CN104393118A - Crystalline silicon solar cell wet chemical treatment method for performing texture surface making and cleaning steps - Google Patents

Abstract

The invention discloses a method for wet chemical treatment of crystalline silicon solar cells in which texturing and cleaning are carried out step by step. The steps of the method are as follows: (1) providing a pre-treated silicon wafer; (2) adopting the first cleaning The silicon wafer is pre-cleaned with the liquid to remove the particle impurities and pollution on the surface of the silicon wafer; (3) The silicon wafer is polished with the polishing and etching liquid to corrode the mechanical damage layer on the surface; (4) The silicon wafer is treated with the texturing liquid Carry out texturing treatment to form a textured structure on the surface; (5) Use the second cleaning solution to clean the silicon wafer to remove surface metal ions, neutralize alkaline impurities, and reduce surface chemical residues; (6) Use oxidation The etching solution treats the silicon wafer to remove the oxide layer and form a hydrophobic dry structure on its surface. The silicon wafers can be stored for a long time after texturing, and the surface cleanliness and anti-reflection effect reach a higher level, which greatly reduces the production time and improves the production efficiency.

Description

Wet chemical treatment method for crystalline silicon solar cells by performing texturing and cleaning step by step

technical field

The invention relates to a method for wet chemical treatment of crystalline silicon solar cells by performing texturing and cleaning step by step.

Background technique

At present, the existing wet chemical treatment methods for crystalline silicon solar cells are generally composed of silicon wafer pretreatment, polishing, texturing, RCA cleaning, drying and other processes. The production efficiency is seriously limited. After wet chemical treatment, the uniformity of the suede surface of the silicon wafer is poor, the size of the "pyramid" structure is large, and the anti-reflection effect is average. It is easy to be brought into the cleaning process, causing solution pollution, reducing the service life of the cleaning solution, and affecting the cleaning effect.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the defects of the prior art, and to provide a wet chemical treatment method for crystalline silicon solar cells in which texturing and cleaning are carried out step by step. After texturing, the silicon wafer can be stored for a long time, and its surface The cleanliness and anti-reflection effect have reached a high level, greatly reducing production time and improving production efficiency.

In order to solve the above technical problems, the technical solution of the present invention is: a method for wet chemical treatment of crystalline silicon solar cells by performing texturing and cleaning step by step, the steps of the method are as follows:

(1) Provide a pre-treated silicon wafer; the pre-treatment is: put the silicon wafer in the flower basket into pure water to soak and overflow, rinse for 1-10 minutes, and remove dust, etc. The resistivity of pure water is 10-18MΩ;

(2) Pre-cleaning the silicon wafer with the first cleaning solution to remove particle impurities and pollution on the surface of the silicon wafer;

(3) Polishing the silicon wafer with a polishing etchant to corrode the mechanically damaged layer on the surface;

(4) adopt texturing liquid to carry out texturing process to silicon chip, make its surface form the textured structure;

(5) Using the second cleaning solution to clean the silicon wafer to remove surface metal ions, neutralize alkaline impurities, and reduce surface chemical residues;

(6) Treat the silicon wafer with an oxidative etching solution to remove the oxide layer and form a hydrophobic dry structure on its surface;

(7) Repeated oxidation-corrosion treatment on the surface of the silicon wafer;

(8) Using the third cleaning solution to clean the silicon wafer to remove surface particle impurities and chemically neutralize them;

(9) Finally, the fourth cleaning solution is used to clean the silicon wafer to remove the oxide layer and surface metal ions, and at the same time form a passivated hydrophobic surface to complete the wet chemical treatment of the crystalline silicon solar cell.

Further, because the storage time does not affect the anti-reflection effect of the suede, the steps (6) and (7) also include the step of putting the silicon wafer into a drying cabinet for storage.

Further, in the step (2), the first cleaning solution is a mixed solution of sodium hydroxide and hydrogen peroxide; and wherein the mass percentage concentration of sodium hydroxide is 0.1% to 3%, and the mass percentage of hydrogen peroxide is The percentage concentration is 1% to 10%.

Further, the step (2) specifically includes: putting the pretreated silicon wafer into the first cleaning solution for 1-5 minutes of pre-cleaning, the temperature is controlled at 50-80°C; and then rinsing with pure water.

Further, in the step (3), the polishing and etching solution is sodium hydroxide with a concentration of 10%-50% by mass.

Further, the step (3) specifically includes: placing the silicon wafer in a polishing etchant, the temperature is controlled at 60°C to 100°C, and the mechanical damage layer formed during the slicing process of the silicon wafer is etched away, and the reaction time is 1-100°C. For 10 minutes, corrode 3-20um on each side of the silicon wafer; then rinse with pure water.

Further, in the step (4), the texturing solution is a mixed solution of sodium hydroxide and a texturing additive; and wherein the mass percent concentration of sodium hydroxide is 0.5% to 8%, the texturing The mass percent concentration of the additive is 0.5%-5%.

Further, the step (4) specifically includes: putting the silicon wafer into the texturing solution for texturing, the reaction temperature is 70-90° C., and the reaction time is 10-30 minutes; and then rinsed with pure water.

Further, in the step (5), the second cleaning solution is an SC2 cleaning solution, and the SC2 cleaning solution is a mixed solution of HCL, H ₂ O ₂ and H ₂ O; and wherein, HCL, H ₂ The volume ratio of O ₂ and H ₂ O is 1:(1-3):(10-15).

Further, the step (5) specifically includes: placing the silicon wafer in the second cleaning solution for 3-10 minutes to neutralize residual alkaline substances and metal ions on the surface of the silicon wafer; and then rinsing with pure water.

Further, in the step (6), the oxidizing corrosion solution is a hydrofluoric acid solution with a concentration of 0.5% to 5% by mass.

Further, in the step (7), in the mixed solution of HF and _HNO3 , the silicon wafer surface is repeatedly oxidized-corroded; and wherein, the volume ratio of HF and _HNO3 is 1:(50～100 ).

Further, the step (7) specifically includes: placing the silicon wafer in a mixed solution of HF and HNO ₃ to react for 0.5-2 minutes, increasing bubbling or ultrasonic treatment in the solution; and then rinsing with pure water.

Further, in the step (8), the third cleaning solution is an SC1 mixed cleaning solution, and the SC1 mixed cleaning solution is a mixed solution of NH ₄ OH, H ₂ O ₂ and H ₂ O; and wherein, The volume ratio of NH ₄ OH, H ₂ O ₂ and H ₂ O is: 1:(0.5-5):(10-15).

Further, the step (8) specifically includes: placing the silicon wafer in a third cleaning solution at a temperature of 60-80° C. to react for 1-10 minutes; and then rinsing with pure water.

Further, in the step (9), the fourth cleaning solution is a mixed solution of hydrofluoric acid and hydrochloric acid; and wherein, the mass percent concentration of hydrofluoric acid is 0.5% to 5%, and the mass percent concentration of hydrochloric acid The percentage concentration is 0.5% to 5%.

Further, the step (9) specifically includes: placing the silicon wafer in the fourth cleaning solution for 1 to 10 minutes to remove the oxide layer and surface metal ions, and passivate the surface of the silicon wafer to form a hydrophobic surface; then use Rinse with pure water.

After adopting the above-mentioned technical scheme, the present invention divides the wet chemical process into two sections, that is, the texturing section and the cleaning section, wherein the texturing section adopts a specific texturing method to form uniform and compact small-sized " Pyramid" structure suede, and can be carried out in large quantities continuously. After the texturing, the silicon wafer can be stored for a long time after simple treatment, and the preserved silicon wafer can be taken out and cleaned according to the need. The surface cleanliness and anti-reflection effect can reach a high level. The chemical process time is reduced to about 1.5h, which improves the production efficiency. In addition, the silicon wafer forms a hydrophobic and dry surface after being treated in the texturing section, and the hydrophobic surface enters the cleaning section process for cleaning with the cleaning solution, which avoids uneven etching of the hydrophilic silicon wafer due to concentration differences in the cleaning solution. The wet chemical method improves production efficiency, simplifies the process, and prevents solution cross-contamination, and the efficiency of the heterojunction high-efficiency solar cells prepared by the wet chemical method can reach 20%.

Description of drawings

Fig. 1 is the process flow diagram of the texturing section of the present invention;

Fig. 2 is the process flow diagram of cleaning section of the present invention;

Fig. 3 is the top view of the mechanically damaged layer on the surface of the silicon chip of the present invention;

Fig. 4 is the top view of the silicon chip suede surface after the texturing of the present invention;

Fig. 5 is the side view of the silicon chip suede surface after the texturing of the present invention;

Fig. 6 is a diagram showing changes in reflectivity of silicon wafers before and after texturing.

Detailed ways

In order to make the content of the present invention more clearly understood, the present invention will be further described in detail below based on specific embodiments and in conjunction with the accompanying drawings.

As shown in Figures 1 to 2, a wet chemical treatment method for crystalline silicon solar cells is carried out in steps of texturing and cleaning. The steps of the method are as follows:

Embodiment one

The operation of the velvet section is as follows:

(1) Provide a pre-treated silicon wafer; the pre-treatment is: put the silicon wafer in the flower basket into pure water to soak and overflow, rinse for 5 minutes, and remove dust, etc. The resistivity of pure water is 10-18MΩ.

(2) Pre-cleaning the silicon wafer with the first cleaning solution to remove particle impurities and pollution on the surface of the silicon wafer;

(3) Polishing the silicon wafer with a polishing etchant to corrode the mechanically damaged layer on the surface, the mechanically damaged layer is shown in Figure 3;

(4) adopt texturing liquid to carry out texturing process to silicon chip, make its surface form the textured structure;

(5) Using the second cleaning solution to clean the silicon wafer to remove surface metal ions, neutralize alkaline impurities, and reduce surface chemical residues;

(6) Treat the silicon wafer with an oxidative etching solution to remove the oxide layer and form a hydrophobic dry structure on its surface;

Textured silicon wafers can be stored in a drying cabinet. Due to the high repeatability of the texturing process, it can be carried out continuously in large quantities. The silicon wafers after texturing can be taken out as needed, and low reflectivity and low surface composite can be obtained through the following cleaning process. speed silicon wafers.

The specific operation steps of the cleaning section are as follows:

(7) Repeated oxidation-corrosion treatment on the surface of the silicon wafer;

(8) Using the third cleaning solution to clean the silicon wafer to remove surface particle impurities and chemically neutralize them;

(9) Finally, the fourth cleaning solution is used to clean the silicon wafer to remove the oxide layer and surface metal ions, and at the same time form a passivated hydrophobic surface to complete the wet chemical treatment of the crystalline silicon solar cell.

Wherein, in the step (2), the first cleaning solution is a mixed solution of sodium hydroxide and hydrogen peroxide; and wherein, the mass percent concentration of sodium hydroxide is 0.1%, and the mass percent concentration of hydrogen peroxide 1%.

The step (2) specifically includes: putting the pretreated silicon wafer into the first cleaning solution for 3 minutes of pre-cleaning, the temperature is controlled at 60° C.; and then rinsing with pure water for 5 minutes.

In the step (3), the polishing and etching solution is sodium hydroxide with a concentration of 30% by mass.

The step (3) specifically includes: placing the silicon wafer in a polishing etching solution, controlling the temperature to 90° C., etching away the mechanically damaged layer formed during the slicing process of the silicon wafer, with a reaction time of 3 minutes, and etching each side of the silicon wafer 10um; then rinse with pure water for 5min.

In described step (4), described texturing liquid is the mixed solution of sodium hydroxide and texturing additive; And wherein, the mass percentage concentration of sodium hydroxide is 5%, the mass percentage of texturing additive The concentration is 3%.

The step (4) specifically includes: putting the silicon chip into the texturing solution for texturing, the reaction temperature is 80° C., and the reaction time is 12 minutes; and then rinsed with pure water for 5 minutes.

In the step (5), the second cleaning solution is an SC2 cleaning solution, and the SC2 cleaning solution is a mixed solution of HCL, H ₂ O ₂ and H ₂ O; and wherein, HCL, H ₂ O ₂ , The volume ratio of H ₂ O is 1:1:10.

The step (5) specifically includes: placing the silicon wafer in the second cleaning solution for 5 minutes to neutralize residual alkaline substances and metal ions on the surface of the silicon wafer; and then rinsing with pure water for 5 minutes.

In the step (6), the oxidation corrosion solution is a hydrofluoric acid solution with a concentration of 5% by mass.

In the step (7), the surface of the silicon wafer is repeatedly oxidized-etched in a mixed solution of HF and HNO ₃ ; and wherein the volume ratio of HF and HNO ₃ is 1:50.

The step (7) specifically includes: placing the silicon wafer in a mixed solution of HF and HNO ₃ to react for 1 min, adding bubbling or ultrasonic treatment in the solution; and then rinsing with pure water for 5 min.

In the step (8), the third cleaning solution is an SC1 mixed cleaning solution, and the SC1 mixed cleaning solution is a mixed solution of NH ₄ OH, H ₂ O ₂ and H ₂ O; and wherein, NH ₄ The volume ratio of OH, H ₂ O ₂ and H ₂ O is: 1:1:10.

The step (8) specifically includes: placing the silicon wafer in the third cleaning solution at a temperature of 60-80° C. for 1 min; then rinsing with pure water for 5 min.

In the described step (9), the fourth cleaning solution is a mixed solution of hydrofluoric acid and hydrochloric acid; and wherein the mass percent concentration of hydrofluoric acid is 5%, and the mass percent concentration of hydrochloric acid is 5%. %.

The step (9) specifically includes: placing the silicon chip in the fourth cleaning solution for 3 minutes to remove the oxide layer and surface metal ions, and passivating the surface of the silicon chip to form a hydrophobic surface; then rinse with pure water Treat for 5min.

Embodiment two

The operation of the velvet section is as follows:

(1) Provide a pre-treated silicon wafer; the pre-treatment is: put the silicon wafer in the flower basket into pure water to soak and overflow, rinse for 8 minutes, and remove dust, etc. The resistivity of pure water is 10-18MΩ.

(2) Pre-cleaning the silicon wafer with the first cleaning solution to remove particle impurities and pollution on the surface of the silicon wafer;

(3) Polishing the silicon wafer with a polishing etchant to corrode the mechanically damaged layer on the surface, the mechanically damaged layer is shown in Figure 3;

(4) adopt texturing liquid to carry out texturing process to silicon chip, make its surface form the textured structure;

(5) Using the second cleaning solution to clean the silicon wafer to remove surface metal ions, neutralize alkaline impurities, and reduce surface chemical residues;

(6) Treat the silicon wafer with an oxidative etching solution to remove the oxide layer and form a hydrophobic dry structure on its surface;

Textured silicon wafers can be stored in a drying cabinet. Due to the high repeatability of the texturing process, it can be carried out continuously in large quantities. The silicon wafers after texturing can be taken out as needed, and low reflectivity and low surface composite can be obtained through the following cleaning process. speed silicon wafers.

The specific operation steps of the cleaning section are as follows:

(7) Repeated oxidation-corrosion treatment on the surface of the silicon wafer;

(8) Using the third cleaning solution to clean the silicon wafer to remove surface particle impurities and chemically neutralize them;

(9) Finally, the fourth cleaning solution is used to clean the silicon wafer to remove the oxide layer and surface metal ions, and at the same time form a passivated hydrophobic surface to complete the wet chemical treatment of the crystalline silicon solar cell.

Wherein, in the described step (2), the first cleaning solution is a mixed solution of sodium hydroxide and hydrogen peroxide; and wherein, the mass percent concentration of sodium hydroxide is 2%, and the mass percent concentration of hydrogen peroxide 5%.

The step (2) specifically includes: putting the pretreated silicon wafer into the first cleaning solution for 3 minutes of pre-cleaning, the temperature is controlled at 60° C.; and then rinsing with pure water for 5 minutes.

In the step (3), the polishing and etching solution is sodium hydroxide with a concentration of 30% by mass.

The step (3) specifically includes: placing the silicon wafer in a polishing etchant, controlling the temperature to 80° C., etching away the mechanically damaged layer formed during the slicing process of the silicon wafer, with a reaction time of 5 minutes, and etching each side of the silicon wafer 11um; then rinse with pure water for 5min.

In described step (4), described texturing liquid is the mixed solution of sodium hydroxide and texturing additive; And wherein, the mass percentage concentration of sodium hydroxide is 4%, the mass percentage of texturing additive The concentration is 3%.

The step (4) specifically includes: putting the silicon chip into the texturing solution for texturing, the reaction temperature is 80° C., and the reaction time is 30 minutes; and then rinsed with pure water for 5 minutes.

In the step (5), the second cleaning solution is an SC2 cleaning solution, and the SC2 cleaning solution is a mixed solution of HCL, H ₂ O ₂ and H ₂ O; and wherein, HCL, H ₂ O ₂ , The volume ratio of H ₂ O is 1:2:13.

The step (5) specifically includes: placing the silicon wafer in the second cleaning solution for 7 minutes to neutralize residual alkaline substances and metal ions on the surface of the silicon wafer; and then rinsing with pure water for 5 minutes.

In the step (6), the oxidizing corrosion solution is a hydrofluoric acid solution with a concentration of 3% by mass.

In the step (7), the surface of the silicon wafer is repeatedly oxidized-etched in a mixed solution of HF and HNO ₃ ; and wherein the volume ratio of HF and HNO ₃ is 1:75.

The step (7) specifically includes: placing the silicon wafer in a mixed solution of HF and HNO ₃ to react for 1.5 min, adding bubbling or ultrasonic treatment in the solution; and then rinsing with pure water for 5 min.

In the step (8), the third cleaning solution is an SC1 mixed cleaning solution, and the SC1 mixed cleaning solution is a mixed solution of NH ₄ OH, H ₂ O ₂ and H ₂ O; and wherein, NH ₄ The volume ratio of OH, H ₂ O ₂ and H ₂ O is: 1:3:10.

The step (8) specifically includes: placing the silicon wafer in the third cleaning solution at a temperature of 70° C. for 5 minutes; then rinsing with pure water for 5 minutes.

In said step (9), said fourth cleaning solution is a mixed solution of hydrofluoric acid and hydrochloric acid; and wherein, the mass percent concentration of hydrofluoric acid is 3%, and the mass percent concentration of hydrochloric acid is 3%. %.

The step (9) specifically includes: placing the silicon wafer in the fourth cleaning solution for 5 minutes to remove the oxide layer and surface metal ions, and passivate the surface of the silicon wafer to form a hydrophobic surface; then rinse with pure water Treat for 5min.

Embodiment three

The operation of the velvet section is as follows:

(1) Provide a pre-treated silicon wafer; the pre-treatment is: put the silicon wafer in the flower basket into pure water to soak and overflow, rinse for 1 min, and remove dust, etc. The resistivity of pure water is 10-18MΩ.

(2) Pre-cleaning the silicon wafer with the first cleaning solution to remove particle impurities and pollution on the surface of the silicon wafer;

(3) Polishing the silicon wafer with a polishing etchant to corrode the mechanically damaged layer on the surface, the mechanically damaged layer is shown in Figure 3;

(4) adopt texturing liquid to carry out texturing process to silicon chip, make its surface form the textured structure;

(5) Using the second cleaning solution to clean the silicon wafer to remove surface metal ions, neutralize alkaline impurities, and reduce surface chemical residues;

(6) Treat the silicon wafer with an oxidative etching solution to remove the oxide layer and form a hydrophobic dry structure on its surface;

Textured silicon wafers can be stored in a drying cabinet. Due to the high repeatability of the texturing process, it can be carried out continuously in large quantities. The silicon wafers after texturing can be taken out as needed, and low reflectivity and low surface composite can be obtained through the following cleaning process. speed silicon wafers.

The specific operation steps of the cleaning section are as follows:

(7) Repeated oxidation-corrosion treatment on the surface of the silicon wafer;

(8) Using the third cleaning solution to clean the silicon wafer to remove surface particle impurities and chemically neutralize them;

(9) Finally, the fourth cleaning solution is used to clean the silicon wafer to remove the oxide layer and surface metal ions, and at the same time form a passivated hydrophobic surface to complete the wet chemical treatment of the crystalline silicon solar cell.

Wherein, in the described step (2), the first cleaning solution is a mixed solution of sodium hydroxide and hydrogen peroxide; and wherein the mass percent concentration of sodium hydroxide is 1%, and the mass percent concentration of hydrogen peroxide 5%.

The step (2) specifically includes: putting the pretreated silicon wafer into the first cleaning solution for 1 min pre-cleaning, the temperature is controlled at 50-80°C; and then rinsing with pure water.

In the step (3), the polishing and etching solution is sodium hydroxide with a concentration of 10% by mass.

The step (3) specifically includes: placing the silicon wafer in a polishing etchant, controlling the temperature to 60° C., etching away the mechanical damage layer formed during the slicing process of the silicon wafer, with a reaction time of 1 min, and etching each side of the silicon wafer 3um; then rinse with pure water.

In described step (4), described texturing liquid is the mixed solution of sodium hydroxide and texturing additive; And wherein, the mass percentage concentration of sodium hydroxide is 0.5%, the mass percentage of texturing additive The concentration is 0.5%.

The step (4) specifically includes: putting the silicon chip into the texturing solution for texturing, the reaction temperature is 70° C., and the reaction time is 10 minutes; and then rinsed with pure water.

In the step (5), the second cleaning solution is an SC2 cleaning solution, and the SC2 cleaning solution is a mixed solution of HCL, H ₂ O ₂ and H ₂ O; and wherein, HCL, H ₂ O ₂ , The volume ratio of H ₂ O is 1:2:12.

The step (5) specifically includes: placing the silicon wafer in the second cleaning solution for 3 minutes to neutralize residual alkaline substances and metal ions on the surface of the silicon wafer; and then rinse with pure water.

In the step (6), the oxidizing corrosion solution is a hydrofluoric acid solution with a concentration of 0.5% by mass.

In the step (7), the surface of the silicon wafer is repeatedly oxidized-etched in a mixed solution of HF and HNO ₃ ; and wherein the volume ratio of HF and HNO ₃ is 1:80.

The step (7) specifically includes: placing the silicon wafer in a mixed solution of HF and HNO ₃ to react for 0.5 min, increasing bubbling or ultrasonic treatment in the solution; and then rinsing with pure water.

In the step (8), the third cleaning solution is an SC1 mixed cleaning solution, and the SC1 mixed cleaning solution is a mixed solution of NH ₄ OH, H ₂ O ₂ and H ₂ O; and wherein, NH ₄ The volume ratio of OH, H ₂ O ₂ and H ₂ O is: 1:0.5:10.

The step (8) specifically includes: placing the silicon wafer in the third cleaning solution at a temperature of 60-80° C. for 1 min; and then rinsing with pure water.

In said step (9), said fourth cleaning solution is a mixed solution of hydrofluoric acid and hydrochloric acid; and wherein, the mass percent concentration of hydrofluoric acid is 0.5%, and the mass percent concentration of hydrochloric acid is 0.5% %.

The step (9) specifically includes: placing the silicon chip in the fourth cleaning solution for 1 min, removing the oxide layer and surface metal ions, and passivating the surface of the silicon chip to form a hydrophobic surface; then rinse with pure water Treat for 5min.

Embodiment four

The operation of the velvet section is as follows:

(1) Provide a pre-treated silicon wafer; the pre-treatment is: put the silicon wafer in the flower basket into pure water to soak and overflow, rinse for 10 minutes, and remove dust, etc. The resistivity of pure water is 10-18MΩ.

(2) Pre-cleaning the silicon wafer with the first cleaning solution to remove particle impurities and pollution on the surface of the silicon wafer;

(3) Polishing the silicon wafer with a polishing etchant to corrode the mechanically damaged layer on the surface, the mechanically damaged layer is shown in Figure 3;

(4) adopt texturing liquid to carry out texturing process to silicon chip, make its surface form the textured structure;

(5) Using the second cleaning solution to clean the silicon wafer to remove surface metal ions, neutralize alkaline impurities, and reduce surface chemical residues;

(6) Treat the silicon wafer with an oxidative etching solution to remove the oxide layer and form a hydrophobic dry structure on its surface;

Textured silicon wafers can be stored in a drying cabinet. Due to the high repeatability of the texturing process, it can be carried out continuously in large quantities. The silicon wafers after texturing can be taken out as needed, and low reflectivity and low surface composite can be obtained through the following cleaning process. speed silicon wafers.

The specific operation steps of the cleaning section are as follows:

(7) Repeated oxidation-corrosion treatment on the surface of the silicon wafer;

(8) Using the third cleaning solution to clean the silicon wafer to remove surface particle impurities and chemically neutralize them;

(9) Finally, the fourth cleaning solution is used to clean the silicon wafer to remove the oxide layer and surface metal ions, and at the same time form a passivated hydrophobic surface to complete the wet chemical treatment of the crystalline silicon solar cell.

Wherein, in the step (2), the first cleaning solution is a mixed solution of sodium hydroxide and hydrogen peroxide; and wherein, the mass percent concentration of sodium hydroxide is 3%, and the mass percent concentration of hydrogen peroxide 10%.

The step (2) specifically includes: putting the pretreated silicon wafer into the first cleaning solution for 5 minutes of pre-cleaning, the temperature is controlled at 80° C.; and then rinsing with pure water.

In the step (3), the polishing and etching solution is sodium hydroxide with a concentration of 50% by mass.

The step (3) specifically includes: placing the silicon wafer in a polishing etchant, the temperature is controlled at 100° C., and the mechanical damage layer formed during the slicing process of the silicon wafer is etched away. The reaction time is 10 minutes, and each side of the silicon wafer is etched. 20um; then rinse with pure water.

In described step (4), described texturing liquid is the mixed solution of sodium hydroxide and texturing additive; And wherein, the mass percentage concentration of sodium hydroxide is 8%, the mass percentage of texturing additive The concentration is 5%.

The step (4) specifically includes: putting the silicon chip into the texturing solution for texturing, the reaction temperature is 90° C., and the reaction time is 30 minutes; and then rinsed with pure water.

In the step (5), the second cleaning solution is an SC2 cleaning solution, and the SC2 cleaning solution is a mixed solution of HCL, H ₂ O ₂ and H ₂ O; and wherein, HCL, H ₂ O ₂ , The volume ratio of H ₂ O is 1:3:15.

The step (5) specifically includes: placing the silicon wafer in the second cleaning solution for 10 minutes to neutralize residual alkaline substances and metal ions on the surface of the silicon wafer; and then rinse with pure water.

In the step (6), the oxidation corrosion solution is a hydrofluoric acid solution with a concentration of 5% by mass.

In the step (7), the surface of the silicon wafer is repeatedly oxidized-etched in a mixed solution of HF and HNO ₃ ; and wherein the volume ratio of HF and HNO ₃ is 1:100.

The step (7) specifically includes: placing the silicon wafer in a mixed solution of HF and HNO ₃ to react for 2 minutes, increasing bubbling or ultrasonic treatment in the solution; and then rinsing with pure water.

In the step (8), the third cleaning solution is an SC1 mixed cleaning solution, and the SC1 mixed cleaning solution is a mixed solution of NH ₄ OH, H ₂ O ₂ and H ₂ O; and wherein, NH ₄ The volume ratio of OH, H ₂ O ₂ and H ₂ O is: 1:5:15.

The step (8) specifically includes: placing the silicon wafer in the third cleaning solution at a temperature of 60-80° C. for 10 minutes; and then rinsing with pure water.

In the described step (9), the fourth cleaning solution is a mixed solution of hydrofluoric acid and hydrochloric acid; and wherein the mass percent concentration of hydrofluoric acid is 5%, and the mass percent concentration of hydrochloric acid is 5%. %.

The step (9) is specifically: placing the silicon wafer in the fourth cleaning solution for 10 minutes to remove the oxide layer and surface metal ions, and passivate the surface of the silicon wafer to form a hydrophobic surface; then rinse with pure water Treat for 5min.

The silicon wafer is taken out from the pure water by "slow pulling" operation, and after being dried, the subsequent process can be carried out.

After testing, as shown in Figures 4 and 5, the size of the "pyramid" structure of the textured silicon wafer treated by the above wet chemical process is 1-4um, and its surface recombination rate is less than 10cm/s, as shown in Figure 6, at 300-1100nm The reflectivity of the range is about 11%, and the wet chemical process time is reduced to about 1.5h, thereby reducing the reflectivity, improving the cleanliness of the silicon wafer surface, and meeting the requirements of high-efficiency heterojunction solar cells.

The specific embodiments described above have further described the technical problems, technical solutions and beneficial effects solved by the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (17)

1., by the crystal silicon solar batteries Wet chemical processing method that making herbs into wool is carried out with cleaning substep, it is characterized in that the step of the method is as follows:

(1) silicon chip after pre-treatment is provided;

(2) the first cleaning fluid is adopted to carry out prerinse to silicon chip, to remove silicon chip surface particle impurity and pollution;

(3) adopt polishing etch liquid to carry out polishing to silicon chip, erode the mechanical damage layer on surface;

(4) adopt Woolen-making liquid to carry out making herbs into wool process to silicon chip, make its surface form suede structure;

(5) adopt the second cleaning fluid to clean silicon chip, to remove surface metal ion, and in and alkaline impurities, reduce surface chemistry remain;

(6) adopt oxide etch liquid to process silicon chip, to remove oxide layer, and form hydrophobic drying structure on its surface;

(7) to oxidation-corrosion treatment that silicon chip surface carries out repeatedly;

(8) adopt the 3rd cleaning fluid to clean silicon chip, to remove surface particles impurity, carry out chemical neutralization;

(9) finally adopt the 4th cleaning fluid to clean silicon chip, to remove oxide layer and surface metal ion, form the hydrophobic surface of passivation simultaneously, complete crystal silicon solar batteries wet-chemical treatment.

2. crystal silicon solar batteries Wet chemical processing method making herbs into wool carried out with cleaning substep according to claim 1, is characterized in that: also comprise step in described step (6) and step (7): silicon chip is put into drying cupboard and deposits.

3. the crystal silicon solar batteries Wet chemical processing method that making herbs into wool is carried out with cleaning substep according to claim 1 and 2, it is characterized in that: in described step (2), the first described cleaning fluid is the mixed solution of NaOH and hydrogen peroxide; And wherein, the mass percentage concentration of NaOH is 0.1% ~ 3%, and the mass percentage concentration of hydrogen peroxide is 1% ~ 10%.

4. the crystal silicon solar batteries Wet chemical processing method that making herbs into wool is carried out with cleaning substep according to claim 3, it is characterized in that: described step (2) is specially: the silicon chip after pre-treatment is put into the first cleaning fluid and carries out 1 ~ 5min prerinse, temperature controls at 50-80 DEG C; Then flushing process is carried out with pure water.

5. the crystal silicon solar batteries Wet chemical processing method that making herbs into wool is carried out with cleaning substep according to claim 1 and 2, it is characterized in that: in described step (3), described polishing etch liquid to be mass percentage concentration be 10% ~ 50% NaOH.

6. the crystal silicon solar batteries Wet chemical processing method that making herbs into wool is carried out with cleaning substep according to claim 5, it is characterized in that: described step (3) is specially: silicon chip is placed in polishing etch liquid, it is 60 DEG C ~ 100 DEG C that temperature controls, erode the mechanical damage layer that silicon chip is formed in slicing processes, reaction time is 1 ~ 10min, the every face corrosion of silicon chip 3 ~ 20um; Then flushing process is carried out with pure water.

7. the crystal silicon solar batteries Wet chemical processing method that making herbs into wool is carried out with cleaning substep according to claim 1 and 2, it is characterized in that: in described step (4), described Woolen-making liquid is the mixed solution of NaOH and making herbs into wool additive; And wherein, the mass percentage concentration of NaOH is 0.5% ~ 8%, and the mass percentage concentration of making herbs into wool additive is 0.5% ~ 5%.

8. the crystal silicon solar batteries Wet chemical processing method that making herbs into wool is carried out with cleaning substep according to claim 7, it is characterized in that: described step (4) is specially: silicon chip is put into Woolen-making liquid and carries out making herbs into wool, reaction temperature is 70 ~ 90 DEG C, and the reaction time is 10 ~ 30min; Then flushing process is carried out with pure water.

9. the crystal silicon solar batteries Wet chemical processing method that making herbs into wool is carried out with cleaning substep according to claim 1 and 2, it is characterized in that: in described step (5), the second described cleaning fluid is SC2 cleaning fluid, and this SC2 cleaning fluid is HCL, H ₂o ₂and H ₂the mixed solution of O; And wherein, HCL, H ₂o ₂, H ₂the volume ratio of O is 1:(1 ~ 3): (10 ~ 15).

10. the crystal silicon solar batteries Wet chemical processing method that making herbs into wool is carried out with cleaning substep according to claim 9, it is characterized in that: described step (5) is specially: silicon chip is placed in second cleaning fluid process 3 ~ 10min, in and silicon chip surface remain alkaline matter and metal ion; Then flushing process is carried out with pure water.

The 11. crystal silicon solar batteries Wet chemical processing methods that making herbs into wool is carried out with cleaning substep according to claim 1 and 2, it is characterized in that: in described step (6), described oxide etch liquid to be mass percentage concentration be 0.5% ~ 5% hydrofluoric acid solution.

12. crystal silicon solar batteries Wet chemical processing methods making herbs into wool carried out with cleaning substep according to claim 1 and 2, is characterized in that: in described step (7), at HF and HNO ₃mixed solution in carry out repeatedly to silicon chip surface oxidation-corrosion treatment; And wherein, HF and HNO ₃volume ratio be 1:(50 ~ 100).

13. crystal silicon solar batteries Wet chemical processing methods making herbs into wool carried out with cleaning substep according to claim 12, is characterized in that: described step (7) is specially: silicon chip is placed in HF and HNO ₃mixed solution in reaction 0.5 ~ 2min, increase bubbling or ultrasonic process in solution; Then flushing process is carried out with pure water.

The 14. crystal silicon solar batteries Wet chemical processing methods that making herbs into wool is carried out with cleaning substep according to claim 1 and 2, it is characterized in that: in described step (8), the 3rd described cleaning fluid is SC1 mixing cleaning fluid, and this SC1 mixing cleaning fluid is NH ₄oH, H ₂o ₂and H ₂the mixed solution of O; And wherein, NH ₄oH, H ₂o ₂and H ₂the volume ratio of O is: 1:(0.5 ~ 5): (10 ~ 15).

15. crystal silicon solar batteries Wet chemical processing methods making herbs into wool carried out with cleaning substep according to claim 14, is characterized in that: described step (8) is specially: silicon chip is put into the 3rd cleaning fluid reaction 1 ~ 10min that temperature is 60 ~ 80 DEG C; Then flushing process is carried out with pure water.

The 16. crystal silicon solar batteries Wet chemical processing methods that making herbs into wool is carried out with cleaning substep according to claim 1, it is characterized in that: in described step (9), the 4th described cleaning fluid is the mixed solution of hydrofluoric acid and hydrochloric acid; And wherein, the mass percentage concentration of hydrofluoric acid is 0.5% ~ 5%, and the mass percentage concentration of hydrochloric acid is 0.5% ~ 5%.

The 17. crystal silicon solar batteries Wet chemical processing methods that making herbs into wool is carried out with cleaning substep according to claim 16, it is characterized in that: described step (9) is specially: silicon chip is placed in the 4th cleaning fluid process 1 ~ 10min, remove oxide layer and surface metal ion, and passivation is carried out to silicon chip surface, form hydrophobic surface; Then flushing process is carried out with pure water.