Patent ID: 7579241

Claim:
A method of manufacturing a semiconductor device comprising: forming an island semiconductor portion comprising a first side surface and a second side surface opposed to the first side surface in a main surface of a semiconductor substrate or above the semiconductor substrate by forming a trench in the main surface of the semiconductor substrate; forming a first insulating film on a top surface of the island semiconductor portion; forming a second insulating film on the first and second side surfaces of the island semiconductor portion forming a first conductive film on a region including the island semiconductor portion, the first insulating film, and the second insulating film; forming a charge storage layer selectively on a side surface of the first insulating film and a side surface of the second insulating film by overall etching of the first conductive film such that the first conductive film remains on both the side surface of the first insulating film and the side surface of the second insulating film, the charge storage layer comprising a first sidewall provided on the first side surface of the island semiconductor portion and a second sidewall provided on the second side surface of the island semiconductor portion; forming a third insulating film on the charge storage layer; and forming a control gate electrode on the third insulating film.