Solar grade polycrystalline silicon chip surface treatment method

Abstract

The invention discloses a solar grade polycrystalline silicon chip surface treatment method. The method comprises the steps that coarse boron carbide with the particle size diameter of 12 to 16 nm isused for mechanical rough grinding of the surface of a polycrystalline silicon chip; fine boron carbide with the particle size diameter of 1.5 to 2.5 nm is used for mechanical fine grinding of the surface of the roughly ground polycrystalline silicon chip; the finely ground polycrystalline silicon chip is placed in a polishing liquid to be etched and polished to remove a damage layer produced by grinding the surface of the polycrystalline silicon chip; residual polishing slurry on the surface of the polycrystalline silicon chip is neutralized by strong alkali and weak acid salt; the acquired polycrystalline silicon chip is placed in a rotating drum for edge polishing; residual polishing slurry on the surface of the acquired polycrystalline silicon chip is neutralized by strong alkali and weak acid salt; and the acquired polycrystalline silicon chip is cleaned and dried. According to the invention, the polycrystalline silicon chip has the advantages of high hardness and smooth surface.

Description

technical field [0001] The invention relates to the field of processing solar-grade semiconductor monocrystalline silicon wafers, in particular to a surface treatment method for solar-grade polycrystalline silicon wafers. Background technique [0002] During the processing of solar-grade semiconductor monocrystalline silicon wafers, the polycrystalline silicon wafers produced by wire sawing cannot be sliced ​​directly due to their rough surface and serious line marks. [0003] Before slicing polycrystalline silicon wafers, it is necessary to process the line marks on the surface of polycrystalline silicon wafers. The existing patent 201110121543.5 discloses a surface treatment method for solar-grade polycrystalline silicon wafers. The surface of polycrystalline silicon wafers is subjected to physical and mechanical processing using a diamond grinding wheel. Grinding treatment to remove line marks on the surface of polysilicon wafers. However, a new damage layer will be form...

AI Technical Summary

Problems solved by technology

However, a new damage layer will be formed on the surface of the polysilicon wafer when dealing with line marks on the surface of the polysilicon wafer, which will easily lead to defects and defects such as edge jumping on the edge of the monocrystalline silicon wafer after slicing. The method of alkali etching is used to corrode the damaged layer. However, when it is etched, it is easy to cause corrosion pits on the edge of the silicon wafer, so that the stress of the silicon wafer is not concentrated and the hardness is poor.