPa or higher while being heated to a temperature of 1600°C or higher. This procedure promotes sintering of the highly thermally conductive and electrically conductive materials contained in the compact, resulting in a dense sintered body with few pores. The temperature can be selected as needed, and may be 1600 to 1900°C or 1650 to 1800°C, for example. The heating time can be selected as needed, and may be, for example, 1 to 5 hours, 3 to 8 hours, or 6 to 12 hours.

[0072] The conductive ceramic can be obtained by the above steps, and the obtained conductive ceramic can be processed to obtain the base 3. The method for processing the obtained conductive ceramic can be selected arbitrarily. For example, the base 3 may be formed by joining a plurality of members having arbitrarily selected shapes.

[0073] <Bonding Layer> The bonding layer 4 is made of a metal material and bonds the electrostatic chuck member 2 and the base 3 together.

[0074] FIG. 2 is a cross-sectional view of an example of an electrostatic chuck device 1A, and is a scanning electron microscope (SEM) photograph of a cross section of the electrostatic chuck device 1A, focusing on the bonding layer 4. In the electrostatic chuck device 1A shown in FIG. 2, the bonding layer 4 has a first metal layer 41 and a second metal layer 42. In FIG. 2, the white band-shaped layer is the second metal layer 42, and the layer sandwiched between the pair of second metal layers 42 (42a, 42b) is the first metal layer 41. Note that one of the second metal layers, for example, the second metal layer 42a, may be omitted. Furthermore, a stripe-shaped region (indicated by reference symbol 41a in FIG. 2) can be seen inside the first metal layer 41. The term "sandwiched" may refer to being sandwiched between two layers or sandwiched between two layers.

[0075] 2 is manufactured by brazing an electrostatic chuck member 2 and a base 3 using an Al brazing material containing Si, using a manufacturing method described below. The Al brazing material is a brazing material containing Al as a main component.

[0076] The first metal layer 41 contains a total of 50 volume % or more of Ag or Al relative to the total volume of the first metal layer. It may contain 60 volume % or more, 70 volume % or more, 80 volume % or more, or 90 volume % or more. When the first metal layer 41 contains 50 volume % or more of Ag, the remainder may include Cu or Sn. These metals are known as constituent metals of Ag brazing filler metals. Ag brazing filler metals are brazing filler metals containing Ag as a primary component. When the first metal layer 41 contains 50 volume % or more of Al, the remainder may include Zn, Mg, and Si. These metals are known as constituent metals of Al brazing filler metals. These brazing filler metals are used in manufacturing the electrostatic chuck device 1A by the method described below. These brazing filler metals preferably form the first metal layer. Note that the term "total of 50 volume % or more" is used instead of simply "50 volume % or more" because some of the Ag or Al may precipitate as a eutectic structure.

[0077] The first metal layer 41 may contain at least one active metal selected from the group consisting of Ti, Zr, Hf, and Nb, but it is preferable that the first metal layer 41 does not contain any active metal.

[0078] The second metal layer 42 is a layer containing at least one active metal selected from the group consisting of Ti, Zr, Hf, and Nb. The amount of the active metal in the second metal layer can be selected arbitrarily, such as 90 to 100 mass%, 95 to 100 mass%, or 98 to 100 mass%, but preferably consists solely of these active metals. The proportion of the second metal layer in the bonding layer may be, for example, 3 to 60 volume%, 3 to 40 volume%, 3 to 20 volume%, 3 to 10 volume%, or 3 to 6 volume%, but is not limited to these. The second metal layer 42a is sandwiched between the electrostatic chuck member 2 and the first metal layer 41. The second metal layer 42b is sandwiched between the base 3 and the first metal layer 41. In this embodiment, the second metal layer 42 is formed on both the entire interface between the electrostatic chuck member 2 and the first metal layer 41 and the entire interface between the base 3 and the first metal layer 41. For example, the second metal layer 42 may be a Ti layer.

[0079] Figures 3 to 5 show the results of EDX phase analysis performed in the same field of view as the enlarged photograph shown in Figure 2. Figure 3 is an elemental map of Al in the field of view of Figure 2. Figure 4 is an elemental map of Ti in the field of view of Figure 2. Figure 5 is an elemental map of Si in the field of view of Figure 2. In Figures 3 to 5, the closer to black (the lower the brightness), the smaller the amount of the measured element present, and the closer to white (the higher the brightness), the greater the amount of the measured element present. Furthermore, the area marked with the symbol 42a in Figure 4 is shown in white, emphasizing the brightness based on actual measurement results, in order to prioritize ease of viewing the figure.

[0080] In the electrostatic chuck device 1A shown in FIGS. 2 to 5, the dielectric substrate 11 of the electrostatic chuck member 2 is made of Al. ２ O ３ The first metal layer 41 is made of AlN--TiN, and the base 3 is made of AlN--TiN. The first metal layer 41 contains 50% or more by volume of Al.

[0081] As shown in Fig. 3, there is a region between the first metal layer 41 and the electrostatic chuck member 2, which is shown in black and clearly contains a small amount of Al. Referring to Fig. 4, the presence of Ti can be confirmed in this position. From this, it can be determined that this region is the second metal layer 42 (42a) containing Ti.

[0082] Since the base 3 is made of AlN-TiN, EDX phase analysis confirms the presence of both Al and Ti in the base 3. Therefore, in FIGS. 3 and 4, the second metal layer 42 (42b) cannot be clearly seen between the first metal layer 41 and the base 3. However, in FIG. 2, a layer that appears white is also present in this area. Furthermore, as described above, by confirming that it is Ti in FIG. 4, it can be determined that one of the white layers in FIG. 2 is the second metal layer 42a. From these facts, it can be determined that the white stripe layer that can be seen between the first metal layer 41 and the base 3 in FIG. 2 is also the second metal layer 42b containing Ti.

[0083] 3, the region 41a formed inside the first metal layer 41 clearly has a smaller amount of Al than the surrounding first metal layer 41. Referring to FIG. 5 for this region 41a, the presence of Si can be confirmed in the region 41a. That is, since Al and Si can be confirmed in the region 41a, it can be determined that a eutectic structure of Al and Si has precipitated in the region 41a.

[0084] The Si contained in the precipitated eutectic structure is considered to be the Si contained in the Al brazing material used for brazing. Similarly, if the metals contained in the metal brazing material are capable of forming a eutectic structure, it is considered that a eutectic structure derived from the metal contained in the metal brazing material is formed in the first metal layer 41. For example, an Ag-Cu alloy formed from Ag and Cu contained in an Ag brazing material can be used. Note that the brazing material may refer to an alloy, metal foil, or metal paste used to join components and having a melting point lower than that of the components to be joined.

[0085] The thickness of the bonding layer 4 can be selected arbitrarily, but is preferably 0.005 mm to 0.5 mm. It may also be 0.01 mm to 0.4 mm, or 0.1 mm to 0.3 mm. The thickness of the second metal layer 42 can be selected arbitrarily, but may also be 10 nm to 10 μm, 20 nm to 5 μm, 30 nm to 1 μm, or 50 nm to 500 nm.

[0086] The thickness of the first metal layer 41 can be the thickness of the above-mentioned bonding layer 4 minus the thickness of the second metal layer 42. When the bonding layer 4 has a pair of second metal layers 42 sandwiching the first metal layer 41 as shown in FIG. 2 , the thickness of the first metal layer 41 can be the thickness of the bonding layer 4 minus the thickness of the pair of second metal layers 42.

[0087] The thicknesses of the bonding layer 4, the first metal layer 41, and the second metal layer 42 can be determined by taking an SEM photograph of a cross section of the electrostatic chuck device 1A as shown in FIG. 2 and measuring the thickness of each layer in the field of view of the SEM photograph. When measuring the thickness of each layer, for example, the thickness can be measured at multiple locations (e.g., n = 5) in the field of view of the SEM photograph, and the arithmetic average of the measured values ​​can be calculated. The thicknesses can be determined using the SEM photograph by using image processing software attached to the scanning electron microscope used to take the enlarged photograph.

[0088] When manufacturing the electrostatic chuck device 1A, the material for the bonding layer 4 may be a metal foil or a metal paste made by adding a binder to metal powder. These materials are commercially available as "brazing filler metals." These materials are placed between the electrostatic chuck member 2 and the base 3 and heated to a temperature equal to or higher than the melting point of the metal material that forms the bonding layer 4. The molten metal material spreads between the electrostatic chuck member 2 and the base 3, thereby forming the bonding layer 4.

[0089] Furthermore, the inventors have confirmed through their studies that when the brazing filler metal used contains Ti as an active metal, discrete areas of poor bonding (hereinafter, "defective areas") may be formed at the interface between the bonding layer 4 and the base 3 and at the interface between the bonding layer 4 and the electrostatic chuck member 2. Furthermore, it has been confirmed that in the case of a paste-like brazing filler metal, the defective areas are formed irregularly at the interface, and in the case of a sheet-like brazing filler metal, the defective areas are formed in the form of stripes along the rolling direction of the sheet-like brazing filler metal.

[0090] The analysis revealed that Ti oxide aggregates were formed at the defective locations. Since poor bonding occurred at the locations where Ti oxide aggregated, it is believed that Ti oxide inhibits the reaction between the main raw material (Al or Ag) contained in the metallic brazing material and the base 3.

[0091] The above phenomenon is not limited to Ti, and is thought to occur when the metallic brazing material contains an active metal.

[0092] That is, when the brazing filler metal contains an active metal but the active metal is not present on the surfaces of the electrostatic chuck member 2 or the base 3, the active metal contained in the metal brazing filler metal is thought to separate from the brazing filler metal and precipitate on the surfaces of the electrostatic chuck member 2 or the base 3. At this time, the active metal is thought to precipitate discretely on the surfaces of the electrostatic chuck member 2 or the base 3 and then spread over the entire surfaces. However, the precipitated active metal is easily oxidized. Therefore, it is thought that after being precipitated on the surfaces of the electrostatic chuck member 2 or the base 3, it is easily oxidized to form an oxide. Therefore, when the active metal is not precipitated simultaneously and uniformly on the surfaces of the electrostatic chuck member 2 or the base 3 as described above, oxidation of the previously precipitated active metal (formation of an oxide) and the precipitation of the active metal are thought to occur simultaneously on the surfaces of the electrostatic chuck member 2 or the base 3.

[0093] As a result, it is expected that there will be areas on the surfaces of the electrostatic chuck member 2 and the base 3 where the active metal is deposited first (i.e., areas where an oxide of the active metal is formed first) and areas where the active metal is deposited later, resulting in an uneven surface condition. The inventors believed that the above-mentioned defective areas such as voids and cracks were caused by such an uneven surface condition.

[0094] If many of the above-described defects are formed, the bonding strength between the electrostatic chuck member 2 and the base 3 may decrease, making the electrostatic chuck member 2 more susceptible to breakage. Furthermore, the defects inhibit the transfer of heat from the electrostatic chuck member 2 to the base 3. Therefore, if the defects are formed unevenly, there is a risk that unevenness will occur in the surface temperature distribution of the electrostatic chuck member 2 during use of the electrostatic chuck device.

[0095] Taking Ti as an example of the active metal, the Ti oxides are thought to be generated when a portion of Ti contained in the brazing filler metal separates from the brazing filler metal and reacts with the surface of the electrostatic chuck member 2 and the surface of the base 3. Therefore, when the bonding layer 4 contains Ti as an active metal, it is thought that the temperature conditions and pressure conditions during brazing should be adjusted so as to prevent the Ti contained in the brazing filler metal from being oxidized. However, even in such a case, it is thought that the Ti contained in the brazing filler metal will precipitate on the surfaces of the electrostatic chuck member 2 and the base 3, and the precipitated Ti will be oxidized to form Ti oxides discretely. Therefore, it is difficult to suppress the occurrence of defects even if the manufacturing conditions are adjusted as described above.

[0096] To address the above-described problem, in the manufacturing method of the present invention, a Ti film is formed on at least one of the front surface of the base 3 and the back surface 2b of the dielectric substrate 11, and then brazing is performed. Because the Ti film is formed in advance, non-uniform deposition does not occur. The electrostatic chuck device 1A obtained by this method is a laminate in which the electrostatic chuck member 2 and the base 3 are bonded together by the bonding layer 4, which is made of the first metal layer 41 and the second metal layer 42 laminated together as described above. The manufacturing method will be described in detail later.

[0097] <Other Components> (Support Plate) The support plate 5 preferably supports the base 3 from the lower surface 3b of the base 3. The support plate 5 is made of a material having a higher Young's modulus than the material of the base 3. For example, any of metal, MMC, and ceramics can be used as the material of the support plate 5. Among these, Al, which has a higher Young's modulus than the material of the base 3, is preferably used as the support plate 5. ２ O ３ It is preferable to use a ceramic plate such as the above.

[0098] The ceramic material used for the support plate 5 is preferably the same as the material used for the electrostatic chuck member 2. Specific examples of the ceramic material include aluminum oxide, aluminum nitride, and Al. ２ O ３ By using the same material for the support plate 5 and the electrostatic chuck member 2, the difference in thermal expansion coefficient between the support plate 5 and the electrostatic chuck member 2 can be reduced, and warping of the electrostatic chuck device 1A can be suppressed.

[0099] (Insulator) The insulator 23 is inserted into the hole 17 and assembled to the base 3. That is, the insulator 23 functions as an insertion part that is inserted into the hole 17. The insulator 23 has a cylindrical shape that extends in the vertical direction. The power supply terminal 16 is disposed inside the insulator 23. The outer circumferential surface of the insulator 23 is joined to the inner surface of the hole 17 using a joining means such as adhesive. The insulator 23 insulates the metal base 3 from the power supply terminal 16.

[0100] The insulator 23 is made of, for example, ceramic. That is, the insulator 23 is made of an insulating material. This allows the insulator 23 to prevent the gas introduction hole from becoming a starting point for abnormal discharge. The insulator 23 has durability against plasma. Examples of ceramics that make up the insulator 23 include AlN, Al ２ O ３ , Si ３ N ４ , zirconium oxide (ZrO ２ ), sialon, boron nitride (BN), and SiC.

[0101] An upper end face of the insulator 23 (hereinafter referred to as upper end face 23a) is in contact with the electrostatic chuck member 2 or is disposed adjacent to the electrostatic chuck member with an insulating adhesive interposed therebetween.

[0102] (Power Supply Terminal) The power supply terminal 16 extends downward from the chucking electrode 13. The power supply terminal 16 is connected to an external power supply 21. The power supply 21 applies a voltage to the chucking electrode 13. The number, shape, etc. of the power supply terminals 16 are determined depending on the type of the chucking electrode 13, i.e., whether it is a monopolar type or a bipolar type.

[0103] The power supply terminal 16 passes through a first hole 17a in the dielectric substrate 11, a second hole 17b in the bonding layer 4, and a third hole 17c in the support plate 5. The first hole 17a is provided in a portion of the dielectric substrate 11 below the chucking electrode 13.

[0104] The first hole 17a, the second hole 17b, and the third hole 17c are each circular when viewed in the stacking direction. The first hole 17a, the second hole 17b, and the third hole 17c are in communication with the hole 17 of the base 3.

[0105] The inner circumferential surfaces of the first hole 17a, the second hole 17b, and the third hole 17c are continuous with the inner circumferential surface of the insulator 23 when viewed from the stacking direction. The inner diameters of the first hole 17a, the second hole 17b, and the third hole 17c are approximately equal to the inner diameter of the insulator 23 and slightly larger than the outer diameter of the power supply terminal 16.

[0106] 6 and 7 are explanatory views showing examples of a method for manufacturing an electrostatic chuck device and a method for manufacturing a laminate according to this embodiment. These drawings will be used to explain the manufacturing method of the electrostatic chuck device 1A described above.

[0107] First, as shown in Fig. 6, a Ti film 401 is formed on the main surface (support surface 3a) of the base 3 (a step of forming an active metal film). The Ti film 401 can be formed by a known PVD method such as vapor deposition or sputtering. Alternatively, the Ti film 401 may be formed by applying a slurry containing Ti fine powder and then heating it. As a result, a film of active metal is simultaneously and uniformly formed on the main surface of the base 3.

[0108] Similarly, a Ti film 401 is formed on the main surface (rear surface 2b) of the electrostatic chuck member 2 (not shown).

[0109] In this step, the Ti film 401 may be formed on only one of the main surface of the electrostatic chuck member 2 and the main surface of the base 3 .

[0110] Next, a metal brazing material 411 is prepared, and as shown in Fig. 7, the Ti film 401 and the metal brazing material 411 are brought into contact with each other, so that the back surface 2b of the electrostatic chuck member 2 and the support surface 3a of the base 3 face each other and are brazed together. The temperature, time, and pressure used in brazing can be selected as needed. In this way, the electrostatic chuck device 1A is obtained (a process for obtaining an electrostatic chuck device).

[0111] The brazing metal material 411 used in this case contains Ag or Al in a total amount of 50% by volume or more relative to the entire brazing metal material. The brazing metal material 411 does not contain both Ag and Al. The brazing metal material 411 may contain an active metal such as Ti, but it is preferable that the brazing metal material 411 does not contain an active metal.

[0112] As described above, it has been confirmed that when the Ti film 401 is not formed in advance on the main surface of the electrostatic chuck member 2 and the main surface of the base 3 and when the brazing filler metal used contains Ti as an active metal, discrete, i.e., discontinuous, areas of poor bonding (hereinafter, referred to as defective areas) may be formed at the interface between the bonding layer 4 and the base 3.

[0113] In contrast, in the present manufacturing method, the Ti film 401 is formed in advance on the main surface of the electrostatic chuck member 2 and the main surface of the base 3. This allows Ti constituting the Ti film 401 to contribute as an active metal species during brazing. The metallic brazing material 411 becomes the first metal layer 41 described above, and the Ti film 401 becomes the second metal layer 42 described above.

[0114] Furthermore, by forming the Ti film 401 in advance, bonding defects can be preferably prevented. That is, when the brazing filler metal contains Ti, a part of the Ti contained in the brazing filler metal separates from the brazing filler metal first, and the separated Ti forms an oxide before the remaining Ti, resulting in an uneven surface condition and bonding defects.

[0115] As a result, according to the present manufacturing method, no discrete defects are formed at the interface between the bonding layer 4 and the base 3. Similarly, no discrete defects are formed at the interface between the bonding layer 4 and the electrostatic chuck member 2.

[0116] In the above-described manufacturing method, the Ti film 401 is formed in advance on the main surfaces of the electrostatic chuck member 2 and the base 3, but this is not limiting. By forming a film in advance on the main surfaces of the electrostatic chuck member 2 and the base 3 using at least one active metal selected from the group consisting of Ti, Zr, Hf, and Nb, it is possible to achieve the same effect as the Ti film 401. In addition, when the metal brazing material contains an active metal, the active metal contained in the metal brazing material and the active metal constituting the film formed on the main surfaces of the electrostatic chuck member 2 and the base 3 may be the same as or different from each other.

[0117] In this manner, it is possible to manufacture the electrostatic chuck device 1A in which the electrostatic chuck member 2 and the base 3 are stacked via the bonding layer 4. The obtained electrostatic chuck device 1A has few defects at the interface between the bonding layer 4 and other members (the electrostatic chuck member 2, the base 3), and is highly reliable.

[0118] The method for manufacturing a laminate according to this embodiment includes the steps of: forming a Ti film on one or both of a main surface of a first ceramic substrate and a main surface of a second inorganic substrate; and bringing the Ti film into contact with a brazing metal material, brazing the main surface of the first substrate to the main surface of the second substrate so that the main surface of the first substrate faces the main surface of the second substrate, and obtaining a laminate of the first and second substrates. For example, in the above description of the method for manufacturing an electrostatic chuck device, the electrostatic chuck member 2 can be read as the "first ceramic substrate" and the base 3 as the "second inorganic substrate." This method for manufacturing a laminate according to this embodiment can be understood.

[0119] According to the electrostatic chuck device having the above-described configuration, by using a conductive ceramic as the material for the base 3, it is possible to provide a novel electrostatic chuck device in which the electrostatic chuck member 2 and the base 3 are joined by brazing.

[0120] 8 is a schematic explanatory diagram of an electrostatic chuck device 1B according to a second embodiment of the present invention. The electrostatic chuck device 1B of this embodiment has some components in common with the electrostatic chuck device 1A of the first embodiment. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0121] The electrostatic chuck device 1B includes an electrostatic chuck member 2, a base 3, a bonding layer 6, a support plate 5, an insulator (insertion component) 23, and a power supply terminal 16. The electrostatic chuck member 2 and the base 3 are stacked together via the bonding layer 6. The bonding layer 6 has two bonding layers. A stress relaxation layer 61 is present between the two bonding layers.

[0122] (Bonding Layer) The bonding layer 6 includes a stress relief layer 61, a first bonding layer 62 that bonds the stress relief layer 61 to the electrostatic chuck member 2, and a second bonding layer 63 that bonds the stress relief layer 61 to the base 3. The first bonding layer 62 includes a first metal layer 621 and a second metal layer 622 formed at the interface between the first metal layer 621 and the electrostatic chuck member 2. The second bonding layer 63 includes a first metal layer 631 and a second metal layer 632 formed at the interface between the first metal layer 631 and the base 3.

[0123] The bonding layer 6 has a higher thermal conductivity than the base 3. The difference in thermal conductivity between the bonding layer 6 and the base 3 can be selected arbitrarily, and may be, for example, 50 to 180 W / (m·K), 70 to 160 W / (m·K), or 100 to 130 W / (m·K).

[0124] The stress relaxation layer 61 is made of a material that is easily plastically deformed, and relieves thermal stress caused by the difference in thermal expansion coefficient between the electrostatic chuck member 2 and the base 3. The material of the stress relaxation layer 61 can be selected arbitrarily, but it is preferable to use a metal foil made of at least one metal selected from the group consisting of Cu, Al, and Ti, for example.

[0125] Alternatively, the material of the stress relaxation layer 61 may be the same as that of the electrostatic chuck member 2. ２ O ３ Materials with a small difference in thermal expansion coefficient from Al can also be used. ２ O ３ Thermal expansion coefficient (7 to 7.7 × 10 －６ / K) and is used as a material for the stress relaxation layer. －６ / K), Nb (7.1 × 10 －６ / K), W (4.6 × 10 －６ / K).

[0126] The thickness of the stress relaxation layer 61 can be selected arbitrarily, but is preferably 0.1 mm to 1 cm, and more preferably 1 mm to 1 cm. It may be 0.5 mm to 8 mm, or 3 mm to 6 mm, for example. When the thickness of the stress relaxation layer 61 is within this range, thermal stress can be sufficiently relaxed, and peeling between the electrostatic chuck member 2 and the base 3 can be suppressed.

[0127] The material of the first bonding layer 62 and the second bonding layer 63 has a lower melting point than the material of the stress relaxation layer. The first bonding layer 62 and the second bonding layer 63 may be made of the same material or different materials.

[0128] The material of the first metal layer 621 can be the same as the material of the first metal layer 41 of the first embodiment. That is, when the entire first metal layer 621 is taken as 100% by volume, the material of the first metal layer 621 contains 50% by volume or more of Al or Ag and does not contain Ti.

[0129] The second metal layer 622 can be made of the same material as the second metal layer 42 of the first embodiment. Like the second metal layer 42 of the first embodiment, the second metal layer 622 is a layer containing an active metal.

[0130] As with the first metal layer 621, the material of the first metal layer 631 in the second bonding layer 63 can be the same as the material of the first metal layer 41 in the first embodiment.

[0131] Like the second metal layer 622, the second metal layer 632 can be made of the same material as the second metal layer 42 of the first embodiment, and is a layer containing an active metal.

[0132] The thickness of the first bonding layer 62 and the second bonding layer 63 can be selected arbitrarily, but is preferably 0.005 mm or more and 0.5 mm or less.

[0133] The thickness of the second metal layer 622 and the second metal layer 632 can be selected arbitrarily, and may be 10 nm or more and 10 μm or less, 20 nm or more and 20 μm or less, 30 nm or more and 1 μm or less, or 50 nm or more and 500 nm or less, respectively.

[0134] The thickness of the first metal layer 621 can be the thickness of the first bonding layer 62 minus the thickness of the second metal layer 622. The thickness of the first metal layer 631 can be the thickness of the second bonding layer 63 minus the thickness of the second metal layer 632.

[0135] By providing the bonding layer 6 with the stress relaxation layer 61, the stress occurring at the interface between the base 3 and the electrostatic chuck member 2 is further relaxed, and peeling of the bonding layer 6 can be suppressed.

[0136] The electrostatic chuck device 1B can be suitably manufactured by first forming a Ti film 401 on the main surface of the electrostatic chuck member 2 and the main surface of the base 3, and then using a metal brazing material that does not contain Ti, which is the material for the first metal layer 621 and the first metal layer 631.

[0137] The electrostatic chuck device 1B may have only one of the second metal layer 622 and the second metal layer 632 .

[0138] Even with the electrostatic chuck device 1B configured as described above, the electrostatic chuck member 2 and the base 3 are brazed together, making it possible to provide a novel electrostatic chuck device having excellent heat resistance.

[0139] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. The shapes and combinations of the components shown in the above examples are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0140] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0141] The following test pieces were prepared and used in the examples and comparative examples. ２ O ３ :SiC=95:5 (mass ratio), thickness 2 mm) Conductive ceramic substrate (AlN:TiN=50:50, thickness 1 mm) Aluminum substrate (thickness 1 mm)

[0142] The conductive ceramic substrate was prepared by the following method.

[0143] (Preparation of Conductive Ceramic Substrate) A mixture of AlN particles having an average primary particle size of 1 μm, TiN particles having an average primary particle size of 1 μm, a dispersant, and ethanol was mixed for 12 hours using a ball mill using aluminum oxide media having a diameter of 1 mm to 5 mm. The AlN particles and TiN particles were weighed to have a volume ratio of 50:50.

[0144] The resulting mixture was then air-dried to obtain a raw material powder for the conductive ceramics, which was then heated at 500° C. in a nitrogen atmosphere for 12 hours.

[0145] The heated raw material powder was uniaxially press-molded at a pressure of 8 MPa using a die molding method to obtain a molded body, which was then set in a graphite mold and pressure-sintered at 1700°C for 2 hours under a nitrogen atmosphere at a pressure of 20 MPa to obtain a conductive ceramic substrate.

[0146] The obtained conductive ceramic substrate was processed to a thickness of 1 mm to obtain a test piece of the conductive ceramic substrate.

[0147] Example 1 Ti was sputtered onto one surface of a dielectric substrate to form a Ti film having a thickness of 100 nm.Similarly, Ti was sputtered onto one surface of a conductive ceramic to form a Ti film having a thickness of 100 nm.

[0148] Next, the dielectric substrate and the conductive ceramic Ti film were placed opposite each other, and a metal brazing sheet (TB-608 (composition: Ag 72%, Cu 28%, manufactured by Tokyo Blaze Co., Ltd.), thickness: 50 μm) was placed and sandwiched between the Ti films to form a laminate. The resulting laminate was pressurized at 29 kPa and heat-treated at 840°C for 60 minutes to form a braze-joint.

[0149] The resulting bonded body was observed, and it was confirmed that no cracks had occurred in either the dielectric substrate or the conductive substrate, and that bonding could be performed without any problems.

[0150] When the obtained bonded body was inspected with an ultrasonic flaw detector (ultrasonic digital imaging diagnostic system IS-600, manufactured by Insight Co., Ltd.), almost no voids were found in the bonding layer, confirming that defects in the bonding layer were suppressed.

[0151] Comparative Example 1 Two laminates were produced by placing a metal brazing filler metal (TKC-661, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., composition: Ag 66.0%, Cu 29.5%, Ti 1.5%, Sn balance (approximately 3%)) between a dielectric substrate and a conductive ceramic substrate. One of the resulting laminates was brazed at 840°C for 60 minutes under a pressure of 13 kPa. The other laminate was brazed under the same conditions as above, except that the pressure was changed to 29 kPa. As a result, no cracks were observed in either the dielectric substrate or the conductive substrate in these bonded bodies, confirming that they could be bonded without any problems. However, when these bonded bodies were inspected with an ultrasonic flaw detector, multiple voids were confirmed in the bonding layer. The number of voids formed in the bonded body of Comparative Example 1 was clearly greater than that of the bonded body of Example 1.

[0152] Although the results of Example 1 and Comparative Example 1 described above are for test pieces, it is believed that similar behavior also occurs at the interface between the electrostatic chuck member 2 made of a dielectric substrate and the base 3 made of a conductive ceramic. That is, when the electrostatic chuck part made of a dielectric substrate and the base are brazed by the joining method described in Example 1, it is expected that the joining can be performed without generating defects in the joint.

[0153] From the above results, it was confirmed that the present invention is useful.

[0154] DESCRIPTION OF SYMBOLS 1A, 1B Electrostatic chuck device 2 Electrostatic chuck member 2a Mounting surface 2b Back surface 3 Base 3a Support surface 3b Lower surface 3f Flow path 4, 6 Bonding layer 5 Support plate 11 Dielectric substrate 13 Adsorption electrode 16 Power supply terminal 17 Hole portion 17a First hole in dielectric substrate 17b Second hole in bonding layer 17c Third hole in support plate 21 Power source 22 High frequency power source 23 Insulator 23a Upper end surface 41, 621, 631 First metal layer 41a Strip-shaped region 42, 42a, 42b, 622, 632 Second metal layer 61 Stress relaxation layer 62 First bonding layer 63 Second bonding layer 401 Ti film 411 Metal brazing material W Wafer

Claims

1. An electrostatic chuck device comprising: an electrostatic chuck member having a dielectric substrate and an internal electrode; a base formed of a conductive material containing ceramics; and a bonding layer made of a metal material bonding the electrostatic chuck member to the base, wherein the bonding layer has a laminated structure in which a first metal layer and a second metal layer are laminated; the first metal layer contains a total of 50 volume % or more of Ag or Al relative to the total volume of the first metal layer; the second metal layer is a layer containing at least one active metal selected from the group consisting of Ti, Zr, Hf and Nb; and the second metal layer is sandwiched between the base and the first metal layer, and between the electrostatic chuck member and the first metal layer, or both.

2. An electrostatic chuck device according to claim 1, wherein the first metal layer does not contain the active metal.

3. An electrostatic chuck device according to claim 1 or 2, wherein the base is made of a conductive ceramic or metal-based composite material.

4. An electrostatic chuck device according to claim 3, wherein the conductive ceramic is composed of a highly thermally conductive material and a conductive material, and the volume ratio of the highly thermally conductive material to the conductive material is 10:90 to 90:

10.

5. The high thermal conductivity material is AlN, SiC, GaN, Al ２ O ３ , SmAlO ３ , MgO, SiO ２ , Si ３ N ４ , Al(OH) ３ , MgO, Mg(OH) ２ , BN, ZnO, BeO, B ４ The conductive material is at least one selected from the group consisting of C, carbon, aluminum, copper, silver, and gold, and the conductive material is SiC, TiO ２ , TiN, TiC, W, WC, Mo, MoC, Mo ２ 5. The electrostatic chuck device according to claim 4, wherein the material is at least one selected from the group consisting of C, TaC, TaN, NbC, VC, and C.

6. An electrostatic chuck device according to claim 1 or 2, further comprising a support plate on the opposite side of the base from the electrostatic chuck member, the support plate being made of a material having a higher Young's modulus than the material of the base.

7. A method for manufacturing an electrostatic chuck device, comprising: a step of forming a film of at least one active metal selected from the group consisting of Ti, Zr, Hf, and Nb on one or both of a main surface of an electrostatic chuck member having a dielectric substrate and an internal electrode and a main surface of a base; and a step of bringing the active metal film into contact with a metallic brazing material, brazing the electrostatic chuck member to the base by arranging the main surface of the electrostatic chuck member and the main surface of the base opposite each other, thereby obtaining an electrostatic chuck device, wherein the metallic brazing material contains a total of 50 volume % or more of Ag or Al relative to the entire metallic brazing material.

8. The method for manufacturing an electrostatic chuck device according to claim 7, wherein the metallic brazing material does not contain the active metal.

9. A method for manufacturing a laminate, comprising the steps of: forming a film of at least one active metal selected from the group consisting of Ti, Zr, Hf, and Nb on either or both of the main surface of a first substrate made of ceramics and the main surface of a second substrate made of an inorganic material; bringing the active metal film into contact with a brazing metal material, brazing the first substrate to the second substrate by arranging the main surface of the first substrate and the main surface of the second substrate opposite each other, and obtaining a laminate of the first substrate and the second substrate, wherein the brazing metal material contains a total of 50% by volume or more of Ag or Al relative to the entire brazing metal material.

10. The method for producing a laminate according to claim 9, wherein the metallic brazing material does not contain the active metal.

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