JP2022036105A - Electrostatic chuck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic chuck capable of suppressing peeling of a ceramic dielectric substrate from a base plate or cracking of the ceramic dielectric substrate in a cryogenic environment.

SOLUTION: The electrostatic chuck includes: a ceramic dielectric substrate; a metal base plate for supporting the ceramic dielectric substrate; and a bonding layer, provided between the ceramic dielectric substrate and the base plate, containing a resin material. Bonding strength β1 of the bonding layer at -60°C is 0.4 MPa or more and 10 MPa or less.

SELECTED DRAWING: Figure 6

COPYRIGHT: (C)2022,JPO&INPIT

Description

Aspects of the invention generally relate to electrostatic chucks.

Electrostatic chuck as a means for adsorbing and holding objects to be adsorbed (objects) such as semiconductor wafers and glass substrates in substrate processing equipment that performs etching, CVD (Chemical Vapor Deposition), sputtering, ion implantation, ashing, exposure, inspection, etc. Is used.

The electrostatic chuck is manufactured by sandwiching an electrode between ceramic dielectric substrates such as alumina and firing it. The electrostatic chuck applies an electrostatic adsorption power to a built-in electrode and adsorbs a substrate such as a silicon wafer by the electrostatic force.

In recent years, in such a substrate processing apparatus, with the miniaturization of the process, in order to improve the processing accuracy, it has been studied to perform the processing in an environment lower than the conventional one. Along with this, the electrostatic chuck is also required to have low temperature resistance that can be used in a lower temperature environment than before.

Japanese Patent Application Laid-Open No. 2003-273202

The conventional electrostatic chuck can be used in an environment of a low temperature of, for example, about -20 ° C, but in an environment of an extremely low temperature of -60 ° C or less, the flexible bonding layer for joining the ceramic dielectric substrate and the base plate is flexible. It has been found that the properties are deteriorated and the ceramic dielectric substrate may be peeled off from the base plate, or the ceramic dielectric substrate may be cracked and damaged depending on the surface pattern, shape, thickness, etc., for example.

The present invention has been made based on the recognition of such a problem, and provides an electrostatic chuck capable of suppressing peeling of a ceramic dielectric substrate from a base plate and cracking of a ceramic dielectric substrate in an extremely low temperature environment. The purpose is.

The first invention comprises a ceramic dielectric substrate, a metal base plate that supports the ceramic dielectric substrate, and a bonding layer provided between the ceramic dielectric substrate and the base plate and containing a resin material. The electrostatic chuck is characterized in that the bonding strength β1 of the bonding layer at −60 ° C. is 0.4 MPa or more and 10 MPa or less.

According to this electrostatic chuck, the anchoring effect of the bonding layer located between the ceramic dielectric substrate and the base plate is not excessively weakened in an extremely low temperature environment of −60 ° C. or lower. As a result, the ceramic dielectric substrate and the base plate can be more reliably bonded to each other in an extremely low temperature environment. Further, according to this electrostatic chuck, the anchor effect of the bonding layer located between the ceramic dielectric substrate and the base plate does not become too strong in an extremely low temperature environment of −60 ° C. or lower. As a result, the stress applied to the ceramic dielectric substrate can be suppressed in an extremely low temperature environment, and the peeling of the ceramic dielectric substrate from the base plate and the cracking of the ceramic dielectric substrate can be suppressed.

The second invention is an electrostatic chuck characterized in that, in the first invention, the bonding strength β1 is 0.4 MPa 2.0 MPa or less.

According to this electrostatic chuck, it is possible to further suppress that the anchor effect of the bonding layer located between the ceramic dielectric substrate and the base plate becomes too weak in an extremely low temperature environment of −60 ° C. or lower. As a result, the ceramic dielectric substrate and the base plate can be more reliably bonded to each other in an extremely low temperature environment. Further, according to this electrostatic chuck, it is possible to further suppress that the anchor effect of the bonding layer located between the ceramic dielectric substrate and the base plate becomes too strong in an extremely low temperature environment of −60 ° C. or lower. As a result, the stress applied to the ceramic dielectric substrate can be further suppressed in an extremely low temperature environment, and the peeling of the ceramic dielectric substrate from the base plate and the cracking of the ceramic dielectric substrate can be further suppressed.

A third invention comprises a ceramic dielectric substrate, a metal base plate that supports the ceramic dielectric substrate, and a bonding layer provided between the ceramic dielectric substrate and the base plate and containing a resin material. The electrostatic chuck is characterized in that the ratio β1 / β2 of the bonding strength β1 of the bonding layer at −60 ° C. to the bonding strength β2 of the bonding layer at 25 ° C. is 0.6 or more and 10 or less.

According to this electrostatic chuck, it is possible to maintain sufficient bonding strength of the bonding layer located between the ceramic dielectric substrate and the base plate even in an extremely low temperature environment of -60 ° C or lower even at room temperature, and the ceramic dielectric can be maintained. A strong bond between the substrate and the base plate can be maintained. Further, according to this electrostatic chuck, the effect of the bonding layer located between the ceramic dielectric substrate and the base plate can be sufficiently suppressed even at room temperature or in an extremely low temperature environment of −60 ° C. or lower. As a result, the stress applied to the ceramic dielectric substrate can be suppressed when the ceramic dielectric substrate is placed in an environment of extremely low temperature from room temperature, and the peeling of the ceramic dielectric substrate from the base plate and the cracking of the ceramic dielectric substrate can be suppressed.

The fourth invention is an electrostatic chuck characterized in that, in the third invention, the ratio β1 / β2 is 0.8 or more.

According to this electrostatic chuck, it is possible to more reliably maintain sufficient bonding strength of the bonding layer located between the ceramic dielectric substrate and the base plate even in an extremely low temperature environment of -60 ° C or lower even at room temperature. It is possible to more reliably maintain a strong bond between the ceramic dielectric substrate and the base plate. Further, according to this electrostatic chuck, the effect of the bonding layer located between the ceramic dielectric substrate and the base plate can be more reliably suppressed even in an environment of room temperature or an extremely low temperature of −60 ° C. or lower. As a result, the stress applied to the ceramic dielectric substrate can be further suppressed when the ceramic dielectric substrate is placed in an environment of extremely low temperature from room temperature, and the peeling of the ceramic dielectric substrate from the base plate and the cracking of the ceramic dielectric substrate can be further suppressed.

A fifth aspect of the invention is an electrostatic chuck according to any one of the first to fourth aspects, wherein the elastic modulus γ1 of the bonding layer at −60 ° C. is 0.1 MPa or more and 10 MPa or less. ..

According to this electrostatic chuck, the bonding layer has sufficient resilience in an extremely low temperature environment of -60 ° C or lower, so that even when stress is generated between the ceramic dielectric substrate and the base plate, the ceramic is ceramic. It is easy to suppress the warp of the dielectric substrate. This makes it possible to suppress deterioration of the in-plane temperature uniformity of the object in an extremely low temperature environment. Further, according to this electrostatic chuck, it is possible to prevent the bonding layer from becoming too hard in an extremely low temperature environment of −60 ° C. or lower. As a result, the stress applied to the ceramic dielectric substrate can be suppressed in an extremely low temperature environment, and the peeling of the ceramic dielectric substrate from the base plate and the cracking of the ceramic dielectric substrate can be suppressed.

In the sixth aspect of the invention, in any one of the first to fifth inventions, the ratio γ1 / γ2 of the elastic modulus γ1 of the bonding layer at −60 ° C. to the elastic modulus γ2 of the bonding layer at 25 ° C. is 0. It is an electrostatic chuck characterized by being 6 or more and 30 or less.

According to this electrostatic chuck, when stress is generated between the ceramic dielectric substrate and the base plate, the bonded layer maintains sufficient resilience even in an extremely low temperature environment of -60 ° C or lower even at room temperature. However, it is easy to suppress the warp of the ceramic dielectric substrate. As a result, deterioration of the in-plane temperature uniformity of the object can be suppressed when the object is placed in an environment of room temperature to extremely low temperature. Further, according to this electrostatic chuck, it is possible to prevent the bonding layer from becoming too hard even at room temperature or in an extremely low temperature environment of −60 ° C. or lower. As a result, the stress applied to the ceramic dielectric substrate can be suppressed when the ceramic dielectric substrate is placed in an environment of extremely low temperature from room temperature, and the peeling of the ceramic dielectric substrate from the base plate and the cracking of the ceramic dielectric substrate can be suppressed.

A seventh aspect of the present invention is the electrostatic chuck according to any one of the first to sixth aspects, wherein the elongation rate α1 of the bonding layer at −60 ° C. is 120% or more.

According to this electrostatic chuck, since the bonded layer has a sufficient elongation rate in an environment of an extremely low temperature of −60 ° C. or lower, sufficient flexibility can be ensured for the bonded layer. As a result, the stress applied to the ceramic dielectric substrate can be suppressed in an extremely low temperature environment, and the peeling of the ceramic dielectric substrate from the base plate and the cracking of the ceramic dielectric substrate can be suppressed.

In the eighth aspect of the invention, in any one of the first to seventh inventions, the ratio α1 / α2 of the elongation rate α1 of the bonding layer at −60 ° C. to the elongation rate α2 of the bonding layer at 25 ° C. is 0. It is an electrostatic chuck characterized by having 60 or more.

According to this electrostatic chuck, the difference in thermal expansion rate between the ceramic dielectric substrate and the base plate can be alleviated when the ceramic dielectric substrate is placed in an extremely low temperature environment of −60 ° C. or lower from room temperature. This makes it possible to suppress peeling of the ceramic dielectric substrate from the base plate and cracking of the ceramic dielectric substrate.

A ninth aspect of the invention is an electrostatic chuck according to any one of the third to eighth aspects, wherein the bonding strength β1 of the bonding layer at −60 ° C. is 0.4 MPa or more and 1.9 MPa or less. Is.

According to this electrostatic chuck, the anchor effect of the bonding layer located between the ceramic dielectric substrate and the base plate is not excessively weakened in an extremely low temperature environment of −60 ° C. or lower. As a result, the ceramic dielectric substrate and the base plate can be more reliably bonded to each other in an extremely low temperature environment. Further, according to this electrostatic chuck, the anchor effect of the bonding layer located between the ceramic dielectric substrate and the base plate does not become too strong in an extremely low temperature environment of −60 ° C. or lower. As a result, the stress applied to the ceramic dielectric substrate can be suppressed in an extremely low temperature environment, and the peeling of the ceramic dielectric substrate from the base plate and the cracking of the ceramic dielectric substrate can be suppressed.

A tenth aspect of the present invention is that in any one of the first to ninth aspects, the ceramic dielectric substrate contains at least one of aluminum oxide, aluminum nitride, silicon carbide, silicon nitride, and yttrium oxide. It is a characteristic electrostatic chuck.

In the electrostatic chuck according to the embodiment, for example, by using a ceramic dielectric substrate containing these ceramics, various characteristics such as plasma resistance, stability of mechanical properties, thermal conductivity, and electrical insulation can be obtained. An excellent electrostatic chuck can be provided.

An eleventh invention is an electrostatic chuck according to a tenth aspect, wherein the ceramic dielectric substrate contains aluminum oxide.

According to this electrostatic chuck, since the ceramic dielectric substrate contains aluminum oxide, both plasma resistance and mechanical strength can be achieved at the same time.

According to the aspect of the present invention, there is provided an electrostatic chuck capable of suppressing peeling of a ceramic dielectric substrate from a base plate and cracking of a ceramic dielectric substrate in an extremely low temperature environment of −60 ° C. or lower.

It is sectional drawing which shows typically the electrostatic chuck which concerns on embodiment. 2 (a) to 2 (c) are explanatory views showing a method of measuring the elongation rate and the joint strength of the joint layer. It is explanatory drawing which shows the calculation method of the elastic modulus of a bonded layer. It is explanatory drawing which illustrates the measurement point of the elongation rate and the joint strength of a joint layer. It is a graph which shows the physical property of an example of the junction layer of the electrostatic chuck which concerns on embodiment. It is a graph which shows the physical property of an example of the junction layer of the electrostatic chuck which concerns on embodiment. It is a table which shows the physical property of an example of the junction layer of the electrostatic chuck which concerns on embodiment. It is a table which shows the physical property of an example of the junction layer of the electrostatic chuck which concerns on embodiment. It is sectional drawing which shows typically the wafer processing apparatus provided with the electrostatic chuck which concerns on embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, similar components are designated by the same reference numerals and detailed description thereof will be omitted as appropriate.

FIG. 1 is a schematic cross-sectional view illustrating the electrostatic chuck according to the embodiment.
As shown in FIG. 1, the electrostatic chuck 110 includes a ceramic dielectric substrate 11, a base plate 50, and a bonding layer 60.

The ceramic dielectric substrate 11 is, for example, a flat plate-shaped substrate made of sintered ceramic. The ceramic dielectric substrate 11 contains, for example, at least one of aluminum oxide (alumina: Al ₂ O ₃ ), aluminum nitride, silicon carbide, silicon nitride, and yttrium oxide (itria: _Y2 O ₃ ). In the electrostatic chuck 110 according to the embodiment, for example, by using a ceramic dielectric substrate 11 containing these ceramics, plasma resistance, stability of mechanical properties (for example, mechanical strength), thermal conductivity, and heat conductivity can be obtained. It is possible to provide an electrostatic chuck excellent in various characteristics such as electrical insulation.

The ceramic dielectric substrate 11 preferably contains aluminum oxide. Since the ceramic dielectric substrate 11 contains aluminum oxide, both plasma resistance and mechanical strength can be achieved. Further, since the ceramic dielectric substrate 11 contains aluminum oxide, the transparency of the ceramic dielectric substrate 11 can be increased, the infrared transmittance can be improved, and heat transfer can be promoted. Further, since it has high sinterability, it is possible to form a dense sintered body without using, for example, a sintering aid, and it is possible to keep the heat distribution in the plane to the minimum.

The ceramic dielectric substrate 11 is preferably made of high-purity aluminum oxide. The concentration of aluminum oxide in the ceramic dielectric substrate 11 is, for example, 90% by mass (mass%) or more and 100 mass% or less, preferably 95% by mass (mass%) or more and 100 mass% or less, and more preferably 99% by mass (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. The concentration of aluminum oxide can be measured by fluorescent X-ray analysis or the like.

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 the object W to be adsorbed is placed. The second main surface 11b is a surface opposite to the first main surface 11a. The object W to be adsorbed is, for example, a semiconductor substrate such as a silicon wafer.

In the specification of the present application, the direction from the base plate 50 toward the ceramic dielectric substrate 11 is defined as the Z-axis direction. The Z-axis direction is, for example, a direction connecting the first main surface 11a and the second main surface 11b, as illustrated in each figure. The Z-axis direction is, for example, a direction substantially perpendicular to the first main surface 11a and the second main 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" means, for example, in the XY plane.

An 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. The electrode layer 12 may be incorporated, for example, by being integrally sintered on the ceramic dielectric substrate 11.

The electrode layer 12 is provided in a thin film shape 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 unipolar type or a bipolar type. The electrode layer 12 shown in FIG. 1 is a bipolar type, and a two-pole electrode layer 12 is provided on the same surface.

The electrode layer 12 is provided with a connecting portion 20 extending toward the second main surface 11b of the ceramic dielectric substrate 11. The connecting portion 20 is formed by connecting a via (solid type), a via hole (hollow type), or a metal terminal that conducts with the electrode layer 12 by an appropriate method such as brazing.

The electrostatic chuck 110 generates an electric charge on the first main surface 11a side of the electrode layer 12 by applying a voltage (adsorption voltage) from the adsorption power supply 505 (see FIG. 9) to the electrode layer 12, and the electrostatic force is generated. Adsorbs and holds the object W.

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 thinning the ceramic dielectric substrate 11 in this way, the distance between the base plate 50 connected to the high frequency power supply 504 (see FIG. 9) and the upper electrode 510 (see FIG. 9) can be shortened.

The base plate 50 is a member that supports the ceramic dielectric substrate 11. The ceramic dielectric substrate 11 is fixed on 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.

The bonding layer 60 contains a resin material. In embodiments, the bonding layer 60 is configured to be capable of maintaining flexibility at cryogenic temperatures. For example, the bonding layer 60 is a silicone-based, acrylic-based, modified silicone-based, or epoxy-based polymer material, and is composed of carbon (C), hydrogen (H), nitrogen (N), silicon (Si), and oxygen ( Contains a polymer material containing at least one of O) as a main component.
Here, in the present specification, "ultra-low temperature" means a low temperature environment of −60 ° C. or lower. Specifically, it refers to −60 ° C. to −120 ° C.

The bonding layer 60 preferably contains silicone. Since the bonding layer 60 contains silicone having excellent flexibility, the flexibility of the bonding layer 60 can be easily maintained in an extremely low temperature environment. This makes it 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 in an extremely low temperature environment.

In the bonding layer 60, as the silicone, a 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, for example, at least one of 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, it is possible to improve the cold resistance, strength, elongation, etc. of the bonding layer 60 in an extremely low temperature environment.

The bonding layer 60 preferably further contains an inorganic filler. By further containing the inorganic filler in the bonding layer 60, it is possible to improve the in-plane temperature uniformity of the object W in an extremely low temperature environment.

The inorganic filler is 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). It is preferable to include. More specifically, the inorganic filler preferably contains, for example, at least one of Al ₂ O ₃ , SiC, Al N, Si ₃ N ₄ , AlON, SIALON, and SiO ₂ . When the bonding layer 60 contains such an inorganic filler, the thermal conductivity and the stability of the mechanical properties of the bonding layer 60 can be enhanced in an extremely low temperature environment.

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

The base plate 50 also serves to adjust the temperature of the electrostatic chuck 110. For example, when cooling the electrostatic chuck 110, a cooling medium such as helium gas flows in from the input path 51, passes through the communication passage 55, and flows out from the output path 52. As a result, the heat of the base plate 50 can be absorbed by the cooling medium, and the ceramic dielectric substrate 11 mounted on the base plate 50 can be cooled. On the other hand, when the electrostatic chuck 110 is kept warm, it is also possible to put a heat insulating medium in the communication passage 55. It is also possible to incorporate a heating element in the ceramic dielectric substrate 11 or 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.

In this example, the 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 to the second main surface 11b, and continuously extends in the XY plane. On the first main surface 11a, a plurality of convex portions 13 (dots) are provided in at least a part of the region where the groove 14 is not provided. The object W is placed on the plurality of convex portions 13 and supported by the plurality of convex portions 13. The convex portion 13 is a surface in contact with the back surface of the object W. If the plurality of convex portions 13 are provided, a space is formed between the back surface of the object W placed on the electrostatic chuck 110 and the first main surface 11a. By appropriately selecting the height and number of the convex portions 13, the area ratio of the convex portions 13, the shape, and the like, the particles adhering to the object W can be in a preferable state, for example. For example, the height (dimension in the Z-axis direction) of the plurality of convex portions 13 can 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.

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 from the second main surface 11b to the first main surface 11a in the Z-axis direction and penetrates the ceramic dielectric substrate 11.

The base plate 50 is provided with a gas introduction path 53. The gas introduction path 53 is provided so as to penetrate the base plate 50, for example. The gas introduction path 53 may not penetrate the base plate 50 and may be branched from the middle of the other gas introduction path 53 to the ceramic dielectric substrate 11 side. Further, the gas introduction paths 53 may be provided at a plurality of locations on the base plate 50.

The gas introduction path 53 communicates with the through hole 15. That is, the transmission gas (helium (He) or the like) that has flowed into the gas introduction path 53 flows into the through hole 15 after passing through the gas introduction path 53.

The transmitted gas that has flowed 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. As a result, the object W can be directly cooled by the transmission gas.

The conventional electrostatic chuck can be used in an environment of a low temperature of about -20 ° C, for example, but in an environment of an extremely low temperature of about -60 ° C, a bonding layer for joining the ceramic dielectric substrate 11 and the base plate 50. The flexibility of the 60 is reduced, and the ceramic dielectric substrate 11 may be peeled off from the base plate 50, or the ceramic dielectric substrate 11 may be cracked and damaged in some cases.

Therefore, in the embodiment, attention is paid to, for example, the elongation rate α as the physical characteristics related to the flexibility of the bonding layer 60. In the following description, the elongation rate of the bonding layer 60 at −60 ° C. is α1, and the elongation rate of the bonding layer 60 at 25 ° C. is α2.

In the embodiment, the elongation rate α1 of the bonding layer 60 at −60 ° C. is, for example, 120% or more, preferably 175% or more, more preferably 200% or more, still more preferably 220% or more, still more preferably 240% or more. be.

When the elongation rate α1 is 120% or more, the bonding layer 60 has a sufficient elongation rate α in an extremely low temperature environment, so that sufficient flexibility can be ensured for the bonding layer 60. As a result, the stress applied to the ceramic dielectric substrate 11 can be suppressed in an extremely low temperature environment, 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. The upper limit of the elongation rate α1 is not particularly limited, but is, for example, 1000% or less.

The elongation rate 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.

When the elongation rate α2 is 150% or more, the bonding layer 60 has a sufficient elongation rate α in an environment at room temperature, so that sufficient flexibility can be ensured for the bonding layer 60. As a result, the stress applied to the ceramic dielectric substrate 11 can be suppressed in an environment of room temperature, 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. The upper limit of the elongation rate α2 is not particularly limited, but is, for example, 1650% or less.

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

When the ratio α1 / α2 of the elongation rate α is 0.60 or more, the difference in the thermal expansion rate between the ceramic dielectric substrate 11 and the base plate 50 can be alleviated when the ceramic dielectric substrate 11 is placed in an extremely low temperature environment. can. As a result, peeling of the ceramic dielectric substrate 11 from the base plate 50 and cracking of the ceramic dielectric substrate 11 can be suppressed. The upper limit of the ratio α1 / α2 of the elongation rate α is not particularly limited, but is, for example, 1.5 or less.

Further, in the embodiment, attention is paid to, for example, the bonding strength β 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.

In the embodiment, the bonding strength β1 of the bonding layer 60 at −60 ° C. is, for example, 0.4 MPa or more and 10 MPa or less, preferably 0.4 MPa or more and 2.0 MPa or less, more preferably 0.4 MPa or more and 1.9 MPa or less, and further. It is preferably 0.4 MPa or more and 1.4 MPa or less. The bonding strength β1 is preferably 0.7 MPa or more.

When the bonding strength β1 is 0.4 MPa or more, the anchor effect of the bonding layer 60 located between the ceramic dielectric substrate 11 and the base plate 50 does not become too weak in an extremely low temperature environment. As a result, the ceramic dielectric substrate 11 and the base plate 50 can be more reliably bonded to each other in an extremely low temperature environment.

When the bonding strength β1 is 10 MPa or less, the anchor effect of the bonding layer 60 located between the ceramic dielectric substrate 11 and the base plate 50 does not become too strong in an extremely low temperature environment. As a result, the stress applied to the ceramic dielectric substrate 11 can be suppressed in an extremely low temperature environment, 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.

The bonding strength β2 of the bonding layer 60 at 25 ° C. is, for example, 0.5 MPa or more and 1.5 MPa or less, preferably 0.5 MPa or more and 0.8 MPa or less.

When the bonding strength β2 is 0.5 MPa or more, the anchor effect of the bonding layer 60 penetrating the surface of the ceramic dielectric substrate 11 and the surface of the base plate 50 is not too weak in an environment at room temperature. As a result, the ceramic dielectric substrate 11 and the base plate 50 can be more reliably bonded to each other in an environment at room temperature.

When the bonding strength β2 is 1.5 MPa or less, the anchoring effect of the bonding layer 60 adhering to the surface of the ceramic dielectric substrate 11 does not become too strong in an environment at room temperature. As a result, the stress applied to the ceramic dielectric substrate 11 can be suppressed in an environment of room temperature, 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.

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, and more preferably 0.6 or more and 3 or less. The ratio β1 / β2 is preferably 0.8 or more, more preferably 1.1 or more. The ratio β1 / β2 is preferably 1.9 or less.

When the ratio β1 / β2 of the bonding strength β is 0.6 or more, sufficient bonding strength of the bonding layer 60 located between the ceramic dielectric substrate 11 and the base plate 50 is maintained even in an environment of room temperature or extremely low temperature. It is possible to maintain a strong bond between the ceramic dielectric substrate 11 and the base plate 50.

When the ratio β1 / β2 of the bonding strength β is 10 or less, the effect of the bonding layer 60 located between the ceramic dielectric substrate 11 and the base plate 50 can be sufficiently suppressed even in an environment of room temperature or extremely low temperature. .. As a result, the stress applied to the ceramic dielectric substrate 11 can be suppressed when the ceramic dielectric substrate 11 is placed in an environment of extremely low temperature from room temperature, 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. ..

Further, in the embodiment, attention is paid to, for example, the elastic modulus γ as a physical property 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 defined as γ1, and the elastic modulus of the bonding layer 60 at 25 ° C. is defined as γ2.

In the embodiment, the elastic modulus γ1 of the bonding layer 60 at −60 ° C. is, for example, 0.1 MPa or more and 10 MPa or less, preferably 0.1 MPa or more and 3 MPa or less, and more preferably 0.1 MPa or more and 1 MPa or less. The elastic modulus γ1 is preferably 0.3 MPa or more, more preferably 0.4 MPa or more.

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 warp of the ceramic dielectric substrate 11. This makes it possible to suppress deterioration of the in-plane temperature uniformity of the object W in an extremely low temperature environment.

When the elastic modulus γ1 is 10 MPa or less, it is possible to prevent the bonding layer 60 from becoming too hard in an extremely low temperature environment. As a result, the stress applied to the ceramic dielectric substrate 11 can be suppressed in an extremely low temperature environment, 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.

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, preferably 0.2 MPa or more and 0.4 MPa or less.

When the elastic modulus γ2 is 0.2 MPa or more, the bonding layer 60 has sufficient resilience in an environment at room temperature, so that even when stress is generated between the ceramic dielectric substrate 11 and the base plate 50, It is easy to suppress the warp of the ceramic dielectric substrate 11. This makes it possible to suppress deterioration of the in-plane temperature uniformity of the object W in an environment of room temperature.

When the elastic modulus γ2 is 1.0 MPa or less, it is possible to prevent the bonding layer 60 from becoming too hard in an environment at room temperature. As a result, the stress applied to the ceramic dielectric substrate 11 can be suppressed in an environment of room temperature, 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.

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, and more preferably 0.6 or more and 3 or less. The ratio γ1 / γ2 is preferably 0.8 or more, more preferably 0.9 or more. The ratio γ1 / γ2 is preferably 2.1 or less.

When the ratio γ1 / γ2 of the elastic modulus γ is 0.6 or more, the bonding layer 60 maintains sufficient resilience even in an environment of room temperature or extremely low temperature, so that the space between the ceramic dielectric substrate 11 and the base plate 50 is maintained. It is easy to suppress the warp of the ceramic dielectric substrate 11 even when stress is generated in the ceramic dielectric substrate 11. As a result, deterioration of the in-plane temperature uniformity of the object W can be suppressed when the object W is placed in an environment of room temperature to extremely low temperature.

When the ratio γ1 / γ2 of the elastic modulus γ is 30 or less, it is possible to prevent the bonding layer 60 from becoming too hard even in an environment of room temperature or extremely low temperature. As a result, the stress applied to the ceramic dielectric substrate 11 can be suppressed when the ceramic dielectric substrate 11 is placed in an environment of extremely low temperature from room temperature, 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. ..

Further, as described above, the ceramic dielectric substrate 11 should be made thin in order to shorten the distance between the base plate 50 connected to the high frequency power supply 504 and the upper electrode 510, or from the viewpoint of thermal uniformity. Is preferable. 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 crack and be damaged. On the other hand, according to the embodiment, since the bonding layer 60 has sufficient flexibility in an extremely low temperature environment, even when the ceramic dielectric substrate 11 is as thin as 5 mm or less, there are problems such as breakage. Can be effectively suppressed.

2 (a) to 2 (c) are explanatory views showing a method of measuring the elongation rate and the joint strength of the joint layer.
FIG. 3 is an explanatory diagram showing a method of calculating the elastic modulus of the bonded layer.
FIG. 4 is an explanatory diagram illustrating the measurement points of the elongation rate and the joint strength of the joint layer.
In the embodiment, the elongation rate α and the bonding strength β of the bonding layer 60 can be measured by the methods shown in FIGS. 2A to 2C.

When measuring the elongation rate α and the bonding strength β of the bonding layer 60, first, as shown in FIG. 2A, the test piece TP is collected from the electrostatic chuck 110. The test piece TP is collected so as to penetrate the electrostatic chuck 110 in the Z-axis direction. That is, the test piece TP is collected so as to include the base plate 50 laminated in the Z-axis direction, the bonding layer 60, and the ceramic dielectric substrate 11. The test piece TP is collected in a cylindrical shape having a diameter of 30 mm. The sampling method is, for example, helical processing, water jet cutting processing, or the like.

Next, as shown in FIG. 2B, 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 in the X-axis direction, and pressure is applied to the base plate 50 in the positive direction in the X-axis direction. The pressure is applied, for example, by an autograph. While measuring the elongation rate α and the shear stress of the joint layer 60, the pressure applied to the test piece TP is increased to break the joint layer 60 as shown in FIG. 2 (c).

The relationship between the elongation rate α and the shear stress measured by the above method is represented by, for example, the curve shown in FIG. As shown in FIG. 3, the shear stress increases until the joint layer 60 breaks, and decreases when the joint layer 60 breaks. That is, the time point at which the shear stress becomes maximum can be regarded as the time point at which the joint layer 60 breaks.

The elongation rate α is represented by 100 × (elongation L1 of the bonding layer 60 when broken) / (thickness T2 of the bonding layer 60). The elongation L1 of the joint layer 60 at the time of breakage is the amount of change in the length of the joint layer 60 in the pressurizing direction (in this example, the X-axis direction) at the time of breakage. The thickness T2 of the bonding layer 60 is the length of the bonding layer 60 in the Z-axis direction. The joint strength β is the magnitude of the shear stress when the joint layer 60 is broken. That is, the joint strength β can be obtained from the magnitude of the shear stress when the joint layer 60 breaks.

For the measurement of the elongation rate α and the bonding strength β, for example, an autograph (AGS-X (5 kN) manufactured by Shimadzu Corporation) can be used. The measurement conditions are, for example, a compression rate: 0.1 to 10 mm / min, a load cell used: 5 kN, a measurement temperature: 25 ° C., and −60 ° C.

As shown in FIG. 3, 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 rate α and the bonding strength β. Specifically, the elastic modulus γ is (bonding strength β of the bonding layer 60 at the time of fracture) / (distortion of the bonding layer 60 at the time of fracture ((elongation L1 of the bonding layer 60 at the time of fracture) / (bonding). The thickness of the layer 60 is represented by T2))).

In the embodiment, in the test piece TP collected from at least one position of the electrostatic chuck 110, the bonding layer 60 has an elongation rate α (elongation rate ratio), a bonding strength β (bonding strength ratio), or elasticity as described above. It suffices to have a modulus γ (elastic modulus ratio). In each of the test piece TPs collected from a plurality of locations of the electrostatic chuck 110, the bonding layer 60 has an elongation rate α (elongation rate ratio), a bonding strength β (bonding strength ratio), or an elastic modulus γ (elastic modulus) as described above. It is preferable to have a rate ratio). Further, the average value of the elastic modulus α (elongation ratio), the bonding strength β (bonding strength ratio), or the elastic modulus γ (elastic modulus ratio) of the test piece TP collected from a plurality of locations of the electrostatic chuck 110 is the above. It is also preferable that the elastic modulus α (elongation ratio), the bonding strength β (bonding strength ratio), or the elastic modulus γ (elastic modulus ratio) is satisfied.

When the test piece TP is collected from a plurality of places of the electrostatic chuck 110, for example, as shown in FIG. 4, the test piece TP is collected from a plurality of places on the XY plane of the electrostatic chuck 110, and the test piece TP is collected for each. , The elongation rate α and the bonding strength β of the bonding layer 60 are measured by the methods shown in FIGS. 2 (b) and 2 (c). In this example, the test piece TP is provided from a total of 9 locations, 4 locations at the central portion 110a and the outer peripheral portion 110b of the XY plane of the electrostatic chuck 110, and 4 locations at the intermediate portion 110c between the central portion 110a and the outer peripheral portion 110b. It shows the case of collecting.

For example, in at least one of the test piece TPs collected from the above nine locations, the bonding layer 60 has an elongation rate α (elongation rate ratio), a bonding strength β (bonding strength ratio), or an elastic modulus γ (as described above). It suffices to have an elastic modulus ratio).

5 and 6 are graphs showing the physical properties of an example of the bonding layer of the electrostatic chuck according to the embodiment.
FIG. 6 is an enlarged graph of part A in FIG.
FIG. 7 is a table showing the physical properties of an example of the bonding layer of the electrostatic chuck according to the embodiment.
The first embodiment is an example of the electrostatic chuck 110 according to the 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.

Elongation rate α, bonding strength β, and elastic modulus γ of the bonding layer 60 of Example 1 and Reference Example 1 measured / calculated by the measurement / calculation methods shown in FIGS. 2 (a) to 2 (c) and FIG. Is shown in FIGS. 5 to 7.

Further, FIG. 7 shows the results of peeling / cracking tests performed on Example 1 and Reference Example 1. In the peeling / cracking test, a sample in which the ceramic dielectric substrate 11 and the base plate 50 are bonded by the bonding layer 60 is prepared, and the sample is left at -60 ° C. for at least 3000 hours and then returned to room temperature to form the ceramic dielectric substrate 11. The presence or absence of peeling from the base plate 50 and the presence or absence of cracks in the ceramic dielectric substrate 11 were evaluated. The presence or absence of peeling of the bonding layer 60 is determined by direct observation in which the cross section of the bonding layer 60 is observed with a microscope to evaluate the presence or absence of cracks, and ultrasonic waves in which ultrasonic waves are applied to evaluate the presence or absence of cracks or the like inside the bonding layer 60. I went with a flaw detection. Those with cracks in at least one of direct observation and ultrasonic flaw detection were evaluated as “with”, and those without cracks in both direct observation and ultrasonic flaw detection were evaluated as “without peeling”. The presence or absence of cracks in the ceramic dielectric substrate 11 was evaluated by visually observing the ceramic dielectric substrate 11 and evaluating those with cracks as "yes" and those without cracks as "no cracks". did.

As shown in FIGS. 5 to 7, in Reference Example 1, the elongation rate α1 is 107%, the elongation rate α2 is 195%, and the ratio α1 / α2 of the elongation rate α is 0.5. In Reference Example 1, since the bonding layer 60 has such an elongation rate α (elongation rate ratio), the ceramic dielectric substrate 11 can be peeled off from the base plate 50 or the ceramic dielectric in an environment of room temperature (25 ° C.). Although the body substrate 11 is not cracked, the ceramic dielectric substrate 11 is peeled off from the base plate 50 and the ceramic dielectric substrate 11 is cracked in an extremely low temperature (-60 ° C.) environment.

On the other hand, in Example 1, the elongation rate α1 is 225%, the elongation rate α2 is 190%, and the ratio α1 / α2 of the elongation rate α is 1.2. In Example 1, since the bonding layer 60 has such an elongation rate α (elongation rate ratio), the ceramic dielectric can be used in both a room temperature (25 ° C.) environment and an extremely low temperature (-60 ° C.) environment. No peeling of the body substrate 11 from the base plate 50 or cracking of the ceramic dielectric substrate 11 occurred.

In this way, by setting the elongation rate α1 of the bonding layer 60 to 120% or more, or setting the ratio α1 / α2 of the elongation rate α to 0.60 or more, the base plate of the ceramic dielectric substrate 11 in an extremely low temperature environment It is possible to suppress peeling from 50 and cracking of the ceramic dielectric substrate 11.

Further, as shown in FIGS. 5 to 7, in Reference Example 1, the bonding strength β1 is 29.8 MPa, the bonding strength β2 is 0.56 MPa, and the ratio β1 / β2 of the bonding strength β 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 can be peeled off from the base plate 50 or the ceramic dielectric in an environment of room temperature (25 ° C.). Although the body substrate 11 is not cracked, the ceramic dielectric substrate 11 is peeled off from the base plate 50 and the ceramic dielectric substrate 11 is cracked in an extremely low temperature (-60 ° C.) environment.

On the other hand, in Example 1, the bonding strength β1 is 1.42 MPa, the bonding strength β2 is 0.83 MPa, and the ratio β1 / β2 of the bonding strength β is 1.7. In Example 1, since the bonding layer 60 has such a bonding strength β (bonding strength ratio), the ceramic dielectric can be used in both a room temperature (25 ° C.) environment and an extremely low temperature (-60 ° C.) environment. No peeling of the body substrate 11 from the base plate 50 or cracking of the ceramic dielectric substrate 11 occurred.

By setting the bonding strength β1 of the bonding layer 60 to 0.4 MPa or more and 10 MPa or less in this way, the ceramic dielectric substrate 11 can be peeled from the base plate 50 and the ceramic dielectric substrate 11 can be cracked in an extremely low temperature environment. Can be suppressed.

Further, as shown in FIGS. 5 to 7, in Reference Example 1, the elastic modulus γ1 is 28 MPa, the elastic modulus γ2 is 0.29 MPa, and the ratio γ1 / γ2 of the elastic modulus γ is 96.6. In Reference Example 1, since the bonding layer 60 has such an elastic coefficient γ (elasticity ratio), the ceramic dielectric substrate 11 can be peeled off from the base plate 50 or the ceramic dielectric in an environment of room temperature (25 ° C.). Although the body substrate 11 is not cracked, the ceramic dielectric substrate 11 is peeled off from the base plate 50 and the ceramic dielectric substrate 11 is cracked in an extremely low temperature (-60 ° C.) environment.

On the other hand, in Example 1, the elastic modulus γ1 is 0.63 MPa, the elastic modulus γ2 is 0.44 MPa, and the ratio γ1 / γ2 of the elastic modulus γ is 1.4. In Example 1, since the bonding layer 60 has such an elastic modulus γ (elastic modulus ratio), the ceramic dielectric can be used in both a room temperature (25 ° C.) environment and an extremely low temperature (-60 ° C.) environment. No peeling of the body substrate 11 from the base plate 50 or cracking of the ceramic dielectric substrate 11 occurred.

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

FIG. 8 is a table showing the physical properties of an example of the bonding layer of the electrostatic chuck according to the embodiment.
Examples 2 to 14 are examples of the electrostatic chuck 110 according to the embodiment.
FIG. 8 shows the elongation rate α, the bonding strength β, and the elastic modulus γ of the bonding layer 60 of Examples 2 to 14 measured and calculated in the same manner as in Example 1 and Reference Example 1. Further, FIG. 8 shows the results of the peeling / cracking test performed in the same manner as in Example 1 and Reference Example 1.

As shown in FIGS. 8, in Examples 2 to 14, the elongation rate α1 is 175% or more and 247% or less, the elongation rate α2 is 150% or more and 280% or less, and the ratio α1 / α2 of the elongation rate α is 0.80 or more. It is 1.17 or less. In Examples 2 to 14, since the bonding layer 60 has such an elongation rate α (elongation rate ratio), it can be used in either a room temperature (25 ° C.) environment or an extremely low temperature (-60 ° C.) environment. No peeling of the ceramic dielectric substrate 11 from the base plate 50 or cracking of the ceramic dielectric substrate 11 occurred.

In this way, by setting the elongation rate α1 of the bonding layer 60 to 120% or more, or setting the ratio α1 / α2 of the elongation rate α to 0.60 or more, the base plate of the ceramic dielectric substrate 11 in an extremely low temperature environment It is possible to suppress peeling from 50 and cracking of the ceramic dielectric substrate 11.

As shown in FIGS. 8, 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 ratio β1 / β2 of the bonding strength β is It 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), it can be used in either a room temperature (25 ° C.) environment or an extremely low temperature (-60 ° C.) environment. No peeling of the ceramic dielectric substrate 11 from the base plate 50 or cracking of the ceramic dielectric substrate 11 occurred.

By setting the bonding strength β1 of the bonding layer 60 to 0.4 MPa or more and 10 MPa or less in this way, the ceramic dielectric substrate 11 can be peeled from the base plate 50 and the ceramic dielectric substrate 11 can be cracked in an extremely low temperature environment. Can be suppressed.

As shown in FIGS. 8, 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 elastic modulus γ ratio γ1 / γ2 is. It 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), it can be used in either a room temperature (25 ° C.) environment or an extremely low temperature (-60 ° C.) environment. No peeling of the ceramic dielectric substrate 11 from the base plate 50 or cracking of the ceramic dielectric substrate 11 occurred.

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

FIG. 9 is a sectional view schematically showing a wafer processing apparatus including the electrostatic chuck according to the embodiment.
As shown in FIG. 9, the wafer processing apparatus 500 includes a processing container 501, a high frequency power supply 504, a suction power supply 505, an upper electrode 510, and an electrostatic chuck 110. The ceiling of the processing container 501 is provided with a processing gas introduction port 502 for introducing the processing gas into the inside and an upper electrode 510. The bottom plate of the processing container 501 is provided with an exhaust port 503 for decompressing and exhausting the inside. The electrostatic chuck 110 is arranged inside the processing container 501 under the upper electrode 510. 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 suction power supply 505.

The base plate 50 and the upper electrode 510 are provided substantially in parallel with each other at a predetermined distance from each other. The object W is placed on the first main surface 11a located between the base plate 50 and the upper electrode 510.

When a voltage (high frequency voltage) is applied from the high frequency power supply 504 to the base plate 50 and the upper electrode 510, a high frequency discharge occurs and the processing gas introduced into the processing container 501 is excited and activated by plasma to generate the object W. It is processed.

When a voltage (adsorption voltage) is applied to the electrode layer 12 from the adsorption power supply 505, an electric charge is generated on the first main surface 11a side of the electrode layer 12, and the object W is attracted to the electrostatic chuck 110 by electrostatic force. Be retained.

The embodiment of the present invention has been described above. However, the present invention is not limited to these descriptions. The above-mentioned embodiments which have been appropriately designed by those skilled in the art are also included in the scope of the present invention as long as they have the features of the present invention. For example, the shape, dimensions, material, arrangement, installation form, and the like of each element included in the electrostatic chuck are not limited to those exemplified, and can be appropriately changed. Further, the elements included in each of the above-described embodiments can be combined as much as technically possible, and the combination thereof is also included in the scope of the present invention as long as the features of the present invention are included.

11 Ceramic dielectric substrate, 11a 1st main surface, 11b 2nd main surface, 12 electrode layer, 13 convex part, 14 groove, 15 through hole, 20 connection part, 50 base plate, 50a upper part, 50b lower part, 51 input path, 52 Output path, 53 Gas introduction path, 55 consecutive passages, 60 junction layer, 110 electrostatic chuck, 110a central part, 110b outer peripheral part, 110c middle part, 500 wafer processing equipment, 501 processing container, 502 processing gas inlet, 503 Exhaust port, 504 high frequency power supply, 505 power supply for adsorption, 510 upper electrode, TP test piece, W object

Claims (11)

Ceramic dielectric substrate and
A metal base plate that supports the ceramic dielectric substrate, and
A bonding layer provided between the ceramic dielectric substrate and the base plate and containing a resin material,
Equipped with
An electrostatic chuck characterized in that the bonding strength β1 of the bonding layer at −60 ° C. is 0.4 MPa or more and 10 MPa or less. The electrostatic chuck according to claim 1, wherein the bonding strength β1 is 0.4 MPa or more and 2.0 MPa or less. Ceramic dielectric substrate and
A metal base plate that supports the ceramic dielectric substrate, and
A bonding layer provided between the ceramic dielectric substrate and the base plate and containing a resin material,
Equipped with
An electrostatic chuck characterized in that the ratio β1 / β2 of the bonding strength β1 of the bonding layer at −60 ° C. to the bonding strength β2 of the bonding layer at 25 ° C. is 0.6 or more and 10 or less. The electrostatic chuck according to claim 3, wherein the ratio β1 / β2 is 0.8 or more. The electrostatic chuck according to any one of claims 1 to 4, wherein the elastic modulus γ1 of the bonding layer at −60 ° C. is 0.1 MPa or more and 10 MPa or less. Any of claims 1 to 5, wherein the ratio γ1 / γ2 of the elastic modulus γ1 of the bonding layer at −60 ° C. to the elastic modulus γ2 of the bonding layer at 25 ° C. is 0.6 or more and 30 or less. The electrostatic chuck described in one. The electrostatic chuck according to any one of claims 1 to 6, wherein the elongation rate α1 of the bonded layer at −60 ° C. is 120% or more. One of claims 1 to 7, wherein the ratio α1 / α2 of the elongation rate α1 of the bonding layer at −60 ° C. to the elongation rate α2 of the bonding layer at 25 ° C. is 0.60 or more. The electrostatic chuck described in. The electrostatic chuck according to any one of claims 3 to 8, wherein the bonding strength β1 of the bonding layer at −60 ° C. is 0.4 MPa or more and 1.9 MPa or less. The electrostatic chuck according to any one of claims 1 to 9, wherein the ceramic dielectric substrate contains at least one of aluminum oxide, aluminum nitride, silicon carbide, silicon nitride, and yttrium oxide. .. The electrostatic chuck according to claim 10, wherein the ceramic dielectric substrate contains aluminum oxide.

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