A method for improving pa anomalies in a semiconductor device cavity

Abstract

This invention discloses a method for improving PA (Power Atomizer) anomalies in semiconductor device cavities. The method involves first preparing a base layer using an arc spraying process on the surface of a substrate after sandblasting and cleaning, and then preparing a secondary atomized coating layer on top of the base layer using a secondary atomization process. This invention combines primary and secondary atomization technologies. The coating prepared by primary atomization is used as the base layer. By controlling parameters such as atomizing gas, voltage, current, and gas pressure, a coating with relatively low porosity, relatively high adhesion, and relatively high roughness is prepared as the base layer. A secondary atomized coating is then prepared on this base layer. By adjusting the corresponding parameters of the secondary atomized coating, a composite coating with better performance is prepared. The composite coating prepared using this method achieves an adhesion strength of over 21 MPa, a porosity as low as 0.394%, and a roughness as high as 37.5 μm, all exceeding 34 μm.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor manufacturing equipment remanufacturing technology, specifically relating to a method for preparing a protective coating on the inner wall of the cavity and key components of a physical vapor deposition (PVD) equipment, and particularly relating to a method for preparing a high-performance protective coating on the cavity surface through a composite arc spraying process to significantly reduce the generation and shedding of particulate matter (PA) during the process. Background Technology

[0002] In the PVD process of semiconductor manufacturing, reactants or target materials inevitably deposit on the inner wall of the cavity and the surface of components (such as shielding covers, heat spreaders, cavity wall bushings, etc.). As the process cycle lengthens, the deposited film continuously thickens and generates internal stress under the action of thermal cycling and plasma bombardment, leading to film rupture and peeling, producing micron / submicron-sized particles. These particles falling onto the wafer surface can cause fatal defects such as short circuits and open circuits, resulting in severe particulate contamination (PA) anomalies. To further improve the corrosion resistance and peeling resistance of semiconductor equipment components, the industry has begun to use ARC arc spraying to prepare protective coatings. The principle of arc spraying is that two metal wires (anode and cathode) intersect at the front end of the spray gun to form an electric arc, melting the ends of the wires, and then atomizing the molten material and spraying it onto the substrate through a high-speed airflow (usually compressed air).

[0003] Conventional arc spraying relies on a plasma gas stream to atomize the molten electrode material in a single pass. This method produces droplets with a wide size distribution, and some large droplets fail to melt fully or reach low speeds, resulting in coarse and sharp particles on the workpiece surface. This makes it difficult to meet the stringent requirements of semiconductor-grade surfaces. To overcome the limitations of single atomization, secondary atomization, with its advantages of fine, uniform particles and dense, strong coatings, has become an ideal choice for high-performance applications. However, secondary atomization suffers from drawbacks such as complex equipment, difficulty in long-term stable operation, low deposition efficiency, and stringent substrate requirements. Furthermore, while secondary atomization produces coatings with lower porosity and greater uniformity, it also results in lower surface roughness. Lower roughness means it can only hold a limited number of particles, requiring coating replacement after a short period of operation. This significantly increases the cost of semiconductor equipment maintenance and semiconductor product manufacturing. Summary of the Invention

[0004] To address the problems existing in the prior art, the purpose of this invention is to provide a method for improving PA anomalies in semiconductor device cavities. Specifically, it provides a coating and its preparation method that can effectively overcome the problems of poor quality of conventional arc spray coatings and low deposition efficiency and difficulty in achieving the required roughness of secondary atomization coatings. By combining primary and secondary atomization, a protective coating with extremely strong adhesion to the substrate, density, uniformity, and high efficiency in bearing contaminants can be prepared, thereby reducing the risk of particulate contamination peeling at the source. To achieve the above objectives, the present invention first provides a method for improving PA abnormalities within a semiconductor device cavity, the specific steps of which are as follows: S1. Substrate sandblasting: The surface of the inner lining substrate of the semiconductor equipment cavity is sandblasted to make the surface roughness Ra of the substrate 5~12μm. S2, Physical cleaning: The substrate after sandblasting in step S1 is rinsed with deionized water, high-pressure water gun and ultrapure water respectively, and then dried with air gun. S3. Preheating: Place the substrate cleaned in step S2 into an oven for preheating. After preheating, the surface temperature of the substrate is greater than 50°C. S4. Arc spraying: The base layer is prepared on the sandblasted surface of the substrate after preheating in step S3 using an arc spraying device. S5. Preparation of secondary atomized coating: A secondary atomized coating is prepared on the substrate surface containing the underlayer obtained in step S4 using an arc melting spraying equipment with a secondary atomization nozzle. S6. Cleaning after molten spraying: The substrate obtained after molten spraying in step S5 is subjected to dry ice cleaning, physical cleaning and ultrasonic cleaning to remove particulate matter attached to the molten surface. After cleaning, it is dried to obtain a protective composite coating.

[0005] In one embodiment of the present invention, the sandblasting in step S1 involves sandblasting the substrate with WA24# and / or WA16# white corundum abrasive at a pressure of 2-5 kgf / cm. 2 The distance between the spray gun and the substrate is 150-200mm, and the blasting angle is 45-90°. The substrate is blasted evenly from left to right and from top to bottom to ensure uniform roughness after blasting. Preferably, the white corundum alumina used for blasting is a mixture of WA24# and WA16# white corundum alumina, with a mass ratio of WA24#:WA16# = 2:1.

[0006] In one embodiment of the present invention, for a stainless steel substrate, the roughness Ra range after sandblasting is 5-8 μm, and for an aluminum substrate, the roughness Ra range after sandblasting is 9-12 μm.

[0007] In one embodiment of the present invention, in step S2, the rinsing time with deionized water is more than 30 seconds, the rinsing time with a high-pressure water gun is 0.5-2 minutes at a distance of 15±5 cm, and the rinsing time with ultrapure water is 0.5-2 minutes at a distance of 15±5 cm.

[0008] In one embodiment of the present invention, the oven temperature in step S3 is 60~90°C and the preheating time is 30~60 min.

[0009] In one embodiment of the present invention, in step S4, the spraying voltage during the preparation of the underlayer is 28-40V, the spraying current is 100-180A, the spraying gas pressure is 28-40psi, the spraying material is aluminum wire, preferably 1017A aluminum wire, the spraying distance is 70-160mm, and the spraying angle is 60-90°.

[0010] In one embodiment of the present invention, in step S4, the atomizing gas pressure during the preparation of the base layer is compressed air or nitrogen.

[0011] In one embodiment of the present invention, in step S4, the thickness of the base layer is 80~120μm, the roughness Ra is controlled at 25-35μm, the porosity is less than 7%, and the bonding strength is greater than 10MPa.

[0012] In one embodiment of the present invention, in step S5, the sputtering material for preparing the secondary atomized coating is aluminum wire, preferably 1017A aluminum wire, the sputtering current is 150~200A, the sputtering voltage is 25~35V, the first atomization gas pressure and the second atomization gas pressure are both 28~40psi, the sputtering distance is 70-160mm, and the sputtering angle is 60°-90°.

[0013] In one embodiment of the present invention, in step S5, when preparing the secondary atomized coating, the atomizing gas used for the first atomization is compressed air or high-purity argon, wherein the purity of the high-purity argon is ≥99.996%, and the atomizing gas used for the second atomization is compressed air or high-purity argon, wherein the purity of the high-purity argon is ≥99.996%.

[0014] In one embodiment of the present invention, in step S5, the thickness of the secondary atomized coating is 150±50μm, the roughness Ra is 30-40μm, the porosity is less than 7%, and the bonding strength is greater than 10Mpa. During the secondary atomization, the spray gun of the arc welding equipment scans twice at a scanning rate of 8cm / min.

[0015] In one embodiment of the present invention, the air pressure of the dry ice cleaning in step S6 is 0.6-0.8 MPa, the dry ice discharge rate is 1-2 kg / min, and the distance is 10-15 cm.

[0016] In one embodiment of the present invention, the physical cleaning in step S6 involves grinding the substrate surface with a grinder for 1-5 minutes to remove contaminants, brushing the melt-sprayed area to remove dust residue, rinsing with deionized water for more than 30 seconds, rinsing with a high-pressure water gun for 0.5-2 minutes at a distance of 15±5cm, and rinsing with ultrapure water for 0.5-2 minutes at a distance of 15±5cm.

[0017] In one embodiment of the present invention, the ultrasonic cleaning in step S6 uses an ultrasonic frequency of 40 kHz, an oscillation time of 20 s, and a temperature of 35-40 ℃.

[0018] The present invention also provides a protective composite coating prepared according to the above method.

[0019] In one embodiment of the present invention, the protective composite coating comprises an underlayer and a secondary atomized coating in contact with the substrate. The underlayer is prepared by arc spraying through a single atomization process, and the secondary atomized coating is obtained through a second atomization process. The thickness of the underlayer is 80-120 μm, the roughness Ra is controlled at 25-35 μm, and the porosity is less than 7%. The thickness of the secondary atomized coating is 150±50 μm, the roughness Ra is 30-40 μm, and the porosity is less than 7%.

[0020] Beneficial effects: (1) This invention combines primary atomization technology with secondary atomization technology. The coating prepared by primary atomization technology is used as the base layer. By adjusting the atomizing gas (nitrogen or compressed air is selected as the primary atomizing gas), voltage, current and air pressure (low current, low voltage and high air pressure parameters are selected) and other parameters, a coating with relatively small porosity, relatively high bonding force and relatively high roughness is prepared as the base layer. Then, a secondary atomization coating is prepared on this basis. By adjusting the corresponding parameters of the secondary atomization coating, a composite coating with better performance is prepared. The composite coating prepared by the method of this invention can achieve a bonding force of more than 21 MPa, a porosity as low as 0.394%, and a roughness as high as 37.5 μm, all of which are above 34 μm.

[0021] (2) Thanks to the ideal bonding interface provided by the bottom layer, the top layer can achieve a bonding strength far exceeding that of direct spraying on the substrate, ensuring that the coating does not fall off under thermal shock and mechanical stress. In addition, the micro-droplets of secondary atomization impact the surface of the formed bonding layer at extremely high speed, which can achieve more complete spreading and flattening, and fill the micropores of the bottom coating to the maximum extent, thereby forming an extremely dense, uniform, and low-porosity surface working layer. This method can effectively remove coarse and sharp particles from the surface of the primary atomized coating, reducing the problem of PA abnormalities in the PVD cavity. Attached Figure Description

[0022] Figure 1 SEM images of the protective coatings prepared in Examples 1-4 and Comparative Examples 1-5; Figure 2 Box plots of porosity for the protective coatings prepared in Examples 1-4 and Comparative Examples 1-5; Figure 3 Box plots of the adhesion of the protective coatings prepared in Examples 1-4 and Comparative Examples 1-5; Figure 4 The surface microstructure of the protective coatings prepared in Examples 1-4 and Comparative Examples 1-5 was measured using a 3D profilometer; Figure 5 Box plots of roughness for the protective coatings prepared in Examples 1-4 and Comparative Examples 1-5. Detailed Implementation

[0023] The present invention will be described in detail below with reference to the accompanying drawings and embodiments, but the content of the present invention is not limited to the following embodiments.

[0024] In the embodiments and comparative examples of this invention, the materials used for preparing the undercoat and secondary atomized coating are aluminum wires with a purity of 99.85% and a diameter of 1.6 mm, to ensure the high purity and excellent electrical and thermal conductivity of the molten spray layer.

[0025] Example 1 A method for improving PA abnormalities within a semiconductor device cavity, the method comprising preparing a high-purity aluminum (purity >99.8%) protective coating on the semiconductor device cavity liner (aluminum alloy cavity liner, i.e., the substrate described below), the specific steps of which are as follows: S1. Matrix Sandblasting: The matrix is ​​sandblasted using a mixture of WA24# and WA16# white corundum abrasive (WA24# and WA16# abrasive in a 2:1 mass ratio) at a sandblasting pressure of 3 kgf / cm². 2 The distance between the spray gun and the substrate is 200mm, the sandblasting angle is 90°, and the substrate is sandblasted evenly from left to right and from top to bottom. After sandblasting, the roughness Ra of the substrate is 9-12μm. S2. Physical cleaning: Rinse the substrate with deionized water for 30 seconds, then replace with a high-pressure water gun and continue rinsing for 1 minute. Keep the high-pressure water gun 150mm away from the substrate. Finally, rinse the substrate with ultrapure water for 1 minute. Keep the ultrapure water 150mm away from the substrate. After cleaning, use CDA to dry the surface moisture of the substrate. S3. Preheating: Place the substrate treated in S2 into an oven, set the oven temperature to 80℃, and preheat the substrate for 30 minutes to remove residual moisture on the substrate surface and moisture that has seeped into the interior.

[0026] S4. Arc Spraying: Arc spraying equipment is used, and compressed air is selected as the atomizing gas to make the base layer. The voltage during the base layer preparation is 28V, the current is 100A, the air pressure is 40psi, and the spraying distance is 145mm. During arc spraying, the angle between the spray gun and the cavity surface is kept at 90°, and the scanning speed is 8cm / min once to ensure that the prepared atomized coating is uniform and the coating thickness is controlled between 80~120μm. S5. Preparation of the secondary atomized coating: A secondary atomization auxiliary nozzle is installed in the arc spraying equipment. Compressed air is used as the atomizing gas, and the parameters are set as follows: voltage 35 V, current 150 A, and primary atomization gas pressure 35 psi. This gas pressure is used to blow the initially molten aluminum droplets away from the wire end and complete the first atomization. The secondary atomization auxiliary nozzle is turned on, also using compressed air, with the gas pressure adjusted to 35 psi. The angle between the secondary atomization airflow direction and the primary atomization particle flow direction is 90°, which strongly shears the molten aluminum droplets after primary atomization, further refining them. During spraying, the spraying distance is controlled at 70 mm, the angle between the spray gun and the cavity surface is maintained at 90°, and the spray gun is moved twice at a scanning speed of 8 cm / min to ensure that the secondary atomized coating is uniform, and the coating thickness is controlled at 150 ± 50 μm. S6. Cleaning: The substrate surface is rinsed using a dry ice cleaner. During cleaning, the dry ice cleaner's air pressure is 0.8 MPa, the dry ice output is 2 kg / min, and the distance is 15 cm. The substrate surface is then uniformly polished using a grinder for 2 minutes to remove the surface oxide layer and solidified contaminants, while simultaneously forming a new, activated surface. Subsequently, the entire weld area is carefully brushed with a clean nylon brush to ensure no dust or polishing residue remains. The substrate is rinsed with deionized water for at least 30 seconds, then rinsed again with a high-pressure water gun for 0.5 minutes, with the high-pressure water gun held 15 cm away from the substrate. Finally, the substrate is rinsed with ultrapure water for 1 minute, with the ultrapure water held 15 cm away from the substrate. Finally, the substrate is ultrasonically cleaned using an ultrasonic cleaner at a frequency of 40 kHz, a vibration time of 20 seconds, and a temperature of 40°C. After cleaning, the substrate is dried using a CDA blower and then placed in an oven.

[0027] Example 2 The difference between Example 2 and Example 1 is that, in step S5, high-purity argon gas (purity ≥99.996%) is used as the atomizing gas for both the first and second atomization processes when preparing the secondary atomized coating. The specific steps of step S5 are as follows: A secondary atomization auxiliary nozzle is installed, using argon gas (purity ≥99.996%) as the atomizing gas. The parameters are set to voltage 35 V, current 150 A, and primary atomization pressure 35 psi. This pressure is used to blow the initially molten aluminum droplets away from the wire end and complete the first atomization. The secondary atomization auxiliary nozzle is then activated, also using high-purity argon gas, with the pressure adjusted to 35 psi. The angle between the secondary atomization airflow and the primary atomization particle flow is 90°, providing strong shearing to further refine the molten aluminum droplets after primary atomization. The spraying distance is controlled at 70 mm. Maintaining a 90° angle between the spray gun and the cavity surface, the nozzle is moved twice at a scanning speed of 8 cm / min to ensure uniform secondary atomization coating, with a coating thickness controlled at 150 ± 50 μm.

[0028] Example 3 The difference between Example 3 and Example 1 is that the current used to prepare the secondary atomized coating in step S5 is 100A, and the gas pressure during the first and second atomizations is 40psi.

[0029] Example 4 The difference between Example 4 and Example 2 is that nitrogen is used as the atomizing gas during arc spraying in step S4.

[0030] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that step S5 is omitted.

[0031] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that step S4 is omitted, and the spray gun moves three times at a scanning speed of 8 cm / min to ensure that the secondary atomized coating is uniform and the coating thickness is controlled at 200±50 μm.

[0032] Comparative Example 3 The difference between Comparative Example 3 and Example 2 is that step S4 is omitted, and the spray gun moves three times at a scanning speed of 8 cm / min to ensure that the secondary atomized coating is uniform and the coating thickness is controlled at 200±50 μm.

[0033] Comparative Example 4 The difference between Comparative Example 4 and Example 2 is that step S4 is omitted, and the voltage and current used in step S5 to prepare the secondary atomized coating are different. The specific steps of step S5 are as follows: An electric arc spraying system was employed, equipped with a secondary atomization auxiliary nozzle. Argon gas (purity ≥99.996%) was used as the atomizing gas, with parameters set at 25 V voltage and 180 A current. The primary atomization gas pressure was 35 psi, used to blow the initially molten aluminum droplets away from the wire end and complete the first atomization. The secondary atomization auxiliary nozzle was then activated, also using high-purity argon gas, with the pressure adjusted to 35 psi. The angle between the secondary atomization airflow and the primary atomization particle flow was 90°, providing strong shearing to further refine the molten aluminum droplets after the first atomization. The spraying distance was controlled at 70 mm. The spray gun was kept at a 90° angle to the cavity surface and moved at a scanning speed of 8 cm / min to ensure uniform coating, with the coating thickness controlled at 200 ± 50 μm.

[0034] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that step S5 is omitted, and the voltage, current, and air pressure in step S4 are different. The specific steps of step S4 are as follows: An electric arc spraying system was used, with compressed air as the atomizing gas. The parameters were set to 25 V voltage and 180 A current. The primary atomizing gas pressure was 28 psi, used to blow the initially molten aluminum droplets away from the wire end and complete the first atomization. The spraying distance was controlled at 160 mm. The spray gun was kept at a 90° angle to the cavity surface and moved at a scanning speed of 8 cm / min to ensure uniform coating. The coating thickness was controlled at 200 ± 50 μm.

[0035] The appearance of the substrate after coating preparation is inspected to confirm the absence of contaminants and water spots. In a dark room environment, a UV lamp with a wavelength range of 365nm is used to irradiate the surface at a distance of 10-15cm. The lamp head is slowly moved, and the surface is observed from different angles. A qualified substrate surface should be free of any fluorescent bright spots, marks, and attached fibers.

[0036] The cross-sectional morphology, porosity, and adhesion data of the coatings prepared in Examples 1-4 and Comparative Examples 1-5 are as follows: Figure 1 and 2 As shown in ~3, from Figure 1 and Figures 2-3It can be seen that the sprayed layers in Comparative Examples 1 and 5 have larger porosity, poorer density, and lower adhesion. This is because the droplet size generated by direct arc spraying without a secondary atomizing nozzle (droplet size of primary atomization) has a wide distribution range, and larger droplets may not fully melt before bonding with the substrate. In contrast, the secondary atomization coating, based on primary atomization, can generate more, smaller, more uniform, more fully melted, and faster-moving metal droplets. These droplets can better spread, fill, and stack upon impact with the substrate, thus forming a denser coating structure. Furthermore, it can be seen from Examples 1 and Comparative Examples 1, 2, and 5 that the coatings prepared using compressed air as the atomizing gas have larger porosity, are more porous, and have lower adhesion. This is because oxygen in the air reacts violently with the high-temperature molten metal particles, producing a large amount of oxides. These oxides have high melting points and poor fluidity, hindering good fusion and spreading between metal droplets, resulting in numerous pores and voids within the coating. Comparing Examples 2 and 3, it can be concluded that optimized parameters can effectively improve coating performance. This is because the current determines the melting and deposition efficiency of the aluminum wire, while the air pressure determines the atomization effect and kinetic energy of the particles. Low current and high air pressure allow the droplets to melt more fully and achieve higher functionality, enabling the droplets to spread, fill, and stack better when impacting the substrate, thus forming a denser coating structure. Furthermore, comparing Examples 2 and 3, it can be observed that the melt-sprayed layer prepared using a combination of a primary atomized underlayer and a secondary atomized toplayer performs better than the secondary atomized coating. This is because the coating produced by primary atomization has high porosity and a very rough surface. This rough surface provides a large surface area and numerous "anchor points" for the subsequent secondary atomized toplayer, generating a strong mechanical interlocking effect. The porous underlayer structure has a certain degree of elasticity and stress buffering effect, which may help alleviate some of the stress caused by the mismatch in thermal expansion coefficients between the toplayer and the substrate. In addition, the melting and spraying rate of primary atomization is usually very high, allowing for rapid thickness accumulation and efficient completion of dimensional recovery or the construction of a sufficiently thick transition layer. Furthermore, its requirements for substrate surface pretreatment (such as roughening) can be relatively relaxed because its own rough structure can tolerate a certain degree of surface unevenness. Comparing Examples 1, 2, and 4, it can be seen that nitrogen and argon have lower porosity as atomizing gases, and the coating adhesion of nitrogen as an atomizing gas is lower than that of argon. This is because in the high-temperature zone of the electric arc, a small number of nitrogen molecules will dissociate into active nitrogen atoms. These nitrogen atoms may penetrate into the surface of the metal droplets, forming an extremely thin and potentially diffuse nitride layer, thereby reducing the adhesion of the coating.

[0037] Figure 4 The surface microstructure of the prepared protective coating is presented. Figure 5 Roughness data is given, from Figure 4 and Figure 5It can be seen that the primary atomization produces larger surface particles and higher roughness. This is because the droplets from primary atomization are large and uneven, resulting in a surface composed of many incompletely fused layers and large particle protrusions after deposition, exhibiting significant microscopic undulations. In contrast, the secondary atomization produces fine and uniform droplets that form a smooth, dense layered structure with lower surface roughness. Compared to Comparative Examples 2 and 3, Comparative Example 4 has larger surface particles and higher roughness. This is because the excessive current causes excess molten metal to accumulate at the wire end, leading to droplet aggregation and the formation of larger, more unevenly sized particles. These large droplets are the main source of roughness. Furthermore, in the examples, the coating prepared using argon as the atomizing gas is the most uniform, with the smallest particles and a lower range of roughness fluctuations. This is because argon, as the atomizing gas, maintains a "clean" liquid metal surface. When these pure, high-temperature droplets impact the substrate at high speed, they can fully deform, spread, and fuse, seamlessly filling the depressions of the previous layer of particles to form a smooth coating with almost no pores and excellent interlayer bonding. This is the physical basis for achieving low roughness and high uniformity. It is worth noting that the coatings prepared by the bottom layer plus top layer combination in the examples all have higher roughness than the single secondary atomized coating, while the particle size is not much different from that of the secondary atomized coating. For fields that require thick coatings, high performance or complex working conditions, the bottom layer plus top layer combination is the preferred strategy for preparing coating structures.

[0038] Based on the data from Examples 1-4 and Comparative Examples 1-5, it is evident that the coating prepared by conventional arc spraying without a secondary atomizing nozzle is a primary atomizing coating. Primary atomizing coatings have larger surface particles and higher roughness. This higher roughness helps the substrate to bear more contaminants, significantly improving PA anomalies within the cavity and extending the cavity's service life. However, using only a primary atomizing coating as the cavity's protective coating has significant drawbacks. The uneven droplet distribution in primary atomizing coatings results in higher porosity, leading to poor coating adhesion. Consequently, the coating on the cavity lining surface easily detaches during subsequent thin film deposition within the cavity. This not only fails to effectively improve PA anomalies within the cavity but also exacerbates contamination of the deposited thin film.

[0039] Reducing the atomization current and increasing the gas pressure helps to reduce porosity and increase its adhesion to the substrate, but the roughness of the coating is significantly reduced. In addition, although changing the type of atomizing gas and changing parameters such as voltage can also control the adhesion and roughness, it is difficult to simultaneously meet the requirements of high adhesion and high roughness.

[0040] Secondary atomization coating technology utilizes a secondary atomization nozzle to assist in purging the droplets generated by primary atomization. The atomized gas from the secondary nozzle breaks up the droplets, effectively reducing their size and allowing them to spread more evenly and fully on the substrate surface, resulting in a coating with lower porosity and more uniform droplet distribution. However, while the secondary atomization coating has lower porosity, its adhesion is also weaker, making it prone to peeling. Furthermore, its roughness is lower, making it difficult to effectively improve the coating's ability to retain contaminants and mitigate PA anomalies overall.

[0041] This invention combines primary and secondary atomization technologies. A coating prepared using primary atomization is used as the base layer. By adjusting parameters such as the atomizing gas (nitrogen or argon as the primary atomizing gas), voltage, current, and pressure (using low current, low voltage, and high pressure parameters), a coating with relatively low porosity, relatively high adhesion, and relatively high roughness is prepared as the base layer. A secondary atomization coating is then prepared on this base layer. By adjusting the corresponding parameters of the secondary atomization coating, a composite coating with better performance is prepared. For example, in Examples 2-4 of this invention, the adhesion can reach over 21 MPa, the porosity is as low as 0.394%, and the roughness is as high as 37.5 μm, all above 34 μm.

[0042] 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 method for improving PA abnormalities within a semiconductor device cavity, characterized in that, The specific steps are as follows: S1. Substrate sandblasting: The surface of the inner lining substrate of the semiconductor equipment cavity is sandblasted to make the surface roughness Ra of the substrate 5~12μm. S2, Physical cleaning: The substrate after sandblasting in step S1 is rinsed with deionized water, high-pressure water gun and ultrapure water respectively, and then dried with air gun. S3. Preheating: Place the substrate cleaned in step S2 into an oven for preheating. After preheating, the surface temperature of the substrate is greater than 50°C. S4. Arc spraying: The base layer is prepared on the sandblasted surface of the substrate after preheating in step S3 using an arc spraying device. S5. Preparation of secondary atomized coating: A secondary atomized coating is prepared on the substrate surface containing the underlayer obtained in step S4 using an arc melting spraying equipment with a secondary atomization nozzle. S6. Cleaning after molten spraying: The substrate obtained after molten spraying in step S5 is subjected to dry ice cleaning, physical cleaning and ultrasonic cleaning to remove particulate matter attached to the molten surface. After cleaning, it is dried to obtain a protective composite coating.

2. The method according to claim 1, characterized in that, The oven temperature for step S3 is 60~90℃, and the preheating time is 30~60min.

3. The method according to claim 1, characterized in that, In step S4, the spraying voltage during the preparation of the underlayer is 28-40V, the spraying current is 100-180A, the spraying gas pressure is 28-40psi, the spraying material is aluminum wire, the spraying distance is 70-160mm, and the spraying angle is 60-90°.

4. The method according to claim 1, characterized in that, In step S4, the atomizing gas pressure during the preparation of the bottom layer is compressed air or nitrogen.

5. The method according to claim 1, characterized in that, In step S4, the thickness of the base layer is 80~120μm, the roughness Ra is controlled at 25-35μm, the porosity is less than 7%, and the bonding strength is greater than 10MPa.

6. The method according to claim 1, characterized in that, In step S5, the sputtering material used to prepare the secondary atomized coating is aluminum wire, the sputtering current is 150~200A, the sputtering voltage is 25~35V, the first atomization gas pressure and the second atomization gas pressure are both 28~40psi, the sputtering distance is 70-160mm, the sputtering angle is 60°-90°, and the atomizing gas used for the first atomization and the second atomization is compressed air or high-purity argon, wherein the purity of the high-purity argon is ≥99.996%.

7. The method according to claim 1, characterized in that, In step S5, the thickness of the secondary atomized coating is 150±50μm, the roughness Ra is 30-40μm, the porosity is less than 7%, and the bonding strength is greater than 10Mpa. During the secondary atomization, the spray gun of the arc welding equipment scans twice at a scanning rate of 8cm / min.

8. The method according to claim 1, characterized in that, In step S6, the air pressure for dry ice cleaning is 0.6-0.8 MPa, the dry ice discharge rate is 1-2 kg / min, and the distance is 10-15 cm. The physical cleaning involves grinding the substrate surface with a grinder for 1-5 minutes to remove contaminants, and brushing the melt-sprayed area to remove dust residue. The surface is then rinsed with deionized water for more than 30 seconds, rinsed with a high-pressure water gun for 0.5-2 minutes at a distance of 15±5 cm, and rinsed with ultrapure water for 0.5-2 minutes at a distance of 15±5 cm. The ultrasonic cleaning uses an ultrasonic frequency of 40 kHz, an oscillation time of 20 seconds, and a temperature of 35-40℃.

9. The protective composite coating prepared by the method according to claim 1.

10. The protective composite coating according to claim 9, characterized in that, The protective composite coating is sequentially deposited on the substrate as an underlayer and a secondary atomized coating. The underlayer is prepared by arc spraying through a single atomization process, and the secondary atomized coating is obtained through a second atomization process. The thickness of the underlayer is 80-120 μm, the roughness Ra is controlled at 25-35 μm, and the porosity is less than 7%. The thickness of the secondary atomized coating is 150±50 μm, the roughness Ra is 30-40 μm, and the porosity is less than 7%.

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