Electrostatic chuck

Abstract

The present invention provides an electrostatic chuck that can suppress the peeling of a ceramic dielectric substrate from a base plate and the cracking of the ceramic dielectric substrate in an extremely low temperature environment. An electrostatic chuck comprises: a ceramic dielectric substrate; a metal base plate that supports the ceramic dielectric substrate; and a bonding layer that is provided between the ceramic dielectric substrate and the base plate and contains a resin material, wherein at least one of the first to sixth conditions related to the elongation, bonding strength, and elastic modulus of the bonding layer is satisfied.

Description

Technical Field

[0001] Aspects of the present invention generally relate to an electrostatic chuck. Background Art

[0002] In substrate processing apparatuses that perform etching, chemical vapor deposition (CVD), sputtering, ion implantation, polishing, exposure, inspection, etc., an electrostatic chuck is used as a method of adsorbing and holding an adsorbed object (object) such as a semiconductor wafer or a glass substrate.

[0003] Electrostatic chucks are made by sandwiching electrodes between ceramic dielectric substrates such as alumina and firing them. Electrostatic chucks apply electrostatic attraction power to the built-in electrodes and use electrostatic force to attract substrates such as silicon wafers.

[0004] In recent years, in such substrate processing apparatuses, as the process becomes more miniaturized, research has been conducted on processing in a lower temperature environment than before in order to improve processing accuracy. In response, even electrostatic chucks are required to have low temperature resistance that allows them to be used in a lower temperature environment than before.

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2003-273202 Summary of the invention

[0007] The following knowledge has been obtained. Although the existing electrostatic suction cup can be used in a low temperature environment of, for example, around -20°C, in an extremely low temperature environment of below -60°C, the flexibility of the bonding layer between the ceramic dielectric substrate and the base plate is reduced, and there is a possibility that the ceramic dielectric substrate may peel off from the base plate, or the ceramic dielectric substrate may crack and be damaged, for example due to the surface pattern, shape, thickness, etc.

[0008] The present invention has been made based on the recognition of such problems, and the technical problem to be solved is to provide an electrostatic chuck that can suppress the peeling of a ceramic dielectric substrate from a base plate and the cracking of the ceramic dielectric substrate in an extremely low temperature environment.

[0009] The first invention is an electrostatic chuck, comprising: a ceramic dielectric substrate; a metal base plate supporting the ceramic dielectric substrate; and a bonding layer provided between the ceramic dielectric substrate and the base plate and containing a resin material, characterized in that at least any one of the following conditions 1 to 6 is satisfied. The first condition: the elongation α1 of the bonding layer at -60°C is 120% or more. The second condition: the ratio α1 / α2 of the elongation α1 to the elongation α2 of the bonding layer at 25°C is 0.60 or more. The third condition: the bonding strength β1 of the bonding layer at -60°C is 0.4 MPa or more and 10 MPa or less. The fourth condition: the ratio β1 / β2 of the bonding strength β1 to the bonding strength β2 of the bonding layer at 25°C is 0.6 or more and 10 or less. The fifth condition: the elastic modulus γ1 of the bonding layer at -60°C is 0.1 MPa or more and 10 MPa or less. Sixth condition: a ratio γ1 / γ2 of the elastic modulus γ1 to the elastic modulus γ2 of the bonding layer at 25° C. is 0.6 or more and 30 or less.

[0010] According to the electrostatic chuck, when the first condition is satisfied, sufficient flexibility can be ensured in the bonding layer because the bonding layer has sufficient elongation in an extremely low temperature environment of -60°C or lower. As a result, in an extremely low temperature environment, stress applied to the ceramic dielectric substrate is suppressed, and peeling of the ceramic dielectric substrate from the base plate and cracking of the ceramic dielectric substrate can be suppressed.

[0011] Furthermore, according to the electrostatic chuck, when the second condition is satisfied, the difference in thermal expansion coefficient between the ceramic dielectric substrate and the base plate can be mitigated in an environment of extremely low temperature from room temperature to below -60°C. This can suppress the ceramic dielectric substrate from peeling off from the base plate and the ceramic dielectric substrate from cracking.

[0012] In addition, according to the electrostatic chuck, when the third condition is satisfied, in an extremely low temperature environment of -60°C or below, the anchoring effect of the bonding layer between the ceramic dielectric substrate and the base plate will not be too weak. Thus, in an extremely low temperature environment, the ceramic dielectric substrate and the base plate can be more reliably bonded. In addition, according to the electrostatic chuck, in an extremely low temperature environment of -60°C or below, the anchoring effect of the bonding layer between the ceramic dielectric substrate and the base plate will not be too strong. Thus, in an extremely low temperature environment, the stress applied to the ceramic dielectric substrate is suppressed, and the peeling of the ceramic dielectric substrate from the base plate and the cracking of the ceramic dielectric substrate can be suppressed.

[0013] In addition, according to the electrostatic chuck, when the fourth condition is satisfied, the sufficient bonding strength of the bonding layer between the ceramic dielectric substrate and the base plate can be maintained regardless of the room temperature or the extremely low temperature environment of -60°C or below, and the strong bonding between the ceramic dielectric substrate and the base plate can be maintained. In addition, according to the electrostatic chuck, the effect of the bonding layer between the ceramic dielectric substrate and the base plate can be fully suppressed regardless of the room temperature or the extremely low temperature environment of -60°C or below. Thus, when the room temperature is in an extremely low temperature environment, the stress applied to the ceramic dielectric substrate is suppressed, and the peeling of the ceramic dielectric substrate from the base plate and the cracking of the ceramic dielectric substrate can be suppressed.

[0014] In addition, according to the electrostatic chuck, when the fifth condition is satisfied, in an extremely low temperature environment below -60°C, since the bonding layer has sufficient resilience, it is easy to suppress the ceramic dielectric substrate from warping even when stress is generated between the ceramic dielectric substrate and the base plate. Thus, in an extremely low temperature environment, it is possible to suppress the deterioration of the in-plane temperature uniformity of the object. In addition, according to the electrostatic chuck, in an extremely low temperature environment below -60°C, it is possible to suppress the bonding layer from becoming too hard. Thus, in an extremely low temperature environment, it is possible to suppress the stress applied to the ceramic dielectric substrate, and it is possible to suppress the peeling of the ceramic dielectric substrate from the base plate and the cracking of the ceramic dielectric substrate.

[0015] In addition, according to the electrostatic chuck, when the sixth condition is satisfied, the bonding layer maintains sufficient resilience regardless of whether it is at room temperature or in an extremely low temperature environment below -60°C, so even when stress is generated between the ceramic dielectric substrate and the base plate, it is easy to suppress the ceramic dielectric substrate from warping. As a result, when the temperature uniformity within the surface of the object is reduced from room temperature to an extremely low temperature environment. In addition, according to the electrostatic chuck, the bonding layer can be suppressed from becoming too hard regardless of whether it is at room temperature or in an extremely low temperature environment below -60°C. As a result, when the temperature is reduced from room temperature to an extremely low temperature environment, the stress applied to the ceramic dielectric substrate is suppressed, and the peeling of the ceramic dielectric substrate from the base plate and the cracking of the ceramic dielectric substrate can be suppressed.

[0016] A second invention is the electrostatic chuck according to the first invention, wherein the elongation α1 is 175% or more.

[0017] According to the electrostatic chuck, since the bonding layer has a greater elongation, the flexibility of the bonding layer can be further improved, thereby further suppressing the stress applied to the ceramic dielectric substrate in an extremely low temperature environment, and further suppressing the peeling of the ceramic dielectric substrate from the base plate and the cracking of the ceramic dielectric substrate.

[0018] A third invention is the electrostatic chuck according to the second invention, wherein the elongation α1 is 200% or more.

[0019] According to the electrostatic chuck, since the bonding layer has a greater elongation, the flexibility of the bonding layer can be further improved, thereby further suppressing the stress applied to the ceramic dielectric substrate in an extremely low temperature environment, and further suppressing the peeling of the ceramic dielectric substrate from the base plate and the cracking of the ceramic dielectric substrate.

[0020] A fourth invention is an electrostatic chuck according to any one of the first to third inventions, wherein the ratio α1 / α2 is equal to or greater than 0.7.

[0021] According to this electrostatic chuck, the difference in thermal expansion coefficient between the ceramic dielectric substrate and the base plate can be further reduced in an environment of extremely low temperature from room temperature to -60°C or lower. This can further suppress the ceramic dielectric substrate from peeling off the base plate and cracking of the ceramic dielectric substrate.

[0022] A fifth invention is an electrostatic chuck according to any one of the first to fourth inventions, wherein the bonding strength β1 is not less than 0.4 MPa and not more than 2.0 MPa.

[0023] According to the electrostatic chuck, in an extremely low temperature environment of below -60°C, it is possible to further suppress the fixing effect of the bonding layer between the ceramic dielectric substrate and the base plate from becoming too weak. Thus, in an extremely low temperature environment, the ceramic dielectric substrate and the base plate can be more reliably bonded. In addition, according to the electrostatic chuck, in an extremely low temperature environment of below -60°C, it is possible to further suppress the fixing effect of the bonding layer between the ceramic dielectric substrate and the base plate from becoming too strong. Thus, in an extremely low temperature environment, the stress applied to the ceramic dielectric substrate is further suppressed, and the peeling of the ceramic dielectric substrate from the base plate and the cracking of the ceramic dielectric substrate can be further suppressed.

[0024] A sixth invention is an electrostatic chuck according to any one of the first to fifth inventions, wherein the ratio β1 / β2 is 0.8 or more.

[0025] According to the electrostatic chuck, the sufficient bonding strength of the bonding layer between the ceramic dielectric substrate and the base plate can be more reliably maintained regardless of whether it is at room temperature or in an extremely low temperature environment of -60°C or below, and the firm bonding between the ceramic dielectric substrate and the base plate can be more reliably maintained. In addition, according to the electrostatic chuck, the effect of the bonding layer between the ceramic dielectric substrate and the base plate can be more reliably suppressed regardless of whether it is at room temperature or in an extremely low temperature environment of -60°C or below. As a result, when the room temperature is in an extremely low temperature environment, the stress applied to the ceramic dielectric substrate is further suppressed, and the peeling of the ceramic dielectric substrate from the base plate and the cracking of the ceramic dielectric substrate can be further suppressed.

[0026] A seventh invention is an electrostatic chuck according to any one of the first to sixth inventions, wherein the elastic modulus γ1 is 0.3 MPa or more.

[0027] According to the electrostatic chuck, in an extremely low temperature environment below -60°C, since the bonding layer has sufficient resilience, it is easier to suppress the ceramic dielectric substrate from warping even when stress is generated between the ceramic dielectric substrate and the base plate. As a result, in an extremely low temperature environment, the deterioration of the in-plane temperature uniformity of the object can be further suppressed. In addition, according to the electrostatic chuck, in an extremely low temperature environment below -60°C, the bonding layer can be further suppressed from becoming too hard. As a result, in an extremely low temperature environment, the stress applied to the ceramic dielectric substrate is further suppressed, and the peeling of the ceramic dielectric substrate from the base plate and the cracking of the ceramic dielectric substrate can be further suppressed.

[0028] An eighth invention is an electrostatic chuck according to any one of the first to seventh inventions, wherein the ratio γ1 / γ2 is equal to or greater than 0.8.

[0029] According to the electrostatic chuck, since the bonding layer maintains sufficient resilience regardless of whether it is at room temperature or in an extremely low temperature environment below -60°C, it is easier to suppress the ceramic dielectric substrate from warping even when stress is generated between the ceramic dielectric substrate and the base plate. As a result, when the temperature uniformity within the surface of the object is further reduced from room temperature to an extremely low temperature environment. In addition, according to the electrostatic chuck, regardless of whether it is at room temperature or in an extremely low temperature environment below -60°C, it is possible to further suppress the bonding layer from becoming too hard. As a result, when the temperature is further reduced from room temperature to an extremely low temperature environment, the stress applied to the ceramic dielectric substrate is further suppressed, and the peeling of the ceramic dielectric substrate from the base plate and the cracking of the ceramic dielectric substrate can be further suppressed.

[0030] A ninth invention is an electrostatic chuck according to any one of the first to eighth inventions, wherein the ceramic dielectric substrate contains at least one of aluminum oxide, aluminum nitride, silicon carbide, silicon nitride, and yttrium oxide.

[0031] In the electrostatic chuck according to the embodiment, for example, by using a ceramic dielectric substrate including these ceramics, it is possible to provide an electrostatic chuck having excellent various properties such as plasma resistance, stability of mechanical properties, heat conductivity, and electrical insulation.

[0032] A tenth invention is an electrostatic chuck according to the ninth invention, wherein the ceramic dielectric substrate contains alumina.

[0033] According to this electrostatic chuck, since the ceramic dielectric substrate contains alumina, both plasma resistance and mechanical strength can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a cross-sectional view schematically showing an electrostatic chuck according to an embodiment.

[0035] Figure 2 (a)~ Figure 2 (c) is a schematic diagram showing a method for measuring the elongation and bonding strength of the bonding layer.

[0036] Figure 3 It is a schematic diagram showing a method of calculating the elastic modulus of the bonding layer.

[0037] Figure 4 It is a schematic diagram illustrating measurement locations of the elongation and bonding strength of the bonding layer.

[0038] Figure 5 This is a graph showing physical properties of an example of a bonding layer of the electrostatic chuck according to the embodiment.

[0039] Figure 6 This is a graph showing physical properties of an example of a bonding layer of the electrostatic chuck according to the embodiment.

[0040] Figure 7 This is a table showing physical properties of an example of a bonding layer of the electrostatic chuck according to the embodiment.

[0041] Figure 8 This is a table showing physical properties of an example of a bonding layer of the electrostatic chuck according to the embodiment.

[0042] Fig. 9 It is a cross-sectional view schematically showing a wafer processing apparatus including an electrostatic chuck according to an embodiment.

[0043] Explanation of symbols

[0044] 11-ceramic dielectric substrate; 11a-first main surface; 11b-second main surface; 12-electrode layer; 13-convex portion; 14-groove; 15-through hole; 20-connecting portion; 50-base plate; 50a-upper portion; 50b-lower portion; 51-input path; 52-output path; 53-gas inlet path; 55-connecting path; 60-joining layer; 110-electrostatic suction cup; 110a-central portion; 110b-peripheral portion; 110c-middle portion; 500-wafer processing device; 501-processing container; 502-processing gas inlet port; 503-exhaust port; 504-high-frequency power supply; 505-power supply for adsorption; 510-upper electrode; TP-test piece; W-object. DETAILED DESCRIPTION

[0045] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each of the drawings, the same components are denoted by the same reference numerals and detailed descriptions thereof are appropriately omitted.

[0046] Figure 1 It is a schematic cross-sectional view illustrating an electrostatic chuck according to an embodiment.

[0047] like Figure 1 As shown, the electrostatic chuck 110 includes a ceramic dielectric substrate 11 , a base plate 50 , and a bonding layer 60 .

[0048] The ceramic dielectric substrate 11 is a flat plate-shaped base material formed of, for example, sintered ceramics. The ceramic dielectric substrate 11 contains, for example, at least one of aluminum oxide (Al2O3), aluminum nitride, silicon carbide, silicon nitride, and yttrium oxide (Y2O3). In the electrostatic chuck 110 involved in the embodiment, for example, by using the ceramic dielectric substrate 11 containing these ceramics, it is possible to provide an electrostatic chuck having various excellent properties such as plasma resistance, stability of mechanical properties (for example, mechanical strength), thermal conductivity, and electrical insulation.

[0049] The ceramic dielectric substrate 11 preferably contains alumina. By making the ceramic dielectric substrate 11 contain alumina, plasma resistance and mechanical strength can be achieved at the same time. In addition, by making the ceramic dielectric substrate 11 contain alumina, the transparency of the ceramic dielectric substrate 11 is improved, and the infrared transmittance is improved to promote heat transfer. In addition, since it has high sinterability, it is possible to form a dense sintered body without using, for example, a sintering aid, and the heat distribution in the plane can be kept to a minimum.

[0050] The ceramic dielectric substrate 11 is preferably formed of high-purity aluminum oxide. The concentration of aluminum oxide in the ceramic dielectric substrate 11 is, for example, 90 mass % or more and 100 mass % or less, preferably 95 mass % or more and 100 mass % or less, and more preferably 99 mass % or more and 100 mass % or less. By using high-purity aluminum oxide, the plasma resistance of the ceramic dielectric substrate 11 can be improved. In addition, the concentration of aluminum oxide can be measured by fluorescent X-ray analysis or the like.

[0051] The ceramic dielectric substrate 11 has a first main surface 11a and a second main surface 11b. The first main surface 11a is a surface on which an adsorption object W is placed. The second main surface 11b is a surface opposite to the first main surface 11a. The adsorption object W is, for example, a semiconductor substrate such as a silicon wafer.

[0052] Furthermore, in the present specification, the direction from the base plate 50 toward the ceramic dielectric substrate 11 is referred to as the Z-axis direction. For example, as illustrated in the various figures, the Z-axis direction is a direction connecting the first principal surface 11a and the second principal surface 11b. The Z-axis direction is, for example, a direction substantially perpendicular to the first principal surface 11a and the second principal surface 11b. One of the directions orthogonal to the Z-axis direction is referred to as the X-axis direction, and the direction orthogonal to the Z-axis direction and the X-axis direction is referred to as the Y-axis direction. In the present specification, "in-plane" is, for example, in the XY plane.

[0053] The electrode layer 12 is provided inside the ceramic dielectric substrate 11. The electrode layer 12 is provided between the first main surface 11a and the second main surface 11b. That is, the electrode layer 12 is provided so as to be inserted into the ceramic dielectric substrate 11. For example, the electrode layer 12 may be built-in by being integrally sintered in the ceramic dielectric substrate 11.

[0054] The electrode layer 12 is provided in a thin film along the first main surface 11a and the second main surface 11b of the ceramic dielectric substrate 11. The electrode layer 12 is an adsorption electrode for adsorbing and holding the object W. The electrode layer 12 may be a monopolar type or a bipolar type. Figure 1 The electrode layer 12 shown is of a bipolar type, and two electrode layers 12 are provided on the same surface.

[0055] The electrode layer 12 is provided with a connection portion 20 extending toward the second main surface 11b of the ceramic dielectric substrate 11. The connection portion 20 is a via (solid type) or a via hole (hollow type) that is electrically connected to the electrode layer 12, or a portion connected to a metal terminal by an appropriate method such as soldering.

[0056] The electrostatic chuck 110 is as follows, by receiving an adsorption power source 505 (see Fig. 9 ) A voltage (adsorption voltage) is applied to the electrode layer 12, thereby generating electric charges on the first main surface 11a side of the electrode layer 12, and the object W is adsorbed and held by electrostatic force.

[0057] The thickness T1 of the ceramic dielectric substrate 11 is, for example, 5 mm or less. The thickness T1 of the ceramic dielectric substrate 11 is the length of the ceramic dielectric substrate 11 in the Z-axis direction. In other words, the thickness T1 of the ceramic dielectric substrate 11 is the distance between the first main surface 11a and the second main surface 11b in the Z-axis direction. By making the ceramic dielectric substrate 11 thinner, the length of the substrate connected to the high-frequency power source 504 (see Fig. 9 ) of the base plate 50 and the upper electrode 510 (refer to Fig. 9 ) between the two.

[0058] The base plate 50 is a member that supports the ceramic dielectric substrate 11. The ceramic dielectric substrate 11 is fixed to the base plate 50 via the bonding layer 60. That is, the bonding layer 60 is provided between the ceramic dielectric substrate 11 and the base plate 50.

[0059] The bonding layer 60 contains a resin material. In the embodiment, the bonding layer 60 is configured to maintain flexibility at extremely low temperatures. For example, the bonding layer 60 contains a silicone, acrylic, modified silicone or epoxy polymer material and a polymer material containing at least one of carbon (C), hydrogen (H), nitrogen (N), silicon (Si), and oxygen (O) as a main component.

[0060] Here, in the present specification, "extremely low temperature" refers to a low temperature environment of -60°C or lower. Specifically, it refers to -60°C to -120°C.

[0061] The bonding layer 60 preferably contains silicone. By making the bonding layer 60 contain silicone having excellent flexibility, the flexibility of the bonding layer 60 can be easily maintained in an extremely low temperature environment. As a result, in an extremely low temperature environment, it is possible to more reliably suppress the peeling of the ceramic dielectric substrate 11 from the base plate 50 and the cracking of the ceramic dielectric substrate 11.

[0062] In the bonding layer 60, silicone having a molecular structure in which various functional groups are bonded to a siloxane skeleton can be used. More specifically, the functional group bonded to the siloxane skeleton preferably contains at least one of, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a phenyl group, and a hexyl group. By using silicone containing such a functional group in the bonding layer 60, the cold resistance, strength, elongation, etc. of the bonding layer 60 can be improved in an extremely low temperature environment.

[0063] It is preferable that the bonding layer 60 further contains an inorganic filler. When the bonding layer 60 further contains an inorganic filler, the in-plane temperature uniformity of the object W can be improved in an extremely low temperature environment.

[0064] The inorganic filler preferably contains at least one compound having at least one element of silicon (Si) and aluminum (Al) and at least one element of carbon (C), nitrogen (N) and oxygen (O). More specifically, the inorganic filler preferably contains at least one of Al2O3, SiC, AlN, Si3N4, AlON, SIALON and SiO2. By making the bonding layer 60 contain such an inorganic filler, the thermal conductivity and mechanical property stability of the bonding layer 60 can be improved in an extremely low temperature environment.

[0065] The base plate 50 is made of metal such as aluminum. The base plate 50 is divided into an upper portion 50a and a lower portion 50b, and a communication path 55 is provided between the upper portion 50a and the lower portion 50b. One end of the communication path 55 is connected to the input path 51, and the other end is connected to the output path 52.

[0066] The base plate 50 also plays a role in adjusting the temperature of the electrostatic chuck 110. For example, when cooling the electrostatic chuck 110, a cooling medium such as helium flows in from the input path 51 and flows out from the output path 52 through the connecting path 55. Thus, the cooling medium absorbs the heat of the base plate 50, and the ceramic dielectric substrate 11 mounted thereon can be cooled. On the other hand, when the electrostatic chuck 110 is kept warm, a heat-insulating medium can be placed in the connecting path 55. A heating element can also be placed inside the ceramic dielectric substrate 11 and the base plate 50. By adjusting the temperature of the base plate 50 and the ceramic dielectric substrate 11, the temperature of the object W adsorbed and held by the electrostatic chuck 110 can be adjusted.

[0067] In this example, a groove 14 is provided on the first main surface 11a side of the ceramic dielectric substrate 11. The groove 14 is recessed in the direction (Z-axis direction) from the first main surface 11a toward the second main surface 11b, and extends continuously in the XY plane. On the first main surface 11a, a plurality of protrusions 13 (points) are provided in at least a portion of the area where the groove 14 is not provided. The object W is placed on the plurality of protrusions 13 and supported by the plurality of protrusions 13. The protrusion 13 is a surface that contacts the back side of the object W. If a plurality of protrusions 13 are provided, a space is formed between the back side of the object W placed on the electrostatic suction cup 110 and the first main surface 11a. By appropriately selecting the height, number, area ratio, shape, etc. of the protrusions 13, it is possible, for example, to control the particles attached to the object W in a preferred state. For example, the height (dimension in the Z-axis direction) of the plurality of projections 13 can be set to be 1 μm or more and 100 μm or less, preferably 1 μm or more and 30 μm or less, and more preferably 5 μm or more and 15 μm or less.

[0068] The ceramic dielectric substrate 11 has a through hole 15 connected to the groove 14. The through hole 15 is provided from the second main surface 11b to the first main surface 11a. That is, the through hole 15 extends in the Z-axis direction from the second main surface 11b to the first main surface 11a and penetrates the ceramic dielectric substrate 11.

[0069] The gas introduction path 53 is provided on the base plate 50. The gas introduction path 53 is provided, for example, to penetrate the base plate 50. The gas introduction path 53 may not penetrate the base plate 50 but may branch from other gas introduction paths 53 in the middle and be provided to the ceramic dielectric substrate 11 side. In addition, the gas introduction path 53 may be provided at multiple locations on the base plate 50.

[0070] The gas introduction path 53 communicates with the through hole 15 . That is, the heat transfer gas (helium (He) or the like) that flows into the gas introduction path 53 flows into the through hole 15 after passing through the gas introduction path 53 .

[0071] The heat transfer gas flowing into the through hole 15 flows into the space provided between the object W and the groove 14 after passing through the through hole 15. Thus, the object W can be directly cooled by the heat transfer gas.

[0072] Although the existing electrostatic suction cup can be used in a low temperature environment of, for example, around -20°C, in an extremely low temperature environment of around -60°C, the flexibility of the bonding layer 60 bonding the ceramic dielectric substrate 11 and the base plate 50 decreases, and the ceramic dielectric substrate 11 may peel off from the base plate 50, or sometimes the ceramic dielectric substrate 11 may crack and be damaged.

[0073] Therefore, in the embodiment, for example, the elongation α is focused on as a physical property related to the flexibility of the bonding layer 60. In the following description, the elongation of the bonding layer 60 at -60°C is α1, and the elongation of the bonding layer 60 at 25°C is α2.

[0074] In the embodiment, the elongation α1 of the bonding layer 60 at -60°C is, for example, 120% or more, preferably 175% or more, more preferably 200% or more, further preferably 220% or more, and still more preferably 240% or more.

[0075] If the elongation α1 is 120% or more, the bonding layer 60 has a sufficient elongation α in an extremely low temperature environment, so that sufficient flexibility can be ensured in the bonding layer 60. Therefore, in an extremely low temperature environment, the stress applied to the ceramic dielectric substrate 11 is suppressed, and the peeling of the ceramic dielectric substrate 11 from the base plate 50 and the cracking of the ceramic dielectric substrate 11 can be suppressed. In addition, although the upper limit of the elongation α1 is not particularly limited, it is, for example, 1000% or less.

[0076] The elongation α2 of the bonding layer 60 at 25° C. is, for example, 150% or more, preferably 200% or more, and more preferably 250% or more.

[0077] If the elongation α2 is 150% or more, the bonding layer 60 has a sufficient elongation α under room temperature, and thus sufficient flexibility can be ensured in the bonding layer 60. Thus, under room temperature, stress applied to the ceramic dielectric substrate 11 is suppressed, and the peeling of the ceramic dielectric substrate 11 from the base plate 50 and the cracking of the ceramic dielectric substrate 11 can be suppressed. In addition, although the upper limit of the elongation α2 is not particularly limited, it is, for example, 1650% or less.

[0078] The ratio α1 / α2 of the elongation α1 to the elongation α2 is, for example, 0.60 or more, preferably 0.80 or more, and more preferably 0.90 or more.

[0079] If the ratio α1 / α2 of the elongation α is 0.60 or more, the difference in thermal expansion coefficient between the ceramic dielectric substrate 11 and the base plate 50 can be alleviated when the room temperature is changed to an extremely low temperature environment. As a result, it is possible to suppress the peeling of the ceramic dielectric substrate 11 from the base plate 50 and the cracking of the ceramic dielectric substrate 11. In addition, although the upper limit of the ratio α1 / α2 of the elongation α is not particularly limited, it is, for example, 1.5 or less.

[0080] In the embodiment, for example, bonding strength β is focused on as a physical property related to the flexibility of the bonding layer 60. In the following description, the bonding strength of the bonding layer 60 at -60°C is β1, and the bonding strength of the bonding layer 60 at 25°C is β2.

[0081] In the embodiment, the bonding strength β1 of the bonding layer 60 at -60°C is, for example, 0.4 MPa to 10 MPa, preferably 0.4 MPa to 2.0 MPa, more preferably 0.4 MPa to 1.9 MPa, further preferably 0.4 MPa to 1.4 MPa. The lower limit is preferably 0.7 MPa or more.

[0082] When the bonding strength β1 is 0.4 MPa or more, the fixing effect of the bonding layer 60 between the ceramic dielectric substrate 11 and the base plate 50 does not become too weak in a very low temperature environment. Therefore, the ceramic dielectric substrate 11 and the base plate 50 can be more reliably bonded in a very low temperature environment.

[0083] If the bonding strength β1 is 10 MPa or less, the fixing effect of the bonding layer 60 between the ceramic dielectric substrate 11 and the base plate 50 will not become too strong in an extremely low temperature environment. Therefore, in an extremely low temperature environment, the stress applied to the ceramic dielectric substrate 11 is suppressed, and the peeling of the ceramic dielectric substrate 11 from the base plate 50 and the cracking of the ceramic dielectric substrate 11 can be suppressed.

[0084] The bonding strength β2 of the bonding layer 60 at 25° C. is, for example, 0.5 MPa to 1.5 MPa, and preferably 0.5 MPa to 0.8 MPa.

[0085] If the bonding strength β2 is 0.5 MPa or more, the fixing effect of the bonding layer 60 that permeates the surfaces of the ceramic dielectric substrate 11 and the base plate 50 at room temperature will not be too weakened. Therefore, the ceramic dielectric substrate 11 and the base plate 50 can be more reliably bonded at room temperature.

[0086] If the bonding strength β2 is 1.5 MPa or less, the fixing effect of the bonding layer 60 bonded to the surface of the ceramic dielectric substrate 11 will not become too strong under room temperature. Therefore, under room temperature, the stress applied to the ceramic dielectric substrate 11 is suppressed, and the peeling of the ceramic dielectric substrate 11 from the base plate 50 and the cracking of the ceramic dielectric substrate 11 can be suppressed.

[0087] The ratio β1 / β2 of the bonding strength β1 to the bonding strength β2 is, for example, 0.6 or more and 10 or less, preferably 0.6 or more and 5 or less, more preferably 0.6 or more and 3 or less. It is preferably 0.8 or more, more preferably 1.1 or more. In addition, the ratio β1 / β2 is preferably 1.9 or less.

[0088] If the ratio β1 / β2 of the bonding strength β is greater than 0.6, the sufficient bonding strength of the bonding layer 60 between the ceramic dielectric substrate 11 and the base plate 50 can be more reliably maintained regardless of room temperature or extremely low temperature environments, and a firm bond between the ceramic dielectric substrate 11 and the base plate 50 can be maintained.

[0089] If the ratio β1 / β2 of the bonding strength β is 10 or less, the effect of the bonding layer 60 between the ceramic dielectric substrate 11 and the base plate 50 can be sufficiently suppressed regardless of whether it is in a room temperature or extremely low temperature environment. Therefore, when the room temperature changes to an extremely low temperature environment, the stress applied to the ceramic dielectric substrate 11 is suppressed, and the peeling of the ceramic dielectric substrate 11 from the base plate 50 and the cracking of the ceramic dielectric substrate 11 can be suppressed.

[0090] In the embodiment, for example, elastic modulus γ is focused on as physical properties related to the flexibility of the bonding layer 60. In the following description, the elastic modulus of the bonding layer 60 at -60°C is γ1, and the elastic modulus of the bonding layer 60 at 25°C is γ2.

[0091] In the embodiment, the elastic modulus γ1 of the bonding layer 60 at -60°C is, for example, 0.1 MPa to 10 MPa, preferably 0.1 MPa to 3 MPa, more preferably 0.1 MPa to 1 MPa. In addition, the elastic modulus γ1 is preferably 0.3 MPa or more, more preferably 0.4 MPa or more.

[0092] When the elastic modulus γ1 is 0.1 MPa or more, the bonding layer 60 has sufficient resilience in an extremely low temperature environment, so that even when stress is generated between the ceramic dielectric substrate 11 and the base plate 50, it is easy to suppress the ceramic dielectric substrate 11 from warping. As a result, in an extremely low temperature environment, it is possible to suppress the deterioration of the in-plane temperature uniformity of the object W.

[0093] If the elastic modulus γ1 is 10 MPa or less, the bonding layer 60 can be prevented from becoming too hard in an extremely low temperature environment. Thus, in an extremely low temperature environment, the stress applied to the ceramic dielectric substrate 11 can be suppressed, and the ceramic dielectric substrate 11 can be prevented from peeling off from the base plate 50 and cracking.

[0094] The elastic modulus γ2 of the bonding layer 60 at 25° C. is, for example, 0.2 MPa or more and 1.0 MPa or less, and preferably 0.2 MPa or more and 0.4 MPa or less.

[0095] When the elastic modulus γ2 is 0.2 MPa or more, the bonding layer 60 has sufficient resilience under room temperature conditions, so that even if stress is generated between the ceramic dielectric substrate 11 and the base plate 50, the ceramic dielectric substrate 11 is easily suppressed from warping. As a result, under room temperature conditions, it is possible to suppress the in-plane temperature uniformity of the object W from deteriorating.

[0096] If the elastic modulus γ2 is 1.0 MPa or less, the bonding layer 60 can be prevented from becoming too hard at room temperature. Thus, the stress applied to the ceramic dielectric substrate 11 can be suppressed at room temperature, and the ceramic dielectric substrate 11 can be prevented from peeling off from the base plate 50 and cracking.

[0097] The ratio γ1 / γ2 of the elastic modulus γ1 to the elastic modulus γ2 is, for example, 0.6 or more and 30 or less, preferably 0.6 or more and 10 or less, more preferably 0.6 or more and 3 or less. It is preferably 0.8 or more, more preferably 0.9 or more. In addition, the ratio γ1 / γ2 is preferably 2.1 or less.

[0098] If the ratio γ1 / γ2 of the elastic modulus γ is 0.6 or more, the bonding layer 60 maintains sufficient resilience regardless of whether it is in a room temperature or extremely low temperature environment, so that even when stress is generated between the ceramic dielectric substrate 11 and the base plate 50, it is easy to suppress the ceramic dielectric substrate 11 from warping. As a result, when the temperature in the surface of the object W is changed from room temperature to an extremely low temperature environment, it is possible to suppress the deterioration of the temperature uniformity.

[0099] If the ratio γ1 / γ2 of the elastic modulus γ is 30 or less, the bonding layer 60 can be prevented from becoming too hard regardless of whether it is in a room temperature or extremely low temperature environment. Therefore, when the room temperature changes to an extremely low temperature environment, the stress applied to the ceramic dielectric substrate 11 is suppressed, and the peeling of the ceramic dielectric substrate 11 from the base plate 50 and the cracking of the ceramic dielectric substrate 11 can be suppressed.

[0100] In addition, as described above, in order to shorten the distance between the base plate 50 connected to the high-frequency power source 504 and the upper electrode 510, or from the viewpoint of heat uniformity, it is also preferable to make the ceramic dielectric substrate 11 thinner. On the other hand, when the ceramic dielectric substrate 11 is thin, if the bonding layer 60 loses its flexibility in an extremely low temperature environment, the ceramic dielectric substrate 11 may be cracked and damaged. In contrast, according to the embodiment, in an extremely low temperature environment, since the bonding layer 60 has sufficient flexibility, even when the ceramic dielectric substrate 11 is thinner than 5 mm, accidents such as damage can be effectively suppressed.

[0101] Figure 2 (a)~ Figure 2 (c) is a schematic diagram showing a method for measuring the elongation and bonding strength of the bonding layer.

[0102] Figure 3 It is a schematic diagram showing a method of calculating the elastic modulus of the bonding layer.

[0103] Figure 4 It is a schematic diagram illustrating measurement locations of the elongation and bonding strength of the bonding layer.

[0104] In the implementation mode, it is possible to Figure 2 (a)~ Figure 2 The elongation α and the bonding strength β of the bonding layer 60 were measured by the method shown in (c).

[0105] When measuring the elongation α and the bonding strength β of the bonding layer 60, first, Figure 2 As shown in (a), the test piece TP is selected from the electrostatic chuck 110. The test piece TP is selected in a manner that passes through the electrostatic chuck 110 in the Z-axis direction. That is, the test piece TP is selected in a manner that includes the base plate 50, the bonding layer 60, and the ceramic dielectric substrate 11 stacked in the Z-axis direction. The test piece TP is selected in a cylindrical shape with a diameter of 30 mm. The selection method is, for example, spiral processing, high-pressure water jet cutting processing, etc.

[0106] Next, if Figure 2 As shown in (b), pressure is applied to the ceramic dielectric substrate 11 and the base plate 50 of the test piece TP in opposite directions along the XY plane. In this example, pressure is applied to the ceramic dielectric substrate 11 in the negative direction of the X-axis direction, and pressure is applied to the base plate 50 in the positive direction of the X-axis direction. For example, pressure is applied by an automatic plotter. While measuring the elongation α and shear stress of the bonding layer 60, the pressure applied to the test piece TP is increased, and as shown in FIG. Figure 2 As shown in (c), the bonding layer 60 is broken.

[0107] For example, with Figure 3The curve shown shows the relationship between the elongation α and the shear stress measured by the above method. Figure 3 As shown, the shear stress increases until the bonding layer 60 breaks, and decreases when the bonding layer 60 breaks. That is, the time when the shear stress is the largest can be regarded as the time when the bonding layer 60 breaks.

[0108] The elongation α is expressed by 100×(elongation L1 of the bonding layer 60 when the fracture occurs) / (thickness T2 of the bonding layer 60). The elongation L1 of the bonding layer 60 when the fracture occurs is the change in the length of the bonding layer 60 in the pressurization direction (in this example, the X-axis direction) at the moment of fracture. The thickness T2 of the bonding layer 60 is the length of the bonding layer 60 in the Z-axis direction. The bonding strength β is the magnitude of the shear stress when the bonding layer 60 fractures. That is, the bonding strength β can be calculated from the magnitude of the shear stress when the bonding layer 60 fractures.

[0109] The elongation α and the bonding strength β can be measured using, for example, an autograph (AGS-X (5 kN) manufactured by Shimadzu Corporation). The measurement conditions are, for example, a compression speed of 0.1 to 10 mm / min, a load cell of 5 kN, and a measurement temperature of 25°C or -60°C.

[0110] like Figure 3 As shown, the elastic modulus γ of the bonding layer 60 is represented by the slope of the curve until the bonding layer 60 breaks. In other words, the elastic modulus γ is calculated from the elongation α and the bonding strength β. Specifically, the elastic modulus γ is represented by (bonding strength β of the bonding layer 60 when the bond is broken) / (deformation of the bonding layer 60 when the bond is broken ((elongation L1 of the bonding layer 60 when the bond is broken) / (thickness T2 of the bonding layer 60))).

[0111] In an embodiment, in a test piece TP selected from at least one portion of the electrostatic chuck 110, the bonding layer 60 may have the elongation α (elongation ratio), bonding strength β (bonding strength ratio) or elastic modulus γ (elastic modulus ratio) as described above. In each test piece TP selected from multiple portions of the electrostatic chuck 110, the bonding layer 60 preferably has the elongation α (elongation ratio), bonding strength β (bonding strength ratio) or elastic modulus γ (elastic modulus ratio) as described above. In addition, it is also preferred that the average value of the elongation α (elongation ratio), bonding strength β (bonding strength ratio) or elastic modulus γ (elastic modulus ratio) of the test pieces TP selected from multiple portions of the electrostatic chuck 110 satisfies the above-mentioned elongation α (elongation ratio), bonding strength β (bonding strength ratio) or elastic modulus γ (elastic modulus ratio).

[0112] When the test piece TP is selected from a plurality of locations of the electrostatic chuck 110, for example Figure 4As shown, test pieces TP are selected from multiple locations on the XY plane of the electrostatic chuck 110, and Figure 2 (b) and Figure 2 The method shown in (c) measures the elongation α and the bonding strength β of the bonding layer 60. In this example, the test piece TP is selected from a total of 9 locations, namely, the central portion 110a of the electrostatic chuck 110, 4 locations of the peripheral portion 110b, and 4 locations of the intermediate portion 110c between the central portion 110a and the peripheral portion 110b.

[0113] For example, in at least one of the test pieces TP selected from the above nine locations, the bonding layer 60 may have the above-described elongation α (elongation ratio), bonding strength β (bonding strength ratio), or elastic modulus γ (elastic modulus ratio).

[0114] Figure 5 and Figure 6 This is a graph showing physical properties of an example of a bonding layer of the electrostatic chuck according to the embodiment.

[0115] Figure 6 Is magnification Figure 5 A graph of part A of FIG.

[0116] Figure 7 This is a table showing physical properties of an example of a bonding layer of the electrostatic chuck according to the embodiment.

[0117] Example 1 is an example of an electrostatic chuck 110 according to an embodiment. Reference example 1 is an example of an electrostatic chuck having a bonding layer 60 having different physical properties from that of Example 1.

[0118] Figure 5 to Figure 7 Indicated by Figure 2 (a)~ Figure 2 (c) and Figure 3 The elongation α, the bonding strength β, and the elastic modulus γ of the bonding layer 60 of Example 1 and Reference Example 1 were measured and calculated by the measurement and calculation methods shown.

[0119] in addition, Figure 7The results of the peeling / cracking test on Example 1 and Reference Example 1 are shown in the figure. In the peeling / cracking test, a sample in which a ceramic dielectric substrate 11 and a base plate 50 are bonded by a bonding layer 60 is prepared, and the sample is placed at -60°C for at least 3000 hours, and then returned to room temperature to evaluate whether the ceramic dielectric substrate 11 peels off from the base plate 50 and whether the ceramic dielectric substrate 11 cracks. The evaluation of whether the bonding layer 60 peels off is performed by direct observation such as observing the cross section of the bonding layer 60 with a microscope to evaluate whether cracks have occurred, and ultrasonic testing such as irradiating ultrasonic waves to evaluate whether cracks have occurred inside the bonding layer 60. When cracks are observed in at least one of direct observation and ultrasonic testing, the peeling is evaluated as "yes", and when cracks are not observed in both direct observation and ultrasonic testing, the peeling is evaluated as "no". In addition, when the ceramic dielectric substrate 11 is visually observed and cracks are observed, whether the ceramic dielectric substrate 11 cracks or not is evaluated as "yes", and when cracks are not observed, the cracks are evaluated as "no".

[0120] like Figure 5 to Figure 7 As shown, in Reference Example 1, the elongation α1 is 107%, the elongation α2 is 195%, and the ratio of the elongation α α1 / α2 is 0.5. In Reference Example 1, since the bonding layer 60 has such an elongation α (elongation ratio), the ceramic dielectric substrate 11 does not peel off from the base plate 50 and the ceramic dielectric substrate 11 does not crack under the environment of room temperature (25°C), but the ceramic dielectric substrate 11 peels off from the base plate 50 and the ceramic dielectric substrate 11 cracks under the environment of extremely low temperature (-60°C).

[0121] In contrast, in Example 1, the elongation α1 is 225%, the elongation α2 is 190%, and the ratio of the elongation α α1 / α2 is 1.2. In Example 1, since the bonding layer 60 has such an elongation α (elongation ratio), the ceramic dielectric substrate 11 does not peel off from the base plate 50 and the ceramic dielectric substrate 11 does not crack even in any environment of room temperature (25° C.) and extremely low temperature (-60° C.).

[0122] By setting the elongation α1 of the bonding layer 60 to 120% or more or setting the ratio α1 / α2 of the elongation α to 0.60 or more, the ceramic dielectric substrate 11 can be prevented from peeling off from the base plate 50 and cracking in a very low temperature environment.

[0123] In addition, if Figure 5 to Figure 7As shown, in Reference Example 1, the bonding strength β1 is 29.8 MPa, the bonding strength β2 is 0.56 MPa, and the bonding strength β ratio β1 / β2 is 53.2. In Reference Example 1, since the bonding layer 60 has such a bonding strength β (bonding strength ratio), the ceramic dielectric substrate 11 does not peel off from the base plate 50 and the ceramic dielectric substrate 11 does not crack under the room temperature (25°C) environment, but the ceramic dielectric substrate 11 peels off from the base plate 50 and the ceramic dielectric substrate 11 cracks under the extremely low temperature (-60°C) environment.

[0124] In contrast, in Example 1, the bonding strength β1 is 1.42 MPa, the bonding strength β2 is 0.83 MPa, and the bonding strength β ratio β1 / β2 is 1.7. In Example 1, since the bonding layer 60 has such a bonding strength β (bonding strength ratio), the ceramic dielectric substrate 11 does not peel off from the base plate 50 or crack the ceramic dielectric substrate 11 even in any environment of room temperature (25°C) and extremely low temperature (-60°C).

[0125] By setting the bonding strength β1 of the bonding layer 60 to be 0.4 MPa or more and 10 MPa or less in this manner, it is possible to suppress the ceramic dielectric substrate 11 from peeling off from the base plate 50 and the ceramic dielectric substrate 11 from cracking in an extremely low temperature environment.

[0126] In addition, if Figure 5 to Figure 7 As shown, in Reference Example 1, the elastic modulus γ1 is 28 MPa, the elastic modulus γ2 is 0.29 MPa, and the ratio of the elastic moduli γ γ1 / γ2 is 96.6. In Reference Example 1, since the bonding layer 60 has such an elastic modulus γ (elastic modulus ratio), the ceramic dielectric substrate 11 does not peel off from the base plate 50 and the ceramic dielectric substrate 11 does not crack under the room temperature (25° C.) environment, but the ceramic dielectric substrate 11 peels off from the base plate 50 and the ceramic dielectric substrate 11 cracks under the extremely low temperature (-60° C.) environment.

[0127] In contrast, in Example 1, the elastic modulus γ1 is 0.63 MPa, the elastic modulus γ2 is 0.44 MPa, and the ratio of the elastic moduli γ γ1 / γ2 is 1.4. In Example 1, since the bonding layer 60 has such an elastic modulus γ (elastic modulus ratio), the ceramic dielectric substrate 11 does not peel off from the base plate 50 or crack the ceramic dielectric substrate 11 even in any environment of room temperature (25° C.) and extremely low temperature (-60° C.).

[0128] In this way, by making the elastic modulus γ1 of the bonding layer 60 greater than 0.1 MPa and less than 10 MPa or making the ratio γ1 / γ2 of the elastic modulus γ greater than 0.6 and less than 30, it is possible to suppress the peeling of the ceramic dielectric substrate 11 from the base plate 50 and the cracking of the ceramic dielectric substrate 11 in an extremely low temperature environment.

[0129] Figure 8 This is a table showing physical properties of an example of a bonding layer of the electrostatic chuck according to the embodiment.

[0130] Examples 2 to 14 are examples of the electrostatic chuck 110 according to the embodiment.

[0131] The elongation α, the bonding strength β, and the elastic modulus γ of the bonding layer 60 of Examples 2 to 14, which were measured and calculated in the same manner as in Example 1 and Reference Example 1, are shown in FIG. Figure 8 In addition, the results of the peeling / cleavage test performed in the same manner as in Example 1 and Reference Example 1 are shown in Figure 8 .

[0132] like Figure 8 As shown, in Examples 2 to 14, the elongation α1 is 175% or more and 247% or less, the elongation α2 is 150% or more and 280% or less, and the ratio of the elongation α α1 / α2 is 0.80 or more and 1.17 or less. In Examples 2 to 14, since the bonding layer 60 has such an elongation α (elongation ratio), the ceramic dielectric substrate 11 does not peel off from the base plate 50 and the ceramic dielectric substrate 11 does not crack in any environment of room temperature (25° C.) and extremely low temperature (-60° C.).

[0133] By setting the elongation α1 of the bonding layer 60 to 120% or more or setting the ratio α1 / α2 of the elongation α to 0.60 or more, the ceramic dielectric substrate 11 can be prevented from peeling off from the base plate 50 and cracking in a very low temperature environment.

[0134] like Figure 8 As shown, in Examples 2 to 14, the bonding strength β1 is 0.70 MPa or more and 1.90 MPa or less, the bonding strength β2 is 0.51 MPa or more and 1.60 MPa or less, and the bonding strength β ratio β1 / β2 is 0.8 or more and 1.9 or less. In Examples 2 to 14, since the bonding layer 60 has such a bonding strength β (bonding strength ratio), the ceramic dielectric substrate 11 does not peel off from the base plate 50 and the ceramic dielectric substrate 11 does not crack in any environment of room temperature (25° C.) and extremely low temperature (-60° C.).

[0135] By setting the bonding strength β1 of the bonding layer 60 to be 0.4 MPa or more and 10 MPa or less in this manner, it is possible to suppress the ceramic dielectric substrate 11 from peeling off from the base plate 50 and the ceramic dielectric substrate 11 from cracking in an extremely low temperature environment.

[0136] like Figure 8 As shown, in Examples 2 to 14, the elastic modulus γ1 is 0.34 MPa or more and 1.02 MPa or less, the elastic modulus γ2 is 0.19 MPa or more and 0.81 MPa or less, and the ratio of the elastic modulus γ γ1 / γ2 is 0.9 or more and 2.1 or less. In Examples 2 to 14, since the bonding layer 60 has such an elastic modulus γ (elastic modulus ratio), the ceramic dielectric substrate 11 does not peel off from the base plate 50 and the ceramic dielectric substrate 11 does not crack in any environment of room temperature (25° C.) and extremely low temperature (-60° C.).

[0137] In this way, by making the elastic modulus γ1 of the bonding layer 60 greater than 0.1 MPa and less than 10 MPa or making the ratio γ1 / γ2 of the elastic modulus γ greater than 0.6 and less than 30, it is possible to suppress the peeling of the ceramic dielectric substrate 11 from the base plate 50 and the cracking of the ceramic dielectric substrate 11 in an extremely low temperature environment.

[0138] Fig. 9 It is a cross-sectional view schematically showing a wafer processing apparatus including an electrostatic chuck according to an embodiment.

[0139] like Fig. 9 As shown, the wafer processing apparatus 500 includes a processing container 501, a high frequency power supply 504, a power supply for adsorption 505, an upper electrode 510, and an electrostatic chuck 110. A processing gas inlet 502 for introducing a processing gas into the interior and the upper electrode 510 are provided on the top surface of the processing container 501. An exhaust port 503 for decompressing and exhausting the interior is provided on the bottom plate of the processing container 501. The electrostatic chuck 110 is arranged below the upper electrode 510 in the processing container 501. The base plate 50 and the upper electrode 510 of the electrostatic chuck 110 are connected to the high frequency power supply 504. The electrode layer 12 of the electrostatic chuck 110 is connected to the power supply for adsorption 505.

[0140] The base plate 50 and the upper electrode 510 are disposed substantially parallel to each other with a predetermined distance therebetween. The object W is placed on the first main surface 11 a located between the base plate 50 and the upper electrode 510 .

[0141] When a voltage (high frequency voltage) is applied to the susceptor plate 50 and the upper electrode 510 from the high frequency power supply 504, high frequency discharge is generated and the processing gas introduced into the processing container 501 is excited and activated by plasma, so that the object W is processed.

[0142] When a voltage (attraction voltage) is applied to the electrode layer 12 from the attraction power supply 505 , electric charges are generated on the first main surface 11 a side of the electrode layer 12 , and the object W is attracted and held on the electrostatic chuck 110 by electrostatic force.

[0143] The above is a description of the embodiments of the present invention. However, the present invention is not limited to the above contents. Regarding the aforementioned embodiments, as long as they have the characteristics of the present invention, the technology that is appropriately designed and changed by those skilled in the art is also included in the scope of the present invention. For example, the shape, size, material, configuration, setting method, etc. of each element possessed by the electrostatic chuck are not limited to the exemplified contents, but can be appropriately changed. In addition, as long as it is technically feasible, the various elements possessed by the aforementioned embodiments can be combined, and as long as the technology after these combinations includes the characteristics of the present invention, it is also included in the scope of the present invention.

Claims

1. An electrostatic chuck, comprising: Ceramic dielectric substrate; A metal base plate supporting the ceramic dielectric substrate; and a bonding layer, which is provided between the ceramic dielectric substrate and the base plate and is used to bond the ceramic dielectric substrate and the base plate, and contains a resin material, The resin material is silicone resin, The electrostatic chuck is characterized by: Satisfy any one of the following conditions 1, 2, and 3, Condition 1: the elongation α1 of the bonding layer at -60°C is 120% or more and the ratio α1 / α2 of the elongation α1 to the elongation α2 of the bonding layer at 25°C is 0.60 or more; Second condition: the bonding strength β1 of the bonding layer at -60°C is 0.4 MPa or more and 10 MPa or less, and the ratio β1 / β2 of the bonding strength β1 to the bonding strength β2 of the bonding layer at 25°C is 0.6 or more and 10 or less; Condition 3: The elastic modulus γ1 of the bonding layer at -60°C is 0.1 MPa or more and 10 MPa or less, and the ratio γ1 / γ2 of the elastic modulus γ1 to the elastic modulus γ2 of the bonding layer at 25°C is 0.6 or more and 30 or less.

2. The electrostatic chuck according to claim 1, characterized in that: The elongation α1 is 175% or more.

3. The electrostatic chuck according to claim 2, characterized in that: The elongation α1 is 200% or more.

4. The electrostatic chuck according to any one of claims 1 to 3, characterized in that: The ratio α1 / α2 is greater than or equal to 0.

80.

5. The electrostatic chuck according to any one of claims 1 to 3, characterized in that: The bonding strength β1 is not less than 0.4 MPa and not more than 2.0 MPa.

6. The electrostatic chuck according to any one of claims 1 to 3, characterized in that: The ratio β1 / β2 is greater than or equal to 0.

8.

7. The electrostatic chuck according to any one of claims 1 to 3, characterized in that: The elastic modulus γ1 is greater than or equal to 0.3 MPa and less than or equal to 0.9 MPa.

8. The electrostatic chuck according to any one of claims 1 to 3, characterized in that: The ratio γ1 / γ2 is greater than or equal to 0.

8.

9. The electrostatic chuck according to any one of claims 1 to 3, characterized in that: The ceramic dielectric substrate contains at least any one of aluminum oxide, aluminum nitride, silicon carbide, silicon nitride, and yttrium oxide.

10. The electrostatic chuck according to claim 9, characterized in that: The ceramic dielectric substrate contains aluminum oxide.

11. The electrostatic chuck according to claim 4, wherein: The elongation α1 is greater than or equal to 120%, and the elongation α2 is greater than or equal to 150%.

12. The electrostatic chuck according to claim 5, wherein: The bonding strength β1 is not less than 0.4 MPa and not more than 0.95 MPa.

13. The electrostatic chuck according to claim 1, wherein: The elastic modulus γ1 of the bonding layer at -60°C is 0.1 MPa or more and 0.63 MPa or less.

14. The electrostatic chuck according to claim 13, wherein: The elastic modulus γ1 is 0.3 MPa or more.

15. The electrostatic chuck according to any one of claims 1 to 3, characterized in that: The bonding layer contains silicone.

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