Patent ID: 7144764

Claim:
A method of manufacturing a semiconductor device, said semiconductor device comprising a MOS transistor on an SOI layer of an SOI substrate obtained by sequentially stacking a semiconductor substrate, a buried insulating film, and said SOI layer, and a trench isolation oxide film which defines an active region serving as a region in which said MOS transistor is formed and electrically isolates said MOS transistor, wherein said trench isolation oxide film includes a combined isolation oxide film which is a combination of a full isolation oxide film penetrating said SOI layer and reaching said buried insulating film of said SOI substrate, and a partial isolation oxide film having the SOI layer under said partial isolation oxide film, and in said combined isolation oxide film, a portion around the active region except for a portion near a gate electrode of said MOS transistor is constructed by said full isolation oxide film and the other portion is constructed by said partial isolation oxide film, the method comprises the steps of (a) preparing field data of a source/drain layer for forming a partial trench which defines a region in which the source/drain layer is formed in said active region; (b) preparing gate data for forming said gate electrode; and (c) preparing full isolation data for forming said full isolation oxide film, and said step (c) includes a step of obtaining said full isolation data from said field data and said gate data.