Patent ID: 7416935

Claim:
A method of manufacturing a nonvolatile semiconductor memory device, comprising: forming a gate insulating film on a semiconductor substrate; forming a first conductive layer on the gate insulating film; forming a mask on the first conductive layer; forming a plurality of element-isolating regions in the mask layer, first conductive layer, gate insulating film and semiconductor substrate; making a plurality of first trenches in those parts of the first conductive layer which have been separated by the element-isolating region, the first conductive layer providing a plurality of floating gates; forming inter-gate insulating films on sides of each floating gate; forming second conductive layers in the first trenches, thereby forming control gates; making second trenches in those parts of the mask layer and first conductive layer in which selection gates should be formed, and in those parts of the element-isolating regions which are adjacent to said parts of the mask layer and first conductive layer; forming conductive members in the second trenches, a top of the conductive members is same level as an upper surface of the mask layer; and removing the first conductive layer and the gate insulating film, except those parts which include the conductive members.