Patent ID: 7056793

Claim:
A method for manufacturing a semiconductor device, comprising: forming a trench in a surface region of a semiconductor substrate, of a first conductivity type; forming a drift region, of a second conductivity type, around the trench; forming a gate insulating film, having a uniform thickness, along a side surface and a bottom surface of the trench and inside the trench; forming a first conductor along a surface of the gate insulating film etching back the first conductor in an active region so that the first conductor remains only in side surface regions of the trench; forming a base region of, the first conductivity type, and a source region, of said second conductivity type, in a surface region of the semiconductor substrate outside the trench; forming an interlayer dielectric inside said first conductor; selectively removing a bottom of the interlayer dielectric in the active region; forming a drain region of, the second conductivity type, at the bottom of the trench; and forming a second conductor in the trench, the second conductor electrically connecting to the drain region.