| 摘要 |
PROBLEM TO BE SOLVED: To provide a polycrystalline silicon cleaning method excellent in cleaning effect. SOLUTION: The system used for this cleaning method is a multistage cleaning system provided with at least two cleaning tanks each having a circulation passage for withdrawing a cleaning liquid from the bottom of the cleaning tank, filtering the withdrawn cleaning liquid and thereafter returning the filtered cleaning liquid to the cleaning tank. More specifically, in this multistage cleaning system, a first cleaning tank 10 provided with a filter having >=0.1μm pore size in a filtration section 13 installed in a circulation passage 11, and a second cleaning tank 30 provided with a filter having <0.1μm pore size in a filtration section 33 installed in a circulation passage 31, are placed. The cleaning method comprises firstly performing cleaning in the first cleaning vessel 10 and thereafter performing cleaning in the second cleaning tank 30, to subject fine particles sticking to polycrystalline silicon to acid cleaning and stepwise removal.
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