Thermal spray coating and cooling plate

Abstract

This thermal spray coating contains a zirconium oxide component and a stabilizing component that stabilizes the crystal structure of zirconium oxide. The crystal structure of the thermal spray coating includes at least two crystal systems. The at least two crystal systems may include a tetragonal system and a monoclinic system. The content of the stabilizing component may be more than 0 mol% to not more than 6 mol%. The thermal spray coating may be formed of a partially stabilized zirconia.

Description

Thermal spray coating and cooling plate

[0001] Furthermore, one embodiment of the present invention relates to a thermal spray coating. Another embodiment of the present invention relates to a cooling plate including the thermal spray coating.

[0002] Semiconductor devices are incorporated into almost all electronic devices and play a crucial role in their functionality. Semiconductor devices utilize the semiconductor properties of materials such as silicon, and are constructed by laminating semiconductor films, insulating films, and conductive films onto a substrate, followed by patterning of these films. These films are laminated using methods such as vapor deposition, sputtering, chemical vapor deposition (CVD), atomic layer deposition (ALD), or chemical reactions of the substrate, and then formed into predetermined shapes using photolithography and dry etching.

[0003] The characteristics of the film described above are greatly influenced by the conditions under which the film is deposited or etched. One of the conditions that influences the characteristics of the film is the performance of the mounting stage (hereinafter referred to as "stage") on which the substrate is placed. The stage includes, for example, an electrostatic chuck for adsorbing the substrate and a cooling plate installed on the electrostatic chuck. In recent years, with the miniaturization of semiconductor devices, the ratio of the diameter of the hole to be processed to the thickness of the film to be processed has increased. As a result, the bias voltage to the electrostatic chuck increases, and the RF power increases. Consequently, the stray potential and induced voltage increase, so improved voltage withstand performance is required for the cooling plate as well. Patent documents 1 and 2 disclose a stage in which an insulating film (thermal spray film) is formed on a metal plate by ceramic thermal spraying, which is one of the thermal spraying methods.

[0004] Japanese Patent No. 6027407, Registered Utility Model No. 2600558

[0005] The dielectric strength of components such as cooling plates manufactured using thermal spraying is greatly influenced by the dielectric strength of the thermal spray coating that makes up the surface of the component. If the thermal spray coating has high dielectric strength, the dielectric strength of the component will improve. The dielectric strength of the thermal spray coating can change not only depending on the conditions of the thermal spraying method, but also on the components of the thermal spray material used in the thermal spraying method, that is, the components contained in the thermal spray coating.

[0006] Therefore, one objective of one embodiment of the present invention is to provide a thermal spray coating with improved voltage resistance. Another objective of one embodiment of the present invention is to provide a cooling plate with improved voltage resistance.

[0007] A thermal spray film according to one embodiment of the present invention is a thermal spray film comprising a zirconium oxide component and a stabilizing component that stabilizes the crystal structure of zirconium oxide, wherein the crystal structure of the thermal spray film comprises at least two types of crystal systems.

[0008] At least two of the crystal systems may include tetragonal and monoclinic systems.

[0009] The content of the stabilizing component may be greater than 0 mol% and less than or equal to 6.0 mol%.

[0010] The stabilizing component may include at least one of yttrium oxide, magnesium oxide, cerium oxide, and calcium oxide.

[0011] The thermal spray coating may be composed of partially stabilized zirconia.

[0012] The thermal spray coating may further contain an oxide component having a crystal structure different from that of zirconium oxide. The thermal spray coating may have a layered structure comprising a first thermal spray layer containing the zirconium oxide component and a stabilizing component, and a second thermal spray layer containing the oxide component. The oxide component may include at least one of yttrium oxide, aluminum oxide, magnesium oxide, cerium oxide, and calcium oxide.

[0013] The dielectric breakdown voltage of the thermal spray coating may be 50 kV / mm or higher.

[0014] Furthermore, a cooling plate according to one embodiment of the present invention includes a substrate containing a recirculating channel through which a medium flows, and the thermal spray film covering the substrate.

[0015] The thermal spray coating according to one embodiment of the present invention has an increased dielectric breakdown voltage and improved dielectric strength. Furthermore, the cooling plate according to one embodiment of the present invention has a substrate covered with the thermal spray coating and improved dielectric strength.

[0016] This is a schematic perspective view showing the configuration of a cooling plate according to one embodiment of the present invention. This is a schematic cross-sectional view showing the configuration of a cooling plate according to one embodiment of the present invention. This is a schematic cross-sectional view showing the configuration of an etching apparatus according to one embodiment of the present invention. This is an SEM image of the thermal spray material used in the formation of the thermal spray film in the example. This is a graph showing the evaluation results of the dielectric breakdown test of the thermal spray films of the example, comparative example 1, and comparative example 2.

[0017] The embodiments of the invention disclosed in this application will be described below with reference to the drawings. However, the present invention can be implemented in various forms without departing from its spirit, and is not to be construed as being limited to the descriptions of the embodiments exemplified below.

[0018] While drawings may schematically represent the width, thickness, and shape of components compared to actual embodiments in order to clarify the explanation, they are merely examples and do not limit the interpretation of the present invention. Furthermore, in this specification and drawings, components having the same function as those described in previously shown drawings may be denoted by the same reference numerals, and redundant explanations may be omitted.

[0019] <First Embodiment> The thermal spray material according to one embodiment of the present invention is a granular material used in a thermal spraying method, and is made of zirconium oxide (ZrO ２ It contains ) components and stabilizing components. In the thermal spraying method, a thermal spray film can be formed by spraying the thermal spray material.

[0020] The thermal spray material contains zirconium oxide as its main component and contains stabilizing components in an amount exceeding 0 mol% and up to 6.0 mol%. The lower limit of the stabilizing component content may be, for example, 0.5 mol%, 1.0 mol%, or 1.5 mol. The upper limit of the stabilizing component content may be, for example, 5.0 mol%, 4.0 mol%, or 3.0 mol%. In addition to the components described above, the thermal spray material may contain unavoidable impurities. Here, unavoidable impurities refer to impurities that could not be removed during the manufacturing process of the raw materials of the thermal spray material.

[0021] The crystal structure of zirconium oxide changes with temperature, but stabilizing components contained in thermal spray materials can stabilize the crystal structure of zirconium oxide. For example, yttrium oxide (Y) can be used as a stabilizing component. ２ O ３ ), magnesium oxide (MgO), cerium oxide (CeO ２ ), or calcium oxide (CaO), or a combination thereof can be used. For convenience, the following explanation may use the case where yttrium oxide is used as a stabilizing component of the thermal spray material as an example.

[0022] The granular material constituting the thermal spray material has a crystalline structure that includes at least two types of crystal systems. For example, the granular material has a tetragonal crystal structure in which the zirconium oxide crystal structure is stabilized, and a monoclinic crystal structure in which the zirconium oxide crystal structure is not stabilized. When yttrium oxide is used as a stabilizing component, the tetragonal crystal structure is due to yttria-stabilized zirconia (YSZ). In this case, the thermal spray material partially contains YSZ in which the zirconium oxide crystal structure is stabilized by yttrium oxide. That is, the thermal spray material is not almost entirely YSZ, but is so-called partially stabilized zirconia (PSZ) that contains YSZ in part.

[0023] Thermal spray materials can be manufactured using a granulation and sintering method. The granulation and sintering method includes a granulation step, a sintering step, and a classification step. In the granulation step, powders of compounds corresponding to each component are mixed, and then granulated particles are produced by granulating the mixed powder using a wet granulation or dry granulation method. The content of components in the thermal spray material generally corresponds to the content of powders of the corresponding compounds. Therefore, for a thermal spray material containing 2 mol% yttrium oxide, it is sufficient to mix 98 mol% zirconium oxide powder with 2 mol% yttrium oxide. In the sintering step, the granulated particles are fired. In the classification step, the fired granulated particles are crushed and classified to obtain a granular material containing granulated particles of a predetermined size (particle size), i.e., the thermal spray material. Thermal spray materials manufactured using the granulation and sintering method may contain granulated particles with high sphericity. Here, the predetermined size of the granulated particles contained in the granular material is between 1 μm and 100 μm. The lower limit of the size of the molded particles may be, for example, 5 μm or 10 μm or larger. The upper limit of the size of the molded particles may be, for example, 70 μm, 60 μm, 50 μm, or 45 μm.

[0024] The size of the molded particles contained in the thermal spray material can be measured, for example, using the laser diffraction / scattering method. In the laser diffraction / scattering method, a laser is irradiated onto a sample in which particles are dispersed in a dispersion medium such as a gas or liquid, and the particle size distribution can be measured by measuring the angle dependence of the intensity of the light scattered from the sample. Furthermore, from the particle size distribution, for example, the 90% particle size and the 50% particle size can be calculated. The 90% particle size refers to the particle size corresponding to the cumulative frequency of 90% in the particle size distribution, and is called "D ９０ It is expressed as ". The 50% particle size refers to the particle size that corresponds to 50% of the cumulative frequency in the particle size distribution, and is "D ５０ It is expressed as "[...]. The 50% particle size is also called the median diameter."

[0025] The upper limit of the size of the molded particles mentioned above is D ９０ It may also be a value corresponding to the D of the molded particles contained in the thermal spray material. ５０ The particle size is 15 μm or more and 30 μm or less, preferably 20 μm or more and 25 μm or less, but is not limited to this.

[0026] Furthermore, thermal spray materials can also be manufactured using methods other than granulation sintering.

[0027] As will be described in detail later, the thermal spray film formed by thermal spraying the thermal spray material according to this embodiment has a high dielectric breakdown voltage. Therefore, the thermal spray material according to this embodiment can improve the dielectric strength of the thermal spray film.

[0028] <Second Embodiment> The thermal spray film according to one embodiment of the present invention is formed by thermal spraying the thermal spray material described in the first embodiment.

[0029] The thermal spray coating contains the same components as the thermal spray material. Specifically, the thermal spray coating contains zirconium oxide as its main component, and contains stabilizing components in an amount exceeding 0 mol% and 6.0 mol% or less. Furthermore, the thermal spray coating has a crystalline structure that includes at least two types of crystal systems, such as the tetragonal and monoclinic systems resulting from YSZ. Therefore, the thermal spray coating is composed of PSZ, just like the thermal spray material. As will be explained in more detail later, the content of stabilizing components in the thermal spray coating may exceed 6 mol%.

[0030] The thickness of the thermal spray coating is, for example, between 100 μm and 900 μm. If the thickness of the thermal spray coating is less than 100 μm, the effect of the thickness of the thermal spray coating will outweigh the effect of the thermal spray material, making it difficult to improve the dielectric strength of the thermal spray coating.

[0031] Furthermore, the thermal spray coating may further contain an oxide component different from PSZ. That is, the thermal spray coating may contain an oxide component having a crystal structure different from the crystal structure of zirconium oxide. The phrase "different crystal structures" as used herein includes not only cases where the crystal system is different, but also cases where the crystal system is the same but the lattice constant is different. The content of the oxide component is, for example, 10 vol% or more and 90 vol% or less. As the oxide component, for example, yttrium oxide, aluminum oxide, magnesium oxide, cerium oxide, calcium oxide, or a combination thereof is used, but is not limited thereto. The thermal spray coating can be formed by using a thermal spray material in which granules containing a zirconium oxide component and a stabilizing component (i.e., PSZ granules) and granules containing an oxide component are mixed. Since the thermal spray coating formed in this manner also contains PSZ, the withstand voltage performance of the thermal spray coating is improved.

[0032] The thermal spray coating may have a single-layer structure or a layered structure.

[0033] For example, a thermal spray coating having a layered structure has a structure in which a first thermal spray layer composed of PSZ containing a zirconium oxide component and a stabilizing component and a second thermal spray layer containing an oxide component are formed in layers. In this case, a thermal spray material containing a zirconium oxide component and a stabilizing component (i.e., a thermal spray material composed of PSZ granules) is thermally sprayed to form the first thermal spray layer, and a thermal spray material containing an oxide component is thermally sprayed on the first thermal spray layer to form the second thermal spray layer. The components of the first thermal spray layer and the second thermal spray layer may be reversed. In addition, the layered structure of the thermal spray coating includes not only a structure in which the first thermal spray layers and the second thermal spray layers are alternately and uniformly formed, but also a structure in which the second thermal spray layer is partially formed between two adjacent first thermal spray layers. Further, in the thermal spray coating having a layered structure, the number of thermal spray layers constituting the layered structure is not particularly limited. Since the thermal spray coating having such a layered structure also includes the first PSZ thermal spray layer, the withstand voltage performance of the thermal spray coating is improved.

[0034] Note that when the same material as the stabilizing component (for example, yttrium oxide) is used as the oxide component, the content of the stabilizing component in the thermal spray coating may exceed 6.0 mol%. Even in such a case, the presence of the oxide component in the thermal spray coating can be confirmed by identifying a crystal structure originating from the oxide component that is different from the crystal structure of zirconium oxide through crystal structure analysis.

[0035] The thermal spray coating according to the present embodiment has a higher dielectric breakdown voltage than a thermal spray coating having only an aluminum oxide component. Further, the thermal spray coating according to the present embodiment can also have a higher dielectric breakdown voltage than a thermal spray coating that is YSZ. The dielectric breakdown voltage of the thermal spray coating according to the present embodiment is 45 kV / mm or higher, 50 kV / mm or higher, or 55 kV / mm or higher.

[0036] Although details will be described later, the thermal spray coating according to the present embodiment has a high dielectric breakdown voltage. Therefore, the withstand voltage performance of the thermal spray coating according to the present embodiment is improved.

[0037] <Third Embodiment> A cooling plate 10 according to one embodiment of the present invention will be described with reference to Figure 1 and Figure 2. For example, the cooling plate 10 can be used as one of the members constituting a stage of an etching apparatus. Specifically, the cooling plate 10 can control the temperature of a substrate placed on the stage by cooling an electrostatic chuck of the stage.

[0038] Figure 1 is a schematic perspective view showing the configuration of the cooling plate according to one embodiment of the present invention. Figure 2 is a schematic cross-sectional view showing the configuration of the cooling plate 10 according to one embodiment of the present invention. Specifically, Figure 2 is a cross-sectional view of the cooling plate 10 cut along the line AA' shown in Figure 1.

[0039] As shown in Figure 1 and Figure 2, the cooling plate 10 includes a base material 110 and a thermal spray coating 120. The thermal spray coating 120 is provided so as to cover the surface of the base material 110. That is, the thermal spray coating 120 constitutes the surface of the cooling plate 10. The thermal spray coating 120 may be provided so as to cover all of the upper surface, lower surface, and side surfaces of the base material 110, or may be provided so as to cover a part of the upper surface, lower surface, and side surfaces of the base material 110.

[0040] The base material 110 has a configuration in which the small circular first flat plate 111 is disposed and joined on the large circular second flat plate 112. In other words, a step is provided on the outer peripheral portion of the base material 110. A groove portion 113 is formed on the surface of the second flat plate 112. The groove portion 113 forms a closed space by joining the first flat plate 111 and the second flat plate 112. The closed space in the base material 110 can function as an annular flow path through which a medium flows. That is, the base material 110 includes the annular flow path. The medium flowing through the annular flow path may be a liquid or a gas. For example, the cooling plate 10 is attached to an electrostatic chuck so as to fit with the step. By allowing a cooling medium to flow through the annular flow path in the base material 110, the electrostatic chuck in contact with the cooling plate 10 can be cooled.

[0041] As each of the first flat plate 111 and the second flat plate 112, a metal material or a ceramic material can be used. The metal material is, for example, stainless steel (SUS), or an alloy (FeCrSi alloy) containing iron (Fe), chromium (Cr), and silicon (Si), but is not limited thereto. The ceramic material is, for example, zirconia (ZrO ２ ), yttria-stabilized zirconia (YSZ), magnesia (MgO), ceria (CeO ２ ), gadolinia-doped ceria (GDC), steatite (MgO·SiO ２ ), mullite (3Al ２ O ３ ·2SiO ２ ), titania (TiO ２ ), silica (SiO ２ ), and oxides such as sialon (SiAlON), or nitrides such as aluminum nitride (AlN) and silicon nitride (Si ３ N ４ ), but is not limited thereto.

[0042] The materials of the first plate 111 and the second plate 112 may be the same or different. Specifically, when the first plate 111 contains a metallic material, the second plate 112 may contain a metallic material or a ceramic material. Similarly, when the first plate 111 contains a ceramic material, the second plate 112 may contain a metallic material or a ceramic material. The first plate 111 and the second plate 112 can be joined together using brazing or diffusion bonding.

[0043] The number of flat plates included in the base material 110 is not limited to two. The base material 110 may have a configuration in which three or more flat plates are laminated together.

[0044] The thermal spray coating 120 is a thermal spray coating having a high dielectric breakdown voltage, as described in the second embodiment. The thermal spray coating 120 can be formed by thermal spraying the thermal spray material described in the first embodiment onto the substrate 110.

[0045] In this embodiment, the cooling plate 10 has a thermal spray coating 120 with a high dielectric breakdown voltage formed on its surface. Therefore, the dielectric strength of the cooling plate 10 is improved.

[0046] <Fourth Embodiment> Referring to Figure 3, an etching apparatus 50 according to one embodiment of the present invention will be described.

[0047] Figure 3 is a schematic cross-sectional view showing the configuration of an etching apparatus 50 according to one embodiment of the present invention.

[0048] The etching apparatus 50 includes a stage 20 and a chamber 502. In the etching apparatus 50, a substrate is placed on the stage 20, and dry etching can be performed on a film such as a conductor, insulator, or semiconductor formed on the substrate.

[0049] Although not shown, the stage 20 includes an electrostatic chuck for fixing the position of the substrate, a cooling plate 10 for cooling the electrostatic chuck, and a heater unit for heating the substrate. The configuration of the cooling plate 10 was described in the third embodiment, so it is omitted here. The electrostatic chuck and heater unit are connected to power supplies 524 and 526, which can control the operation of the electrostatic chuck and heater unit. In the stage 20, the electrostatic chuck is cooled by the cooling medium flowing through the circulating channel of the cooling plate 10, making it possible to control the temperature of the substrate with high precision. The stage 20 may optionally be connected to a temperature controller 528 that controls the temperature of the cooling medium flowing in the circulating channel of the cooling plate 10. The stage 20 may also be connected to a rotation control device (not shown) for rotating the stage 20.

[0050] An exhaust device 504 is connected to the chamber 502, which allows the chamber 502 to be set to a reduced-pressure atmosphere. The chamber 502 is further provided with an introduction pipe 506 for introducing reaction gas, and the etching reaction gas is introduced into the chamber 502 via a valve 508. As the reaction gas, for example, carbon tetrafluoride (CF4) ４ ), octafluorocyclobutane (c-C ４ F ８ ), decafluorocyclopentane (c-C ５ F １０ ), or hexafluorobutadiene (C ４ F ６ Fluorine-containing organic compounds such as ) can be used.

[0051] A microwave source 512 can be installed at the top of the chamber 502 via a waveguide 510. The microwave source 512 has an antenna for supplying microwaves and outputs high-frequency microwaves, such as 2.45 GHz microwaves or 13.56 MHz radio waves (RF). The microwaves generated by the microwave source 512 propagate to the top of the chamber 502 via the waveguide 510 and are introduced into the chamber 502 through a window 514 containing quartz or ceramic. The reaction gas is turned into plasma by the microwaves, and the etching of the film proceeds due to electrons, ions, or radicals contained in the plasma.

[0052] A stage 20 for placing a substrate is provided at the bottom of the chamber 502. A power supply 530 is connected to the stage 20, and high-frequency power is supplied to the stage 20, forming a microwave electric field perpendicular to the surface of the stage 20 and the substrate surface. Magnets 516, 518, and 520 can be provided on the top and sides of the chamber 502. Magnets 516, 518, and 520 may be permanent magnets or electromagnets with electromagnetic coils. Magnets 516, 518, and 520 generate a magnetic field parallel to the stage 20 and the substrate surface. Through the cooperation of the magnetic field and the microwave electric field, electrons in the plasma resonate under the Lorentz force and are bound to the stage 20 and the substrate surface. As a result, a high-density plasma can be generated on the substrate surface.

[0053] In the etching apparatus 50 according to this embodiment, a stage 20 is used which includes a cooling plate 10 on which a thermal spray film 120 having a high dielectric breakdown voltage is formed on its surface. As a result, the dielectric strength of the stage 20 is improved, and the voltage applied to the stage 20 can be increased.

[0054] The embodiments of the present invention will be described in more detail below based on the examples. However, the embodiments of the present invention are not limited to the following examples.

[0055] [1. Formation of Thermal Spray Film] (Example) A thermal spray material consisting of granular PSZ containing zirconium oxide and yttrium oxide components was thermal sprayed onto an aluminum plate (50 mm in length x 50 mm in width x 10 mm in thickness) to obtain the thermal spray film of the example. That is, the thermal spray film of the example is a film composed of PSZ. The thickness of the thermal spray film of the example was 200 μm.

[0056] In the thermal spray material, the yttrium oxide content was 1.7 mol%. The granular material was manufactured using a granulation sintering method, and the size of the granulated particles contained in the granular material was between 10 μm and 45 μm. Furthermore, the D of the granulated particles ５０ The size was 23.2 μm.

[0057] Figure 1 is an SEM image of the thermal spray material used in the example. As can be seen from Figure 1, the thermal spray material used in the example contains granulated particles with high sphericity.

[0058] (Comparative Example 1) A thermal spray material consisting solely of aluminum oxide granules was thermal sprayed onto an aluminum plate (50 mm long x 50 mm wide x 10 mm thick) to obtain the thermal spray film of Comparative Example 1. That is, the thermal spray film of Comparative Example 1 is a film composed of aluminum oxide. The thickness of the thermal spray film of Comparative Example 1 was 200 μm.

[0059] (Comparative Example 2) A thermal spray material consisting of YSZ granules was thermal sprayed onto an aluminum plate (length 50 mm x width 50 mm x thickness 10 mm) to obtain the thermal spray film of Comparative Example 2. That is, the thermal spray film of Comparative Example 2 is a film composed of YSZ. The thickness of the thermal spray film of Comparative Example 2 was 200 μm.

[0060] [2. Dielectric Breakdown Test] To evaluate the dielectric strength of the thermal spray coatings, dielectric breakdown tests were performed at 100°C on each of the thermal spray coatings of Example, Comparative Example 1, and Comparative Example 2. In the dielectric breakdown test, an aluminum plate was connected to GND (0V), an electrode was brought into contact with the surface of the thermal spray coating, and the voltage applied to the electrode was increased at a constant rate (0.5kV / sec) from 0V. The voltage at which the thermal spray coating broke was normalized by the thickness of the thermal spray coating, and the dielectric breakdown voltage was calculated. The dielectric breakdown test was performed at five points (N=5) in the center and four corners of the aluminum plate. The evaluation results of the dielectric breakdown test are shown in Figure 5. The minimum, maximum, and average dielectric breakdown voltages for each of the thermal spray coatings of Example, Comparative Example 1, and Comparative Example 2 are shown in Table 1.

[0061]

[0062] As can be seen from Figure 2 and Table 1, the dielectric breakdown voltage of the thermal spray coatings increases in the order of Comparative Example 1, Comparative Example 2, and the Example. In particular, the thermal spray coating of the Example has a dielectric breakdown voltage of 50 kV / mm or more, which cannot be obtained with the thermal spray coatings of Comparative Examples 1 and 2. In particular, the thermal spray coating of the Example (a thermal spray coating composed of PSZ) has a dielectric breakdown voltage that is more than 1.5 times higher on average than the thermal spray coating of Comparative Example 2 (a thermal spray coating composed of YSZ), even though it only partially contains YSZ. This is a remarkable effect that a person skilled in the art could not have predicted. Thus, it was confirmed that the thermal spray coating of the Example has a high dielectric breakdown voltage and that the dielectric strength of the thermal spray coating of the Example is improved.

[0063] The embodiments described above as examples of the present invention can be combined and implemented as appropriate, insofar as they do not contradict each other. Furthermore, any additions, deletions, or design modifications made by those skilled in the art based on these embodiments are also included within the scope of the present invention, as long as they retain the essence of the present invention.

[0064] Furthermore, any effects or benefits other than those brought about by the embodiments described above, if they are clear from the description herein or easily predictable to those skilled in the art, are naturally understood to be brought about by the present invention.

[0065] 10: Cooling plate, 20: Stage, 50: Etching device, 110: Substrate, 111: First plate, 112: Second plate, 113: Groove, 120: Thermal spray coating, 502: Chamber, 504: Exhaust device, 506: Inlet tube, 508: Valve, 510: Waveguide, 512: Microwave source, 514: Window, 516: Magnet, 518: Magnet, 520: Magnet, 524: Power supply, 526: Power supply, 528: Temperature controller, 530: Power supply

Claims

1. A thermal spray coating comprising a zirconium oxide component and a stabilizing component that stabilizes the crystal structure of the zirconium oxide, wherein the crystal structure of the thermal spray coating comprises at least two types of crystal systems.

2. The thermal spray film according to claim 1, wherein the at least two types of crystal systems include a tetragonal system and a monoclinic system.

3. The thermal spray film according to claim 1, wherein the content of the stabilizing component is greater than 0 mol% and 6 mol% or less.

4. The thermal spray film according to claim 1, wherein the stabilizing component comprises at least one of yttrium oxide, magnesium oxide, cerium oxide, and calcium oxide.

5. The thermal spray coating according to claim 1, wherein the thermal spray coating is composed of partially stabilized zirconia.

6. The thermal spray film according to claim 1, further comprising an oxide component having a crystal structure different from the crystal structure of the zirconium oxide.

7. The thermal spray film according to claim 6, wherein the thermal spray film has a layered structure comprising a first thermal spray layer containing the zirconium oxide component and the stabilizing component, and a second thermal spray layer containing the oxide component.

8. The thermal spray film according to claim 6, wherein the oxide component comprises at least one of yttrium oxide, aluminum oxide, magnesium oxide, cerium oxide, and calcium oxide.

9. The thermal spray coating according to any one of claims 1 to 8, wherein the dielectric breakdown voltage of the thermal spray coating is 50 kV / mm or more.

10. A cooling plate comprising a substrate including a recirculating channel through which a medium flows, and a thermal spray film according to any one of claims 1 to 8 covering the substrate.

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