| 摘要 |
A manufacturing process of a semiconductor device, includes: forming a ground oxide film, which includes over a well region of a first conductive type, on a silicon semiconductor substrate; forming a nitride film over the ground oxide film; forming a mask pattern by selectively etching the nitride film and the ground oxide film; forming a trench by etching the semiconductor substrate according to the mask pattern; wet etching to retreat an edge part of the ground oxide film; oxidizing a surface inside the trench through a dry oxidation atmosphere at a temperature of 1,030 to 1,070° C.; annealing at a temperature higher than the oxidation; embedding an insulating film inside the trench; leveling out the insulating film; removing the mask pattern; removing a remaining film of the ground oxide film; forming a pre-oxide film on the semiconductor substrate; forming on the first conductive type region an impurity region of a second conductive type with a depth crossing the insulating film; etching to eliminate the pre-oxide film, and, at the same time, to make a round shape surface of an upper part of the trench exposed; forming a gate insulating film on the first conductive type region such that the edge part side may be placed from over the edge part of the impurity region of the second conductive type to over the edge part of the insulating film; and forming a gate electrode on the gate insulating film.
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