Silicon wafer suede pyramid rounding device and method

Abstract

The invention discloses a silicon wafer suede pyramid rounding device and method, and relates to the technical field of crystalline silicon cell preparation, the rounding device comprises an electrolytic anode material and an electrolytic cathode material which are arranged in an ECP tank, and the electrolytic anode material and the electrolytic cathode material are connected to an external direct current power supply through acid-resistant and oxidation-resistant wires; an aeration device is arranged in the ECP tank, and the aeration device is connected to an external air compressor through a pipeline; the electrolytic cathode material is obtained through modification treatment of a substrate material, the substrate material adopts one of CF, NF and GF, and the substrate material is subjected to modification treatment through an electrochemical catalyst; and the electrolytic anode material is an inert electrode. The electrochemical advanced oxidation technology is introduced into the field of pyramid rounding, the dosage of chemicals can be reduced, self-cleaning of ECP can be achieved, and pollution caused by residual additives is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of crystalline silicon cell preparation, and in particular relates to a device and method for rounding a silicon slice velvet pyramid. Background Art

[0002] In recent years, with the increasing exhaustion of traditional energy, new energy sources such as solar energy have received more and more attention. With its mature technology and gradually reduced costs, solar cells will occupy an important position in the field of new energy. Its development and use can greatly alleviate the problem of traditional energy exhaustion. At present, the mainstream solar cells on the market are crystalline silicon cells. In the preparation process of crystalline silicon cells, silicon wafers need to be textured. In order to improve the light trapping effect of the texture, the texture rounding technology is used to optimize the texture. This process requires the consumption of a large amount of hazardous chemicals and there is a certain degree of corrosion and oxidizing gas leakage risk.

[0003] Currently, pyramid rounding technology mainly relies on chemical oxidation and etching, which consumes a lot of chemicals and has the risk of corrosion and oxidizing gas leakage. Another method is to achieve pyramid rounding through additives, but this method will increase the COD value of wastewater and increase the pressure of subsequent environmental assessment.

[0004] In summary, it is necessary to propose a device and method for rounding silicon wafer velvet pyramids, which can efficiently round the pyramids by introducing advanced oxidation process (AOPs) to obtain a better velvet structure while saving the use of a large amount of hazardous chemicals. Summary of the invention

[0005] The purpose of the present invention is to provide a silicon wafer velvet pyramid rounding device and method to solve the above-mentioned technical problems existing in the prior art.

[0006] To achieve the above-mentioned purpose, in one aspect, the present invention provides a silicon wafer velvet pyramid rounding device, comprising an electrolytic anode material and an electrolytic cathode material arranged in an ECP tank, wherein the electrolytic anode material and the electrolytic cathode material are connected to an external DC power supply through acid-resistant and oxidation-resistant wires; an aeration device is arranged in the ECP tank, and the aeration device pipeline is connected to an external air compressor; the electrolytic cathode material is obtained by modifying a base material, wherein the base material adopts one of CF, NF, and GF, and the base material is modified by an electrochemical catalyst; the electrolytic anode material is an inert electrode.

[0007] As an optional manner, the electrochemical catalyst is an iron-based catalyst, specifically an iron-containing double-layer hydroxide or a MOFs-coated magnetic iron oxide.

[0008] As an optional method, the electrochemical catalyst is prepared by a hydrothermal method, including: mixing ferric nitrate and nitrate containing one or more metals of copper, nickel, cobalt, and zinc in 75 mL of pure water at a molar ratio of 1:1 to 1:10, adding 10 to 100 mg of a surfactant and 1 to 5 mL of concentrated nitric acid and continuing to mix evenly, transferring to a 100 mL high-pressure reactor, reacting at 100 to 200° C. for 12 to 24 h, cooling to room temperature, washing with pure water, and vacuum drying at 60 to 80° C. for 8 to 12 h to obtain an electrochemical catalyst.

[0009] As an optional method, the electrochemical catalyst and methanol are mixed in a ratio of 1:10 to 1:20, ultrasonically stirred for 10 to 30 min, 1 to 10 μL of an adhesive is added, and ultrasonic stirring is continued for 30 to 60 min. The uniformly mixed electrochemical catalyst mixture is added dropwise onto the base material of the electrolytic cathode material, air-dried for 1 to 5 h, and after drying, the electrolytic cathode material is annealed in a nitrogen atmosphere at 100 to 500° C. for 30 to 60 min, rinsed with pure water 3 to 6 times after cooling, and vacuum dried at 60° C. for 6 to 8 h to obtain the electrolytic cathode material.

[0010] As an optional method, the distribution density of the electrochemical catalyst is controlled at 1 mg / cm 2 ~20 mg / cm 2 between.

[0011] As an optional manner, the ECP cell includes a composite cell 1 and a composite cell 2, the electrolytic anode material is arranged in the composite cell 1, and the electrolytic cathode material covers the entire inner wall of the composite cell 2.

[0012] As an optional method, the ECP cell is arranged in a closed photoreaction box, a xenon lamp light source is arranged in the closed photoreaction box, and the electrolytic anode material is conductive glass laid in a surrounding manner in the ECP cell.

[0013] As an optional embodiment, a photocatalyst is carried on the conductive glass.

[0014] As an optional method, an oxygen concentration probe is also provided in the ECP tank.

[0015] As an optional manner, a rotor flowmeter is connected to the pipeline connecting the aeration device and the air compressor.

[0016] On the other hand, the present invention also provides a method for rounding a pyramid surface of a silicon wafer, using any of the above-mentioned devices for rounding a pyramid surface of a silicon wafer, comprising: placing a silicon wafer in the ECP tank, energizing the electrolytic anode material and the electrolytic cathode material, and generating reactions S1 to S10 to obtain a rounded pyramid surface; the reactions S1 to S10 are: S1, O 2 +2H + ﹣2e - → H 2 O 2 ; S2、Fe 2+ +H 2 O 2 +H + →Fe 3+ +H 2 O+·OH; S3, Fe 3+ + e - →Fe 2+ ; S4、Fe 3+ + H 2 O 2 →Fe 2+ +·OOH+ H + ; S5, H 2 O 2 +·OH→·OOH+H 2 O; S6, ·OH+·OH→ H 2 O 2 ; S7, 2·OH+Si→SiO 2 +H 2 O; S8, 2H 2 O 2 +Si→SiO 2 +H 2 O; S9、SiO 2 +4HF→SiF 4 +2H 2 O; S10, OR + ·OH → CO 2 +H 2 O+ small molecule inorganic substances; Among them, OR represents the organic additives remaining in the texturing tank; reactions S1 to S6 are reactions in the cathode area, S7 to S9 are reactions on the pyramid surface, and reaction S10 is spread throughout the entire ECP tank.

[0017] The present invention discloses the following technical effects: The present invention proposes to use the electrochemical oxidation technology of high-efficiency cathode materials to realize the pyramid rounding of the CP tank, designs a new type of ECP pyramid rounding tank, saves a lot of hazardous chemicals, and can remove organic additives left over from the texturing tank to achieve self-cleaning of the tank body. In terms of industrialization, there is no need to replace the main body of the equipment, does not affect the original process of battery production, and is conducive to industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a front view of the rounding device proposed in Example 1 of the present invention; Figure 2 A top view of the rounding device provided in Example 1 of the present invention; Figure 3 Axonometric view of the rounding device proposed in Example 1 of the present invention Figure 1 ; Figure 4 Axonometric view of the rounding device proposed in Example 1 of the present invention Figure 2 ; Figure 5 This is a schematic diagram of the structure of the aeration device in the rounding device proposed in Example 1 of the present invention; Figure 6 3 is a morphology comparison diagram of the CF electrode in the present invention and the modified CF electrode; Figure 7 This is a schematic diagram of the structure of the rounding device proposed in Example 2 of the present invention; Figure 8 This is a schematic diagram of the photochemical oxidation principle of the rounding device proposed in Example 2 of the present invention; Fig. 9 This is a schematic diagram of the structure of the rounding device proposed in Example 3 of the present invention; Fig.10 This is a schematic diagram of the photoelectrochemical oxidation principle of the circularization device proposed in Example 3 of the present invention; Fig.11 This is a comparison diagram of the pyramid morphology before and after the rounding of the silicon wafer surface by the rounding method proposed in Example 4 of the present invention; In the figure: 1. ECP tank; 2. Electrolytic anode material; 3. Electric conductor; 4. Electrolytic cathode material; 5. Aeration device; 6. DC power supply; 7. Rotor flowmeter; 8. Air compressor; 9. Air inlet pipe; 10. Aeration hole; 11. Xenon lamp light source. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Texturing is an indispensable step in the preparation of crystalline silicon cells. In order to improve the light trapping effect of the velvet surface, the industry currently often uses a CP groove after texturing, and uses chemicals to oxidize and etch the surface of the velvet surface to achieve rounding of the velvet surface; pyramid rounding can also be achieved by adding additives. However, no matter which method is used, a large amount of chemicals will be consumed, and there is a high risk of corrosion and oxidizing gas leakage. Although the method of adding additives can reduce the use of chemicals to a certain extent, the use of a large amount of organic matter will bring greater environmental impact assessment pressure.

[0022] To this end, the present invention proposes a device and method for rounding a velvet pyramid of a silicon wafer, which realizes the oxidation function of a CP groove (chemical polishing groove) by an electrochemical oxidation method, and uses HF acid to adjust the pH to realize the etching of the oxide layer after oxidation.

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. Example 1

[0024] Reference Figures 1 to 6 As shown, embodiment 1 of the present invention provides a silicon wafer velvet pyramid rounding device, including an ECP tank 1 (electrochemical polishing tank), wherein an electrolytic anode material 2 and an electrolytic cathode material 4 are arranged in the ECP tank 1, and the electrolytic anode material 2 and the electrolytic cathode material 4 arranged in the ECP tank 1 are connected to an external DC power supply 6 through an electric wire 3, and the electric wire 3 adopts an acid-resistant and oxidation-resistant wire; in this embodiment, the electrolytic anode material 2 and the electrolytic cathode material 4 are both sheet-shaped electrode materials, which are respectively fixed on the inner walls of the two opposite sides of the ECP tank 1; an aeration device 5 is arranged in the ECP tank 1, and the aeration device 5 is connected to an external air compressor 8 through an air inlet pipe 9, and the air compressor 8 replaces the ozone bubbling device in the prior art, which can increase the gas flow rate, and an oxygen concentration probe is arranged in the ECP tank 1 to ensure the oxygen concentration in the ECP tank 1; Specifically, the electrolytic cathode material 4 is obtained by modifying a base material, wherein the base material is one of CF (carbon fiber), NF (nitride fiber), and GF (glass fiber), and the base material is modified by an electrochemical catalyst; the electrolytic anode material 2 is an inert electrode, which can be made of inert materials such as platinum sheet and graphite.

[0025] This embodiment is described by taking a CF substrate as an example. The substrate is modified by using an iron-based catalyst to obtain an efficient electrolytic cathode material 4, and HF is used to adjust the pH to control the pH at 2 to 6. The flow rate of compressed air is controlled at 10 to 100 mL / min, and the external DC power supply 6 controls the current density at 10 to 50 mA / cm 2 , 0.05 mol / L sodium sulfate was selected as the electrolyte.

[0026] As an optional manner, the electrochemical catalyst is an iron-based catalyst, specifically an iron-containing double-layer hydroxide, or an iron-containing catalyst such as MOFs-coated magnetic iron oxide.

[0027] As an optional method, the electrochemical catalyst (iron-based catalyst) is prepared by a hydrothermal method, and its preparation method includes: mixing ferric nitrate and nitrate containing one or more metals of copper, nickel, cobalt, and zinc in 75 mL of pure water at a molar ratio of 1:1 to 1:10, adding 10 to 100 mg of a surfactant and 1 to 5 mL of concentrated nitric acid (65% to 68% concentration) and continuing to mix evenly, transferring to a 100 mL high-pressure reactor, reacting at 100 to 200° C. for 12 to 24 h, cooling to room temperature, washing with pure water, and using a vacuum drying oven at 60 to 80° C. for 8 to 12 h to obtain an electrochemical catalyst.

[0028] As an optional method, the surfactant can use PVP (polyvinyl pyrrolidone). PVP is a non-ionic polymer compound with multiple functions and can be used as a surfactant. It can be used as a dispersant, emulsifier, thickener, leveling agent, particle size regulator, anti-reprecipitation agent, coagulant, cosolvent and detergent in different dispersion systems. The amphiphilic nature of PVP, i.e. the hydrophilic pyrrolidone part and the hydrophobic alkyl part, enables it to effectively form a protective layer on the surface of the particles, increase the steric hindrance or charge repulsion between the particles, and thus improve the stability of the system.

[0029] As an optional method, the electrochemical catalyst is fixed to the base material of the electrolytic cathode material 4 by an adhesive, and the adhesive can be selected from PTFE, nafion reagent, etc. First, the catalyst and methanol are mixed evenly in ultrasound at a ratio of 1:10 to 1:20 for 10 to 30 minutes, 1 to 10 μL of adhesive is added and mixed evenly in ultrasound for 30 to 60 minutes, and the mixed catalyst composite solution is added drop by drop to the base material of the electrolytic cathode material 4. After the addition is completed, it is naturally air-dried for 1 to 5 hours. After thorough drying, the electrode is placed in a tubular furnace at 100 to 500°C, annealed in a nitrogen atmosphere for 30 to 60 minutes, and after cooling, it is taken out and rinsed with pure water for 3 to 6 times, and dried in a vacuum drying oven at 60°C for 6 to 8 hours to obtain the electrolytic cathode material 4.

[0030] Further optimizing the scheme of this embodiment, the distribution density of the electrochemical catalyst is controlled to be 1-20 mg / cm 2 between.

[0031] To further optimize the solution of this embodiment, a rotor flowmeter 7 is connected to the pipeline connecting the aeration device 5 and the air compressor 8.

[0032] Further optimizing the scheme of this embodiment, the current density of the DC power supply 6 is 12-18 mA / cm 2 , preferably 16 mA / cm 2 .

[0033] like Figure 5 As shown, Figure 5 A schematic diagram of the structure of the aeration device 5 is provided. The aeration device 5 is one or more aeration pipes designed at the bottom of the ECP tank 1. The aeration pipes are provided with a plurality of aeration holes 10 to achieve uniform gas delivery into the ECP tank 1. The accompanying drawings of this embodiment only provide a schematic diagram of the structure designed with one aeration pipe. It should be understood that multiple aeration pipes may be provided at the bottom of the ECP tank 1, or even the bottom of the ECP tank 1 may be fully covered with aeration pipes.

[0034] To further optimize the scheme of this embodiment, the gas flow rate of the aeration device 5 is controlled at 45-60 mL / min, preferably 55 mL / min.

[0035] To further optimize the scheme of this embodiment, the ECP tank 1 is modified on the basis of the original CP tank, an external DC power supply 6 is added, and it is interconnected with the electrolytic anode material 2 and the electrolytic cathode material 4 through acid-resistant and oxidation-resistant wires; at the same time, the original ozone bubbling device is replaced with an external air compressor 8, and an oxygen concentration probe is added to ensure the oxygen concentration in the tank.

[0036] In some other embodiments, the ECP cell 1 can be designed as an up-and-down or left-and-right composite cell structure, including a composite cell one (anode cell) and a composite cell two (cathode cell), the electrolytic anode material 2 is arranged in the composite cell one, and the electrolytic cathode material 4 covers the inner wall of the entire composite cell two to increase the efficiency of the reaction.

[0037] Embodiment 1 of the present invention aims to optimize and transform the original cleaning equipment tank body, add high-efficiency cathode materials, and design a new ECP tank 1 that cooperates with a DC power supply 6. The purpose is to introduce electrochemical advanced oxidation technology into the field of pyramid rounding. This reaction can not only reduce the amount of chemicals used, but also achieve self-cleaning of ECP and avoid pollution from residual additives.

[0038] Experiments have shown that Example 1 of the present invention introduces electrochemical advanced oxidation technology into the field of pyramid rounding, precisely controls the electrochemical oxidation process and the preparation and application of catalysts, and achieves efficient and controllable oxide layer etching, which is suitable for specific industrial applications.

[0039] It should be understood that in practical applications, the electrochemical catalyst is not limited to the iron-based catalyst proposed in this embodiment, and other electrochemical catalysts such as copper-based and nickel-based catalysts that can play the same role can also be used. Example 2

[0040] Reference Figure 7 and Figure 8 As shown, Embodiment 2 of the present invention provides another silicon wafer velvet pyramid rounding device, which uses a photochemical method instead of an electrochemical method to oxidize the pyramid surface, thereby achieving pyramid rounding. The PCP groove structure is as follows Figure 7 As shown, the photochemical reaction principle is as follows Figure 8 The rounding device of Example 2 includes a PCP tank (Photochemical polishing tank), which is arranged in a closed photoreaction box, and a xenon lamp light source 11 is arranged in the closed photoreaction box; the electrolytic anode material 2 is a conductive glass laid in the PCP tank in a surrounding manner, and a photocatalyst is carried on the conductive glass, and the photocatalyst is ZnO, TiO 2 One or more of the above; the electrolytic cathode material 4 is porous carbon. In this embodiment, the surrounding fixed bed catalyst has a carrier which is a xenon lamp light source 11. The xenon lamp light source 11 emits light which can activate the photocatalyst and cause a corresponding reaction. Example 3

[0041] Reference Fig. 9 and Fig.10 As shown, Embodiment 3 of the present invention provides another silicon wafer velvet pyramid rounding device, which uses a photoelectrochemical method instead of an electrochemical method to oxidize the pyramid surface, thereby achieving pyramid rounding. Fig. 9 As shown, the principle of photoelectrochemical reaction is as follows Fig.10 The rounding device of Example 3 includes a PECP tank (Photoelectricity chemical polishing tank), which is an external DC power supply 6 added to the PCP tank of Example 2, thereby increasing the activation of the photochemical reaction and accelerating the progress of the photochemical reaction. It applies the reaction principle of Example 1 and is improved on the basis of the structure of Example 2.

[0042] In some possible embodiments, an electrochemical anode material with a high oxidation potential can also be used to achieve oxidation and re-etching of the silicon wafer surface, and the pyramid rounding effect can be achieved by controlling the input current density or voltage. This method utilizes the high oxidation potential of the anode and the holes generated by the anode material under the high oxidation potential to oxidize the silicon wafer surface in the tank.

[0043] In some possible embodiments, ultrasonic oxidation technology may be used instead of electro-oxidation, and the rounding of the pyramid may be achieved by controlling the ultrasonic power. Example 4

[0044] The present invention also provides a method for rounding a pyramid surface of a silicon wafer, using the device for rounding a pyramid surface of a silicon wafer as described in any one of the above embodiments 1 to 4, comprising: placing a silicon wafer in the ECP tank 1, energizing the electrolytic anode material 2 and the electrolytic cathode material 4, and performing reactions S1 to S10 in the ECP tank 1 to obtain a rounded pyramid surface; the reactions S1 to S10 are: S1, O 2 +2H + ﹣2e - → H 2 O 2 ; S2、Fe 2+ +H 2 O 2 +H + →Fe 3+ +H 2 O+·OH; S3, Fe 3+ + e - →Fe 2+ ; S4、Fe 3+ + H 2 O 2 →Fe 2+ +·OOH+ H + ; S5, H 2 O 2 +·OH→·OOH+H2 O; S6, ·OH+·OH→ H 2 O 2 ; S7, 2·OH+Si→SiO 2 +H 2 O; S8, 2H 2 O 2 +Si→SiO 2 +H 2 O; S9、SiO 2 +4HF→SiF 4 +2H 2 O; S10, OR + ·OH → CO 2 +H 2 O+small molecule inorganic matter.

[0045] Among them, OR represents the organic additives remaining in the texturing tank; reactions S1 to S6 are reactions in the cathode area, S7 to S9 are reactions on the pyramid surface, and reaction S10 is spread throughout the entire ECP tank 1.

[0046] The above reaction process can not only reduce the amount of chemicals used, but also realize the self-cleaning of the ECP tank 1 and avoid the pollution of residual additives.

[0047] The pyramids treated by ECP slot 1 have almost no sharp spires, which reduces the probability of spires falling off and pyramid incompleteness; the suede reflectivity after optimization is reduced from 11% to below 9%. The comparison of the pyramid morphology before and after rounding treatment by ECP slot 1 can be referred to Fig.11 shown.

[0048] Compared with the prior art, the present invention at least discloses the following beneficial effects: 1. Reduction of chemical usage: By introducing electrochemical advanced oxidation technology into the field of pyramid rounding, the use of chemicals is reduced and the impact on the environment is reduced.

[0049] 2. Self-cleaning function: ECP tank 1 can achieve self-cleaning, avoiding pollution from residual additives and reducing the pressure of subsequent environmental assessment.

[0050] 3. Improve the light-trapping effect of the suede surface: The pyramids are rounded by electrochemical oxidation, which optimizes the suede surface structure and improves the light-trapping effect of solar cells.

[0051] 4. Reduce the risk of corrosion and oxidizing gas leakage: Using electrochemical methods instead of traditional chemical oxidation and etching methods reduces the risk of corrosion and oxidizing gas leakage.

[0052] 5. Improve alloy plasticity and strength: Although alloys are mentioned in the document, this may be an error in the document because the mention of alloys is not relevant to the subject of the silicon wafer velvet pyramid rounding device and method. The correct technical effect should be to improve the rounding quality and efficiency of the silicon wafer velvet pyramid.

[0053] 6. Convenience of industrialization: In terms of industrialization, there is no need to replace the main body of the equipment, which does not affect the original battery production process and is conducive to industrialization.

[0054] 7. Reduce the probability of pyramid damage: The pyramid treated by ECP slot 1 has almost no sharp spires, which reduces the probability of the spire falling off and the pyramid being damaged.

[0055] 8. Reduce the suede reflectivity: After the ECP slot 1 is rounded, the suede reflectivity is reduced from 11% to below 9%, thereby improving the photoelectric conversion efficiency of the solar cell.

[0056] 9. Environmentally friendly: By reducing the use of chemicals and achieving self-cleaning of the tank, the impact on the environment is reduced, making it a more environmentally friendly technology.

[0057] The present invention proposes to use the electrochemical oxidation technology of high-efficiency cathode materials to realize the pyramid rounding of the CP tank, designs a new type of ECP pyramid rounding tank, saves a lot of hazardous chemicals, and can remove organic additives left over from the texturing tank to achieve self-cleaning of the tank body. In terms of industrialization, there is no need to replace the main body of the equipment, does not affect the original process of battery production, and is conducive to industrialization.

[0058] The details not disclosed in the present invention are conventional technical means well known to those skilled in the art.

[0059] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0060] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A silicon wafer velvet pyramid rounding device, characterized in that: The invention comprises an electrolytic anode material (2) and an electrolytic cathode material (4) arranged in an ECP tank (1), wherein the electrolytic anode material (2) and the electrolytic cathode material (4) are connected to an external DC power supply (6) via an acid-resistant and oxidation-resistant wire; an aeration device (5) is arranged in the ECP tank (1), and a pipeline of the aeration device (5) is connected to an external air compressor (8); the electrolytic cathode material (4) is obtained by modifying a base material, wherein the base material is one of CF, NF and GF, and the base material is modified by an electrochemical catalyst; The electrolysis anode material (2) is an inert electrode.

2. The silicon wafer velvet pyramid rounding device according to claim 1, characterized in that: The electrochemical catalyst is an iron-containing double-layer hydroxide or a MOFs-coated magnetic iron oxide.

3. The silicon wafer velvet pyramid rounding device according to claim 2, characterized in that: The electrochemical catalyst is prepared by a hydrothermal method, comprising: mixing ferric nitrate and nitrate containing one or more metals of copper, nickel, cobalt and zinc in 75 mL of pure water at a molar ratio of 1:1 to 1:10, adding 10 to 100 mg of a surfactant and 1 to 5 mL of concentrated nitric acid and continuing to mix evenly, transferring to a 100 mL high-pressure reactor, reacting at 100 to 200° C. for 12 to 24 hours, cooling to room temperature, washing with pure water, and vacuum drying at 60 to 80° C. for 8 to 12 hours to obtain the electrochemical catalyst.

4. The silicon wafer velvet pyramid rounding device according to claim 3, characterized in that: The electrochemical catalyst and methanol are mixed in a ratio of 1:10 to 1:20, ultrasonically stirred for 10 to 30 minutes, 1 to 10 μL of an adhesive is added, ultrasonically stirred for 30 to 60 minutes, and the uniformly mixed electrochemical catalyst mixture is dripped onto the base material of the electrolytic cathode material (4) drop by drop, air-dried for 1 to 5 hours, and after drying, the electrolytic cathode material (4) is annealed in a nitrogen atmosphere at 100 to 500° C. for 30 to 60 minutes, rinsed with pure water for 3 to 6 times after cooling, and vacuum dried at 60° C. for 6 to 8 hours to obtain the electrolytic cathode material (4).

5. The silicon wafer velvet pyramid rounding device according to claim 4, characterized in that: The distribution density of the electrochemical catalyst is controlled at 1 mg / cm 2 ~20 mg / cm 2 between.

6. The silicon wafer velvet pyramid rounding device according to claim 1, characterized in that: The ECP cell (1) comprises a composite cell 1 and a composite cell 2, the electrolytic anode material (2) being arranged in the composite cell 1, and the electrolytic cathode material (4) covering the entire inner wall of the composite cell 2.

7. The silicon wafer velvet pyramid rounding device according to claim 1, characterized in that: The ECP tank (1) is arranged in a sealed photoreaction box, a xenon lamp light source (11) is arranged in the sealed photoreaction box, and the electrolytic anode material (2) is conductive glass which is laid in a surrounding manner in the ECP tank (1).

8. The silicon wafer velvet pyramid rounding device according to claim 1, characterized in that: An oxygen concentration probe is also provided in the ECP tank (1).

9. The silicon wafer velvet pyramid rounding device according to claim 1, characterized in that: A rotor flow meter (7) is connected to the pipeline connecting the aeration device (5) and the air compressor (8).

10. A method for rounding a silicon wafer velvet pyramid, using the silicon wafer velvet pyramid rounding device according to any one of claims 1 to 9, characterized in that: The silicon wafer is placed in the ECP tank (1), and the electrolytic anode material (2) and the electrolytic cathode material (4) are energized to generate reactions S1 to S10, thereby obtaining a rounded pyramid velvet surface; the reactions S1 to S10 are: <h2 style=";text-align:left;direction:ltr">S1, O2+2H<h2 style=";text-align:left;direction:ltr"> + <h2 style=";text-align:left;direction:ltr"> ﹣2e<h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> → H2O2; S2、Fe 2+ +H2O2+H + →Fe 3+ +H2O+·OH; <h2 style=";text-align:left;direction:ltr">S3, Fe<h2 style=";text-align:left;direction:ltr"> 3+ <h2 style=";text-align:left;direction:ltr"> + e<h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> →Fe<h2 style=";text-align:left;direction:ltr"> 2+ <h2 style=";text-align:left;direction:ltr"> ; S4、Fe 3+ + H2O2→Fe 2+ +·OOH+ H + ; S5, H2O2+·OH→·OOH+H2O; S6, ·OH+·OH→ H2O2; S7, 2·OH+Si→SiO2+H2O; S8, 2H2O2+Si→SiO2+H2O; S9, SiO2+4HF→SiF4+2H2O; S10, OR+·OH→CO2+H2O+small molecule inorganic matter.

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