Patent ID: 7488646

Claim:
A method for manufacturing a nonvolatile semiconductor memory device, comprising: forming a first insulating film on a semiconductor substrate having a first upper surface; forming a first electrode material film on the first insulating film; etching the first electrode material, the first insulating film, and the semiconductor substrate so as to form a groove in the semiconductor substrate; embedding a second insulating film in the groove and forming an isolation portion so that an upper portion of the isolation portion protrudes from the first upper surface; forming a second electrode material film on the first electrode material and the isolation portion; etching the second electrode material film and the upper portion of the isolation portion so that a pair of inner side surfaces of the isolation portion face to a whole side surface of the first electrode material film via the isolation portion; forming a third insulating film on the second electrode material film and the pair of inner side surfaces of the isolation portion; and forming a control gate on the third insulating film and between the pair of inner side surfaces of the isolation portion.