Method of manufacturing semiconductor memory device, and semiconductor memory device

Abstract

A method of manufacturing semiconductor memory device comprises forming a first wiring layer and a memory cell layer above a semiconductor substrate; forming a plurality of first trenches extending in a first direction in the first wiring layer and the memory cell layer, thereby forming first wirings and separating the memory cell layer; burying a first interlayer film in the first trenches to form a stacked body; forming a second wiring layer above the stacked body; forming a plurality of second trenches, extending in a second direction intersecting the first direction and reaching an upper surface of the first interlayer film in depth, in the first stacked body with the second wiring layer formed thereabove, thereby forming second wirings; removing the first interlayer film isotropically; and digging the second trenches down to an upper surface of the first wirings, thereby forming memory cells.