摘要 |
PURPOSE:To leave an oxide film applied to the bottom and side surface of difference at stages effective for smoothing by forming the oxide film applied, exposing the whole surface in a dry etching atmosphere and removing the unnecessary section of the film applied until the oxide film is exposed. CONSTITUTION:A polycrystal layer 12 and a layer insulating film 13 are formed onto an oxide film 11 on a semiconductor crystal 10, and the oxide film 15 applied is deposited. The whole surface is etched in the dry etching atmosphere, the thin section of the oxide film 15 applied is removed and a section having a smoothing effect is left, and the layer insulating film 13 or the oxide film 11 requiring processing are exposed. When dry etching is executed by a gas such as the mixed gas (20-80% O2) of CF4 and O2, the quantities of the layer insulating film 13 and the oxide film 15 are little when the whole surface is etched because the ratio of approximately 4:1 or higher is obtained at the ratio of etching speed of the oxide film applied to a thermal oxide film and the ratio of approximately 3:1 or higher is acquired to a CVD oxide film. An opening on the polycrystal layer 12 and the processing of the oxide film 11 as necessary are executed extremely easily because of no oxide film applied. |