METHOD OF WASHING POLYCRYSTALLINE SILICON, APPARATUS FOR WASHING POLYCRYSTALLINE SILICON, AND METHOD OF PRODUCING POLYCRYSTALLINE SILICON

摘要

A method of washing polycrystalline silicon is provided. The method includes a step of acid cleaning in which the polycrystalline silicon is cleaned with an acid solution and a step of a water cleaning in which the polycrystalline silicon is cleaned by pure water after the step of acid cleaning. In the step of water cleaning, residual acid solution on the surface of the polycrystalline silicon is removed by immersing the polycrystalline silicon in pure water held in a water cleaning bath, and replacing the pure water in the water cleaning bath at least once. The electrical conductivity (C) of the pure water in the water cleaning bath is measured. Based on the reading of the electrical conductivity (C), the timing for finishing the step of water cleaning is decided.