Patent ID: 6858497

Claim:
A method of producing a non-volatile semiconductor memory device comprising a channel formation region comprised of a first conductivity type semiconductor, two impurity regions separated from each other across said channel formation region and comprised of a second conductivity type semiconductor, two first control electrodes formed on two ends of said channel formation region close to said two impurity regions in a state with charge storage films, each comprised of a plurality of dielectric films, interposed, and a second control electrode facing said channel formation region between the first control electrodes in a state with a single-layer dielectric film interposed and arranged long in the direction of separation of said impurity regions, said method of producing a non-volatile semiconductor memory device including the following steps, forming auxiliary layers in line shapes long in a direction orthogonal to a direction of separation of said impurity regions on said impurity regions or semiconductor regions where said impurity regions are to be formed; forming said charge storage film on surfaces of said auxiliary layers and a surface of said channel formation region; forming said first control electrodes along said auxiliary layers in a state with said charge storage film interposed; removing part of the charge storage film by etching using said first control electrodes as a mask; forming a single-layer dielectric film on a surface of said channel formation region exposed by the removal of said charge storage film and surfaces of said first control electrodes; and forming said second control electrodes on said single-layer dielectric film and said auxiliary layers.