Patent ID: 7312123

Claim:
A method of manufacturing a semiconductor device comprising: a semiconductor substrate; and a plurality of nonvolatile memory cells having a plurality of first electrodes provided over the semiconductor substrate, a plurality of second electrodes provided over the semiconductor substrate so as to cross with the plurality of the first electrodes, and a plurality of third electrodes for electric charge accumulation provided at positions which respectively lie between the plurality of the adjacent first electrodes and overlap with the plurality of the second electrodes in plan view, the method comprising the steps of: (a) depositing a conductor film for forming the first electrodes over the semiconductor substrate via a first insulating film; (b) depositing a second insulating film over the conductor film for forming the first electrodes; (c) depositing a third insulating film over the second insulating film; (d) patterning the conductor film for forming the first electrodes, the second insulating film, and the third insulating film, thereby to form a multilayered pattern of the first electrodes, the second insulating film, and the third insulating film; (e) forming a fourth insulating film over the sides of the first electrodes; (f) forming a fifth insulating film over the parts of the semiconductor substrate between the adjacent portions of the multilayered pattern of the first electrodes, the second insulating film, and the third insulating film; (g) depositing a conductor film for forming the third electrodes over the semiconductor substrate such that the parts between the adjacent portions of the multilayered pattern of the first electrodes, the second insulating film, and the third insulating film are buried; (h) removing the conductor film for forming the third electrodes such that the portions of the conductor film for forming the third electrodes are left between the adjacent portions of the multilayered pattern of the first electrodes, the second insulating film, and the third insulating film, thereby to form a pattern of the conductor film for forming the third electrodes between the adjacent portions of the multilayered pattern of the first electrodes, the second insulating film, and the third insulating film in self-alignment with the first electrodes; (i) removing the third insulating film; (j) depositing a sixth insulating film over the semiconductor substrate; (k) depositing a conductor film for forming the second electrodes over the sixth insulating film; (l) patterning the conductor film for forming the second electrodes, thereby to form the plurality of the second electrodes; and (m) patterning the pattern of the conductor film for forming the third electrodes by the use of the plurality of the second electrodes as a mask, thereby to form the plurality of the third electrodes in such a convex shape in cross section as to be larger in height than the first electrodes in self-alignment with the plurality of the second electrodes.