Electrostatic chuck device

Abstract

An electrostatic chuck device is provided with: an electrostatic chuck member containing a ceramic material; a susceptor containing silicon carbide as a material; and a bonding layer comprising a metal material and bonding the electrostatic chuck member and the susceptor, in which the electrostatic chuck member contains 50 vol% or more of alumina when the entire electrostatic chuck member is 100 vol%, and the susceptor contains 75 vol% or more and 100 vol% or less of silicon carbide when the entire susceptor is 100 vol%.

Description

Technical Field

[0001] The present invention relates to an electrostatic chuck device. Background Art

[0002] Conventionally, in semiconductor manufacturing processes for manufacturing semiconductors such as ICs, LSIs, and VLSIs, when performing plasma processing on a plate-like specimen such as a silicon wafer, an electrostatic chuck device that electrostatically adsorbs the plate-like specimen is used. Among the plate-like specimens held by the electrostatic chuck device, the temperature distribution during processing is uniformly controlled so that the processing state of the plate-like specimen during plasma processing does not become uneven.

[0003] In recent years, with the diversification of semiconductor processes, the temperature of the plate-like specimen during processing is controlled within a wider temperature range than in the past. Therefore, the electrostatic chuck device is exposed to thermal cycling within a wider temperature range than in the past.

[0004] Therefore, as an electrostatic chuck device, an electrostatic chuck device having an electrostatic chuck member made of ceramic and a base made of a metal matrix composite (MMC), which is a composite material of metal and ceramic, has been proposed (for example, refer to Patent Document 1).

[0005] In the electrostatic chuck device described in Patent Document 1, a metal solder is used to join the electrostatic chuck member and the base. In the electrostatic chuck device described in Patent Document 1, by adjusting the amount of metal in the MMC, which is the material of the base, the thermal expansion difference from the ceramic plate is reduced to below a reference value, and the thermal stress during brazing is alleviated.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Laid-Open No. 11-163109 Summary of the Invention

[0009] Technical Problem to be Solved by the Invention

[0010] However, from the viewpoint of an electrostatic chuck device with high heat resistance, there is still room for improvement.

[0011] The present invention has been completed in view of this situation, and an object thereof is to provide a novel electrostatic chuck device with high heat resistance.

[0012] Means for Solving the Technical Problem

[0013] As a result of various studies, the inventors found that when adjusting and manufacturing the base of an MMC, adverse conditions may occur when adjusting only from the perspective of "reducing the difference in thermal expansion coefficient from the ceramic (electrostatic chuck component)". Based on the above insights, as a result of in-depth research by the inventors, the present invention has been completed.

[0014] The present invention provides an electrostatic chuck device including: an electrostatic chuck component containing a ceramic material; a base containing silicon carbide as a material; and a bonding layer composed of a metal material for bonding the electrostatic chuck component and the base. When the entire electrostatic chuck component is set to 100% by volume, the electrostatic chuck component contains 50% by volume or more of alumina.

[0015] Specifically, the present invention provides the following aspects.

[0016] The first aspect of the present invention provides the following electrostatic chuck device.

[0017] [1] An electrostatic chuck device comprising: an electrostatic chuck component containing a ceramic material; a base containing silicon carbide as a material; and a bonding layer composed of a metal material for bonding the electrostatic chuck component and the base. When the entire electrostatic chuck component is set to 100% by volume, the electrostatic chuck component contains 50% by volume or more of alumina. When the entire base is set to 100% by volume, the base contains 75% by volume or more and less than 100% of the silicon carbide.

[0018] The first aspect of the present invention preferably has the following features [2], [6] to [9] individually or in combination of two or more.

[0019] [2] The electrostatic chuck device according to [1], wherein the bonding layer has: a stress relaxation layer; a first bonding layer for bonding the stress relaxation layer and the electrostatic chuck component; and a second bonding layer for bonding the stress relaxation layer and the base.

[0020] The second aspect of the present invention provides the following electrostatic chuck device.

[0021] [3] An electrostatic chuck device comprising: an electrostatic chuck component containing a ceramic material; a base composed of silicon carbide; and a bonding layer composed of a metal material for bonding the electrostatic chuck component and the base. The bonding layer has: a stress relaxation layer; a first bonding layer for bonding the stress relaxation layer and the electrostatic chuck component; and a second bonding layer for bonding the stress relaxation layer and the base. When the entire electrostatic chuck component is set to 100% by volume, the electrostatic chuck component contains 50% by volume or more of alumina.

[0022] The second aspect of the present invention preferably has the following features [6] to [9] individually or in combination of two or more.

[0023] The third aspect of the present invention provides the following electrostatic chuck device.

[0024] [4] An electrostatic chuck device, comprising: an electrostatic chuck member containing a ceramic material; a base formed of a metal matrix composite; and a bonding layer composed of a metal material for bonding the electrostatic chuck member and the base, the bonding layer having: a stress relaxation layer; a first bonding layer for bonding the stress relaxation layer and the electrostatic chuck member; and a second bonding layer for bonding the stress relaxation layer and the base. When the whole of the electrostatic chuck member is 100% by volume, the electrostatic chuck member contains 50% by volume or more of alumina. When the whole of the metal matrix composite is 100% by volume, the metal matrix composite contains 75% by volume or more of silicon carbide and contains 0% by volume or more and 25% by volume or less of a metal having a melting point of 500°C or more and 700°C or less.

[0025] The third aspect of the present invention preferably has the following features [5] to [9] individually or in combination of two or more.

[0026] [5] The electrostatic chuck device according to [4], wherein

[0027] the surface of the base is coated with a metal film.

[0028] [6] The electrostatic chuck device according to any one of [2] to [5], wherein the stress relaxation layer is a metal layer or a metal foil formed of at least one metal selected from the group consisting of Cu, Al, Ti, Nb, and W, and the melting points of the materials of the first bonding layer and the second bonding layer are lower than the melting point of the material forming the stress relaxation layer. When the whole of the first bonding layer is 100% by volume, the material of the first bonding layer is an alloy containing 50% by volume or more of Al or Ag and containing 0.02% by volume or more and 40% by volume or less of at least one metal selected from the group consisting of Ti, Zr, and Hf.

[0029] [7] The electrostatic chuck device according to [6], wherein the first bonding layer and the second bonding layer are made of the same material.

[0030] [8] The electrostatic chuck device according to any one of [1] to [7], wherein a support plate is provided on the side of the base opposite to the electrostatic chuck member, and the support plate is made of a material having a higher Young's modulus than the material of the base.

[0031] [9]The electrostatic chuck device according to any one of [1] to [7], wherein the electrostatic chuck member includes a dielectric substrate and a suction electrode located inside the dielectric substrate, and the dielectric substrate is formed of the ceramic material.

[0032] Advantageous Effects of the Invention

[0033] According to the present invention, a novel electrostatic chuck device with high heat resistance can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a cross-sectional schematic view showing an example of the electrostatic chuck device 1A of the first embodiment.

[0035] Figure 2 It is an explanatory view showing an example of the electrostatic chuck device 1B according to the second embodiment.

[0036] Figure 3 It is a graph showing the number of cycles (times) on the horizontal axis and the amount of dimensional change (mm) on the vertical axis for each test body.

[0037] Figure 4 It is an enlarged cross-sectional view of the base of Comparative Example 1 after the thermal cycle test. DETAILED DESCRIPTION OF THE INVENTION

[0038] Hereinafter, examples of preferred embodiments of the present invention will be described with reference to the drawings. In addition, the following description is for better understanding of the gist of the invention, and the present invention is not limited as long as there is no special specification. Changes, omissions, or additions of quantities, positions, sizes, amounts, numerical values, ratios, orders, shapes, types, components, etc. can be made without departing from the scope of the invention. And as long as there is no special problem, the first embodiment and the second embodiment can use the preferred conditions of each other.

[0039] [First Embodiment]

[0040] Hereinafter, with reference to Figure 1 , a preferred example of the electrostatic chuck device according to the first embodiment of the present invention will be described. In addition, in all the following drawings, in order to more easily observe the drawings, the dimensions, ratios, etc. of each component are appropriately changed.

[0041] Figure 1 It is a cross-sectional schematic view showing an example of the electrostatic chuck device 1A of the 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 part) 23, and a power supply terminal 16. The electrostatic chuck member 2 and the base 3 are laminated with each other with the bonding layer 4 interposed therebetween.

[0042] In this specification, the direction in which the stacked electrostatic chuck member 2 and the base 3 are stacked is referred to as the stacking direction. Further, the side on which the electrostatic chuck member 2 is disposed with respect to the base 3 is referred to as one side in the stacking direction, and the opposite side is referred to as the other side in the stacking direction. And, in the following description, each part of the electrostatic chuck device 1A is described with the vertical direction as the stacking direction. However, the vertical direction here is only a direction used for simplifying the description and does not limit the posture when using the electrostatic chuck device 1A. Further, the upper side corresponds to one side in the stacking direction, and the lower side corresponds to the other side in the stacking direction.

[0043] (Electrostatic chuck member)

[0044] The electrostatic chuck member 2 has a dielectric substrate 11 and a suction electrode 13 located inside the dielectric substrate 11. A placement surface 2a for sucking the wafer W is provided on the upper surface of the electrostatic chuck member 2. A focusing ring surrounding the wafer W can be disposed outside the placement surface 2a of the electrostatic chuck member 2. The electrostatic chuck member may have other features as needed. For example, an insulating layer may be provided around the suction electrode 13 as needed. Two dielectric substrates 11 having the same or different compositions may be disposed above and below the suction electrode 13 or the insulating layer. The electrostatic chuck member 2 can be formed, for example, using ceramics composed only of insulating materials, ceramics composed of a composite or composite sintered body of an insulating material and a conductive material, and the like. Further, in the description, ceramics may sometimes be referred to as ceramic materials.

[0045] The dielectric substrate 11 is preferably composed of a composite sintered body that has sufficient mechanical strength and has durability against corrosive gases and their plasmas. As the dielectric material constituting the dielectric substrate 11, ceramics having mechanical strength and durability against corrosive gases and their plasmas are preferably used.

[0046] The ceramics (ceramic materials) constituting the dielectric substrate 11 can be selected as needed. As the main component, it preferably contains alumina (Al2O3). "Main component" means that it accounts for 50% by volume or more of the whole. Alumina is also preferably contained in the ceramics at 60% by volume or more, 70% by volume or more, 80% by volume or more, 90% by volume or more, 95% by volume or more, 100% by volume. As an example of the ceramic material, for example, an alumina (Al2O3) sintered body, an alumina (Al2O3)-silicon carbide (SiC) composite sintered body, etc. are preferably used. In particular, from the viewpoints of dielectric characteristics at high temperatures, high corrosion resistance, plasma resistance, and heat resistance, the material constituting the dielectric substrate 11 is preferably an Al2O3-SiC composite sintered body containing alumina and silicon carbide.

[0047] The dielectric substrate 11 is circular or substantially circular in plan view and has a mounting surface 2a for mounting the wafer W and a back surface 2b on the side opposite to the mounting surface 2a. On the mounting surface 2a, for example, a plurality of protrusions (not shown) may be formed at a prescribed interval. In this case, the mounting surface 2a supports the wafer W at the front ends of the plurality of protrusions.

[0048] The adsorption electrode 13 is disposed inside the dielectric substrate 11 and does not expose to the outside. The adsorption electrode 13 extends in a plate shape along the mounting surface 2a of the dielectric substrate 11. The adsorption electrode 13 generates an electrostatic adsorption force for holding the wafer W on the mounting surface 2a of the dielectric substrate 11 by applying a voltage. A power supply terminal 16 for applying a DC voltage to the adsorption electrode 13 is connected to the adsorption electrode 13. The shape or number of the adsorption electrodes 13 can be arbitrarily selected.

[0049] The adsorption electrode 13 is preferably composed of a composite body or a composite sintered body of an insulating material and a conductive material. The insulating material is also preferably a ceramic. The insulating material contained in the adsorption electrode 13 is not particularly limited, but is preferably at least one selected from the group consisting of alumina (Al2O3), aluminum nitride (AlN), silicon nitride (Si3N4), yttrium(III) oxide (Y2O3), yttrium-aluminum-garnet (YAG), and SmAlO3. The conductive material contained in the adsorption electrode 13 is preferably at least one selected from the group consisting of molybdenum carbide (Mo2C), molybdenum (Mo), tungsten carbide (WC), tungsten (W), tantalum carbide (TaC), tantalum (Ta), silicon carbide (SiC), carbon black, carbon nanotubes, and carbon nanofibers. In the composite body or the composite sintered body, the content ratio (blending ratio) of the conductive material to the insulating material is not particularly limited and can be arbitrarily selected according to the use. For example, the insulating material contained in the adsorption electrode 13 may be less than 95% by volume of the whole, less than 90% by volume, less than 70% by volume, less than 50% by volume, 30% by volume or less, 20% by volume or less, 10% by volume or less, etc., but is not limited to these examples.

[0050] The thickness of the electrostatic chuck member 2 can be arbitrarily selected, but is preferably 0.5 mm or more and 5 mm or less. For example, it may be 1.0 to 4 mm or 2.0 to 3 mm. If the thickness of the electrostatic chuck member 2 is 0.5 mm or more, the withstand voltage of the electrostatic chuck member 2 becomes higher. And if the thickness of the electrostatic chuck member 2 is 5 mm or less, the heat capacity of the electrostatic chuck member 2 becomes smaller, so it is easy to keep the temperature of the plate-like specimen as the object to be processed uniform in plasma processing.

[0051] When the entire electrostatic chuck member is set to 100% by volume, the electrostatic chuck member 2 may contain 50% by volume or more of alumina, and may also contain 60% by volume or more, 70% by volume or more, 80% by volume or more, 90% by volume or more.

[0052] (Base)

[0053] The base 3 supports the electrostatic chuck member 2 from below. On the base 3, there is provided a support surface 3a facing upward and a lower surface 3b facing downward. The support surface 3a faces the back surface 2b of the dielectric substrate 11 in the vertical direction with the bonding layer 4 therebetween. In the base 3, the electrostatic chuck member 2 is supported on the support surface 3a.

[0054] Preferably, a flow path 3f for circulating a refrigerant is provided inside the base 3. As the refrigerant flowing in the flow path 3f, water, He gas, N2 gas, etc. can be used as needed. The flow path 3f extends along the support surface 3a. The refrigerant in the flow path 3f cools the entire base 3 and cools the electrostatic chuck member 2 via the support surface 3a.

[0055] The base 3 is a member having a circular plate shape or a substantially circular plate shape when viewed from above, and is preferably made of a material having a thermal conductivity of 140 W / m·K or more. In this specification, "viewed from above" means the field of view observed from the thickness direction of the electrostatic chuck member 2. The thermal conductivity may be 160 W / m·K or more, 180 W / m·K or more, 200 W / m·K or more, 300 W / m·K or more, 500 W / m·K or more, 600 W / m·K or more, etc.

[0056] The material of the base 3 can be arbitrarily selected, but preferably contains SiC as a material. Specifically, when the entire base 3 is set to 100% by volume, the material of the base 3 preferably contains 75% by volume or more of SiC, more preferably contains 75% by volume or more and less than 100% by volume of SiC, and further preferably contains 75% by volume or more and 99% by volume or less. The amount can be 80 to 98% by volume, 82 to 96% by volume, 85 to 90% by volume, etc. In addition to SiC, the base 3 preferably further contains one or more of aluminum (Al), silicon (Si), and magnesium (Mg). These amounts can be, for example, 0.1 to 25% by volume, 0.5 to 23% by volume, 1 to 22% by volume, 3 to 21% by volume, 5 to 20% by volume, 10 to 15% by volume, etc. By including these in SiC, the thermal conductivity of the base 3 is increased, and heat dissipation via the base 3 is facilitated. In a material containing 75% by volume or more of SiC as the material of the base 3, by adjusting the type or amount of the target material contained in the material, the coefficient of thermal expansion can be controlled within the range of 2.8×10 -6 / K to 6.8×10 -6 / K. The coefficient of thermal expansion can be, as needed, in the range of 3.2 to 6.5×10-6 / K, 3.6 - 6.0×10 -6 / K, 3.8 - 5.5×10 -6 / K, 4.0 - 5.0×10 -6 within the range of / K, etc.

[0057] When the whole of the base 3 is set to 100% by volume, the material of the base 3 is preferably, for example, a material containing 75% by volume or more and 85% by volume or less of SiC and containing 15% by volume or more and 25% by volume or less of Si or Mg. For example, the amount of SiC can be 76 - 84% by volume, 77 - 83% by volume, 78 - 82% by volume, 80 - 81% by volume, etc. The amount of Si or Mg can be 16 - 24% by volume, 17 - 23% by volume, 18 - 22% by volume, 20 - 21% by volume, etc. The thermal expansion coefficient of the base 3 having such a composition is very close to that of Al2O3 - SiC constituting the electrostatic chuck member, and deformation can be suppressed. The base 3 is also preferably formed only of SiC and Al, Si, or Mg.

[0058] As an example of a material in which Al, Si, or Mg is contained in SiC, for example, a known metal matrix composite (Metal Material Composite, hereinafter referred to as MMC) can be preferably used. MMC can refer to a composite material of a metal and a ceramic, for example, a material in which a reinforcing material of a ceramic such as SiC is compounded in a metal matrix such as Al, Si, or Mg. MMC can be formed by any method. For example, it can be preferably manufactured by a known method (such as a metal infiltration method, a forging method, etc.) in which Al or Si is introduced into the pores of the ceramic substrate after adjusting or forming a porous ceramic substrate.

[0059] The surface of the base 3 is also preferably coated with a metal film as needed. The metal film is preferably provided, for example, on the front surface, back surface, and side surface of the base 3. The metal film can be selected as needed. For example, an Al spray - coated film can be used. The film thickness of the metal film can be arbitrarily selected. For example, it can be set to 100 μm or more and 300 μm or less. Thereby, the base 3 can be used as an internal electrode for plasma generation. From the viewpoint of suppressing discharge, it is also preferable to further provide an insulating film, such as an Al2O3 spray - coated film, on the side surface of the base 3 coated with the metal film. The base 3 is connected to an external high - frequency power supply 22 via a matcher (not shown).

[0060] A hole portion 17 is provided in the base 3. The hole portion 17 extends in the vertical direction. The hole portion 17 penetrates the base 3 in the vertical direction and opens at the support surface 3a and the lower surface 3b of the base 3, respectively. The hole portion 17 is, for example, circular in a plan view. An insulator 23 described later is inserted into the hole portion 17. In Figure 1The case where the hole portion 17 penetrates the base 3 in the vertical direction is shown. In addition, as long as the hole portion 17 opens at least on the support surface 3a and the insulator 23 is inserted therein, it is not necessary for the hole portion 17 to penetrate the base 3.

[0061] (Bonding layer)

[0062] The bonding layer 4 is made of a metal material and bonds the electrostatic chuck member 2 and the base 3. In addition, as the metal material, examples thereof include a material composed of only one or more metals or a material containing one or more metals. For example, it can be a layer composed of one metal or an alloy layer containing a plurality of metals. When the entire bonding layer 4 is set to 100% by volume, the bonding layer 4 is preferably formed of an alloy containing 50% by volume or more of Al or Ag as the main raw material and containing at least one metal (for example, a reactive metal selected from these) selected from the group consisting of Ti, Zr, Hf, and Nb in an amount of 0.02% by volume or more and 40% by volume or less. The amount of Al or Ag can be 55 to 99.8% by volume, 60 to 98% by volume, 70 to 95% by volume, 80 to 90% by volume, etc. The amount of the at least one metal can be 0.1 to 35% by volume, 1 to 30% by volume, 5 to 25% by volume, 10 to 20% by volume, etc. By the bonding layer 4 containing at least one metal selected from the group consisting of Ti, Zr, Hf, and Nb, when bonding the electrostatic chuck member 2 and the base 3, the molten alloy obtained by melting the material of the bonding layer 4 is likely to wet and spread on the surface of the ceramic (electrostatic chuck member 2), so that the bonding becomes easy. And, by the bonding layer 4 containing the above-mentioned metal, the above-mentioned metal is likely to be in close contact with the ceramic (electrostatic chuck member 2), the generation of voids at the interface can be suppressed, and firm bonding can be performed. In addition, the bonding layer 4 may contain one or more metals or elements other than the above as needed. For example, it may contain Cu or Sn, etc.

[0063] In the case where a solder containing Ti as a reactive metal is used for forming the bonding layer 4, if Ti is oxidized to become a Ti oxide, poor bonding is likely to occur. Therefore, in the case where a solder containing Ti is used for forming the bonding layer 4, it is preferable to adjust the temperature conditions or the pressure conditions during soldering so that Ti contained in the solder is not oxidized.

[0064] Alternatively, a Ti film may be formed on at least one of the dielectric substrate 11 and the base 3, and they may be bonded with a Ti-free solder for soldering. The Ti film may be a Ti sputtering film, or may be formed by heating after coating a slurry containing Ti fine powder. In this case, the bonding layer 4 is composed of a Ti film and a solder.

[0065] The thickness of the bonding layer 4 can be arbitrarily selected. For example, it is preferably 0.005 mm or more and 0.5 mm or less. It can be 0.01 - 0.3 mm, 0.05 - 0.1 mm, etc.

[0066] When manufacturing the electrostatic chuck device 1A, as the material of the bonding layer 4, a metal foil can be used, or a metal paste formed by adding an adhesive to metal powder can be used. These materials are disposed between the electrostatic chuck member 2 and the base 3, and heated to a temperature above the melting point of the metal material forming the bonding layer. By the molten metal material wetting and spreading between the electrostatic chuck member 2 and the base 3, the bonding layer 4 can be formed.

[0067] (Support plate)

[0068] The support plate 5 supports the base 3 from the lower surface 3b of the base 3. The support plate 5 is preferably made of a material having a higher Young's modulus than the material of the base 3. For example, the material of the support plate 5 can be any one of metal, MMC, and ceramic. Among them, as the support plate 5, a plate made of ceramic is preferably used. For example, a ceramic plate such as Al2O3 having a higher Young's modulus than the base 3 is preferably used.

[0069] The ceramic used in the support plate 5 is preferably the same as the ceramic (ceramic material) used in the electrostatic chuck member 2. For example, the ceramic constituting the support plate 5 or the insulating substance contained in the ceramic is preferably the same as the ceramic constituting the electrostatic chuck member 2 or the insulating substance contained in the ceramic. As specific examples of the ceramic, alumina or aluminum nitride can be cited. By using the same material in the support plate 5 and the electrostatic chuck member 2, the difference in the thermal expansion coefficient between the support plate 5 and the electrostatic chuck member 2 can be reduced, and the warpage of the electrostatic chuck device 1A can be suppressed.

[0070] (Insulator)

[0071] The insulator 23 is inserted into the hole portion 17 and assembled to the base 3. That is, the insulator 23 functions as an insertion part inserted into the hole portion 17. The insulator 23 is a cylindrical shape extending in the vertical direction (lamination direction). A power supply terminal 16 is disposed inside the insulator 23. The outer peripheral surface of the insulator 23 is joined to the inner side surface of the hole portion 17 by joining means such as adhesion. The insulator 23 insulates the base 3 and the power supply terminal 16. In Figure 1 and Figure 2 the insulator 23 is inserted into the holes of the bonding layer 4, the hole portion of the base 3, and the hole of the support plate 5.

[0072] The insulator 23 can be formed of any material, for example, ceramics can be used as the forming material. That is, the insulator 23 is composed of an insulating member. With this structure, the insulator 23 can prevent the gas introduction hole from becoming a starting point of abnormal discharge. The insulator 23 has durability against plasma. As the ceramics constituting the insulator 23, for example, one or more ceramics selected from AlN, Al2O3, Si3N4, zirconia (ZrO2), sialon, boron nitride (BN), and SiC can be preferably used.

[0073] The end face on the upper side (one side in the stacking direction) of the insulator 23 (hereinafter, the upper end face 23a) abuts against the lower surface of the electrostatic chuck member 2, or is disposed opposite to the electrostatic chuck member with an insulating adhesive interposed therebetween. In addition, as long as the purpose of the insulating power supply terminal 16 can be achieved, conditions such as the position, height, and shape of the insulator 23 can be changed.

[0074] (Power supply terminal)

[0075] The power supply terminal 16 extends downward from the adsorption electrode 13. The power supply terminal 16 is connected to an external power supply 21. The power supply 21 applies a voltage to the adsorption electrode 13. The number, shape, etc. of the power supply terminals 16 can be arbitrarily selected. For example, they can be determined according to the form of the adsorption electrode 13, i.e., whether it is a unipolar type or a bipolar type.

[0076] The power supply terminal 16 passes through the first hole 17a of the dielectric substrate 11, the second hole 17b of the bonding layer 4, the hole portion 17 of the base 3, and the third hole 17c of the support plate 5. The first hole 17a is provided in the dielectric substrate 11 on the lower side of the adsorption electrode 13. There is an insulator 23 between the power supply terminal 16 and the second hole 17b of the bonding layer 4, the hole portion 17 of the base 3, and the third hole 17c of the support plate 5.

[0077] When observed from the stacking direction, the first hole 17a, the second hole 17b, the hole portion 17, and the third hole 17c are circular. The first hole 17a, the second hole 17b, and the third hole 17c communicate with the hole portion 17 of the base 3.

[0078] And when observed from the stacking direction, the inner peripheral surface of the first hole 17a is connected to the inner peripheral surface of the insulator 23. The inner diameter of the first hole 17a is substantially equal to the inner diameter of the insulator 23 and is slightly larger than the outer diameter of the power supply terminal 16. The inner diameters of the second hole 17b and the third hole 17c are slightly larger than the outer diameter of the insulator 23.

[0079] As a result of in-depth research by the inventors, it was found that in the electrostatic chuck device of the present invention, for example, in the electrostatic chuck device 1A as described above, excellent results of withstanding repeated use at high temperatures were shown.

[0080] In the past, for example, when brazing a ceramic component such as the electrostatic chuck component 2 and a base, in order to suppress breakage caused by the difference in the coefficient of thermal expansion of the components, material adjustment was performed based on the idea of minimizing the difference in the coefficient of thermal expansion between the components to be brazed as much as possible. For example, when Al2O3 is the main component of the electrostatic chuck component 2, the coefficient of thermal expansion of the electrostatic chuck component 2 is 7 to 8 (×10 -6 / K). Thus, from the perspective of the past, the coefficient of thermal expansion of the material of the base 3 joined to the electrostatic chuck component 2 is also preferably 7 to 8 (×10 -6 / K). To achieve such a small difference in the coefficient of thermal expansion, in the past, an MMC having a coefficient of thermal expansion of 7 to 8 (×10 -6 / K) was used as the material of the base 3.

[0081] However, through various studies by the inventors and the like, it was found that when the material of the base 3 is MMC, voids caused by the difference in thermal expansion are generated at the interface between the metal structure and the ceramic structure inside the material constituting the base 3, and changes in the size or physical properties of the base 3 can occur. The inventors and the like confirmed that such an adverse situation will occur if the coefficient of thermal expansion of the material of the base 3 is about 7 to 8 (×10 -6 / K) by containing metal.

[0082] Therefore, as a result of various studies, the following effect was found: In the electrostatic chuck device of the present embodiment, for example, in the above-described electrostatic chuck device 1A, the proportion of the ceramic structure is increased, for example, in a manner such that there is a difference in the coefficient of thermal expansion from the electrostatic chuck component 2, and SiC in the material of the base 3 is set to 75% by volume or more, thereby suppressing the occurrence of the above-described adverse situation.

[0083] In the present embodiment, the difference in the coefficient of thermal expansion between the electrostatic chuck component 2 and the material of the base 3 can be, for example, 0.1 to 7 (×10 -6 / K), 0.5 to 5 (×10 -6 / K), 1.0 to 5 (×10 -6 / K), 2.0 to 4 (×10 -6 / K), 2.5 to 3.5 (×10 -6 / K), etc., but is not limited to these examples.

[0084] According to the electrostatic chuck device having the structure as described above, a new electrostatic chuck device with high heat resistance can be provided.

[0085] [Second Embodiment]

[0086] Figure 2FIG. 0 is an explanatory diagram showing a preferred example of the electrostatic chuck device 1B according to the second embodiment of the present invention. The electrostatic chuck device 1B of the present embodiment shares a part with the electrostatic chuck device 1A of the first embodiment. Therefore, in the present embodiment, the same reference numerals are given to the constituent elements common to the first embodiment, and the detailed description thereof is omitted.

[0087] 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 part) 23, and a power supply terminal 16. The electrostatic chuck member 2 and the base 3 are laminated with each other with the bonding layer 6 therebetween.

[0088] (Bonding layer)

[0089] The bonding layer 6 has a stress relaxation layer 61, a first bonding layer 62 between the stress relaxation layer 61 and the electrostatic chuck member 2, and a second bonding layer 63 between the stress relaxation layer 61 and the base 3. The thermal conductivity of the bonding layer 6 is higher than that of the base 3.

[0090] The stress relaxation layer 61 is made of a material that is easily plastically deformed and relaxes the thermal stress caused by the difference in the thermal expansion coefficients of the electrostatic chuck member 2 and the base 3. The stress relaxation layer 61 preferably uses a metal foil as the material, and the metal foil uses at least one metal selected from the group consisting of Cu, Al, and Ti as the material.

[0091] Alternatively, as the material of the stress relaxation layer 61, a material having a small difference in the thermal expansion coefficient from the material such as Al2O3 constituting the electrostatic chuck member 2 can also be used. For example, as a material having a small difference in the thermal expansion coefficient from the thermal expansion coefficient of Al2O3 (7 to 7.7×10 -6 / K) and preferably used as the stress relaxation layer, Ti (8.4×10 -6 / K), Nb (7.1×10 -6 / K), W (4.6×10 -6 / K), etc. can be cited. For example, the stress relaxation layer 61 can be a metal layer containing at least one selected from the group consisting of CU, Al, Ti, Nb, and W or composed of the at least one.

[0092] The thickness of the stress relaxation layer 61 can be arbitrarily selected, but is preferably 0.1 mm or more and 1 cm or less, more preferably 1 mm or more and 1 cm or less. For example, it can be 0.5 mm to 8 mm, 1 mm to 6 mm, or 3 to 5 mm. By making the thickness of the stress relaxation layer 61 fall within this range, the thermal stress can be sufficiently relaxed, and the peeling between the electrostatic chuck member 2 and the base 3 can be suppressed.

[0093] Preferably, the melting points of the materials of the first bonding layer 62 and the second bonding layer 63 are lower than the melting point of the material for forming the stress relaxation layer. The first bonding layer 62 and the second bonding layer 63 may be of the same material.

[0094] The material of the first bonding layer 62 can be the same material as the bonding layer 4 in the first embodiment. For example, when the whole of the first bonding layer 62 is 100% by volume, the material of the first bonding layer 62 is preferably an alloy containing 50% by volume or more of Al or Ag and containing at least 1 kind of metal selected from the group consisting of Ti, Zr, and Hf in an amount of 0.02% by volume or more and 40% by volume or less. The second bonding layer 63 can also be of the same material.

[0095] The thicknesses of the first bonding layer 62 and the second bonding layer 63 can be arbitrarily selected. For example, it can be 0.001 mm or more and 1.0 mm or less, preferably 0.005 mm or more and 0.5 mm or less. It can be 0.01 mm or more and 0.3 mm or less, 0.05 mm or more and 0.1 mm or less, etc.

[0096] In the case of having such a bonding layer 6, when the whole of the base 3 is 100% by volume, the material of the base 3 preferably contains 75% by volume or more and 100% by volume or less of SiC. For example, the amount of SiC can be 80 - 98% by volume, 82 - 96% by volume, or 85 - 90% by volume. In addition to SiC, the base 3 may contain aluminum (Al), silicon (Si), and magnesium (Mg).

[0097] Moreover, the base 3 also preferably uses a metal matrix composite material as the material. When the base 3 is made of a metal matrix composite material, when the whole of the metal matrix composite material is 100% by volume, it also preferably contains 75% by volume or more of silicon carbide and contains 0% by volume or more and 25% by volume or less of a metal having a melting point of 500°C or more and 700°C or less. For example, the amount of silicon carbide can be 75 - 100% by volume, 78 - 99% by volume, 80 - 98% by volume, or 85 - 90% by volume. The amount of the metal can be 0.1 - 24% by volume, 0.5 - 22% by volume, 1 - 21% by volume, 2 - 20% by volume, 3 - 15% by volume, 5 - 10% by volume, etc. The melting point of the metal can be 550°C or more and 680°C or less, 580°C or more and 630°C or less, etc. Examples of such a metal include Al (melting point 660°C) and Mg (melting point 650°C). If the melting point of the metal contained in the metal matrix composite material is 500°C or more, it will not melt even at the operating temperature of the electrostatic chuck. And if the melting point of this metal is 700°C or less, the manufacturing cost can be reduced.

[0098] When SiC (100% by volume) without a metallic structure is used as the material of the base 3, voids do not occur at the interface between the metallic structure and the ceramic structure, so that the generation of voids inside the base 3 can be suppressed. However, on the other hand, when there is a difference in the coefficient of thermal expansion between the base 3 and the electrostatic chuck member 2, due to this expansion difference, stress is generated at the interface between these two members, and thus interface peeling is likely to occur. Even in such a case, by having the stress relaxation layer 61 in the bonding layer 6, the stress generated at the interface between the base 3 and the electrostatic chuck member 2 can be relaxed, and interface peeling can be suppressed.

[0099] Even for an electrostatic chuck device having the structure as described above, a novel electrostatic chuck device with high heat resistance can be provided.

[0100] As described above, with reference to the accompanying drawings, preferred embodiments of the present invention have been described, but the present invention is not limited to this example. The shapes or combinations of the respective constituent members shown in the above examples are merely examples, and various changes can be made according to design requirements and the like without departing from the gist of the present invention.

[0101] Examples

[0102] Hereinafter, the present invention will be described by way of examples, but the present invention is not limited to these examples.

[0103] [Evaluation 1]

[0104] (Examples 1 and 2, Comparative Examples 1 and 2)

[0105] Adjusted and manufactured MMCs in which metals and SiC are compounded are obtained at the ratios described in the following "test piece composition" and used as test bodies (bases) for Examples and Comparative Examples. The shapes and sizes of these test bodies are the same.

[0106] Test piece composition:

[0107] (Example 1) 18Si - SiC (SiC 82% by volume, Si 18% by volume)

[0108] (Example 2) 18Mg - SiC (SiC 82% by volume, Mg 18% by volume)

[0109] (Comparative Example 1) 30Al - SiC (SiC 70% by volume, Al 30% by volume)

[0110] (Comparative Example 2) 40Al - Si (Si 60% by volume, Al 40% by volume)

[0111] (Dimensions: 50 mm in both length and width, 12 mm in height, shape: rectangular parallelepiped)

[0112] (Thermal cycle test)

[0113] For each of the obtained test specimens, using a two-zone thermal shock testing machine, they were maintained for 30 minutes in a test zone at 150 °C (zone 1), and then maintained for 30 minutes in a test zone at -50 °C (zone 2). These operations were repeated multiple times. Specifically, the process from heating up from -50 °C and then returning to -50 °C by cooling was defined as 1 cycle, and it was repeated up to 600 cycles at most.

[0114] Regarding the test specimens after the thermal cycling test, the outer shape (diameter) of the base was measured, and the dimensional changes before and after the test were evaluated. The base with a dimensional change of 0.01 mm or less after 500 or 600 cycles was judged as a qualified product, and the base with a dimensional change exceeding 0.01 mm was judged as unqualified.

[0115] The evaluation results are shown in Figure 3 . Figure 3 It is a graph with the number of cycles (times) represented on the horizontal axis and the dimensional change amount (mm) represented on the vertical axis for each test specimen. The evaluation results imply that the dimensional changes of the bases in Examples 1 and 2 are small, so the stress generation at the interface between the electrostatic chuck member and the base is suppressed. From the above, it is implied that when the base of the electrostatic chuck device contains 75 vol% or more of silicon carbide, excellent effects can be obtained.

[0116] Figure 4 It is an enlarged cross-sectional view of the base of Comparative Example 1 after the thermal cycling test. As Figure 4 shown, it can be confirmed that voids are formed due to the interface peeling between the metal structure and the ceramic grains on the base of the comparative example. The following shows the Figure 4 imaging conditions.

[0117] (Imaging conditions)

[0118] Device: Field emission scanning electron microscope (FE-SEM) (manufactured by Carl Zeiss, Merlin) EDX detector (manufactured by Bruker, XFlash6)

[0119] Accelerating voltage: 1.0 kV (SEM observation)

[0120] Magnification: 5000 times

[0121] Specimen formation: After forming a cross-section by the BIB method, it was used as an evaluation specimen.

[0122] [Evaluation 2]

[0123] (Examples 3, Comparative Example 3 (Reference Example))

[0124] Each test specimen (laminated body) of Example 3 and Comparative Example 3 was formed by the following method.

[0125] (Example 3)

[0126] A test piece (laminated body) was manufactured by the method described below. The materials used are as follows.

[0127] Ceramic plate: Al2O3-SiC circular plate, diameter 12 mm, thickness 3 mm, manufactured by Sumitomo Osaka Cement Co., Ltd. (proportion of Al2O3: 95% by mass)

[0128] Base material: SiC circular plate, diameter 10 mm, thickness 2 mm

[0129] Bonding layer: Laminated body of metal solder (first bonding layer) / copper plate (stress relaxation layer) / metal solder (second bonding layer)

[0130] The above metal solder: TKC-661 (composition: Ag 66.0 ± 1.0%, Cu 29.5 ± 1.0%, Ti 1.5 ± 0.5%, Sn remainder (about 3%)), manufactured by TANAKA PRECIOUS METAL TECHNOLOGIES Co., Ltd., diameter 12 mm, thickness 0.005 mm

[0131] The above copper plate: Oxygen-free copper, diameter 12 mm, thickness 2 mm

[0132] (Comparative Example 3: Reference Example)

[0133] As the bonding layer, only the above metal solder (first bonding layer) was used, and the same materials as in Example 3 were used otherwise. In addition, the thickness of the bonding layer used in Comparative Example 3 was 0.005 mm.

[0134] (Manufacturing method of each test piece)

[0135] A laminated body was formed by sandwiching a bonding layer between the ceramic plate and the base material, and it was placed in a carbon fixture and loaded (1.3 KPa).

[0136] Next, the laminated body was heated according to the following conditions. First, the laminated body was depressurized to 1×10 -3 Pa or less in a vacuum furnace, and then heated by successively performing the following treatments (1) to (3) and brazing was performed. Then, by performing the treatment of the following condition (4), it was cooled to room temperature.

[0137] (Heating conditions)

[0138] 1) Heating from room temperature to 300 °C and holding at 300 °C for 30 minutes.

[0139] 2) Heat it from 300 °C to 770 °C at 10 °C per minute and hold at 770 °C for 10 minutes.

[0140] 3) Heat it from 770 °C to 880 °C at 5 °C per minute and hold at 880 °C for 30 minutes.

[0141] 4) Cool it naturally from 880 °C to room temperature.

[0142] An ultrasonic flaw detection test was conducted on the obtained test pieces. As a result, no voids were confirmed inside the test piece of Example 3, while voids were confirmed inside the test piece of Comparative Example 3. It was confirmed that when there is a difference in the coefficient of thermal expansion between the electrostatic chuck member and the base, there is an excellent effect based on the bonding layer including the buffer layer.

[0143] The evaluation conditions for the ultrasonic flaw detection test are shown below.

[0144] (Evaluation conditions)

[0145] Device: Ultrasonic flaw detector (Model: IS600, Insight k.k.)

[0146] Scanning length: 20 mm

[0147] Scanning pitch: 0.1 mm

[0148] Energy: LOW

[0149] Voltage: 330 V

[0150] Damping: 100 Ω

[0151] Gain: 19 db

[0152] LPF: 300 MHz

[0153] HPF: 5 MHz

[0154] Moreover, for each test piece, a cross-section was formed and observed with an optical microscope. As a result, no cracks were confirmed on the cross-section of the test piece of Example 3, while cracks were confirmed on the cross-section of the test piece of Comparative Example 3.

[0155] Based on the above results, it was confirmed that the present invention is useful.

[0156] Industrial applicability

[0157] The present invention can provide a novel electrostatic chuck device with high heat resistance.

[0158] Explanation of reference numerals

[0159] 1A, 1B - Electrostatic chuck device

[0160] 2 - Electrostatic chuck component

[0161] 2a - Mounting surface

[0162] 2b - Back surface

[0163] 3 - Base

[0164] 3a - Support surface

[0165] 3b - Lower surface

[0166] 3f - Flow path

[0167] 4, 6 - Bonding layer

[0168] 5 - Support plate

[0169] 11 - Dielectric substrate

[0170] 13 - Adsorption electrode

[0171] 16 - Power supply terminal

[0172] 17 - Hole part

[0173] 17a - First hole

[0174] 17b - Second hole

[0175] 17c - Third hole

[0176] 21 - Power supply

[0177] 22 - External high - frequency power supply

[0178] 23 - Insulator

[0179] 23a - Upper end surface

[0180] 61 - Stress relaxation layer

[0181] 62 - First bonding layer

[0182] 63 - Second bonding layer

[0183] W - Wafer

Claims

1. An electrostatic chuck device, comprising: An electrostatic chuck member containing a ceramic material; A base containing silicon carbide as a material; and A bonding layer made of a metal material and bonding the electrostatic chuck member and the base, When the whole of the electrostatic chuck member is set to 100% by volume, the electrostatic chuck member contains 50% by volume or more of alumina, When the whole of the base is set to 100% by volume, the base contains 75% by volume or more and less than 100% of the silicon carbide.

2. The electrostatic chuck device according to claim 1, wherein The bonding layer has: A stress relaxation layer; A first bonding layer bonding the stress relaxation layer and the electrostatic chuck member; and A second bonding layer bonding the stress relaxation layer and the base.

3. An electrostatic chuck device, comprising: An electrostatic chuck member containing a ceramic material; A base made of silicon carbide; and A bonding layer made of a metal material and bonding the electrostatic chuck member and the base, The bonding layer has: A stress relaxation layer; A first bonding layer bonding the stress relaxation layer and the electrostatic chuck member; and A second bonding layer bonding the stress relaxation layer and the base, When the whole of the electrostatic chuck member is set to 100% by volume, the electrostatic chuck member contains 50% by volume or more of alumina.

4. An electrostatic chuck device, comprising: An electrostatic chuck member containing a ceramic material; A base formed of a metal matrix composite material; and A bonding layer made of a metal material and bonding the electrostatic chuck member and the base, The bonding layer has: A stress relaxation layer; A first bonding layer bonding the stress relaxation layer and the electrostatic chuck member; and A second bonding layer bonding the stress relaxation layer and the base, When the whole of the electrostatic chuck member is set to 100% by volume, the electrostatic chuck member contains 50% by volume or more of alumina, When the whole of the metal matrix composite material is set to 100% by volume, the metal matrix composite material contains 75% by volume or more of silicon carbide and contains 0% by volume or more and 25% by volume or less of a metal having a melting point of 500°C or more and 700°C or less.

5. The electrostatic chuck device according to claim 4, wherein The surface of the base is coated with a metal film.

6. The electrostatic chuck device according to any one of claims 2 to 5, wherein The stress relaxation layer is a metal film or a metal foil formed of at least one metal selected from the group consisting of Cu, Al, Ti, Nb, and W, The melting points of the materials of the first bonding layer and the second bonding layer are lower than the melting point of the material forming the stress relaxation layer, When the whole of the first bonding layer is set to 100% by volume, the material of the first bonding layer is an alloy containing 50% by volume or more of Al or Ag and containing 0.02% by volume or more and 40% by volume or less of at least one metal selected from the group consisting of Ti, Zr, and Hf.

7. The electrostatic chuck device according to claim 6, wherein The first bonding layer and the second bonding layer are made of the same material.

8. The electrostatic chuck device according to any one of claims 1 to 5, wherein, a support plate is provided on a side of the base opposite to the electrostatic chuck member, the support plate is made of a material having a higher Young's modulus than that of the material of the base.

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