At present, China has not yet mass-produced 12-inch integrated circuit silicon wafers. Electronic-grade polysilicon for 12-inch wafers is completely monopolized by foreign countries. 8-inch and lower semiconductor wafers have been realized with electronic-grade polysilicon. Yellow River hydroelectric polysilicon has been fully satisfied with 8-inch polishing. Sheet, epitaxial wafer manufacturing requirements, and has been continuously and steadily applied on the 8-inch production line in Zhejiang Jinruiqi since August 2016. The usage has exceeded 600 tons. In addition, China Silicon Hi-tech, Jiangsu Xinhua, Yichang CSG, Yunye The core materials are released to the public, or electronic grade polysilicon research, or the realization of electronic-grade polysilicon industrialization, which shows that the gradual application of China's electronic-grade polysilicon is expected to be widely available. By then, with the continuous improvement of domestic supply capacity, China's high quality The situation that polysilicon is heavily dependent on imports will be eased.
Based on the higher purity requirements of electronic-grade polysilicon products, and the higher the purity, the more difficult the impurity control during the purification and production process is. Therefore, there are many technical difficulties that need to be overcome for electronic-grade polysilicon production. The following aspects are mainly involved:
First of all, it is necessary to use production equipment and pipelines with controllable impurities, and the construction equipment installation process must be strictly cleaned to control the cleanliness of the production system. It is necessary to control the pollution of the production system from the beginning of the equipment construction. Secondly, raw and auxiliary materials must be strictly screened. Materials, including silicon powder, hydrogen, silicon core, pure water, auxiliary gas, etc., control raw material content of impurities in a reasonable range, and establish a complete raw material quality control system to prevent abnormal quality fluctuations.
Thirdly, strict cleanliness operations must be performed, including reduction furnace installation, silicon rod harvesting, crushing, cleaning, sorting and packaging, etc., to control man-made and environmental pollution, and to control the cleanliness of the maintenance process to prevent contamination of the production system due to maintenance. .
Finally, we must establish a quality supervision and control system from the raw and auxiliary materials, intermediate products, production operations, process parameter control, to product post-processing, etc., as well as a testing laboratory that meets the SIMI standards to ensure the quality of each link can be controlled. In control.