Method of manufacturing semiconductor device having trench isolation

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.