DRY ETCHING METHOD OF SILICON OXIDE FILM

PROBLEM TO BE SOLVED: To effectively prevent a deposition film adhering to the inner wall of a manufacturing device from being released by performing the etching treatment of a dummy substrate with a larger area, where a silicon oxide film is exposed to the surface, than a substrate to be treated in the middle of the continuous treatment process of the substrate. SOLUTION: A wafer is carried in, the gas of a plasma to be generated is introduced into a chamber through an approach pipe 7 and a shower hole, a prescribed pressure is maintained, and a high-frequency power is applied from a high-frequency power supply to an upper electrode for generating a plasma, thus etching the surface of the wafer. In this case, an area where silicon oxide is exposed and is subjected to etching ranges from several % to several tens of % of the entire wafer. Then, a foreign object, generated in an oxide film etching process, is made of a deposited film 17 with a film that can be easily released. Then, a dummy film where the oxide film is formed, for example, on the entire surface is installed at a substrate stage for etching with an interval of a certain number of wafers to be etched in the continuous treatment process of a substrate.