Patent ID: 7084031
Filing Date: 2006-08-01
Classification: H01L

Abstract:
1. A method for manufacturing a flash memory device, comprising the steps of: forming a pure oxide layer on a semiconductor by performing a wet oxidization process; forming an oxynitride film as a tunnel insulating film by performing a first annealing process to the pure oxide layer; forming a first polysilicon film on the tunnel insulating film; forming a pad nitride film on the first polysilicon film; forming a trench by selectively etching the pad nitride film, the first polysilicon film, the tunnel insulating film and the semiconductor substrate; forming a wall oxide film at the sidewall of the trench; forming a liner oxide film on the wall oxide film and the sidewall of the pad nitride film; performing a second annealing process; forming a first oxide film and filling the trench with the first oxide; performing a third annealing process to the first oxide film; removing the pad nitride film; forming a second polysilicon film on the first polysilicon layer exposed by removing the pad nitride film, wherein the first polysilicon film and the second polysilicon film form a floating gate; forming a dielectric film on the entire structure having the second polysilicon layer; forming a control gate on the dielectric film; and forming source/drain regions in the semiconductor substrate exposed between the control gate and a second gate.