Patent ID: 8114742

Claim:
A method of forming a nonvolatile semiconductor memory device, said method comprising: forming a semiconductor substrate; forming upper and lower portions of a first gate electrode on a gate insulating film formed on said semiconductor substrate, said lower portion of said first gate electrode formed on said gate insulating film, said upper portion of said first gate electrode formed on said lower portion of said first gate electrode and having a gate length which is less than a gate length of said lower portion of said first gate electrode; forming a spacer insulating film to contact respective surfaces of the upper and lower portions of said first gate electrode, a length of said spacer insulating film combined with the gate length of the upper portion of said first gate electrode being equal to said gate length of said lower portion of said first gate electrode; forming an electric charge trapping film covering a portion of the semiconductor substrate, a surface of the lower portion of the first gate electrode, and a surface of the spacer insulating film; and forming a second gate electrode in a side direction of said first gate electrode and electrically insulated from said first gate electrode by said electric charge trapping film, said second gate electrode having a distance between said upper portion of said first gate electrode that is greater than a distance between said lower portion of said first gate electrode and said second gate electrode, said second gate electrode being separated from said upper portion of said first gate electrode by said electric charge trapping film and said spacer insulating film.