PRODUCING METHOD FOR NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE

PROBLEM TO BE SOLVED: To reduce the area of a memory array. SOLUTION: A producing method for a non-volatile semiconductor memory device is provided with plural memory cells composed of diffusion bit lines formed at least one part of the bottom surface and the side face of a trench formed on a wafer, provided with a selection gate transistor for selecting one of diffusion bit lines, a peripheral circuit transistor and an element separating area, and formed with the element separating area inside a trench. This method is provided with a process for simultaneously forming the trench to form the diffusion bit lines and the trench for forming the element separating area.