Chemical cleaning of polysilicon equipment

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The polysilicon plant, for which cleaning is necessary, is a chemical processing system with high purity requirements, complex processes, and a wide variety of equipment (some of which possess characteristics of metallurgical systems and semiconductor electronic components). To reduce the time required for purification during the commissioning of the process system, minimize commissioning costs (due to the high defect rate during the system purification phase and the low value of the produced products), and enable the facility to start producing high-purity polysilicon products as soon as possible, it is essential to carry out thorough cleaning of the process equipment and pipelines before installation. Depending on different process requirements, equipment materials and types, as well as cleaning requirements and the basic standards to be met (the requirement of being free from oil, water, dust, and impurities, as well as the requirements for pre-coating of circulating water), different cleaning methods must be employed. Cleaning processes can be divided into four categories: spray cleaning, circulation cleaning, immersion cleaning (tank immersion and pouring immersion methods), and wiping cleaning.