Patent ID: 6593186
Filing Date: 2003-07-15
Classification: H01L

Abstract:
A method of manufacturing a non-volatile semiconductor memory device, said method comprising:sequentially depositing in an element forming region, a first gate oxide film, a polysilicon film, a first silicon oxide film, and a first silicon nitride film, in that sequence; processing said first silicon nitride film to a prescribed shape and expose said first silicon oxide film; sequentially forming onto a side wall of said first silicon nitride film, a second silicon oxide film, a second silicon nitride film, and a third silicon oxide film, so as to form a side wall and expose said polysilicon film; etching said exposed polysilicon film; removing said first and second silicon nitride films; removing said exposed silicon oxide film; and using said second and third silicon oxide films on said polysilicon film as a mask, and etching said polysilicon film, thereby forming said floating gate that has a trench.