US Patent 11171222 Semiconductor device and manufacturing method thereof

A semiconductor device manufacturing method includes forming a first trench insulating film of a first depth in a substrate, forming at least one second trench insulating film that is spaced apart from the first trench insulating film and has a second depth that is greater than the first depth, forming a body region of a first conductivity type and a drift region of a second conductivity type in the substrate, forming a gate electrode overlapping the first trench insulating film, forming a source region in the body region and a drain region in the drift region, forming a silicide film on the drain region, and forming a non-silicide film between the first trench insulating film and the drain region, wherein the first trench insulating film overlaps the drift region and the gate electrode.