Spraying process of compact yttrium oxide coating

Abstract

The invention relates to the technical field of coating preparation, in particular to a spraying process of a compact yttrium oxide coating, which comprises the steps of pretreatment, powder activation, matrix surface modification, meltallizing spraying, cooling curing, de-shielding treatment and post-cleaning. Yttrium oxide powder is activated through low-temperature plasma, sand blasting parameters and a high velocity oxy-fuel spraying process are optimized, the porosity of the coating is remarkably reduced to 1.5% or below, and the hardness is improved to 500 HV0.3. Internal stress is reduced in a sectional cooling mode, and balance of coating performance and economical efficiency is achieved in combination with a parameter optimization algorithm based on particle deposition dynamics. The preparation method can meet the requirement of the high-end semiconductor manufacturing field on a high-performance protective coating, and solves the problem of high porosity of a traditional process.

Description

Technical Field

[0001] The invention belongs to the technical field of material surface treatment, and in particular relates to a spraying process for a dense yttrium oxide coating. Background Art

[0002] In the semiconductor manufacturing field, yttrium oxide coatings are widely used to protect the inner walls of etching chambers due to their excellent chemical stability, high-temperature resistance, and outstanding resistance to plasma corrosion. In particular, in dry etching processes, fluorine plasma has a strong corrosive effect on the inner wall materials of the chamber, and yttrium oxide coatings can effectively resist this corrosion, thereby significantly extending the service life of equipment components and reducing the impact of particle contamination on wafer yield. However, the existing yttrium oxide coating spraying process still has significant shortcomings in achieving high density and low porosity, which directly restricts its application in high-end semiconductor manufacturing.

[0003] While traditional spraying processes, such as atmospheric plasma spraying and thermal spraying, can produce yttrium oxide coatings with certain performance characteristics, they generally suffer from high porosity. Studies have shown a significant correlation between coating porosity and etching rate. The higher the porosity, the easier it is for fluorine plasma to penetrate the pores in the coating and reach the substrate, accelerating corrosion of the substrate and significantly reducing the coating's service life and corrosion resistance. Therefore, reducing porosity has become a key technical approach to improving the etching resistance of yttrium oxide coatings.

[0004] In the prior art, patent publication number CN106591820B proposes a method for preparing high-purity yttrium oxide coatings based on cold spraying technology. This method reduces the heat input to the substrate through a lower spraying temperature, resulting in a coating with stable quality and uniform thickness. However, cold spraying technology is limited by powder particle size and spraying speed, and its coverage ability on complex structure surfaces is poor. In addition, tiny pores may still exist within the coating, making it difficult to fully meet the extremely high density requirements of advanced processes. In addition, the high cost of cold spraying equipment is not conducive to large-scale industrial application. Another patent publication number CN119411055B proposes a method for reducing the porosity of the coating by mixing yttrium oxide powder with YAG (yttrium aluminum garnet) powder. This method improves the coating delivery state by optimizing the powder particle size and dispersibility, but it requires simultaneous control of the ratio of the two different materials and their melting behavior, which can easily lead to new defects due to insufficient melting of the yttrium oxide powder or overburning of the YAG powder. In addition, this method has high requirements on the quality of raw material powder, which increases the difficulty and cost of preparation, and fails to fundamentally solve the porosity problem of single yttrium oxide coating in extreme environments.

[0005] In summary, the existing yttrium oxide coating spraying process still has obvious deficiencies in terms of density, process adaptability and production cost. Especially in the field of high-end semiconductor manufacturing, with the continuous reduction of process nodes and the increasing requirements for wafer yield, the demand for high-performance protective coatings is becoming more and more urgent. It is urgent to develop a new spraying process that can significantly reduce the porosity of the coating while enhancing its plasma corrosion resistance, and taking into account the operability and economy of the process. In response to the above technical difficulties, the present invention proposes a spraying process for dense yttrium oxide coating, which aims to achieve a significant improvement in the density of the coating by optimizing the spraying parameters and powder processing methods to meet the needs of high-end application scenarios. Summary of the Invention

[0006] The object of the present invention is to provide a spraying process for a dense yttrium oxide coating to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a spraying process for a dense yttrium oxide coating, comprising the following steps:

[0008] In the pre-processing step, high-resolution laser scanners and infrared thermal imaging technology are used to record the surface of the processed parts from multiple angles;

[0009] A powder activation step involves placing the yttrium oxide powder in a plasma chamber, controlling the chamber temperature at 80 to 100 degrees Celsius, a plasma power at 150 to 200 watts, and a treatment time of 10 to 15 minutes;

[0010] In the substrate surface modification step, silicon carbide sand with a particle size of 80 mesh is used as a sandblasting material, the sandblasting pressure is 0.6 to 0.8 MPa, the spray gun is 18 to 22 cm away from the workpiece surface, and the spray gun angle is 75 to 85 degrees; in the melt spraying step, supersonic flame spraying equipment is used for spraying, the gas flow rate is 50 to 60 standard cubic centimeters per minute of argon and 5 to 12 standard cubic centimeters per minute of hydrogen, the powder feed rate is 10 to 25 grams per minute, the spraying distance is 120 to 150 mm, and the flame temperature is 2800 to 3200 degrees Celsius; in the cooling and curing step, the temperature of the initial cooling stage is controlled at 200 to 300 degrees Celsius for 5 to 10 minutes, followed by a natural cooling stage until the coating temperature drops to room temperature;

[0011] Demasking step, removing the high temperature tape and using a water gun and ultrasonic cleaning operation to remove the coating surface residue;

[0012] In the final cleaning step, the entire part is thoroughly cleaned to ensure that there is no residue on the coating surface.

[0013] Preferably, in the pretreatment step, the surface roughness value Ra of the part to be processed is 4.2 μm.

[0014] Preferably, in the powder activation step, the plasma chamber temperature is 90 degrees Celsius, the power is 180 watts, and the processing time is 12 minutes.

[0015] Preferably, in the substrate surface modification step, the sandblasting pressure is 0.7 MPa, the spray gun distance is 20 cm, the spray gun angle is 80 degrees, and the surface roughness value Ra is 3.0 μm.

[0016] Preferably, in the melt spraying step, the gas flow rate is 55 standard cubic centimeters per minute of argon and 8 standard cubic centimeters per minute of hydrogen, the powder feeding rate is 20 grams per minute, the spraying distance is 130 mm, and the flame temperature is 3000 degrees Celsius.

[0017] Preferably, in the cooling and solidification step, the temperature of the initial cooling stage is 250 degrees Celsius and the duration is 8 minutes.

[0018] Preferably, in the demasking step, the pressure of the steam gun is 0.4 MPa, the ultrasonic cleaning frequency is 40 kHz, and the cleaning time is 10 minutes.

[0019] Preferably, in the post-cleaning step, the same cleaning parameters as those used in the demasking process are used.

[0020] Preferably, the coating porosity is given by the formula It is calculated that Q represents the coating porosity, C represents the gas flow coefficient, V represents the powder feeding rate, T represents the flame temperature, D represents the spraying distance, and R represents the surface roughness of the substrate.

[0021] Compared with existing technologies, this invention significantly reduces coating porosity and improves plasma corrosion resistance by optimizing spray parameters and process flow, meeting the demand for high-performance protective coatings in high-end semiconductor manufacturing. This technical solution not only addresses the high porosity problem inherent in traditional processes but also improves process adaptability and cost-effectiveness through rational parameter design, providing strong support for technological development in related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the process for spraying a dense yttrium oxide coating according to the present invention;

[0023] Figure 2 This is a SEM photograph of the cross-sectional morphology of the yttrium oxide coating prepared in the present invention at 200 times magnification;

[0024] Figure 3 This is a SEM photograph of the cross-sectional morphology of the yttrium oxide coating prepared in the present invention at 500 times magnification. DETAILED DESCRIPTION

[0025] The present invention provides a spraying process for a dense yttrium oxide coating. Figure 1 To the attached Figure 3 For detailed description. Figure 1 As shown, the process flow of the present invention includes seven main steps: pretreatment, powder activation, substrate surface modification, melt spraying, cooling and solidification, demasking, and post-cleaning. These steps together constitute a complete dense yttrium oxide coating spray process system. The following will be combined with specific examples to fully describe these steps and their operating principles and processes.

[0026] As attached Figure 1 As shown, the process flow of the present invention includes seven main steps: pretreatment, powder activation, substrate surface modification, melt spraying, cooling and solidification, deshielding treatment and post-cleaning. These steps together constitute a complete dense yttrium oxide coating spraying process system. First, in the pretreatment stage, it is necessary to conduct a comprehensive inspection of the parts to be processed, and use a high-resolution laser scanner in conjunction with infrared thermal imaging technology to record surface defects from multiple angles. This process can accurately capture micron-level cracks, pits and corrosion areas, providing an important reference basis for subsequent substrate surface modification. For example, in a certain actual application, through scanning and analysis of complex curved surface parts, it was found that its surface roughness value Ra = 4.2μm, and the sandblasting parameters need to be further optimized to improve surface adhesion.

[0027] After the powder activation stage, the yttrium oxide powder is surface-modified using low-temperature plasma technology. The yttrium oxide powder is placed in a plasma chamber, where the chamber temperature is controlled at 80-100°C, the plasma power is 150-200W, and the treatment time is 10-15 minutes. This process effectively removes adsorbed impurities from the powder surface and forms active groups on the surface, thereby improving the powder's melting efficiency during the spraying process. Experimental data shows that the melting point of the yttrium oxide powder after plasma activation increases by approximately 20%, significantly improving the density of the coating.

[0028] Then, the substrate surface modification stage is entered. Silicon carbide sand with a particle size of 80 mesh is selected as the sandblasting material, and the sandblasting pressure is strictly controlled to 0.6-0.8 MPa, the spray gun is 18-22 cm away from the workpiece surface, the spray gun angle is 75°-85°, and the sandblasting time is determined according to the size of the component. The choice of sandblasting pressure directly affects the impact force of the sand material on the workpiece surface. Too low a pressure cannot effectively remove the surface oxide layer, while too high a pressure may cause excessive roughening of the workpiece surface. In particular, the control of the spray gun angle can ensure that the sand material particles hit the workpiece surface at the optimal incident angle, improving the roughening effect while reducing damage to the substrate. For example, in a specific embodiment, when the sandblasting pressure is set to 0.7 MPa, the spray gun distance is 20 cm, and the spray gun angle is 80°, an ideal surface roughness value Ra = 3.0 μm is obtained, providing a good adhesion foundation for subsequent melt spraying.

[0029] After the substrate surface modification is completed, the melt spraying stage begins, using a supersonic flame spraying device. Key process parameters include gas flow rates of 50-60 sccm Ar and 25-12 sccm H, a powder feed rate of 10-25 g / min, a spray distance of 120-150 mm, and a flame temperature of 2800-3200°C. Ar, as the primary gas, maintains flame stability, while H2, as the auxiliary gas, adjusts the flame's thermal efficiency, ensuring that the sprayed particles are fully molten before deposition. Furthermore, precise matching of the powder feed rate and spray distance effectively controls the uniformity of particle deposition. For example, in one specific embodiment, when the gas flow rates are set to 55 sccm Ar and 8 sccm H, a powder feed rate of 20 g / min, and a spray distance of 130 mm, the yttrium oxide coating produced has a uniform thickness and a porosity of less than 1.5%. This result demonstrates that this parameter combination can improve process operability and cost-effectiveness while maintaining coating quality.

[0030] After spraying, the coating enters the cooling and solidification phase, using a segmented cooling method. The initial cooling phase is controlled at 200-300°C for 5-10 minutes, followed by a natural cooling phase until the coating temperature drops to room temperature. This segmented cooling method effectively avoids internal stress concentration caused by rapid cooling, thereby improving the coating's mechanical properties and crack resistance. Experimental results show that the coating hardness after this step reaches 500HV0.3, meeting the stringent requirements of high-end semiconductor manufacturing.

[0031] Next, the demasking stage involves removing the high-temperature tape and using a water jet and ultrasonic cleaning to remove any residue from the coating surface. This two-step cleaning process begins with a water jet to remove large particles of impurities adhering to the surface. Ultrasonic cleaning then further removes fine particles, ultimately resulting in a clean and smooth coating surface. Experimental results show that this treatment significantly improves the surface cleanliness of the coating, meeting the high-performance protective coating requirements of high-end semiconductor manufacturing.

[0032] Finally, the post-cleaning stage thoroughly cleans the entire component to ensure that no residue remains on the coating surface. The air-water gun and ultrasonic equipment used in this cleaning process are both standard industrial equipment, simple to operate and low-cost, making them suitable for large-scale industrial applications.

[0033] The technical solution of the present invention significantly reduces the porosity of the coating and improves the mechanical properties and chemical stability of the coating by introducing low-temperature plasma powder activation technology and a segmented cooling process. Experimental results show that the porosity of the coating can be reduced to below 1.5%, and the hardness reaches 500HV0.3, which is significantly better than the existing technology. The reduction in porosity is due to the synergistic effect of multiple parameters such as gas flow rate, powder feeding rate and spraying distance during the spraying process, which enables the sprayed particles to reach a completely molten state before deposition, thereby forming a dense microstructure. Figure 2 and attached Figure 3 SEM photos of the cross-sectional morphology of the yttrium oxide coating at magnifications of 200 times and 500 times are shown, respectively. It can be seen that the particles inside the coating are tightly bound and the pore distribution is extremely small, further verifying the effectiveness of the technical solution of the present invention.

[0034] In order to achieve precise control of spraying parameters, the present invention proposes an optimization algorithm based on particle deposition dynamics, the formula is as follows:

[0035]

[0036] Here, Q represents the coating porosity, C represents the gas flow coefficient, V represents the powder feed rate, T represents the flame temperature, D represents the spray distance, and R represents the substrate surface roughness. This formula quantifies the impact of various process parameters on coating porosity, providing a theoretical basis for parameter optimization in actual production. For example, in one specific example, when C = 55, V = 20, T = 3000, D = 130, and R = 3.0, the calculated Q = 1.5%, which is highly consistent with experimental results.

[0037] During the pretreatment stage, the parts to be processed are first thoroughly inspected to determine their surface condition, and surface defects are recorded from multiple angles using a high-resolution laser scanner in conjunction with infrared thermal imaging technology. During this process, the laser scanner can accurately capture micron-level cracks, pits, and corrosion areas, while infrared thermal imaging technology can further identify potential areas of thermal stress concentration. For example, in a certain practical application, through scanning and analysis of complex curved surface parts, it was found that its surface roughness value Ra was 4.2μm, and the sandblasting parameters needed to be further optimized to improve surface adhesion. On this basis, a targeted subsequent treatment plan is formulated based on the scanning results to ensure that the substrate surface has good cleanliness and appropriate roughness, providing an important reference basis for subsequent substrate surface modification.

[0038] After entering the powder activation stage, low-temperature plasma technology is used to modify the surface of the yttrium oxide powder. The yttrium oxide powder is placed in a plasma chamber, the temperature in the chamber is controlled at 80-100°C, the plasma power is 150-200W, and the processing time is 10-15min. In this process, low-temperature plasma can effectively remove adsorbed impurities on the surface of the powder and form active groups on its surface, thereby improving the melting efficiency of the powder during the spraying process. Experimental data show that the melting degree of the yttrium oxide powder after plasma activation treatment is increased by about 20%, which significantly improves the density of the coating. For example, in a specific embodiment, when the plasma chamber temperature is set to 90°C, the power is 180W, and the processing time is 12min, the concentration of active groups on the powder surface is significantly increased, and the melting efficiency is significantly improved, providing high-quality raw materials for subsequent spraying.

[0039] Then, the substrate surface modification stage is entered. Silicon carbide sand with a particle size of 80 mesh is selected as the sandblasting material, and the sandblasting pressure is strictly controlled to 0.6-0.8 MPa, the spray gun is 18-22 cm away from the workpiece surface, the spray gun angle is 75°-85°, and the sandblasting time is determined according to the size of the component. The choice of sandblasting pressure directly affects the impact force of the sand material on the workpiece surface. Too low a pressure cannot effectively remove the surface oxide layer, while too high a pressure may cause excessive roughening of the workpiece surface. In particular, the control of the spray gun angle can ensure that the sand material particles hit the workpiece surface at the optimal angle of incidence, improving the roughening effect while reducing damage to the substrate. For example, in a specific embodiment, when the sandblasting pressure is set to 0.7 MPa, the spray gun distance is 20 cm, and the spray gun angle is 80°, an ideal surface roughness value Ra of 3.0 μm is obtained, providing a good adhesion foundation for subsequent melt spraying. In addition, the sandblasting time needs to be flexibly adjusted according to the component size and material properties to ensure that the surface treatment is uniform and free of residual impurities.

[0040] After the substrate surface modification is completed, the melt spraying stage begins, using a supersonic flame spraying device. Key process parameters include gas flow rates of 50-60 sccm Ar and 25-12 sccm H, a powder feed rate of 10-25 g / min, a spray distance of 120-150 mm, and a flame temperature of 2800-3200°C. Ar, as the primary gas, maintains flame stability, while H2, as the auxiliary gas, adjusts the flame's thermal efficiency, ensuring that the sprayed particles are fully molten before deposition. Furthermore, precise matching of the powder feed rate and spray distance effectively controls the uniformity of particle deposition. For example, in one specific embodiment, when the gas flow rates are set to 55 sccm Ar and 8 sccm H, a powder feed rate of 20 g / min, and a spray distance of 130 mm, the yttrium oxide coating produced has a uniform thickness and a porosity of less than 1.5%. This result demonstrates that this parameter combination can improve process operability and cost-effectiveness while maintaining coating quality. During the melt spraying process, the control of flame temperature is particularly critical. Too high or too low temperature will affect the melting state of the sprayed particles, thereby affecting the density and adhesion of the coating.

[0041] After the spraying is completed, it enters the cooling and solidification stage, and the coating is treated by a segmented cooling method. The temperature of the initial cooling stage is controlled at 200-300°C and lasts for 5-10 minutes; then it enters the natural cooling stage until the coating temperature drops to room temperature. The segmented cooling method can effectively avoid the problem of internal stress concentration caused by rapid cooling, thereby improving the mechanical properties and crack resistance of the coating. Experimental results show that the hardness of the coating after this step reaches 500HV0.3, which meets the stringent requirements of the high-end semiconductor manufacturing field. For example, in a specific embodiment, when the temperature of the initial cooling stage is set to 250°C and the duration is 8 minutes, the internal stress distribution of the coating is uniform, and no obvious cracks or peeling occurs, which further verifies the effectiveness of the segmented cooling method.

[0042] Next comes the demasking stage, where the high-temperature tape is removed and residues on the coating surface are removed using a soda gun and ultrasonic cleaning. The cleaning process is divided into two steps. First, a soda gun is used to remove large particles of impurities attached to the surface, and then ultrasonic cleaning is used to further remove tiny particles, ultimately obtaining a clean and smooth coating surface. The experimental results show that the surface cleanliness of the coating is significantly improved after this step, meeting the requirements of high-performance protective coatings in the field of high-end semiconductor manufacturing. For example, in a specific embodiment, when the soda gun pressure is set to 0.4MPa, the ultrasonic cleaning frequency is 40kHz, and the cleaning time is 10min, the surface cleanliness of the coating meets the industry standard requirements, and there is no obvious residue.

[0043] Finally, the post-cleaning stage thoroughly cleans the entire component to ensure that no residue remains on the coating surface. The soda gun and ultrasonic equipment used in this cleaning process are both conventional industrial equipment, simple to operate, low-cost, and suitable for large-scale industrial applications. For example, in one specific embodiment, when the post-cleaning stage uses the same cleaning parameters as the demasking process, the overall cleanliness of the component is further improved, meeting the stringent requirements for high-performance protective coatings in high-end semiconductor manufacturing.

[0044] The technical solution of the present invention significantly reduces the porosity of the coating and improves the mechanical properties and chemical stability of the coating by introducing low-temperature plasma powder activation technology and a segmented cooling process. Experimental results show that the porosity of the coating can be reduced to below 1.5%, and the hardness reaches 500HV0.3, which is significantly better than the existing technology. The reduction in porosity is due to the synergistic effect of multiple parameters such as gas flow rate, powder feeding rate and spraying distance during the spraying process, which enables the sprayed particles to reach a completely molten state before deposition, thereby forming a dense microstructure. Figure 2 and Figure 3 As shown in FIG, there are SEM photos of the cross-sectional morphology of the yttrium oxide coating magnified 200 times and 500 times, respectively. It can be seen that the particles inside the coating are tightly bound and the pore distribution is very small, which further verifies the effectiveness of the technical solution of the present invention.

[0045] In summary, this invention significantly reduces coating porosity and improves its plasma corrosion resistance by optimizing spraying parameters and process flow, meeting the demand for high-performance protective coatings in high-end semiconductor manufacturing. This technical solution not only addresses the high porosity problem inherent in traditional processes but also enhances process adaptability and cost-effectiveness through rational parameter design, providing strong support for technological development in related fields.

[0046] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A spraying process for a dense yttrium oxide coating, characterized by: The following steps are involved: In the pre-processing step, high-resolution laser scanners and infrared thermal imaging technology are used to record the surface of the processed parts from multiple angles; A powder activation step involves placing the yttrium oxide powder in a plasma chamber, controlling the chamber temperature at 80 to 100 degrees Celsius, a plasma power at 150 to 200 watts, and a treatment time of 10 to 15 minutes; In the substrate surface modification step, silicon carbide sand with a particle size of 80 mesh is used as a sandblasting material, the sandblasting pressure is 0.6 to 0.8 MPa, the spray gun is 18 to 22 cm away from the workpiece surface, and the spray gun angle is 75 to 85 degrees; in the melt spraying step, supersonic flame spraying equipment is used for spraying, the gas flow rate is 50 to 60 standard cubic centimeters per minute of argon and 5 to 12 standard cubic centimeters per minute of hydrogen, the powder feed rate is 10 to 25 grams per minute, the spraying distance is 120 to 150 mm, and the flame temperature is 2800 to 3200 degrees Celsius; Cooling and curing step: the temperature of the initial cooling stage is controlled at 200 to 300 degrees Celsius, lasting for 5 to 10 minutes, and then enters the natural cooling stage until the coating temperature drops to room temperature; Demasking step, removing the high temperature tape and using a water gun and ultrasonic cleaning operation to remove the coating surface residue; In the final cleaning step, the entire part is thoroughly cleaned to ensure that there is no residue on the coating surface.

2. The spraying process for a dense yttrium oxide coating according to claim 1, wherein: In the pretreatment step, the surface roughness value Ra of the part to be processed is 4.2 μm.

3. The spraying process for a dense yttrium oxide coating according to claim 1, wherein: During the powder activation step, the plasma chamber temperature was 90 degrees Celsius, the power was 180 watts, and the processing time was 12 minutes.

4. The spraying process for a dense yttrium oxide coating according to claim 1, wherein: In the substrate surface modification step, the sandblasting pressure was 0.7 MPa, the spray gun distance was 20 cm, the spray gun angle was 80 degrees, and the surface roughness value Ra was 3.0 μm.

5. The spraying process for a dense yttrium oxide coating according to claim 1, wherein: In the melt spraying step, the gas flow rate is 55 standard cubic centimeters per minute of argon and 8 standard cubic centimeters per minute of hydrogen, the powder feeding rate is 20 grams per minute, the spraying distance is 130 mm, and the flame temperature is 3000 degrees Celsius.

6. The spraying process for a dense yttrium oxide coating according to claim 1, wherein: In the cooling and solidification step, the temperature of the initial cooling stage is 250 degrees Celsius and the duration is 8 minutes.

7. The spraying process of a dense yttrium oxide coating according to claim 1 is characterized in that: In the masking treatment step, the pressure of the steam gun was 0.4 MPa, the ultrasonic cleaning frequency was 40 kHz, and the cleaning time was 10 minutes.

8. The spraying process for a dense yttrium oxide coating according to claim 1, wherein: In the post-cleaning step, the same cleaning parameters as those used in the demasking process were used.

9. The spraying process of a dense yttrium oxide coating according to claim 1, wherein the coating The porosity is given by the formula It is calculated that Q represents the coating porosity, C represents the gas flow coefficient, V represents the powder feeding rate, T represents the flame temperature, D represents the spraying distance, and R represents the surface roughness of the substrate.

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