Cleaning method of policrystalline silicon raw material

Abstract

The invention discloses a cleaning method of a policrystalline silicon raw material. The method comprises the following steps: 1) placing the policrystalline silicon raw material in ethanol solution for presoaking; 2) rinsing the presoaked policrystalline silicon raw material with deionized water; 3) placing the rinsed policrystalline silicon raw material in a mixed acid liquor of HNO3 and HF to corrode; 4) placing the corroded policrystalline silicon raw material in hydrofluoric acid to soak; 5) after soaking, placing the policrystalline silicon raw material in a deionized water tank with the overflow function to rinse; and 6) placing the rinsed policrystalline silicon raw material in deionized water to perform soaking treatment. The policrystalline silicon raw material cleaned and treated by the method of the invention has no spot on the surface, no oxidation layer and low impurity content, thus the problems of the existing cleaning process of the policrystalline silicon raw material that nonuniform corrosion is easy to cause and an oxidation layer or spots are easy to generate on the surface, can be overcome and the high quality requirement of the policrystalline silicon raw material can be met.

Description

technical field [0001] The invention relates to a method for cleaning polycrystalline silicon raw materials, in particular to a method for cleaning polycrystalline silicon raw materials by using mixed acid liquid to corrode the surface of polycrystalline silicon. Background technique [0002] Generally, the polysilicon raw materials produced cannot be used directly due to size, shape and other restrictions, and need to be processed into polysilicon blocks or rods that meet the requirements of size and shape, which causes a large amount of impurities to be introduced into the polysilicon surface during processing. , so polysilicon blocks or rods must be specially cleaned to remove surface impurities before they can be used. The cleaning method of traditional silicon polycrystalline raw materials is generally to use a certain proportion of HNO 3 +HF mixed acid for etching, and then rinse with deionized water to achieve the purpose of cleaning impurities on the surface of poly...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to overcome the problems of uneven corrosion, impurity oxide film and spots on the surface, unclean cleaning, etc. in the cleaning process of the existing silicon polycrystalline raw materials, and especially provide a method that can make the surface of the silicon polycrystalline raw material free from spots and Cleaning method of high-quality silicon polycrystalline raw material with less oxide layer and impurity content

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