Patent ID: 7759200

Claim:
A method of forming a lateral trench MOSFET comprising: forming a trench in a semiconductor substrate, the trench comprising an LTDMOS segment and a gate bus segment; lining the walls of the trench with a dielectric layer; introducing a first conductive material into the trench; implanting a dopant of a first conductivity type into the substrate to form a body region adjacent a sidewall of the LTDMOS segment of the trench; implanting a dopant of a second conductivity type into the substrate to form a drift region adjacent the body region and the sidewall of the LTDMOS segment of the trench; implanting a dopant of the second conductivity type into the substrate to form a source region adjacent a top surface of the substrate and the body region; implanting a dopant of the second conductivity type into the substrate to form a drain region adjacent the top surface of the substrate laterally spaced apart from the source region; forming a second dielectric layer over the top surface of the substrate; forming a contact hole in the second dielectric layer above the gate bus segment of the trench, the contact hole having substantially vertical walls which intersect the conductive material in the gate bus segment of the trench; filling the contact hole with a second conductive material to form a contact plug in the contact hole; and forming a gate metal layer over the second dielectric layer, the gate metal layer being in contact with the contact plug.