Patent ID: 9231115
Filing Date: 2016-01-05
CPC Classification: H01L

Claim Text:
1. A method of manufacturing a semiconductor device including a memory cell of a nonvolatile memory, the method comprising the steps of: (a) preparing a semiconductor substrate; (b) forming a first gate electrode forming the memory cell over a main surface of the semiconductor substrate via a first gate insulating film; (c) forming a silicon oxide film over the main surface of the semiconductor substrate and a side surface of the first gate electrode; (d) forming, over the silicon oxide film, a second gate electrode adjoining the first gate electrode via the silicon oxide film, and forming the memory cell; (e) removing the silicon oxide film from a portion uncovered with the second gate electrode; (f) after the step (e), removing at least a part of a portion of the silicon oxide film located between a lower surface of the second gate electrode and the semiconductor substrate to form a cavity; (g) forming a first insulating film over a surface of the semiconductor substrate exposed in the cavity, while forming a second insulating film over the lower surface of the second gate electrode exposed in the cavity; and (h) forming a third insulating film between the first insulating film over the surface of the semiconductor substrate and the second insulating film under the lower surface of the second gate electrode, wherein the first and second insulating films are capable of functioning as charge block films, and wherein the third insulating film is capable of functioning as a charge storage portion of the memory cell.