| abstract |
After a polysilicon film is formed on a wafer, a cleaning gas containing ClF3 at 10 to 50 vol % is supplied into a reaction tube and an exhaust pipe system at a flow rate of 3000 to 3500 SCCM, so as to remove a polysilicon-based film deposited on an inner wall surface of the reaction tube, the surface of a member incorporated in the reaction tube, and an inner wall surface of the exhaust pipe system while the film forming process, by etching using ClF3. The cleaning gas is supplied while the temperature in the reaction tube is maintained at 450 DEG C. or higher, and in a pressure condition set at the maintained temperature such that an etching rate of the polysilicon-based film by the cleaning gas is higher than an etching rate of silicon which is the material of the reaction tube or the member incorporated in the reaction tube. |