DEPOSITION OF FILM

PROBLEM TO BE SOLVED: To prevent the opening of a contact hole from becoming excessively narrower by removing an excessively polysilicon film depositing to the step section of the contact hole, etc., by slightly performing etching or simultaneously supplying a film deposition gas and an etching gas in the course of film forming treatment in a film deposition process. SOLUTION: In a first film forming process, a polysilicon film 7A is formed on a wafer by performing film deposition by the CVD method at a high speed by simultaneously supplying SiH4 and PH3 film forming gases together with H2 carrier gas of H2 gas while the temperature of the wafer is maintained at a process temperature of, for example, about 620 deg.C. Then the first film deposition process is stopped before excessive polysilion films 84 joined each other to form a bridge, and an etching process is started. After the film deposition gases, etc., are evacuated form a treating container 14, the surface of the first polysilicon layer 7A is etched by supplying ClF3 etching gas to the container 14 together with the carrier gas at a prescribed flow rate.