Patent ID: 7723172

Claim:
A method of manufacturing a trench type semiconductor device, the method comprising: (i) providing a semiconductor substrate having first and second main surfaces opposite to each other, the semiconductor substrate having a heavily doped region of a first conductivity type at the second main surface and having a lightly doped region of the first conductivity type at the first main surface; (ii) forming in the semiconductor substrate a plurality of mesas and a plurality of trenches, each mesa having an adjacent trench and a first extending portion extending from the first main surface toward the heavily doped region to a first depth position, and at least one mesa having a first sidewall surface and a second sidewall surface, each of the plurality of trenches having a bottom; (iii) doping, with a dopant of a second conductivity type, the first sidewall surface of the at least one mesa to form a first doped region of the second conductivity type; (iv) doping, with a dopant of a second conductivity type, the second sidewall surface of the at least one mesa to form a second doped region of the second conductivity type; (v) filling at least a portion of the plurality of trenches adjacent to the first main surface with a disposable material; (vi) after filling the at least a portion of the plurality of trenches, forming a terminal structure at the first main surface; (vii) after the terminal structure has been formed, removing the disposable material from the plurality of trenches; and (viii) filling the plurality of trenches with at least one of a semi-insulating material, an insulating material, and a combination thereof.