Patent ID: 6495431
Filing Date: 2002-12-17
Classification: H01L

Abstract:
A semiconductor device manufacturing method for selectively forming an element isolating region on a semiconductor substrate so that said semiconductor substrate may be dielectrically isolated into a plurality of element regions by said element isolating region, comprising:a first oxidation preventing film forming step of covering an element-isolating region formation-expected region on said semiconductor substrate with a first oxidation preventing film having a first opening therein; a first field oxide film forming step of performing first field oxidation on said semiconductor substrate to thereby selectively form a first field oxide film at such a position in said element-isolating region formation-expected region that is not covered with said first oxidation preventing film; a second oxidation preventing film forming step of removing said first oxidation preventing film to then cover said first field oxide film with a second oxidation preventing film having a second opening having a set width dimension smaller than said first opening; and a second field oxide film forming step of performing second field oxidation on said semiconductor substrate to thereby selectively form a second field oxide film which overlaps partially with said first field oxide film and also which is located deeper in level than said first field oxide film at such a position in said element-isolating region formation-expected region that corresponds to said second opening in said second oxidation preventing film.