Etch-cleaning method for high purity polycrystalline silicon briquette

Abstract

The invention discloses an etch-cleaning method for a high purity polycrystalline silicon briquette, which relates to a cleaning method for a high purity polycrystalline silicon briquette in the field of polycrystalline silicon production. In the method, hydrofluoric acid solution etching process is arranged after mixed acid etching and pure water (EW-I) rinsing processes; hydrofluoric acid solution is diluted from electronic grade hydrofluoric acid and pure water (EW-I) in a proportion of 1:2-5 (weight part), and the etching soaking time is determined according to the thickness of an oxygen layer on the surface of the silicon briquette and the concentration of the hydrofluoric acid solution; and after ultrasonic cleaning, the briquette is subjected to hot nitrogen water shearing and vacuum drying to obtain the high-purity disposable polycrystalline silicon briquette meeting the requirements of Czochralski single crystals. By adding the hydrofluoric acid solution etching process, the surface oxygen layer of the silicon briquette, which is generated when the polycrystalline silicon briquette is subjected to mixed acid etching and is contacted with air once again, can be removed so as to obtain the disposable high-purity polycrystalline silicon material with good metal glossiness of the surface and better surface quality.

Description

technical field [0001] The invention relates to a method for cleaning a high-purity polysilicon block in the field of polysilicon production, which is used for removing the oxide layer produced on the surface of the polysilicon block when it contacts air. Background technique [0002] Polysilicon is an important raw material in the semiconductor industry and the solar energy industry. In order to finally obtain high-purity polysilicon that meets the quality requirements, acid etching cleaning is an essential step. The design of the Russian Institute of Rare Metals did not give specific instructions on the corrosion and cleaning method of polysilicon, but with the rapid development of the global electronic information industry and photovoltaic industry, higher requirements are put forward for the internal and external quality of polysilicon. [0003] The original process is that the polysilicon block undergoes a certain proportion of hydrofluoric acid (electronic grade) and n...

AI Technical Summary

Problems solved by technology

However, after the mixed acid corrosion, when the silicon block contacts the air again, an oxide layer will be formed on the surface, which affects the surface gloss and surface quality of the silicon block.