Plasma protection composite coating suitable for various base materials and preparation method

Abstract

The invention relates to a plasma protection composite coating suitable for various substrates and a preparation method thereof, and belongs to the technical field of semiconductor manufacturing and surface engineering. The composite coating comprises a first yttrium-containing ceramic coating and a second yttrium-containing ceramic coating which are sequentially deposited on the surface of a base material. The first layer is a micron-structure ceramic layer deposited through a thermal spraying process, the surface roughness of the prepared first layer is reduced to be within 0.5 mu m, and the second layer is a nano-structure ceramic layer deposited through a vacuum cold spraying process. According to the method, the thick film forming capacity of thermal spraying and the compact nanostructure advantage of cold spraying are combined, the yttrium-containing coating is prepared on the surface of the base material through the thermal spraying method, the surface roughness of the base material is reduced to be within 0.5 micrometer, and then the yttrium-containing coating is prepared on the surface of the base material through the vacuum cold spraying method; the prepared composite coating not only has good etching resistance, but also can be suitable for different base materials, and the coating is thin, so that the preparation cost of the coating is greatly reduced.

Description

Technical Field

[0001] This invention relates to the fields of surface engineering and semiconductor manufacturing technology, specifically to a plasma protective composite coating applicable to various substrates and its preparation method. Background Technology

[0002] Plasma etching technology, as one of the key processes in semiconductor manufacturing and display processing, is widely used in various stages such as wafer pattern transfer, metal layer removal, and fine structural engraving. Under the action of plasma, reactive gases (such as CF4, Cl2, O2, etc.) are excited into high-energy ions and active free radicals. These high-energy particles, driven by an electric field, physically bombard and chemically react with the target material, achieving highly selective and anisotropic material removal. During the etching process, components inside the cavity that are in direct contact with the plasma (such as lower electrodes, retaining rings, and sidewall bushings) are inevitably corroded by high-energy particles and reaction byproducts. Especially under high-power plasma and fluorine-based atmospheres, the corrosion rate is accelerated, easily leading to surface erosion, particle shedding, and consequently, wafer defects, equipment contamination, and decreased yield.

[0003] To extend the service life of equipment components, protective coatings, such as yttrium oxide and yttrium aluminum garnet, are widely used to protect critical components from plasma corrosion. These coatings are mostly prepared using thermal spraying methods such as plasma spraying, which have advantages such as fast preparation speed, large thickness, and relatively low cost. However, ceramic coatings formed by thermal spraying usually have large grain size (micrometer level) and high porosity (often above 5%), which makes them prone to forming microcracks, corrosion channels, and particle detachment under long-term etching conditions, reducing their protective ability.

[0004] In contrast, vacuum cold spraying (VCS) technology can deposit coatings using high-speed solid particles at room temperature, avoiding ablation, cracking, or grain coarsening caused by high temperatures. By using nano- or submicron-sized powders, VCS can achieve high-density, low-porosity (<1%) ceramic structures with superior resistance to plasma corrosion and insulation properties. However, VCS technology itself has limitations, such as limited single-layer deposition thickness, insufficient adhesion to certain substrates, high requirements for surface roughness, and inability to form large-area films rapidly. Furthermore, modern plasma equipment uses a variety of substrates, such as ceramics, metals, glass, and their composites, making it difficult for a single process to simultaneously accommodate the physical properties and thermal stress requirements of various substrates. This places higher demands on the interlayer structure design and deposition process combinations of protective coatings.

[0005] Combining the thick-film forming capability of thermal spraying with the dense nanostructure advantages of cold spraying, constructing composite protective coatings with double or multi-layer structures holds promise for solving the corrosion problem of components in high-energy plasma environments. For example, patent CN 110468367 A discloses a method for preparing a protective coating for the surface of key IC equipment components based on plasma spraying and cold spraying technologies. This method uses plasma spraying to first deposit a metal / Y2O3 coating as a transition layer on the substrate, and then uses cold spraying to prepare a high-purity Y2O3 coating on the surface of this first layer, ultimately obtaining a composite coating resistant to plasma etching suitable for metal substrates. However, this method is mainly applicable to metal substrates and suffers from problems such as high coating porosity and rough structure, making it difficult to meet the requirements of plasma etching environments with higher density requirements. Therefore, it is of great significance to develop a protective composite coating that can be applied to different substrates and has good resistance to plasma etching through reasonable design of coating structure and material system. Summary of the Invention

[0006] This invention aims to solve the problems of poor density, insufficient adhesion, high particle release, difficulty in compatibility with various substrates, and the need to improve plasma etching resistance of existing plasma protective ceramic coatings in semiconductor manufacturing and other high-energy plasma environments. It provides a plasma protective composite coating suitable for various substrates and its preparation method.

[0007] This invention constructs a dual-layer coating structure of "thermal spraying + vacuum cold spraying". By adjusting the surface roughness of the thermal spray coating, the bonding strength and plasma etching resistance of the composite coating are further improved. It combines the thick film deposition capability of thermal spraying with the dense nanostructure advantage of cold spraying technology to form a composite ceramic protective coating with good bonding, density and low particle release performance. It is suitable for the protection needs of various substrate components such as ceramics, metals and glass in semiconductor manufacturing equipment.

[0008] To achieve the above objectives, the present invention first provides a plasma protective composite coating applicable to various substrates. The plasma protective composite coating includes a first yttrium-containing ceramic layer and a second yttrium-containing ceramic layer sequentially deposited on the surface of the substrate. The first yttrium-containing ceramic layer is deposited by thermal spraying. After the first yttrium-containing ceramic layer is deposited, a surface pretreatment is performed to make its surface roughness within 0.5 μm. The second yttrium-containing ceramic layer is deposited by vacuum cold spraying.

[0009] In one embodiment of the present invention, the substrate includes, but is not limited to, any one of metal, ceramic and glass, wherein the metal includes, but is not limited to, aluminum, stainless steel and titanium alloy, and the ceramic includes, but is not limited to, alumina and silicon nitride.

[0010] In one embodiment of the present invention, the first yttrium-containing ceramic layer includes, but is not limited to, one or a mixture or composite of two or more of yttrium oxide (Y₂O₃), yttrium aluminum garnet (YAG), and yttrium-doped zirconium oxide (YSZ). The first yttrium-containing ceramic layer primarily provides excellent thermal stability, mechanical strength, and adhesion to the substrate.

[0011] In one embodiment of the present invention, the second yttrium-containing ceramic layer includes, but is not limited to, one or a mixture or composite of two or more of yttrium oxide (Y₂O₃), yttrium fluoride (YF₃), and yttrium oxyfluoride (YOF). The second yttrium-containing ceramic layer mainly serves to directly resist plasma etching, and is required to have high density, low sputtering rate, and excellent chemical inertness.

[0012] In one embodiment of the present invention, the mixture refers to a mixture of two or more materials prepared in a certain proportion. For example, the first yttrium-containing ceramic layer can be selected from any two or three of yttrium oxide, yttrium aluminum garnet, and yttrium oxide-doped zirconium oxide; the second yttrium-containing ceramic layer can be selected from any two or three of yttrium oxide, yttrium fluoride, and yttrium oxyfluoride.

[0013] In one embodiment of the present invention, the composite comprises two or three composites formed by chemical methods. For example, the first yttrium-containing ceramic layer may comprise a composite structure formed by coating a mixture of yttrium oxide, yttrium aluminum garnet, and yttrium oxide-doped zirconium oxide as a coating layer, and coating a mixture of the other two. The second yttrium-containing ceramic layer may comprise a composite structure formed by coating a mixture of yttrium oxide, yttrium fluoride, and yttrium oxyfluoride as a coating layer, and coating a mixture of the other two.

[0014] In one embodiment of the present invention, the material system of the plasma protective composite coating can be customized by using different combinations of first and second layer materials according to the type of etching atmosphere and equipment operating conditions in the specific application environment, in order to achieve targeted protection optimization design. For example, a combination where both the first and second yttrium-containing ceramic layers are yttrium oxide is preferably used in oxygen plasma (O2, Ar / O2) environments of general-purpose dry etching equipment; in the YSZ / Y2O3 combination, YSZ as the bottom layer can enhance thermal shock stability and mechanical support, while Y2O3 provides resistance to chlorine etching, and is preferably used in chlorine-based etching atmospheres such as Cl2 and BCl3; in the YSZ / YF3 combination, YSZ enhances the thermodynamic stability of the entire coating, while YF3 as the outer layer has excellent chemical stability and low sputtering rate, and is preferably used in fluorine plasma etching such as NF3, SF6, or CF4 under high-power, long-term continuous operation conditions; the YAG / YOF combination is preferably used in CF4 / O2 mixed plasma environments of high-density plasma equipment.

[0015] By combining various materials, a suitable composite coating structure can be flexibly selected according to the specific equipment type, process parameters (gas type, temperature, etching power, etc.) and life requirements, thereby achieving customization and optimization of plasma protection performance.

[0016] In one embodiment of the present invention, the thickness of the first yttrium-containing ceramic layer is 5~50 μm, the grain size is 0.1~5 μm, and the coating porosity is less than 10%. This layer has good thick film coverage and primary corrosion resistance, which is beneficial to improving the bonding strength and mechanical stability with the substrate.

[0017] In one embodiment of the present invention, the thermal spraying method includes, but is not limited to, at least one of atmospheric plasma spraying (APS), vacuum plasma spraying (VPS), or suspension plasma spraying (SPS).

[0018] In one embodiment of the present invention, the surface pretreatment includes, but is not limited to, polishing or mechanical finishing.

[0019] In one embodiment of the present invention, after surface pretreatment, the surface roughness Ra of the first yttrium-containing ceramic layer is 0.02~0.5 μm.

[0020] In one embodiment of the present invention, the second yttrium-containing ceramic layer is a nanostructured yttrium-containing ceramic layer deposited using a vacuum cold spraying process, with a thickness of 1~10 μm, a grain size of 10~100 nm, and a porosity of less than 1%. This layer has a dense structure, high insulation, and excellent plasma protection capability and low particle release performance.

[0021] In one embodiment of the present invention, before depositing the first yttrium-containing ceramic layer on the substrate surface, a step of sandblasting pretreatment of the substrate is further included. After sandblasting pretreatment, the surface roughness Ra of the substrate is 1~20 μm. Sandblasting pretreatment can enhance the bonding force between the first layer and the substrate.

[0022] In one embodiment of the present invention, after depositing the second yttrium-containing ceramic layer, the composite coating may be heat-treated as needed. The heat treatment temperature is 200~800 ℃ and the treatment time is 1~10 hours to enhance the interlayer bonding force, release residual stress and optimize the microstructure.

[0023] This invention also discloses a method for preparing a plasma-protective composite coating suitable for various substrates, comprising the following steps: (1) A first yttrium-containing ceramic layer is prepared on the surface of a substrate using a thermal spraying method; (2) The first yttrium-containing ceramic layer obtained in step (1) is subjected to surface pretreatment. After pretreatment, the surface roughness of the first yttrium-containing ceramic layer is below 0.5 μm. (3) A second yttrium-containing ceramic layer is deposited on the surface of the first yttrium-containing ceramic layer after pretreatment in step (2) using a vacuum cold spraying method.

[0024] In one embodiment of the present invention, before depositing the first yttrium-containing ceramic layer in step (1), a step of pre-treating the substrate by sandblasting is further included. After sandblasting pre-treatment, the surface roughness Ra of the substrate is 1~20 μm. Sandblasting pre-treatment can enhance the bonding force between the first layer and the substrate.

[0025] In one embodiment of the present invention, the thermal spraying can be selected from atmospheric plasma spraying. During spraying, the plasma gun power is preferably 30~50 kW, the powder feeding rate is 5~50 g / min, the deposition thickness is 5~50 μm, the porosity is less than 10%, and the particle size D50 of the yttrium-containing ceramic powder is 5~50 μm.

[0026] In one embodiment of the present invention, the thermal spraying can be selected from the suspension plasma spraying process. The plasma gun power is preferably 30~60 kW, the particle size D50 of the yttrium ceramic powder is 0.2~2 μm, the deposition thickness is 5~50 μm, and the porosity is less than 10%.

[0027] In one embodiment of the present invention, the surface pretreatment in step (2) includes, but is not limited to, polishing or mechanical finishing. After the surface pretreatment, the surface roughness Ra of the first yttrium-containing ceramic layer is 0.02~0.5 μm, preferably 0.02~0.4 μm.

[0028] In one embodiment of the present invention, during the vacuum cold spraying in step (3), the particle size D50 of the yttrium-containing ceramic is 0.1~5 μm, the working gas is nitrogen, the spraying distance is 3~20 mm, the powder feeding rate is 0.1~5 g / min, the deposition thickness is 1~10 μm, and the porosity is less than 1%.

[0029] In one embodiment of the present invention, step (3) further includes a heat treatment step of the second yttrium-containing ceramic layer, wherein the heat treatment temperature is 200~800 °C, the treatment time is 1~10 hours, and the heat treatment is carried out in an air atmosphere.

[0030] Beneficial effects: (1) Most of the coatings commonly used to prevent plasma etching are prepared by thermal spraying. Although thermally sprayed coatings have good etching resistance, they are prone to forming microcracks, corrosion channels and particle shedding under long-term etching conditions, which leads to a decrease in their protective ability. In addition, thermally sprayed protective coatings rely on a thicker coating thickness, which increases the cost of coating preparation. Although vacuum cold spraying technology can also obtain plasma protective coatings with good performance, vacuum cold spraying technology itself has many limitations, such as poor adhesion to some substrates. This invention combines the thick film forming capability of thermal spraying with the dense nanostructure advantage of cold spraying. First, a yttrium-containing coating is prepared on the substrate surface using thermal spraying, and the surface of the yttrium-containing coating is pretreated to reduce its surface roughness to within 0.5 μm. Then, a yttrium-containing coating is prepared on its surface using vacuum cold spraying. The resulting composite coating not only has good etching resistance but is also suitable for different substrates. The composite coating of this invention can achieve good performance on various commonly used substrates. Moreover, the coating of this invention is thin, which greatly reduces the coating preparation cost.

[0031] (2) The preparation of the second yttrium-containing ceramic layer in this invention is highly dependent on the roughness of the first yttrium-containing ceramic layer. Specifically, a higher roughness of the first yttrium-containing ceramic layer will reduce the bonding strength and etching resistance of the second yttrium-containing ceramic layer. This invention uses polishing or mechanical finishing to pre-treat the surface of the first yttrium-containing ceramic layer, reducing its roughness to within 0.5 μm, which greatly increases the bonding strength and density of the second yttrium-containing ceramic layer, thereby improving the etching resistance of the composite coating.

[0032] (3) In this invention, yttrium oxide, yttrium aluminum garnet, yttrium oxide doped zirconium oxide and other materials are selected as the materials of the first yttrium-containing ceramic layer, which can increase the bonding ability between the first yttrium-containing ceramic layer and the substrate and improve the overall thermal shock resistance and mechanical stability.

[0033] (4) This invention prepares a nano-ceramic coating with low porosity and high density by controlling the vacuum cold spraying process. This coating can effectively inhibit the penetration of corrosive gases and plasma bombardment, and improve the overall protection performance. In addition, the composite structure of this invention has strong adaptability and can be applied to a variety of materials such as metals, ceramics and glass to achieve high reliability integrated protection. The surface nanostructure is dense and crack-free, which can greatly reduce particle release and meet the cleanliness requirements of chips below 10 nm and large-size display processes. It has strong process compatibility and is suitable for the protection of key components in equipment in highly corrosive environments such as plasma etching, deposition and ashing, and has broad industrial application prospects. Attached Figure Description

[0034] Figure 1This is a schematic diagram of the plasma-protective double-layer composite coating structure prepared in Example 1, where 1 is the substrate, 2 is the composite coating, 21 is the first yttrium-containing ceramic layer prepared by thermal spraying, and 22 is the second yttrium-containing ceramic layer prepared by vacuum cold spraying. Detailed Implementation

[0035] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0036] Example 1: A plasma-protected double-layer composite coating 2 is constructed on an aluminum alloy substrate. The composite coating includes a first yttrium oxide coating 21 and a second yttrium oxide coating 22 deposited sequentially on the aluminum substrate 1. The first yttrium oxide coating 21 is deposited by atmospheric plasma spraying, with a thickness of 30 μm, a porosity of 8%, and an average grain size of 0.3 μm. After the first yttrium oxide is deposited, its surface is finely polished to make its surface roughness 0.1 μm. The second yttrium oxide coating 22 is deposited by vacuum cold spraying, with a thickness of 5 μm, a porosity of 0.5%, and an average grain size of 22 nm.

[0037] A method for constructing a plasma-protective composite coating 2 on the surface of an aluminum alloy substrate 1 includes the following steps: The substrate is made of 6061 aluminum alloy, and the surface roughness Ra is 15 μm after sandblasting. The first yttrium oxide coating 21 is applied using atmospheric plasma spraying, with 99.9% pure yttrium oxide powder (D50 = 30 μm) as the spraying material. The plasma gun power is 40 kW, the powder feed rate is 10 g / min, the deposition thickness is 30 μm, and the porosity is 8%. The surface of the first sprayed coating is then finely polished to reduce the roughness to Ra = 0.1 μm. The second yttrium oxide coating 22 is applied using vacuum cold spraying, with ultrafine yttrium oxide powder (D50 = 0.5 μm) sprayed using nitrogen as the working gas. The spraying distance is 10 mm, the powder feed rate is 2 g / min, the deposition thickness is approximately 5 μm, and the porosity is less than 0.5%. Subsequently, heat treatment is performed in an air atmosphere at a temperature of 800 ℃ for 1 hour to improve the interlayer bonding and structural density.

[0038] The etching test was conducted for 8 hours in a CF4 / O2 plasma atmosphere (power 1000 W). The results showed that there were no visible cracks or particle detachment on the coating surface, the etching rate was 3 nm / min, and the breakdown voltage exceeded 50 kV / mm.

[0039] Example 2: A composite coating of yttrium aluminum garnet (YAG) and yttrium oxide (YO) was constructed on an alumina ceramic substrate. The composite coating consisted of a YAG coating deposited sequentially on the aluminum substrate. The YAG coating was deposited by suspension plasma spraying with a thickness of 20 μm, a porosity of 8%, and an average grain size of 150 nm. After the deposition of the first YO, its surface was finely polished to achieve a surface roughness of 0.1 μm. The first YO coating was deposited by vacuum cold spraying with a thickness of 5 μm, a porosity of 0.5%, and a grain size of 24 nm.

[0040] A method for constructing a plasma-resistant composite coating on a ceramic substrate includes the following steps: Sintered alumina ceramic sheets were used as the substrate, and the surface roughness Ra after sandblasting was 10 μm. The first layer was coated with yttrium aluminum garnet ceramic powder (D50 = 2 μm) using a suspension plasma spraying process. The plasma gun power was 40 kW, the deposition thickness was 20 μm, and the porosity was 5%. After polishing, the surface roughness was reduced to Ra ≈ 0.08 μm. The second layer was coated with yttrium oxide powder (D50 = 0.5 μm) using vacuum cold spraying. The working gas was nitrogen, the spraying distance was 10 mm, the thickness was 5 μm, and the porosity was 0.5%.

[0041] The coating remained intact without peeling after 8 hours of etching under a CF4 / O2 plasma atmosphere (1000 W power), with an etching rate of 2.6 nm / min.

[0042] Example 3: Using a quartz glass substrate as the base material, low-pressure sandblasting was first employed to achieve a surface roughness Ra of approximately 3 μm. The first layer was a yttrium oxide ceramic layer, deposited using suspension plasma spraying technology. The spraying material was yttrium oxide powder with a ceramic particle size D50 of 0.2 μm, a plasma gun power of 38 kW, a coating thickness of 5 μm, and a porosity of 4%. Subsequently, the surface of this layer was mechanically polished to control its surface roughness at Ra ≈ 0.09 μm.

[0043] The second layer is a yttrium oxide layer deposited by vacuum cold spraying, using submicron-sized powder (D50 = 0.4 μm), a powder feed rate of 1.8 g / min, a spraying distance of 10 mm, nitrogen as the working gas, a deposition thickness of approximately 3 μm, and a porosity of 0.5%. The overall surface of the composite coating is smooth and dense, with good adhesion, and no visible delamination or bubbles.

[0044] After etching for 8 hours in a CF4 / O2 atmosphere (1000 W) plasma, the coating showed no cracks or peeling, with an etching rate of 3.1 nm / min, demonstrating excellent adhesion and resistance to plasma corrosion.

[0045] Example 4: The difference between Example 4 and Example 1 is that the surface roughness of the first yttrium-containing ceramic layer is different.

[0046] The first layer uses 99.9% pure yttrium oxide powder (D50 = 30 μm), and yttrium oxide ceramic is sprayed by atmospheric plasma. The thickness is 30 μm and the porosity is about 8%. After preliminary mechanical grinding, the surface is finely finished so that the final surface roughness is controlled at Ra = 0.4 μm.

[0047] The second layer of yttrium oxide was applied using vacuum cold spraying, with ultrafine powder (D50 = 0.5 μm) deposited to a thickness of 6 μm and a porosity of 0.4%. This moderately increased surface roughness of the first layer helps provide more mechanical anchoring points, thereby enhancing interlayer bonding strength without significantly sacrificing interface smoothness.

[0048] In the CF4 / O2 plasma etching test, the coating was stable and defect-free, with an etching rate of 3.3 nm / min, demonstrating good structural stability and process adjustability.

[0049] Example 5: The difference between Example 5 and Example 1 is that the thickness and density of the first yttrium oxide ceramic layer and the second yttrium oxide ceramic layer are different.

[0050] The first layer is a yttrium oxide ceramic layer, applied using atmospheric plasma spraying technology. The sprayed powder has a D50 of 20 μm, increasing the deposition thickness to 50 μm while controlling the porosity at 6%. The spray gun power is 45 kW, and the powder feed rate is 12 g / min. After spraying, polishing is performed to reduce the surface roughness Ra to 0.2 μm.

[0051] The second layer is deposited using vacuum cold spraying with yttrium oxide powder (D50 = 0.5 μm) at a thickness of 10 μm and a powder feed rate of 2 g / min. The porosity is as low as 0.6%. After heat treatment at 800 °C in air for 1 hour, the overall density and interlayer bonding of the composite coating are further enhanced.

[0052] In a continuous etching test for 12 hours (CF4 / O2 plasma, 1000 W), the etching rate decreased to 2.4 nm / min, the breakdown voltage exceeded 60 kV / mm, and no structural damage was observed, demonstrating excellent high-load durability performance.

[0053] Comparative Example 1: A single-layer yttrium oxide coating deposited on an aluminum alloy substrate using APS This comparative example serves as a comparison to demonstrate a method for constructing a single-layer yttrium oxide coating on an aluminum alloy substrate.

[0054] The substrate is made of 6061 aluminum alloy. After sandblasting, the surface roughness Ra is about 13 μm. The first coating layer is applied using atmospheric plasma spraying. The spraying material is yttrium oxide powder (D50 = 30 μm). The plasma gun power is 40 kW, the powder feed rate is 10 g / min, the deposition thickness is about 40 μm, and the porosity is 8%.

[0055] After 8 hours of etching under a CF4 / O2 plasma atmosphere (power 1000 W), multiple cracks and particle peeling appeared on the surface. The etching rate was approximately 18 nm / min, and the breakdown voltage was <30 kV / mm.

[0056] Comparative Example 2: The substrate was made of 6061 aluminum alloy, and the surface roughness Ra after sandblasting was 13 μm. The first layer of yttrium oxide ceramic coating was deposited using atmospheric plasma spraying, with a powder particle size D50 of 30 μm, a spray gun power of 40 kW, a powder feed rate of 10 g / min, a coating thickness of approximately 30 μm, and a porosity of 8%. No surface polishing was performed after deposition, and the tested surface roughness Ra was approximately 6 μm.

[0057] Subsequently, a second yttrium oxide coating was deposited directly on the surface. The powder had a D50 of 0.5 μm and a thickness of approximately 5 μm. The vacuum cold spraying parameters were the same as in Example 1, and the coating porosity was approximately 0.8%. Numerous micron-sized pit-like defects were observed on the coating surface. This was because the second coating layer was only 5 μm thick, and the micron-sized pit-like defects on the surface of the first coating layer were transferred to the surface of the second coating layer.

[0058] After 8 hours of CF4 / O2 plasma (1000 W power) etching test, the composite coating showed multiple interface peelings and local particle disintegration. The etching rate was 14 nm / min and the breakdown voltage was about 34 kV / mm, which was significantly worse than Example 1.

[0059] Comparative Example 3: The substrate was 6061 aluminum alloy, and the surface roughness Ra after sandblasting was approximately 13 μm. The parameters of the first yttrium oxide coating were the same as in Example 1 (30 μm thickness, 8% porosity). After spraying, only light polishing was performed, and the final surface roughness Ra was measured to be 0.7 μm.

[0060] The vacuum cold spraying process parameters are the same as in Example 1, with the second yttrium oxide layer having a thickness of 5 μm and a porosity of 0.5%.

[0061] After 8 hours of CF4 / O2 plasma etching test, some microcracks appeared in the coating, with an etching rate of 8.6 nm / min and a breakdown voltage of only 38 kV / mm.

[0062] Comparative Example 4: The preparation method of the substrate and the first yttrium oxide coating is the same as in Example 1. The thickness of the first yttrium oxide coating is 30 μm, the porosity is 8%, and the surface is polished to Ra = 0.1 μm by standard polishing.

[0063] During the second layer of vacuum cold spraying, the spraying distance was increased to 25 mm to reduce the particle impact velocity, resulting in insufficient compaction of the sprayed particles and an increase in porosity to approximately 2.0%. The deposition thickness was 5 μm, and the remaining parameters were the same as in Example 1.

[0064] Eight hours after CF4 / O2 plasma etching, some particles detached from the coating surface, the etching rate increased significantly to 6.8 nm / min, and the breakdown voltage decreased to 41 kV / mm.

[0065] Table 1 Summary of Results of Examples and Comparative Examples

[0066] Table 1 presents the test results of coating parameters, etching resistance, and breakdown voltage of the composite coatings in the examples and comparative examples. From Table 1 and the test results of each example, it can be seen that the composite coating and preparation method of the present invention are applicable to metal, ceramic, and glass substrates. That is, when the composite coating is prepared on the surface of metal, ceramic, and glass substrates using the method of the present invention, no coating cracking or particle detachment occurs. Furthermore, even with extremely thin composite coatings (as low as 8 μm), good plasma etching resistance (etching rate as low as 3.1 nm / min) can be obtained, significantly reducing the preparation cost of the composite coating. In the present invention, the surface roughness of the first yttrium-containing ceramic layer seriously affects the bonding and etching resistance between the second yttrium-containing ceramic layer and the first coating. Specifically, when the surface roughness of the first yttrium-containing ceramic layer is large, it is difficult to make the second yttrium-containing ceramic layer thin. A thinner surface coating has poor bonding strength with the first yttrium-containing ceramic layer, resulting in poor etching resistance. While increasing the thickness of the second yttrium-containing ceramic layer can overcome the above problems, the preparation cost will increase significantly. In addition, the preparation process of the second yttrium-containing ceramic layer will significantly affect the density of the composite coating, and at the same time affect the etching resistance of the composite coating.

[0067] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A plasma shielding composite coating suitable for a variety of substrates, characterized in that, The plasma protection composite coating comprises a first yttrium-containing ceramic layer and a second yttrium-containing ceramic layer deposited on the surface of the substrate in sequence, the first yttrium-containing ceramic layer is deposited by a thermal spraying method, the surface of the first yttrium-containing ceramic layer is pretreated after deposition, so that the surface roughness is within 0.5 μm, and the second yttrium-containing ceramic layer is deposited by a vacuum cold spraying method.

2. The plasma shielding composite coating of claim 1, wherein, The substrate comprises any one of metal, ceramic and glass, the metal comprises any one of aluminum, stainless steel and titanium alloy, and the ceramic comprises alumina or silicon nitride.

3. The plasma shielding composite coating of claim 1, wherein, The thickness of the first yttrium-containing ceramic layer is 5-50 μm, the grain size is 0.1-5 μm, and the coating porosity is less than 10%.

4. The plasma shielding composite coating of claim 1, wherein, The first yttrium-containing ceramic layer comprises at least one of yttrium oxide, yttrium aluminum garnet and yttrium oxide doped zirconia.

5. The plasma shielding composite coating of claim 1, wherein, The surface pretreatment comprises polishing or mechanical finishing treatment, and the surface roughness Ra of the first yttrium-containing ceramic layer after the surface pretreatment is 0.02-0.5 μm.

6. The plasma shielding composite coating of claim 1, wherein, The second yttrium-containing ceramic layer is a nanostructured yttrium-containing ceramic layer deposited by a vacuum cold spraying process, the thickness is 1-10 μm, the grain size is 10-100 nm, and the porosity is less than 1%.

7. The plasma shielding composite coating of claim 1, wherein, The second yttrium-containing ceramic layer comprises at least one of yttrium oxide, yttrium fluoride, yttrium oxyfluoride and yttrium aluminum garnet.

8. A method for producing the plasma protective composite coating suitable for a variety of substrates according to any one of claims 1 to 7, characterized in that, The method comprises the following steps: (1) preparing a first yttrium-containing ceramic layer on the surface of the substrate by a thermal spraying method; (2) polishing or mechanically finishing the first yttrium-containing ceramic layer obtained in step (1), and the surface roughness Ra of the first yttrium-containing ceramic layer after the treatment is 0.02-0.5 μm; (3) depositing a second yttrium-containing ceramic layer on the surface of the first yttrium-containing ceramic layer pretreated in step (2) by a vacuum cold spraying method.

9. The production method according to claim 8, characterized by, Before step (1) of depositing the first yttrium-containing ceramic layer, a step of sandblasting pretreatment of the substrate is further included, and the surface roughness Ra of the substrate after the sandblasting pretreatment is 1-20 μm.

10. The production method according to claim 8, characterized by, Step (3) further comprises a step of heat treatment of the composite coating, the heat treatment temperature is 200-800 ℃, the treatment time is 1-10 hours, and the heat treatment is carried out in an air atmosphere.

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