Patent ID: 8518795

Claim:
A method of manufacturing a semiconductor device, comprising: forming an isolation region defining an active region in a semiconductor substrate; forming a silicon oxide film in the isolation region and polishing an upper portion of the silicon oxide film formed in the isolation region; forming a sacrifice oxide film over the active region; forming wells in the active region: removing the sacrifice oxide film, a recess being formed in the isolation region adjacent to the boundary between the active region and the isolation region as a result of the removal of the sacrifice oxide film; after removing the sacrifice oxide film, forming a first insulating film over the semiconductor substrate; forming a second insulating film having etching properties different from those of the first insulating film over the first insulating film; selectively removing the second insulating film from a first region over the active region and the isolation region by dry etching using a fluorocarbon-based etching gas to form a fluorocarbon film over the first insulating film; removing the fluorocarbon film using a mixed gas including an oxygen gas, a CF 4 gas, and a forming gas in a downflow etching apparatus; and selectively removing the first insulating film from the first region by wet etching.