Patent ID: 7544568

Claim:
A method of manufacturing a semiconductor device, comprising the steps of: (a) forming a first insulating film over a main surface of a semiconductor substrate of a first conductivity type; (b) patterning the first insulating film to form an opening; (c) forming a gate trench in the semiconductor substrate using as a mask the first insulating film in which the opening has been formed; (d) forming a gate insulating film over the gate trench; (e) forming a polysilicon film over the first insulating film including within the gate trench; (f) removing the polysilicon film formed over the first insulating film and allowing the polysilicon film to remain in the opening of the first insulating film and in the gate trench, to thereby form a gate electrode; (g) removing a portion of the first insulating film to allow a portion of the gate electrode to protrude from the semiconductor substrate; (h) implanting an impurity into the semiconductor substrate to form a source region of the first conductivity type in an adjacent region to the gate electrode; (i) forming a second insulating film over the semiconductor substrate; (j) anisotropically etching the second insulating film to form a sidewall over a side wall portion of the gate electrode that protrudes from the semiconductor substrate; (k) removing a portion of the semiconductor substrate that is between the sidewalls formed on adjacent gate electrodes, to thereby form the body trench deeper than a depth of the source region; (l) implanting an impurity into the semiconductor substrate to form a first semiconductor region that serves as a body contact region of a second conductivity type at a bottom portion of the body trench; and (m) forming a first metal silicide film in the gate electrode, the source region, and the first semiconductor region, wherein in the step (k), the body trench is formed by self-alignment with the gate electrode.