Sulfuric acid etching process method

Abstract

The invention discloses a sulfuric acid etching process method, which comprises the following steps of: in an etching process of a silicon wafer, setting the initial proportioning amount of pure waterin an etching tank to be 220+ / -50g / L, the initial proportioning amount of hydrofluoric acid to be 100+ / -50g / L, the initial proportioning amount of nitric acid to be 510+ / -50g / L and the initial proportioning amount of sulfuric acid to be 220+ / -50g / L; the pure water supplementing amount of the etching tank is set to be 0 mL / piece, the hydrofluoric acid supplementing amount is set to be 4.0+ / -2.0 mL / piece, the nitric acid supplementing amount is set to be 5.0+ / -2.0 mL / piece, and the sulfuric acid supplementing amount is set to be 1.5+ / -1.0 mL / piece; and according to the method, equipment (suitable for rollers of different types or tooth depths) does not need to be improved, sulfuric acid only needs to be supplemented in the primary preparation and production process of the etching groove, polishing of the back face of the silicon wafer and improvement of the reflectivity can be achieved through comprehensive optimization and adjustment of the process temperature, the circulating flow andthe water film amount, then the purpose of improving the conversion efficiency of the single crystal cell is achieved, and various electrical parameters of the prepared silicon wafer completely meetthe original requirements, and the process is simple and easy to implement.

Description

Technical field[0001]The invention belongs to the technical field of crystalline silicon solar cell manufacturing, and specifically relates to a process method for etching sulfuric acid.Background technique[0002]Single crystal etching and polishing use the combined effect of hydrofluoric acid and nitric acid, that is, isotropic corrosion. The corrosion process is to produce nitrous acid from the contact between undissociated nitric acid and silicon, and the reaction rate is determined by nitrous acid. The production of nitrous acid in this reaction is an autocatalytic process. The nitrous acid in the solution reacts with nitric acid to form nitrous acid again. The higher the nitrous acid content in the solution, the faster the rate of nitrous acid formation. The nitrous acid and some + The trivalent nitrogen active material oxidizes the contact surface of the silicon wafer to form silicon dioxide. The silicon dioxide on the contact surface of the silicon wafer reacts with hydrofluor...

AI Technical Summary

Problems solved by technology

[0004] At present, major battery manufacturers in the world are accelerating the production scale and research and development of monocrystalline cells. The efficiency of monocrystalline cells is facing pressure to improve and urgent breakthroughs, and the method of adding sulfuric acid initial preparation and liquid replenishment by etching is used to optimize the backside polishing effect and improve the backside. It is very direct and simple to improve the conversion efficiency of the battery under the challenge of technological innovation and large-scale production, and it is a relatively economical and feasible method under the premise of stable production indicators.

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