Patent ID: 8907404

Claim:
A semiconductor device having a memory cell; the memory cell comprising: a first gate insulating film formed over a semiconductor substrate, a control gate electrode formed over the first gate insulating film, a second gate insulating film formed over the semiconductor substrate and over a side wall of the control gate electrode, a memory gate electrode formed over the second gate insulating film and arranged adjacent with the control gate electrode through the second gate insulating film, a first semiconductor region formed in the semiconductor substrate and positioned on a control gate electrode side, and a second semiconductor region formed in the semiconductor substrate and positioned on a memory gate electrode side, wherein the second gate insulating film includes a first insulating film, a second insulating film, and a third insulating film, wherein the first insulating film is formed over the semiconductor substrate and over a side wall of the control gate electrode, wherein the second insulating film is formed over the first insulating film and contacts the first insulating film between the memory gate electrode and the semiconductor substrate and between the control gate electrode and the memory gate electrode, wherein the third insulating film is formed over the second insulating film, wherein the second insulating film includes a charge storage film, and wherein an contacting face of the first insulating film and the second insulating film has a corner whose interior angle takes a form of an acute angle in a cross-section view.