Texturing and cleaning process for heterojunction solar cells

Abstract

The present application relates to a kind of heterojunction solar cell's texturing cleaning process method, belong to solar cell preparation technical field.The present application includes: using the pre-cleaning fluid of potassium hydroxide and hydrogen peroxide to carry out pre-cleaning to N-type silicon wafer, to remove the organic matter and metal impurity pollutants of N-type silicon wafer surface cutting residue;After washing, using the texturing solution of potassium hydroxide and texturing additive to carry out texturing treatment to silicon wafer;After washing, using the mixed aqueous solution of ozone water and hydrochloric acid to carry out cleaning treatment to silicon wafer;After washing, using the mixed aqueous solution of ozone water and hydrofluoric acid to carry out cleaning treatment to silicon wafer;After washing, using the mixed aqueous solution of hydrogen peroxide and hydrochloric acid to carry out cleaning treatment to silicon wafer;After washing, using the aqueous solution of hydrofluoric acid to clean silicon wafer;To silicon wafer, hot water wash, and clean air is heated and dried.The present application has the advantages of less process steps, low cost, good uniformity of out-rug, more environmental protection and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cell preparation, and particularly relates to a texturing and cleaning process method of a heterojunction solar cell. BACKGROUND

[0002] A solar cell is a kind of semiconductor device capable of converting solar energy into electric energy. Under the condition of light, a photogenerated current is generated inside the solar cell, and the electric energy is output through electrodes. With the continuous progress of solar cell production technology, the development of high-efficiency cells with more advantages in conversion efficiency is increasingly valued. Among them, the silicon-based heterojunction solar cell (HJT cell) using amorphous silicon intrinsic layer (a-Si:H(i)) to passivate the surface is one of the key research directions. The silicon-based heterojunction solar cell has the advantages of high conversion efficiency, high open-circuit voltage, no light-induced degradation (LID), no electrical degradation (PID), low temperature coefficient, and double-sided discovery, and its preparation process temperature is close to 200℃. While ensuring high conversion efficiency, the silicon-based heterojunction cell can be thinned to 100μm, effectively reducing the consumption of silicon material, and can be used to prepare bendable battery components.

[0003] The main process flow of the HJT cell process includes texturing and cleaning, growing amorphous silicon thin film (CVD deposition of boron and phosphorus), double-sided sputtering of TCO transparent conductive film, screen printing, testing and sorting, etc. Among them, the deposition of amorphous silicon thin film is the most core step of the HJT cell process, and the specific steps are as follows: taking an N-type monocrystalline silicon wafer as a substrate, depositing a front-side intrinsic amorphous silicon thin film and a phosphorus-doped amorphous silicon thin film on the front side of the texturing and cleaning silicon wafer in sequence, and depositing a back-side intrinsic amorphous silicon thin film and a boron-doped amorphous silicon thin film on the back side of the silicon wafer in sequence to form a P-N heterojunction. The heterojunction cell is different from the conventional cell, and has higher requirements for the film layer contact interface. The cleanliness of the silicon wafer surface directly affects the contact passivation effect of the intrinsic amorphous silicon film layer and the N-type silicon substrate, so it is necessary to ensure that the surface of the silicon wafer after texturing and cleaning is clean enough.

[0004] At present, the heterojunction cell texturing and cleaning process in the industry can meet the normal cleaning needs. As shown in Figure 1 , it is a flowchart of the existing texturing and cleaning process. As shown in Figure 1 , the existing texturing and cleaning technology uses a large amount of HF, HNO3, NH4OH and other chemicals, which not only has a very high cost of chemicals used, but also has poor uniformity of the textured surface after texturing and cleaning, complicated and complex cleaning steps of the texturing equipment, long process time, and also causes a large amount of waste liquid containing nitrogen to be discharged, polluting the environment and wasting water resources due to repeated cleaning of chemical solutions. Therefore, how to design a texturing and cleaning method that can improve the quality of the textured surface of the silicon wafer, shorten the process time, reduce the cost, and reduce the environmental pollution is a technical problem to be solved in the industry. SUMMARY

[0005] To solve the above technical problems, the application provides a texturing and cleaning process for a heterojunction solar cell.

[0006] A texturing and cleaning process for a heterojunction solar cell, comprising the following steps:

[0007] S1, using a pre-cleaning solution composed of potassium hydroxide and hydrogen peroxide to pre-clean the N-type silicon wafer to remove organic residues and metal impurity pollutants on the surface of the N-type silicon wafer;

[0008] S2, after the first water washing of the silicon wafer treated in S1, using a texturing solution composed of potassium hydroxide and a texturing additive to perform texturing treatment on the silicon wafer to form a pyramid texture;

[0009] S3, after the second water washing of the silicon wafer treated in S2, using a mixed aqueous solution composed of ozone water and hydrochloric acid to perform first cleaning treatment on the silicon wafer after the second water washing to remove organic matter and part of metal impurities on the surface of the silicon wafer;

[0010] S4, after the third water washing of the silicon wafer treated in S3, using a mixed aqueous solution composed of ozone water and hydrofluoric acid to perform second cleaning treatment on the silicon wafer after the third water washing to perform corrosion and rounding on the pyramid texture;

[0011] S5, after the fourth water washing of the silicon wafer treated in S4, using a mixed aqueous solution composed of hydrogen peroxide and hydrochloric acid to perform third cleaning treatment on the silicon wafer after the fourth water washing to remove metal ions on the surface of the silicon wafer;

[0012] S6, after the fifth water washing of the silicon wafer treated in S5, using a hydrofluoric acid aqueous solution to perform fourth cleaning on the silicon wafer after the fifth water washing to remove the oxide layer on the surface of the silicon wafer itself;

[0013] S7, hot water washing of the silicon wafer treated in S6, and heating and drying by clean air.

[0014] Optionally, in the pre-cleaning solution of S1, the volume ratio of potassium hydroxide is 1-3%, the volume ratio of hydrogen peroxide is 3-5%, and the rest is deionized water; the pre-cleaning temperature is 60-70℃, and the time is 120-240s.

[0015] Optionally, in the texturing solution of S2, the volume ratio of potassium hydroxide is 4-5%, the volume ratio of the texturing additive is 0.1-0.4%, and the rest is deionized water; the texturing treatment temperature is 70-85℃, and the time is 600-850s.

[0016] Optionally, in the mixed aqueous solution of ozone water and hydrochloric acid of S3, the volume percentage of hydrochloric acid is 0.1-0.3%, the concentration of ozone water is 25-30ppm, and the rest is deionized water; the first cleaning treatment time is 120-240s, and the temperature is normal temperature.

[0017] Optionally, in the mixed aqueous solution of ozone water and hydrofluoric acid of S4, the volume percentage of hydrofluoric acid is 0.5-1%, the concentration of ozone water is 30-40ppm, and the rest is deionized water; the second cleaning treatment time is 100-150s, and the temperature is normal temperature.

[0018] Optionally, in the mixed aqueous solution of hydrogen peroxide and hydrochloric acid of S5, the volume percentage of hydrogen peroxide is 8-10%, the volume percentage of hydrochloric acid is 8-10%, and the rest is deionized water; the third cleaning treatment temperature is 60-70℃, and the cleaning time is 120-240s.

[0019] Optionally, in the aqueous solution of hydrofluoric acid of S6, the volume percentage of hydrofluoric acid is 10-20%, and the rest is deionized water; the fourth cleaning temperature is normal temperature, and the cleaning time is 120-240s.

[0020] All the optional technical solutions described above can be combined arbitrarily, and the application does not provide detailed description of the structure after combination.

[0021] Through the above scheme, the application has the following advantages:

[0022] By introducing the mixed aqueous solution of ozone water and hydrochloric acid and the mixed aqueous solution of ozone water and hydrofluoric acid into the cleaning process after texturing, the organic matter and part of the metal impurities on the surface of the silicon wafer are removed, and the pyramid surface is corroded and rounded. Not only is the step of removing the damage layer in the traditional texturing process removed, thereby saving the process and shortening the process time, but also the prepared surface is more uniform, and the use of alkali and HNO3, NH4OH, etc. is avoided, thereby saving the cost of chemicals and avoiding the pollution of the environment caused by the discharge of a large amount of waste liquid containing nitrogen elements. By washing with water after each step, cross contamination between chemical solutions can be avoided, and the service life of the chemical solution can be prolonged. Therefore, the method provided by the embodiment of the application can obtain a better surface morphology of the textured surface, ensure that the surface of the silicon wafer is completely clean, improve the passivation effect of amorphous silicon deposition, and improve the minority carrier lifetime, thereby greatly improving the performance of the heterojunction solar cell. The application has the advantages of fewer process steps, low cost, good uniformity of the textured surface, and environmental protection.

[0023] The above description is only a summary of the technical solutions of the application. In order to more clearly understand the technical means of the application and to implement the content of the description, the following will describe the preferred embodiments of the application in detail with reference to the accompanying drawings. Attached Figure Description

[0024] Figure 1 This is a flowchart of the existing texturing and cleaning process.

[0025] Figure 2 This is a flowchart of the present invention. Detailed Implementation

[0026] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0027] like Figure 1 As shown, the texturing and cleaning process for heterojunction solar cells provided by the present invention includes the following steps:

[0028] S1, using a pre-cleaning solution composed of potassium hydroxide and hydrogen peroxide to pre-clean the N-type silicon wafer to remove organic matter and metallic impurities remaining on the surface of the N-type silicon wafer after cutting.

[0029] In the pre-cleaning solution of S1, the volume percentage of potassium hydroxide is 1-3%, the volume percentage of hydrogen peroxide is 3-5%, and the remainder is deionized water; the pre-cleaning temperature is 60-70℃ and the time is 120-240s.

[0030] S2: After the silicon wafers treated in S1 are washed with water for the first time, a texturing solution composed of potassium hydroxide and texturing additives is used to texturize the silicon wafers to form a pyramidal textured surface.

[0031] In the texturing solution of S2, potassium hydroxide accounts for 4-5% by volume, texturing additives account for 0.1-0.4% by volume, and the remainder is deionized water; the texturing treatment temperature is 70-85℃, and the time is 600-850s. The texturing additives are a mixture of sodium carboxymethyl cellulose, polyethylene glycol, etc.

[0032] S3 involves a second water wash of the silicon wafers after the S2 treatment, followed by a first cleaning treatment using a mixed aqueous solution of ozone water and hydrochloric acid to remove organic matter and some metallic impurities from the surface of the silicon wafers.

[0033] In the mixed aqueous solution of ozone water and hydrochloric acid in S3, the volume percentage of hydrochloric acid is 0.1-0.3%, the concentration of ozone water is 25-30 ppm, and the remainder is deionized water; the first cleaning treatment takes 120-240 seconds and is performed at room temperature.

[0034] S4, after the third water washing of the silicon wafer processed in S3, a mixed aqueous solution composed of ozone water and hydrofluoric acid is used to perform second cleaning treatment on the third water washed silicon wafer, so as to corrode and round the pyramid suede.

[0035] In the mixed aqueous solution composed of ozone water and hydrofluoric acid in S4, the volume ratio of hydrofluoric acid is 0.5-1%, the concentration of ozone water is 30-40ppm, and the rest is deionized water; the second cleaning treatment time is 100-150s, and the temperature is normal temperature.

[0036] S5, after the fourth water washing of the silicon wafer processed in S4, a mixed aqueous solution composed of hydrogen peroxide and hydrochloric acid is used to perform third cleaning treatment on the fourth water washed silicon wafer, so as to remove the metal ions on the surface of the silicon wafer.

[0037] In the mixed aqueous solution composed of hydrogen peroxide and hydrochloric acid in S5, the volume ratio of hydrogen peroxide is 8-10%, the volume ratio of hydrochloric acid is 8-10%, and the rest is deionized water; the third cleaning treatment temperature is 60-70℃, and the cleaning time is 120-240s.

[0038] S6, after the fifth water washing of the silicon wafer processed in S5, a hydrofluoric acid aqueous solution is used to perform fourth cleaning on the fifth water washed silicon wafer, so as to remove the oxide layer on the surface of the silicon wafer itself.

[0039] In the hydrofluoric acid aqueous solution in S6, the volume ratio of hydrofluoric acid is 10-20%, and the rest is deionized water; the fourth cleaning temperature is normal temperature, and the cleaning time is 120-240s.

[0040] S7, hot water washing is performed on the silicon wafer processed in S6, and clean air is introduced for heating and drying.

[0041] It should be noted that the purpose of water washing in each step is to completely remove the chemical liquid in the previous step, so as to avoid cross contamination of chemicals in the next tank. The water washing time is not specially limited, and the time is shortened as much as possible under the condition that the chemical liquid is cleaned.

[0042] As shown in Table 1, which is an electrical performance comparison table of a heterojunction solar cell (comparative example) prepared by the existing texturing cleaning process and a heterojunction solar cell (example) prepared by the texturing cleaning process provided by the present application, the electrical performance of the comparative example is taken as the benchmark.

[0043]

[0044] From table one can be obtained: the battery piece prepared by the technical scheme of the embodiment of the present application has better uniformity of surface morphology, the efficiency is 0.15% higher than that of the conventional heterojunction solar cell, and the open circuit voltage and short circuit current are also improved.

[0045] The post-texturing cleaning process provided by the embodiment of the present application introduces the ozone water solution system (a mixed aqueous solution composed of ozone water and hydrochloric acid, a mixed aqueous solution composed of ozone water and hydrofluoric acid) to clean the silicon wafer after texturing, which not only removes the step of removing the damage layer in the traditional texturing cleaning process, but also completely eliminates the use of alkali during post-cleaning, and can obtain a better surface morphology of the textured surface. By washing with water after each step, cross contamination between chemical solutions can be avoided, the service life of the chemical solution is prolonged, the surface of the silicon wafer is completely clean, the passivation effect of amorphous silicon deposition is improved, the minority carrier lifetime is improved, and the performance of the heterojunction solar cell is greatly improved.

[0046] The following describes several specific embodiments of the embodiment of the present application: Embodiment 1

[0047] The texturing cleaning process for the heterojunction solar cell provided by the present application comprises the following steps:

[0048] S1, using a pre-cleaning solution composed of potassium hydroxide and hydrogen peroxide to pre-clean the N-type silicon wafer, wherein the volume ratio of potassium hydroxide is 1.5%, the volume ratio of hydrogen peroxide is 5%, the pre-cleaning temperature is 70℃, and the time is 240s.

[0049] S2, after the first water washing of the silicon wafer treated in S1, using a texturing solution with a volume ratio of potassium hydroxide of 5% and a volume ratio of a mixture of carboxymethyl cellulose sodium and polyethylene glycol of 0.4% as a texturing additive to texturize the silicon wafer, the texturing temperature is 72℃, and the time is 600s.

[0050] S3, after the second water washing of the silicon wafer treated in S2, using a mixed aqueous solution composed of hydrochloric acid with a volume ratio of 0.2% and ozone water with a concentration of 30ppm to perform the first cleaning treatment on the silicon wafer after the second water washing, the first cleaning treatment is carried out at room temperature for 120s.

[0051] S4, after the third water washing of the silicon wafer treated in S3, using a mixed aqueous solution composed of hydrofluoric acid with a volume ratio of 0.5% and ozone water with a concentration of 35ppm to perform the second cleaning treatment on the silicon wafer after the third water washing, the second cleaning treatment is carried out at room temperature for 100s.

[0052] S5, after the fourth water washing of the silicon wafer treated by S4, the third cleaning treatment of the fourth water washing silicon wafer is carried out by using the mixed aqueous solution composed of hydrogen peroxide and hydrochloric acid, the volume ratio of hydrogen peroxide is 8%, and the volume ratio of hydrochloric acid is 8%, the cleaning temperature of the third cleaning treatment is set to 70 DEG C, and the cleaning time is 120s.

[0053] S6, after the fifth water washing of the silicon wafer treated by S5, the fourth cleaning of the fifth water washing silicon wafer is carried out by using the hydrofluoric acid aqueous solution, the volume ratio of hydrofluoric acid is 20%, and the fourth cleaning is carried out at room temperature for 120s.

[0054] S7, after the hot water washing of the silicon wafer treated by S6, clean air is introduced for heating and drying. Embodiment 2

[0055] The present application provides a texturing cleaning process of a heterojunction solar cell, which comprises the following steps:

[0056] S1, the N-type silicon wafer is pre-cleaned by using the pre-cleaning solution composed of potassium hydroxide and hydrogen peroxide, the volume ratio of potassium hydroxide is 1%, the volume ratio of hydrogen peroxide is 3%, the pre-cleaning temperature is 60 DEG C, and the time is 120s.

[0057] S2, after the first water washing of the silicon wafer treated by S1, the silicon wafer is textured by using the texturing solution, the volume ratio of potassium hydroxide is 4%, the volume ratio of the mixture of texturing additives such as carboxymethyl cellulose sodium and polyethylene glycol is 0.1%, the texturing temperature is 70 DEG C, and the time is 600s.

[0058] S3, after the second water washing of the silicon wafer treated by S2, the first cleaning treatment of the second water washing silicon wafer is carried out by using the mixed aqueous solution composed of ozone water and hydrochloric acid, the volume ratio of hydrochloric acid is 0.1%, and the concentration of ozone water is 25ppm, the first cleaning treatment is carried out at room temperature for 120s.

[0059] S4, after the third water washing of the silicon wafer treated by S3, the second cleaning treatment of the third water washing silicon wafer is carried out by using the mixed aqueous solution composed of ozone water and hydrofluoric acid, the volume ratio of hydrofluoric acid is 0.5%, and the concentration of ozone water is 30ppm, and the second cleaning treatment is carried out at room temperature for 100s.

[0060] S5, after the fourth water washing of the silicon wafer treated by S4, the third cleaning treatment of the fourth water washing silicon wafer is carried out by using the mixed aqueous solution composed of hydrogen peroxide and hydrochloric acid, the volume ratio of hydrogen peroxide is 8%, and the volume ratio of hydrochloric acid is 8%, the cleaning temperature of the third cleaning treatment is set to 60 DEG C, and the cleaning time is 120s.

[0061] S6, after the fifth water washing of the silicon wafer treated in S5, the fourth cleaning of the silicon wafer after the fifth water washing is performed by using a hydrofluoric acid aqueous solution with a volume ratio of 10% of hydrofluoric acid, and the fourth cleaning is performed at normal temperature for 120s.

[0062] S7, after the hot water washing of the silicon wafer treated in S6, clean air is introduced for heating and drying. Embodiment 3

[0063] The present application provides a texturing and cleaning process for a heterojunction solar cell, which comprises the following steps:

[0064] S1, the N-type silicon wafer is pre-cleaned by using a pre-cleaning solution composed of potassium hydroxide and hydrogen peroxide, wherein the volume ratio of potassium hydroxide is 3%, the volume ratio of hydrogen peroxide is 5%, the pre-cleaning temperature is 70℃, and the pre-cleaning time is 240s.

[0065] S2, after the first water washing of the silicon wafer treated in S1, the silicon wafer is textured by using a texturing solution with a volume ratio of 5% of potassium hydroxide and a volume ratio of 0.4% of a mixture of texturing additives such as sodium carboxymethyl cellulose and polyethylene glycol, and the texturing temperature is 85℃ and the texturing time is 850s.

[0066] S3, after the second water washing of the silicon wafer treated in S2, the silicon wafer after the second water washing is first cleaned by using a mixed aqueous solution composed of hydrochloric acid with a volume ratio of 0.3% and ozone water with a concentration of 30ppm, and the first cleaning is performed at normal temperature for 240s.

[0067] S4, after the third water washing of the silicon wafer treated in S3, the silicon wafer after the third water washing is second cleaned by using a mixed aqueous solution composed of hydrofluoric acid with a volume ratio of 1% and ozone water with a concentration of 40ppm, and the second cleaning is performed at normal temperature for 150s.

[0068] S5, after the fourth water washing of the silicon wafer treated in S4, the silicon wafer after the fourth water washing is third cleaned by using a mixed aqueous solution composed of hydrogen peroxide with a volume ratio of 10% and hydrochloric acid with a volume ratio of 10%, and the third cleaning is performed at a cleaning temperature of 70℃ for 240s.

[0069] S6, after the fifth water washing of the silicon wafer treated in S5, the fourth cleaning of the silicon wafer after the fifth water washing is performed by using a hydrofluoric acid aqueous solution with a volume ratio of 20%, and the fourth cleaning is performed at normal temperature for 240s.

[0070] S7, after the hot water washing of the silicon wafer treated in S6, clean air is introduced for heating and drying. Embodiment 4

[0071] The present application provides a texturing and cleaning process for a heterojunction solar cell, which comprises the following steps:

[0072] S1, using a pre-cleaning solution composed of potassium hydroxide and hydrogen peroxide to pre-clean the N-type silicon wafer, wherein the volume ratio of potassium hydroxide is 2%, the volume ratio of hydrogen peroxide is 4%, the pre-cleaning temperature is 70℃, and the time is 180s.

[0073] S2, after the first water washing of the silicon wafer treated in S1, using a texturing solution with a volume ratio of potassium hydroxide of 4.5% and a mixture of texturing additives such as carboxymethyl cellulose sodium and polyethylene glycol with a volume ratio of 0.25% to texturing the silicon wafer, the texturing temperature is 78℃, and the time is 675s.

[0074] S3, after the second water washing of the silicon wafer treated in S2, using a mixed aqueous solution composed of hydrochloric acid with a volume ratio of 0.2% and ozone water with a concentration of 27ppm to perform the first cleaning treatment on the silicon wafer after the second water washing, the first cleaning treatment is carried out at room temperature for 180s.

[0075] S4, after the third water washing of the silicon wafer treated in S3, using a mixed aqueous solution composed of hydrofluoric acid with a volume ratio of 0.75% and ozone water with a concentration of 35ppm to perform the second cleaning treatment on the silicon wafer after the third water washing, the second cleaning treatment is carried out at room temperature for 125s.

[0076] S5, after the fourth water washing of the silicon wafer treated in S4, using a mixed aqueous solution composed of hydrogen peroxide with a volume ratio of 9% and hydrochloric acid with a volume ratio of 9% to perform the third cleaning treatment on the silicon wafer after the fourth water washing, the third cleaning treatment is carried out at a cleaning temperature of 65℃ for 180s.

[0077] S6, after the fifth water washing of the silicon wafer treated in S5, using a hydrofluoric acid aqueous solution with a volume ratio of 15% to perform the fourth cleaning on the silicon wafer after the fifth water washing, the fourth cleaning is carried out at room temperature for 180s.

[0078] S7, using hot water to perform hot water washing on the silicon wafer treated in S6, and then heating and drying by introducing clean air.

[0079] The above only describes the preferred embodiments of the present application and is not used to limit the present application. It should be pointed out that for ordinary skilled persons in the technical field, several improvements and modifications can be made without departing from the technical principles of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A texturing and cleaning process method for a heterojunction solar cell, characterized by, The method comprises the following steps: S1, pre-cleaning N-type silicon wafer with a pre-cleaning solution composed of potassium hydroxide and hydrogen peroxide to remove organic residues and metal impurities on the surface of the N-type silicon wafer; S2, after the first water washing of the silicon wafer treated in S1, the silicon wafer is treated with a texturing solution composed of potassium hydroxide and texturing additives to form a pyramid texture; S3, after the second water washing of the silicon wafer treated in S2, the silicon wafer is treated with a mixed aqueous solution composed of ozone water and hydrochloric acid to remove organic matter and part of metal impurities on the surface of the silicon wafer; S4, after the third water washing of the silicon wafer treated in S3, the silicon wafer is treated with a mixed aqueous solution composed of ozone water and hydrofluoric acid to corrode and round the pyramid texture; S5, after the fourth water washing of the silicon wafer treated in S4, the silicon wafer is treated with a mixed aqueous solution composed of hydrogen peroxide and hydrochloric acid to remove metal ions on the surface of the silicon wafer; S6, after the fifth water washing of the silicon wafer treated in S5, the silicon wafer is treated with a hydrofluoric acid aqueous solution to remove the oxide layer on the surface of the silicon wafer; S7, the silicon wafer treated in S6 is washed with hot water and dried by heating with clean air; In the pre-cleaning solution of S1, the volume percentage of potassium hydroxide is 1-3%, the volume percentage of hydrogen peroxide is 3-5%, and the rest is deionized water; the pre-cleaning temperature is 60-70℃, and the time is 120-240s; In the texturing solution of S2, the volume percentage of potassium hydroxide is 4-5%, the volume percentage of texturing additives is 0.1-0.4%, and the rest is deionized water; the texturing temperature is 70-85℃, and the time is 600-850s; the texturing additives include carboxymethyl cellulose sodium and polyethylene glycol; In the mixed aqueous solution composed of ozone water and hydrochloric acid of S3, the volume percentage of hydrochloric acid is 0.1-0.3%, the concentration of ozone water is 25-30ppm, and the rest is deionized water; the first cleaning treatment time is 120-240s, and the temperature is normal temperature; In the mixed aqueous solution composed of ozone water and hydrofluoric acid of S4, the volume percentage of hydrofluoric acid is 0.5-1%, the concentration of ozone water is 30-40ppm, and the rest is deionized water; the second cleaning treatment time is 100-150s, and the temperature is normal temperature; In the mixed aqueous solution composed of hydrogen peroxide and hydrochloric acid of S5, the volume percentage of hydrogen peroxide is 8-10%, the volume percentage of hydrochloric acid is 8-10%, and the rest is deionized water; the third cleaning treatment temperature is 60-70℃, and the cleaning time is 120-240s; In the hydrofluoric acid aqueous solution of S6, the volume percentage of hydrofluoric acid is 10-20%, and the rest is deionized water; the fourth cleaning temperature is normal temperature, and the cleaning time is 120-240s.

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