Application of a Chemical Etching Solution in Surface Texturing of Silicon Wafers

Abstract

The invention provides a chemical etching solution, which belongs to the technical field of silicon wafer etching; the chemical etching solution is characterized in that it contains MnO 2 particulate HNO 3 / HF / H 2 O solution. When this etching solution is used for silicon wafer etching, MnO 2 The particles settle on the surface of the silicon wafer to act as a mask, so that the HNO 3 / HF / H 2 O corrosion reaction of silicon wafer is mainly in MnO 2 The area between the particles occurs, which can increase the aspect ratio of the etching pit and reduce the light reflectance of the silicon wafer surface; at the same time, the MnO 2 Where the particle contacts the silicon oxidizes the silicon to SiO 2 , resulting in SiO 2 Then removed by HF, the exposed silicon and MnO 2 Contact and continue the above reaction, gradually consume MnO 2 The combined effect of the particles and the reaction is to improve the anti-reflection performance of the textured surface, so that a high-performance textured surface with low reflectivity can be obtained on the surface of the polycrystalline silicon wafer, and has the advantages of simple process and low cost.

Description

technical field [0001] The invention relates to the technical field of silicon chip etching, in particular to a chemical etching solution and its application in silicon chip etching. Background technique [0002] It is an important means to improve the efficiency of silicon solar cells to prepare a textured surface on the surface of silicon wafers to reduce light reflectivity. At present, the main methods for preparing texture on the surface of polycrystalline silicon wafers include conventional HNO 3 / HF / H 2 O acid velvet and new black silicon velvet. [0003] HNO 3 / HF / H 2 O texturing uses the isotropic corrosion of silicon wafers by acid to obtain a textured surface with an "etch pit" structure on the surface of polycrystalline silicon wafers. There is a thick damage layer on the surface of the mortar-cut polysilicon wafer, and the position with structural defects can be used as the reaction starting point of acid texturing, and the reflectivity of the obtained "corr...

AI Technical Summary

Problems solved by technology

The problem with this technology is that it needs to remove metal particle contamination on the silicon wafer and additional treatment of metal-containing waste liquid, the process cost is high, and the feature size of the obtained texture is often too small, resulting in low parallel resistance of the final solar cell

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