Semiconductor device and a method of manufacturing the same

A method of manufacturing a semiconductor device, comprising the steps of:

• (a) preparing a semiconductor substrate having a first main surface and a second main surface located on opposite sides to each other along a thickness direction thereof;
• (b) depositing a conductive film over the first main surface of the semiconductor substrate via an insulating film;
• (c) forming a gate electrode in a second circuit region other than a first circuit region of the first main surface of the semiconductor substrate as well as forming a floating gate electrode for nonvolatile memory in the first circuit region of the first main surface of the semiconductor substrate by patterning the conductive film;
• (d) depositing a first insulating film containing nitrogen by a thermochemical vapor deposition method over the first main surface of the semiconductor substrate so that it covers the floating gate electrode and the gate electrode;
• (e) after the step (d), removing the first insulating film in the second circuit region and forming a pattern of the first insulating film so that it covers the floating gate electrode in the first circuit region by subjecting the first insulating film to etching processing;
• (f) after the step (e), depositing a second insulating film containing nitrogen over the first main surface of the semiconductor substrate by a plasma chemical vapor deposition method so that it covers the pattern of the first insulating film and the gate electrode;
• (g) after the step (f), depositing a third insulating film containing oxygen over the second insulating film;
• and
• (h) after the step (g), forming a connection hole in the third insulating film and the second insulating film in the first circuit region and the second circuit region.