Patent ID: 6964904

Claim:
A method for manufacturing semiconductor device, the method comprising the steps of: sequentially forming a gate oxide film, a polysilicon film and a first nitride film on a semiconductor substrate; etching the first nitride film, polysilicon film, gate oxide film and a predetermined depth of the semiconductor substrate to form a trench; forming a device isolation film by filling up the trench to define an active region; removing the first nitride film; etching a predetermined thickness of the device isolation film to form a recess; forming a second nitride film filling the recess; forming a stacked structure of a barrier metal film, a metal layer and a third nitride film on the second nitride film and the polysilicon film; etching the stacked structure and the second nitride film via a photoetching process using a gate line mask to form a gate electrode comprising a stacked structure of second nitride film pattern, a barrier metal film pattern, a metal layer pattern and a third nitride film pattern; forming an insulating film spacer on a sidewall of the gate electrode; etching the polysilicon film using the third nitride film pattern and the insulating film spacer as a mask to form a polysilicon film pattern; and forming an oxide film on a sidewall of the polysilicon film pattern.