Semiconductor device and method for manufacturing the same
AssigneeNEC Corporation
InventorTomokazu Matsuzaki
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Abstract
A first field oxidation is performed by masking an element-isolating region formation-expected region on a substrate by a first oxidation preventing film (silicon nitride film) having therein a first opening to thereby form a first field oxide film, which is then masked by a second oxidation preventing film (silicon nitride film) having a second opening with a smaller width dimension than the first opening in a second field oxidation to thereby locally form a second field oxide film at the middle of the first field oxide film.
Claims20
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.
A semiconductor device manufacturing method for selectively forming a first element isolating region with a larger film thickness and a second element isolating region with a smaller film thickness on a semiconductor substrate so that said semiconductor substrate may be dielectrically isolated into a plurality of element regions by said first element isolating region and said second element isolating region, comprising:
- a first oxidation preventing film forming step of covering a first element-isolating region formation-expected region and a second element-isolating region formation-expected region on said semiconductor substrate with a first oxidation preventing film having a first opening therein in such a way that said first opening may be located above said first element-isolating region formation-expected region;
- 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 only at such a position in said first 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 semiconductor substrate with a second oxidation preventing film having a second opening and a third opening which have set width dimensions smaller than said first opening in such a way that said second opening may be located above said first field oxide film and also that said third opening may be located above said second element-isolating region formation-expected region;
- and
- a second and third 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 only at such a position in said first element-isolating region formation-expected region that corresponds to said second opening in said second oxidation preventing film and, at the same time, selectively forms a third field oxide film only at such a position in said second element-isolating region formation-expected region that corresponds to said third opening.
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 therein which has a set width dimension larger 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 shallower 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.
A semiconductor device manufacturing method for selectively forming a first element isolating region with a larger film thickness and a second element isolating region with a smaller film thickness on a semiconductor substrate so that said semiconductor substrate may be dielectrically isolated into a plurality of element regions by said first element isolating region and said second element isolating region, comprising:
- a first oxidation preventing film forming step of covering a first element-isolating region formation-expected region and a second element-isolating region formation-expected region on said semiconductor substrate with a first oxidation preventing film having a first opening therein in such a way that said first opening may be located above said first element-isolating region formation-expected region;
- 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 only at such a position in said first 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 semiconductor substrate with a second oxidation preventing film having a second opening and a third opening which have set width dimensions larger than said first opening in such a way that said second opening may be located above said first field oxide film and also that said third opening may be located above said second element-isolating region formation-expected region;
- and
- a second and third field oxide films 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 shallower in level than said first field oxide film only at such a position in said first element-isolating region formation-expected region that corresponds to said second opening in said second oxidation preventing film and, at the same time, selectively form a third field oxide film only at such a position in said second element-isolating region formation-expected region that corresponds to said third opening.
A semiconductor device in which a semiconductor substrate thereof is dielectrically isolated into a plurality of element regions by an element isolating region which is selectively formed on said semiconductor substrate, wherein said element isolating region comprises:
- a first field oxide film which is selectively formed at such a position in an element-isolating region formation-expected region that is not covered with a first oxidation preventing film having a first opening therein;
- and
- a second field oxide film which is selectively formed at such a position in said element-isolating region formation-expected region that is not covered with a second opening of a second oxidation preventing film having said second opening with a smaller width dimension than said first opening and also which is locally formed so as to be thicker at around a middle of said first field oxide film.
A semiconductor device in which a first element isolating region with a larger film thickness and a second element isolating region with a smaller film thickness are selectively formed on a semiconductor substrate so that said semiconductor substrate may be dielectrically isolated into a plurality of element regions by said first element isolating region and second element isolating region, wherein:
- said first element isolating region comprises a first field oxide film which is selectively formed at such a position in a first element-isolating region formation-expected region that is not covered with a first oxidation preventing film having a first opening and a second field oxide film which is selectively formed at such a position in said first element-isolating region formation-expected region that is not covered with a second opening of a second oxidation preventing film having said second opening with a smaller width dimension than said first opening and also which is locally formed so as to be thicker at around a middle of said first field oxide film;
- and
- said second element isolating region comprises a third field oxide film which is selectively formed at such a position in a second element-isolating region formation-expected region that is not covered with said second oxidation preventing film having a third opening.
A semiconductor device in which a semiconductor substrate thereof is dielectrically isolated into a plurality of element regions by an element isolating region which is selectively formed on said semiconductor substrate, wherein said element isolating region comprises:
- a first field oxide film which is selectively formed at such a position in an element-isolating region formation-expected region that is not covered with a first oxidation preventing film having a first opening therein;
- and
- a second field oxide film which is selectively formed at such a position in said element-isolating region formation-expected region that is not covered with a second oxidation preventing film having therein a second opening with a larger width dimension than said first opening and which overlaps partially with said first field oxide film and also which is formed shallower in level than said first field oxide film.
A semiconductor device in which a first element isolating region with a larger film thickness and a second element isolating region with a smaller film thickness are selectively formed on a semiconductor substrate so that said semiconductor substrate may be dielectrically isolated into a plurality of element regions by said first element isolating region and second element isolating region, wherein:
- said first element isolating region comprises a first field oxide film which is selectively formed at such a position in a first element-isolating region formation-expected region that is not covered with a first oxidation preventing film having a first opening therein and a second field oxide film which is selectively formed at such a position in said first element-isolating region formation-expected region that is not covered with a second opening of a second oxidation preventing film having said second opening with a larger width dimension than said first opening;
- and
- said second element isolating region comprises a third field oxide film which is selectively formed at such a position in a second element-isolating region formation-expected region that is not covered with said second oxidation preventing film having a third opening.
Dependencies are inferred from the claim text.