Method for cleaning polycrystalline silicon device

Abstract

The invention provides a method for cleaning a polycrystalline silicon device. The method comprises the following steps: (a) degreasing and cleaning the device with a degreasing agent; and (b) drying the cleaned device with oil-free dry air. The dew point of the used oil-free dry air is less than or equal to 40 DEG C below zero, the oil content is less than or equal to 0.01 mg / m<3>, the dust particle is less than or equal to 0.01mu m, and the flow is 40 to 60 m<3> / min. The degreasing agent is 2 to 5 weight percent of sodium hydroxide solution, the water for preparing the sodium hydroxide solution is purified water, the oil content of the purified water is zero, the electric conductivity is less than or equal to 15 us / cm, and the chlorine ions are less than or equal to 5 milligrams per liter. The method for cleaning the polycrystalline silicon device has simple process, is convenient to construct and operate, can achieve better dust removal effect by adopting the oil-free dry air, radically solves the drying problem of the system, ensures the drying before final production, and simultaneously can meet the requirement on environmental protection.

Description

technical field [0001] The invention relates to a cleaning method, in particular to a cleaning method for a polysilicon device. Background technique [0002] A polysilicon plant is a chemical system with high purity requirements, complex processes, and a large variety of equipment. Some polysilicon products also have the characteristics of metallurgical systems and semiconductor electronic components. Since the product requires high purity, correspondingly the pipelines for transporting product raw materials and the equipment for storing and purifying raw materials also require higher and stricter cleanliness. If it is not cleaned before installation, the rust residue and oil stains on the equipment cannot meet the cleanliness requirements only by the washing of system materials; if it is not dried, even a little water in the system will cause hydrolysis of raw materials, equipment corrosion and system blockage. With simple cleaning, it is impossible to completely remove th...

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Problems solved by technology

[0003] At present, the polysilicon cleaning process generally uses carbon tetrachloride for degreasing, and uses the volatility of carbon tetrachloride to achieve the purpose of drying, but carbon tetrachloride is a toxic substance, which is not conducive to environmental protection