Thermal spray coating, method for forming the same, and thermal spray member

Abstract

In non-contact surface shape measurement of a film using a laser, the surface area S (μm²) within a single evaluation region of the measurement surface (SL surface) of the film surface is measured. 2 The area A (μm²) within one evaluation region of the reference surface, which is a plane located at the arithmetic mean height of the measurement surface (SL surface), is defined as the area A within one evaluation region of the reference surface. 2 A thermal spray coating having a film surface in which the area ratio S / A obtained by dividing by ) is 1.75 or more and 3 or less, and the surface roughness Sa within one evaluation area of ​​the measurement surface (SL surface) is 0.4 μm or more and 8 μm or less. [Effects] According to the thermal spray coating and thermal spray component of the present invention, when the thermal spray coating is used as a corrosion-resistant coating and dry etching is performed using gas plasma in semiconductor manufacturing equipment, the generation of particles caused by cracks in the thermal spray coating can be reduced.

Description

[Technical Field]

[0001] The present invention relates to a thermal spray coating excellent as a corrosion-resistant coating for semiconductor manufacturing equipment components, a method for forming the same, and a thermal spray component on which the thermal spray coating has been formed on a substrate. [Background technology]

[0002] Thermal spray coatings are used as corrosion-resistant coatings for semiconductor manufacturing equipment components. In recent years, with the increasing integration of semiconductors, the minimum line width required for circuit patterns formed on wafers by dry etching using gas plasma is becoming 10 nm or less, and there is a need to reduce particles (foreign matter) generated in the semiconductor manufacturing process. Conventionally, studies have been conducted on rare earth element oxyhalide coatings produced by atmospheric plasma spraying to meet the particle resistance performance required for corrosion-resistant coatings for semiconductor manufacturing equipment components. For example, Japanese Patent Application Publication No. 2020-056115 (Patent Document 1) describes a thermal spray coating mainly composed of a rare earth element oxyhalide containing rare earth elements, oxygen, and halogen elements (X) as constituent elements.

[0003] Furthermore, progress is being made in the development of dense rare-earth element oxyfluoride coatings by suspension plasma spraying, which are expected to improve particle resistance. For example, Japanese Patent Publication No. 2018-080401 (Patent Document 2) describes a film containing rare-earth oxyfluoride as the main phase.

[0004] In thermal spray coating formation, molten particles rapidly cool upon impact with the substrate, forming splatters. These splatters then stack to form the thermal spray coating. However, rapid cooling and solidification during splatter formation can cause cracks within the splatters. Furthermore, excessive densification of the coating can release residual stress between splatters, leading to crack formation. In dry etching using gas plasma, it is known that the gas plasma preferentially etches cracks in the thermal spray coating. Therefore, even in dense coatings, the presence of cracks can contribute to particle generation. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-056115 [Patent Document 2] Japanese Patent Publication No. 2018-080401 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The present invention has been made in view of the above circumstances, and aims to provide a thermal spray coating with fewer cracks and a method for forming the same, and to provide a thermal spray member on which a thermal spray coating with fewer cracks is formed on a substrate. [Means for solving the problem]

[0007] The inventors, after diligent research to solve the above problems, have found that in non-contact shape measurement of a film surface using a laser, the surface area S (μm²) of the measurement surface (SL surface) of the film surface is... 2 ) is the area A (μm²) of the reference surface of the measurement surface (SL surface). 2 The present invention was discovered that a thermal spray coating having a film surface in which the area ratio S / A (calculated by dividing by ) is 1.75 or more and 3 or less, and the surface roughness Sa of the measurement surface (SL surface) is 0.4 μm or more and 8 μm or less, can reduce the generation of particles caused by cracks in the thermal spray coating when dry etching is performed using gas plasma with the thermal spray coating as a corrosion-resistant coating.

[0008] Accordingly, the present invention provides the following thermal spray coating, thermal spray member, and method for forming a thermal spray coating. 1. In non-contact shape measurement of a film surface using a laser, the surface area S (μm²) within one evaluation region of the measured surface (SL surface) of the film surface is measured. 2 ) is the area A (μm²) within the above evaluation region of the reference surface, which is a plane located at the height of the arithmetic mean of the above measurement surface (SL surface). 2A thermal spray coating characterized by having a film surface in which the area ratio S / A obtained by dividing by ) is 1.75 or more and 3 or less, and the surface roughness Sa within the above-mentioned evaluation area of ​​the measurement surface (SL surface) is 0.4 μm or more and 8 μm or less. 2. The thermal spray coating according to claim 1, characterized by containing rare earth element oxyfluorides. 3. The thermal spray coating according to claim 2, characterized in that the above rare earth element oxyfluoride is one or more selected from ROF, R5O4F7, R6O5F8, and R7O6F9 (wherein R represents one or more selected from rare earth elements including Sc and Y). 4. A thermal spray coating according to claim 1, which contains a rare earth element oxyfluoride represented by ROF (wherein R represents one or more rare earth elements selected from Sc and Y), and is characterized in that, by X-ray diffraction with Cu-Kα as the characteristic X-ray, the diffraction peak with the maximum integrated intensity among the diffraction peaks detected within the diffraction angle range 2θ = 10 to 70° is the diffraction peak attributed to the above ROF. 5. The thermal spray coating according to claim 1, characterized in that it contains oxygen, and the oxygen content is 5 atomic% or more and 55 atomic% or less. 6. The thermal spray coating according to claim 1, characterized in that its thickness is 10 μm or more and 500 μm or less. 7. A thermal spray member characterized by comprising a base material and a thermal spray coating according to any one of 1 to 6 formed on the base material. 8. The thermal spray member according to claim 7, characterized in that it is a component for semiconductor manufacturing equipment. A method for forming a thermal spray coating according to any one of 9.1 to 9.6, Using a slurry in which a thermal spray material having an average particle size D50 of 1 μm or more and 9 μm or less is dispersed in a dispersion medium, A process of generating a plasma with a current value C of 450A to 1000A, a voltage value V of 20V to 235V, a C / V value (current value C divided by voltage value V) of 1.92 to 30, and an applied power value P of 20kW to 120kW, to which a slurry containing the above-mentioned spray material is supplied to the plasma and sprayed by suspension plasma spraying. A method for forming a thermal spray coating, characterized by including the following: 10. The forming method according to 9, wherein the thermal spraying material contains a rare earth element oxyfluoride, or a rare earth element oxyfluoride and a rare earth element fluoride.

Advantages of the Invention

[0009] According to the thermal spray coating and the thermal spray member of the present invention, when dry etching using gas plasma is performed in a semiconductor manufacturing apparatus or the like using the thermal spray coating as a corrosion-resistant coating, the generation of particles due to cracks in the thermal spray coating can be reduced.

Brief Description of the Drawings

[0010] [Figure 1] It is an image obtained by whitening the scanning electron microscope image of the film surface of the thermal spray coating obtained in Example 1 and making the cracks white. [Figure 2] It is an image obtained by whitening the scanning electron microscope image of the film surface of the thermal spray coating obtained in Example 3 and making the cracks white. [Figure 3] It is an image obtained by whitening the scanning electron microscope image of the film surface of the thermal spray coating obtained in Comparative Example 1 and making the cracks white. [Figure 4] It is an image obtained by whitening the scanning electron microscope image of the film surface of the thermal spray coating obtained in Comparative Example 2 and making the cracks white.

Modes for Carrying Out the Invention

[0011] Hereinafter, the present invention will be described in more detail. In the non-contact type shape measurement of the film surface using a laser, the thermal spray coating of the present invention has a surface (film surface) where the value of the area ratio S / A obtained by dividing the surface area S (μm 2 ) of the evaluation region of the measurement surface (S-L surface) of the film surface by the area A (μm 2 ) of the evaluation region of the reference surface is preferably 1.75 or more.

[0012] The higher the flatness ratio of the splats in the sprayed coating and the larger the diameter of the formed splats, the higher the risk of crack generation in the splats. Within the normal size range of the spraying material used for forming the sprayed coating, the lower the flatness ratio of the splats and the smaller the diameter of the formed splats, the larger the value of the area ratio S / A. If the value of the area ratio S / A is 1.75 or more, the crack generation in the splats is effectively suppressed. The value of the area ratio S / A is more preferably 1.77 or more, still more preferably 1.79 or more, and particularly preferably 1.8 or more. On the other hand, the upper limit of the value of the area ratio S / A is preferably 3 or less, more preferably 2.8 or less, still more preferably 2.6 or less, and particularly preferably 2.4 or less.

[0013] The shape measurement of the film surface of the sprayed coating by a non-contact method using a laser can be carried out in accordance with ISO 25178-2:2021. This shape measurement can be carried out, for example, using a laser microscope. In the present invention, the film surface usually targets a surface (main surface) substantially orthogonal to the thickness direction of the film.

[0014] In the present invention, the measurement surface (S-L surface), the reference surface, and the evaluation region respectively correspond to the measurement surface (S-L surface), the reference surface, and the evaluation region defined in ISO 25178-2:2021. The S-L surface is a surface obtained by applying an L-filter (a filter for removing large-scale shape components (such as wavy shapes, etc.)) to a base surface obtained by applying an S-filter (a filter for removing small-scale shape components (such as measurement noise, etc.)). For the filter, for example, a Gaussian filter can be applied. The reference surface corresponds to, for example, a plane located at the arithmetic mean height of the measurement surface (S-L surface). The evaluation region is set as a common evaluation region (one evaluation region) in the evaluation of the surface area S, the area A, and the surface roughness Sa described later.

[0015] Surface area S represents the area along the film surface of the thermal spray coating. Because the surface of the thermal spray coating includes irregularities and fine textures, it is not a flat surface. Therefore, surface area S represents the area of ​​the surface including these irregularities and fine textures, and differs from the area of ​​a flat surface. On the other hand, area A is the area of ​​a plane, and for measurement areas of the same size, area A will be the same value.

[0016] In this invention, when a laser microscope is used for non-contact measurement of the surface shape of a thermal spray coating using a laser, the magnification can be set according to the size of the thermal spray material used to form the thermal spray coating and the size of the splats in the thermal spray coating formed from the thermal spray material. For example, within the normal range of splat size in the thermal spray coating, it is preferable to set the objective lens magnification to 50x, and more preferably the overall magnification to 1200x, to enable good evaluation of the surface shape of the coating. The settings of the S-filter and L-filter can be applied to individual laser microscope settings according to the objective lens magnification, in accordance with ISO 25178-2:2021. On the other hand, the evaluation area has an area A of 50,000 μm². 2 Evaluation is possible by setting a range that exceeds the above limits. Typically, the evaluation area has an area A of 60,000 μm². 2 The settings will be within the following range.

[0017] The thermal spray coating of the present invention has a film surface in which, in non-contact shape measurement of the film surface using a laser, the surface roughness Sa within the evaluation area of ​​the measurement surface (SL surface) of the film surface is preferably 8 μm or less. In a thermal spray coating having a film surface with a surface roughness S within a predetermined range, crack generation within the splat is effectively suppressed in a thermal spray coating having a film surface with an area ratio S / A within a predetermined range. The surface roughness Sa of the thermal spray coating is more preferably 6 μm or less, even more preferably 4 μm or less, and particularly preferably 3 μm or less. On the other hand, the lower limit of the surface roughness Sa of the thermal spray coating is preferably 0.4 μm or more, more preferably 0.6 μm or more, even more preferably 0.8 μm or more, and particularly preferably 1 μm or more.

[0018] The thermal spray coating of the present invention preferably contains a rare earth element oxyfluoride. The thermal spray coating of the present invention may contain one or both of a rare earth element oxide and a rare earth element fluoride. In particular, when the thermal spray coating contains a rare earth element fluoride, it preferably contains the rare earth element fluoride together with the rare earth element oxyfluoride.

[0019] In the present invention, the rare earth element oxyfluoride is preferably in a crystalline phase. Examples of the rare earth element oxyfluoride include ROF (R1O1F1), R4O3F6, R5O4F7, R6O5F8, R7O6F9, R 17 O 14 F 23 , RO2F, ROF2 (wherein R represents one or more selected from rare earth elements including Sc and Y (the same shall apply hereinafter)). etc. The rare earth element oxyfluoride may be a single species or a mixture of two or more species, and the rare earth element (R) may be common to some or all of the rare earth element oxyfluorides, or may be different for each rare earth element oxyfluoride.

[0020] In the present invention, the rare earth element oxide is preferably in a crystalline phase. Examples of the rare earth element oxide include RO, R2O3, etc. The rare earth element oxide may be a single species or a mixture of two or more species, and the rare earth element (R) may be common to some or all of the rare earth element oxides, or may be different for each rare earth element oxide.

[0021] In the present invention, the rare earth element fluoride is preferably in a crystalline phase. Examples of the rare earth element fluoride include RF2, RF3, etc. The rare earth element fluoride may be a single species or a mixture of two or more species, and the rare earth element (R) may be common to some or all of the rare earth element fluorides, or may be different for each rare earth element fluoride.

[0022] In the present invention, the rare earth element (R) includes scandium (Sc), yttrium (Y), and lanthanides (elements with atomic numbers 57 to 71). Yttrium (Y), scandium (Sc), and ytterbium (Yb) are particularly preferred as the rare earth element (R).

[0023] The thermal spray coating of the present invention preferably contains one or more rare earth element oxyfluorides selected from ROF, R5O4F7, R6O5F8, and R7O6F9, and more preferably contains ROF. When the thermal spray coating contains ROF, it is preferable that the diffraction peak with the maximum integrated intensity among the diffraction peaks detected within the diffraction angle range 2θ = 10 to 70° by X-ray diffraction with Cu-Kα as the characteristic X-ray is the diffraction peak attributed to ROF.

[0024] In a plasma etching apparatus, etching with a fluorine-based gas plasma containing CF4, etc., promotes fluorination near the surface of the thermal spray coating. Furthermore, etching with an oxygen-based gas plasma containing O2, etc., used for ashing to remove photoresist remaining on the wafer after etching, promotes oxidation near the surface of the thermal spray coating. If the diffraction peak with the maximum integrated intensity among the diffraction peaks is attributed to the ROF, then both fluorination of the thermal spray coating due to etching with fluorine-based gas plasma and oxidation of the thermal spray coating due to etching with oxygen-based gas plasma can be suppressed. This is advantageous because it reduces the likelihood of changes in the composition of the thermal spray coating, improving particle resistance and process stability.

[0025] Taking yttrium (Y) as an example of a rare earth element (R), when the characteristic X-ray is Cu-Kα, the maximum peak of the rhombohedral crystal system of yttrium oxyfluoride (YOF) is generally a diffraction peak attributed to the (012) plane of the crystal lattice, although not particularly limited. This diffraction peak is usually detected around 2θ = 28.7°.

[0026] The maximum peak in the orthorhombic crystal system of yttrium oxyfluoride (Y5O4F7) is not particularly limited, but is generally a diffraction peak attributed to the (151) plane of the crystal lattice. This diffraction peak is usually detected around 2θ = 28.1°.

[0027] The maximum peak in the orthorhombic crystal system of yttrium oxyfluoride (Y6O5F8) is not particularly limited, but is generally a diffraction peak attributed to the (161) plane of the crystal lattice. This diffraction peak is usually detected around 2θ = 28.1°.

[0028] The maximum peak in the orthorhombic crystal system of yttrium oxyfluoride (Y7O6F9) is not particularly limited, but is generally a diffraction peak attributed to the (171) plane of the crystal lattice. This diffraction peak is usually detected around 2θ = 28.1°.

[0029] The maximum peak in the cubic crystal system of yttrium oxide (Y2O3) is not particularly limited, but is generally a diffraction peak attributed to the (222) plane of the crystal lattice. This diffraction peak is usually detected around 2θ = 29.2°.

[0030] The maximum peak in the orthorhombic crystal system of yttrium fluoride (YF3) is not particularly limited, but is generally a diffraction peak attributed to the (111) plane of the crystal lattice. This diffraction peak is usually detected around 2θ = 27.9°.

[0031] The thermal spray coating of the present invention preferably contains oxygen. The thermal spray coating of the present invention preferably has an oxygen content of 5 atomic percent or more. Since rare earth element fluorides have cleavage properties, thermal spray coatings containing rare earth element fluorides are prone to cracking depending on the thermal spraying conditions. However, if the oxygen content is 5 atomic percent or more, the amount of rare earth element fluorides contained in the thermal spray coating is relatively small, so the occurrence of cracks is suppressed. The oxygen content is more preferably 15 atomic percent or more, even more preferably 20 atomic percent or more, and particularly preferably 25 atomic percent or more.

[0032] On the other hand, the oxygen content is preferably 55 atomic% or less. Rare earth element oxides undergo fluorination during etching with a fluorine-based gas plasma, generating rare earth fluorides or rare earth oxyfluorides. While particle generation is a concern when rare earth fluorides or rare earth oxyfluorides are generated, if the oxygen content is 55 mass% or less, the generation of rare earth fluorides or rare earth oxyfluorides is relatively reduced, thus suppressing particle generation. The oxygen content is more preferably 52 atomic% or less, even more preferably 49 atomic% or less, and particularly preferably 46 atomic% or less.

[0033] The oxygen content of the thermal spray coating can be adjusted by appropriately adjusting the oxygen content of the thermal spray material, the thermal spray atmosphere, plasma gas flow rate, current, voltage, output, thermal spray distance, and raw material supply rate.

[0034] The thickness of the thermal spray coating of the present invention is preferably 10 μm or more, more preferably 20 μm or more, even more preferably 30 μm or more, particularly preferably 40 μm or more, preferably 500 μm or less, more preferably 400 μm or less, even more preferably 300 μm or less, and particularly preferably 200 μm or less.

[0035] The thermal spray coating of the present invention preferably exhibits high uniformity in the composition of each element contained in the thermal spray coating, particularly in the uniformity of the composition within the plane of the film. High uniformity in the composition of the thermal spray coating reduces the areas that are preferentially etched by the gas plasma, thereby suppressing particle generation. Therefore, for each element contained in the thermal spray coating, preferably all elements, the standard deviation σ of the content in the thermal spray coating, particularly the standard deviation σ of the content within the plane of the film, is preferably less than 14. The standard deviation σ is preferably 13 or less, more preferably 12 or less, and even more preferably 11 or less. The thermal spray coating of the present invention is advantageous because, when it contains rare earth element oxyfluorides, particularly when it contains rare earth element oxyfluorides as the main phase, the standard deviation σ of the content in the thermal spray coating is relatively small, even when the oxygen content of the thermal spray coating is relatively high (for example, when the oxygen content is 25 atomic percent or more).

[0036] The thermal spray coating of the present invention preferably has a crack area ratio of less than 1.1%. The lower the crack area ratio, the more the generation of particles originating from cracks that occur during plasma etching can be suppressed. The crack area ratio is preferably 1% or less, more preferably 0.9% or less, and even more preferably 0.8% or less. The crack area ratio can be evaluated, for example, by identifying cracks from an observation image of the film surface of the thermal spray coating using a scanning electron microscope (SEM), measuring the area of ​​the cracks in the observation image, and expressing it as the ratio (percentage) of the crack area to the total area of ​​the observation image. Image analysis software can be used to measure the crack area.

[0037] The thermal spray component of the present invention comprises a substrate and a thermal spray coating formed on the substrate. The thermal spray coating and thermal spray component of the present invention are suitable as components for semiconductor manufacturing equipment. The substrate can be made of a material known as a substrate for thermal spray components. The material of the substrate can be selected from stainless steel, aluminum, nickel, chromium, zinc and their alloys, alumina, aluminum nitride, silicon nitride, silicon carbide, and quartz glass, and a material suitable for the application of the thermal spray component, for example, as a thermal spray component for semiconductor manufacturing equipment, is selected.

[0038] In thermal sprayed components, the thermal spray coating may be formed directly on the substrate or through an undercoat provided between the substrate and the thermal sprayed coating. The undercoat can be formed by thermal spraying. Preferably, the undercoat contains rare earth element oxides.

[0039] The surface roughness of the undercoat film is preferably low. Specifically, in non-contact measurement of the undercoat film surface using a laser, the surface roughness Sa within the evaluation area of ​​the measurement surface (SL surface) of the undercoat film surface is preferably 3 μm or less. The non-contact measurement of the film surface using a laser, the measurement surface (SL surface), and the evaluation area of ​​the undercoat film can be the same as those for the measurement of the film surface of the thermal spray coating of the present invention.

[0040] In the present invention, a thermal spray member can be manufactured by forming a thermal spray coating on a substrate. The method for forming the thermal spray coating of the present invention is not particularly limited, but plasma spraying is preferred. Examples of plasma spraying include atmospheric plasma spraying, small particle (fine particle) plasma spraying, and suspension plasma spraying, but suspension plasma spraying, in which the thermal spraying material (particles) is dispersed in a dispersion medium and sprayed in a slurry form, is more preferred. The thermal spraying material (particles) used to form the thermal spray coating of the present invention is preferably a rare earth element oxyfluoride, or a material containing both a rare earth element oxyfluoride and a rare earth element fluoride. When the thermal spraying material (particles) contains a rare earth element oxyfluoride, or both a rare earth element oxyfluoride and a rare earth element fluoride, the oxygen content of the thermal spraying material (particles) is preferably 1 atomic% or more, more preferably 3 atomic% or more, and also preferably 33 atomic% or less, more preferably 30 atomic% or less.

[0041] In the case of suspension plasma spraying, the average particle size D50 of the spray material (particles) is preferably 1 μm or more, more preferably 3 μm or more, and also preferably 9 μm or less, and more preferably 7 μm or less. Water and organic solvents (e.g., IPA (isopropyl alcohol)) can be used as the dispersion medium. The slurry concentration is preferably 10% by mass or more, more preferably 20% by mass or more, and also preferably 60% by mass or less, and more preferably 50% by mass or less. The slurry viscosity is preferably 1 mPa·s or more, more preferably 3 mPa·s or more, and also preferably 15 mPa·s or less, and more preferably 10 mPa·s or less.

[0042] In plasma spraying, a spray material or slurry containing the spray material is supplied to the formed plasma. By setting one or more conditions, preferably all of them, selected from the current value C, voltage value V, the C / V value obtained by dividing the current value C by the voltage value V, and applied power value P, within a predetermined range, and generating the plasma and performing plasma spraying, the sprayed coating of the present invention, in particular a sprayed coating having a film surface with an area ratio S / A value of 1.75 or more, can be suitably formed.

[0043] In plasma spraying, the current value C applied to plasma formation is preferably 450A or more, more preferably 455A or more, even more preferably 460A or more, and also preferably 1000A or less, more preferably 700A or less.

[0044] In plasma spraying, the voltage value V applied to plasma formation is preferably 20V or higher, more preferably 60V or higher, even more preferably 100V or higher, particularly preferably 140V or higher, and also preferably 235V or lower, more preferably 230V or lower.

[0045] In plasma spraying, the C / V value obtained by dividing the current value C applied to plasma formation by the voltage value V is preferably 1.92 or higher, more preferably 1.95 or higher, even more preferably 1.98 or higher, and also preferably 30 or lower, more preferably 10 or lower, and even more preferably 5 or lower.

[0046] In plasma spraying, the applied power value P used to form the plasma is preferably 20 kW or more, more preferably 60 kW or more, even more preferably 100 kW or more, particularly preferably 102 kW or more, and also preferably 120 kW or less, more preferably 115 kW or less, even more preferably 110 kW or less, particularly preferably 108 kW or less.

[0047] The plasma gas used to form the plasma in plasma spraying includes a mixture of two or more gases selected from argon, hydrogen, helium, and nitrogen. A mixture of three gases, such as argon, hydrogen, and nitrogen, or a mixture of four gases, such as argon, hydrogen, helium, and nitrogen, is more preferred, but is not particularly limited.

[0048] In plasma spraying, the spraying distance is preferably 150 mm or less. As the spraying distance decreases, the rate of film formation of the sprayed coating improves, and the hardness of the sprayed coating increases, and the porosity decreases. The spraying distance is more preferably 120 mm or less, even more preferably 100 mm or less, and particularly preferably 80 mm or less. On the other hand, as the spraying distance increases, the heat load on the substrate can be reduced, so the spraying distance is preferably 30 mm or more, more preferably 40 mm or more, even more preferably 50 mm or more, and particularly preferably 60 mm or more.

[0049] There are no particular restrictions on other spraying conditions in plasma spraying, such as the supply rate of the spray material and the gas supply rate. Known conditions can be applied and should be set appropriately depending on the substrate, spray material, and intended use of the resulting sprayed component.

[0050] In particular, the temperature of the substrate, or the substrate and the undercoat formed on the substrate, during thermal spraying is preferably 300°C or lower, more preferably 250°C or lower, and even more preferably 200°C or lower. Lower temperatures prevent damage and deformation of the substrate and the undercoat formed on the substrate due to heat. Also, lower temperatures suppress the generation of thermal stress. If the temperature is too high, delamination is more likely to occur between the substrate and the thermal spray coating, or between the undercoat formed on the substrate and the thermal spray coating.

[0051] On the other hand, the temperature of the substrate, or the substrate and the undercoat formed on the substrate, during thermal spraying is preferably 50°C or higher, more preferably 60°C or higher, and even more preferably 80°C or higher. If the temperature is too low, the bond between the substrate and the thermal spray coating, or between the undercoat formed on the substrate and the thermal spray coating, may weaken. Also, the higher the temperature, the stronger the bond between splatters, and the denser the thermal spray coating can be formed. The temperature of the substrate, or the substrate and the undercoat formed on the substrate, during thermal spraying can be achieved by controlling the cooling capacity.

[0052] Furthermore, when forming a thermal spray coating directly on the surface of a substrate, increasing the surface roughness of the substrate surface on which the thermal spray coating is formed, and setting the substrate temperature during thermal spraying to the aforementioned temperature, makes it possible to form a thermal spray coating that is more resistant to peeling, harder, and denser. In this case, the surface roughness Sa of the formed thermal spray coating tends to be high, so by lowering the surface roughness Sa through surface processing such as mechanical polishing (surface grinding, inner cylinder processing, mirror polishing, etc.), blasting using micro beads, or manual polishing using a diamond pad, it is possible to obtain a smooth thermal spray coating that is more resistant to peeling, harder, denser, and has a lower surface roughness Sa. [Examples]

[0053] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0054] [Examples 1-8, Comparative Examples 1-5] The surface of a 20mm x 20mm x 2.5mm thick A5052 aluminum alloy substrate was degreased with acetone, and one side of the substrate was roughened by blast polishing with a corundum abrasive of #150 grit. Next, a thermal spray coating was formed directly onto the substrate by suspension plasma spraying using a slurry in which the thermal spray material (particles) was dispersed in a dispersion medium, thereby obtaining a thermal sprayed component. The average particle size D50, oxygen (O) content, and constituent components (XRD crystal phase) of the thermal spray material, as well as the dispersion medium, concentration, and viscosity of the slurry, are shown in Table 1. Note that IPA in the dispersion medium refers to isopropyl alcohol.

[0055] Suspension plasma spraying was performed using a 100HE plasma spraying system (Progressive Surface) and a LiquifeederHE spraying material supply system (Progressive Surface), with argon, hydrogen, and nitrogen gases used as plasma gases, under atmospheric pressure. The plasma formation conditions (current value C, voltage value V, C / V value, and applied power value P) and spraying distance are shown in Table 2.

[0056] [Example 9] The surface of a 20mm x 20mm x 2.5mm thick A5052 aluminum alloy substrate was degreased with acetone, and one side of the substrate was roughened by blast polishing with a corundum abrasive of #150 grit. Next, a base film (100 μm thick) was formed on the substrate by atmospheric plasma spraying using a thermal spray material (particles) consisting of Y2O3 with an average particle size D50 of 9 μm.

[0057] Atmospheric plasma spraying was performed using an Oerlikon Metco F4MB-XL plasma spraying system and an Oerlikon Metco TWIN-120 spray material supply system, with argon and hydrogen gases used as plasma gases, under atmospheric pressure. The plasma formation current was 500A, the voltage 67V, the applied power 34kW, and the spraying distance 75mm.

[0058] Next, a sprayed coating was formed on a substrate-formed undercoat using a slurry in which the spraying material (particles) was dispersed in a dispersion medium by suspension plasma spraying, thereby obtaining a sprayed component. The average particle size D50, oxygen (O) content, and constituent components (XRD crystalline phase) of the spraying material, as well as the dispersion medium, concentration, and viscosity of the slurry, are shown in Table 1.

[0059] Suspension plasma spraying was carried out in the same manner as in Example 1, except that the plasma formation conditions (current value C, voltage value V, C / V value, and applied power value P) were changed. The plasma formation conditions (current value C, voltage value V, C / V value, and applied power value P) and the spraying distance are shown in Table 2.

[0060] [Table 1]

[0061] [Table 2]

[0062] The obtained thermal spray coatings were subjected to surface shape measurements using the following method, and the surface area S, area A, and surface roughness Sa were measured, and the area ratio S / A was calculated. The obtained thermal spray coatings were subjected to the measurement of the content of each element using the following method, and their compositional uniformity was evaluated. The obtained thermal spray coatings were subjected to X-ray diffraction analysis using the following method to obtain X-ray diffraction profiles, identify the contained components, and evaluate them. The thickness of the obtained thermal spray coatings was measured using the following method. Furthermore, the crack area ratio on the surface of the obtained thermal spray coatings was evaluated using the following method. The results are shown in Table 3.

[0063] In Example 9, the surface shape of the obtained undercoat film was measured using the method described below, and the surface roughness Sa was measured. The surface roughness Sa of the undercoat film was 1.9 μm. Furthermore, in Example 9, X-ray diffraction analysis was performed on the obtained undercoat film using the method described below to obtain an X-ray diffraction profile and identify the contained components. The undercoat film contained Y2O3. The measurement and evaluation methods for each are shown below.

[0064] [Table 3]

[0065] [Measurement of surface area S, area A, and surface roughness Sa] In accordance with ISO 25178-2:2021, non-contact laser-based shape measurement of the film surface was performed. A laser microscope VK-X3000 (manufactured by Keyence Corporation) was used for the measurement, and a microscope image was obtained with an objective lens magnification of 50x (total magnification of 1200x). The obtained microscope image was analyzed using the multi-file analysis application attached to the laser microscope VK-X3000. From the obtained measurement surface (SL surface), the surface area S and area A were measured using the volume area measurement function of the same application, and the area ratio S / A was calculated. In addition, the surface roughness Sa was measured from the obtained measurement surface (SL surface) using the surface roughness measurement function of the same application. The region setting was the entire region (the entire microscope image (the range corresponding to area A)). Both the S-filter and L-filter were Gaussian filters, with the S-filter setting value set to 0.8 μm and the L-filter setting value set to 0.5 mm.

[0066] [Measurement of elemental content and evaluation of compositional uniformity] Evaluation samples were prepared by mirror-polishing the thermal spray coating to a surface roughness Sa of 0.2 μm or less. Using a desktop scanning electron microscope (SEM) JCM-7000 (manufactured by JEOL Ltd.), SEM images of the evaluation samples were obtained at a magnification of 1000x. The composition of rare earth elements (R), oxygen (O), and fluorine (F) was analyzed at five arbitrary points on the film surface using the energy-dispersive X-ray spectrometer (EDX) attached to the JCM-7000. The content of each element at each point was obtained from the integrated intensity ratio of the characteristic X-ray peaks specific to each element, and the average value of the five analyzed points was calculated to determine the content of each element in the thermal spray coating. Furthermore, to evaluate compositional uniformity, the standard deviation σ of the content of each element at the five analyzed points was calculated using the n-1 method.

[0067] [X-ray diffraction (identification and evaluation of constituent components)] X-ray diffraction profiles were obtained using the X'Pert PRO / MPD X-ray diffraction analyzer (Malvern Panalytical), and the constituent components (crystalline phases) were identified using the analysis software HighScore Plus (Malvern Panalytical). The measurement conditions were as follows: characteristic X-ray: Cu-Kα (tube voltage: 45kV, tube current: 40mA), scanning range: 2θ = 10~70°, step size: 0.0167113°, time per step: 13.970 seconds, scan speed: 0.151921° / second. The integrated intensity of each diffraction peak was calculated, and the component (crystalline phase) to which the diffraction peak with the maximum integrated intensity belonged was identified as the main phase.

[0068] [Measure the score] The measurement was performed using an eddy current film thickness gauge LH-300J (manufactured by Kett Scientific Research Institute Co., Ltd.).

[0069] [Measurement of crack area ratio] A scanning electron microscope (SEM) JSM-IT500HR (manufactured by JEOL Ltd.) was used to obtain a backscattered electron image of the main surface of the thermal spray coating at a magnification of 5000x. The obtained backscattered electron images were processed using image processing software Adobe Photoshop Elements 8 (manufactured by Adobe Systems) to whiten the cracks so that they would appear white. The scanning electron microscope images (backscattered electron images) of the thermal spray coatings of Examples 1 and 3 and Comparative Examples 1 and 2, after whitening to make the cracks appear white, are shown in Figures 1 to 4, respectively. From Figures 1 to 4, it can be seen that the thermal spray coatings of Examples (Figures 1 and 2) have fewer cracks compared to the Comparative Examples (Figures 3 and 4). Furthermore, the crack area was quantified using the image analysis software ImageJ (public software from the National Institutes of Health) and evaluated as the crack area ratio, which is the percentage of the crack area relative to the total area of ​​the image.

[0070] The crack area ratio was calculated using the following procedure. (1) After depositing platinum (Pt) onto the surface of the obtained thermal spray coating, a backscattered electron image at a magnification of 5000x is taken using a scanning electron microscope (SEM). (2) Using the image processing software Adobe Photoshop Elements 8, the image is whitened so that cracks on the surface of the thermal spray coating can be detected by setting the image threshold in (5) described later. (3) Using the image analysis software ImageJ, specify the area to be processed in the surface photograph and perform cropping. (4) Convert the image to grayscale. (5) As for setting the image thresholds, set the high-level threshold to 255 and the low-level threshold to a value that makes all cracked areas red. (6) Binarize the image. (7) Identify the cracked area. (8) Set the length unit to pixels and calculate the total area (number of pixels) of the cracked portion. (9) Set the image thresholds to 255 for the high-level side and 0 for the low-level side, and calculate the total area (number of pixels) of the image. (10) Calculate the crack area ratio by dividing the total area (number of pixels) of the cracked portion by the total area (number of pixels) of the image.

Claims

1. In non-contact shape measurement of a film surface using a laser, the surface area S (μm²) within one evaluation region of the measurement surface (S-L surface) of the film surface is measured. 2 ) is the area A (μm²) within the one evaluation region of the reference surface, which is a plane located at the height of the arithmetic mean of the measurement surface (S-L surface). 2 A thermal spray coating characterized in that the area ratio S / A obtained by dividing by ) is 1.75 or more and 3 or less, and the surface roughness Sa within the above evaluation area of ​​the measurement surface (S-L surface) is 0.4 μm or more and 8 μm or less.

2. The thermal spray coating according to claim 1, characterized by containing rare earth element oxyfluorides.

3. The rare earth element oxyfluoride is ROF, R 5 O 4 F 7 , R 6 O 5 F 8 and R 7 O 6 F 9 (wherein R represents one or more selected from rare earth elements including Sc and Y). The sprayed coating according to claim 2, characterized in that it is one or more selected from the above.

4. The thermal spray coating according to claim 1, comprising a rare earth element oxyfluoride represented by ROF (wherein R represents one or more rare earth elements selected from Sc and Y), wherein, by X-ray diffraction with Cu-Kα as the characteristic X-ray, the diffraction peak with the maximum integrated intensity among the diffraction peaks detected within the diffraction angle range 2θ = 10 to 70° is the diffraction peak attributed to the ROF.

5. The thermal spray coating according to claim 1, characterized in that it contains oxygen, and the oxygen content is 5 atomic percent or more and 55 atomic percent or less.

6. The thermal spray coating according to claim 1, characterized in that its thickness is 10 μm or more and 500 μm or less.

7. A thermal spray member characterized by comprising a base material and a thermal spray coating according to any one of claims 1 to 6 formed on the base material.

8. The thermal spray member according to claim 7, characterized in that it is a component for semiconductor manufacturing equipment.

9. A method for forming a thermal spray coating according to any one of claims 1 to 6, Using a slurry in which a thermal spray material having an average particle size D50 of 1 μm or more and 9 μm or less is dispersed in a dispersion medium, A process of supplying a slurry containing the above-mentioned spray material to a plasma generated by suspension plasma spraying, with the current value C set to 450A or more and 1000A or less, the voltage value V set to 20V or more and 235V or less, the C / V value obtained by dividing the current value C by the voltage value V set to 1.92 or more and 30 or less, and the applied power value P set to 20kW or more and 120kW or less. A method for forming a thermal spray coating, characterized by including the following:

10. The forming method according to claim 9, characterized in that the thermal spray material contains a rare earth element oxyfluoride, or a rare earth element oxyfluoride and a rare earth element fluoride.

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