US5004703A
Expired / Lapsed
US
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Multiple trench semiconductor structure method
Assignee: Semiconductor Components Industries LLC
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Filing: 1989-07-21
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Granted: 1991-04-02
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Expires: 2009-07-21
Abstract
Abstract A method of fabricating multiple trench semiconductor structures wherein a preferred embodiment includes forming an epitaxial silicon layer on a silicon substrate and a dielectric layer on the epitaxial silicon layer. An opening is then formed which extends through the dielectric layer and into the epitaxial silicon layer. Sidewall spacers are formed in the opening and an oxide lens is formed in the opening between the sidewall spacers. The sidewall spacers are then removed and trenches are formed in the opening where the sidewall spacers were formerly disposed.
Inventors
- 👤 Peter J. Zdebel
- 👤 Barbara Vasquez
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:34
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/69; H10P50/691; H10P50/693; H10P50/694; H10P50/692
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
106 words
A method of forming a multiple trench semiconductor structure comprising the steps of: providing a semiconductor substrate; forming a blanket buried layer in said semiconductor substrate; forming a dielectric layer on said semiconductor substrate; forming at least one opening in said dielectric layer; and in the following order: forming an oxide layer on the bottom and sidewalls of said at least one opening; forming sidewall spacers in said at least one opening; forming a dielectric lens in said at least one opening between said sidewall spacers; removing said sidewall spacers; and forming trenches in said at least one opening where said sidewall spacers were formerly disposed.
Claim 2
Independent Claim
106 words
A method of forming a multiple trench semiconductor structure comprising the steps of: providing a semiconductor substrate; forming a blanket buried layer in said semiconductor substrate; forming a dielectric layer on said semiconductor substrate; forming at least one opening in said dielectric layer; and in the following order: forming an oxide layer on the bottom and sidewalls of said at least one opening; forming sidewall spacers in said at least one opening; forming a dielectric lens in said at least one opening between said sidewall spacers; removing said sidewall spacers; and forming trenches in said at least one opening where said sidewall spacers were formerly disposed.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein a semiconductor layer is formed on said semiconductor substrate prior to the formation of the dielectric layer.
Claim 4
Dependent Claim
36 words
The method of claim 2 wherein the dielectric layer comprises an oxide layer formed on the semiconductor layer, a nitride layer formed on the oxide layer and a second oxide layer formed on the nitride layer.
Claim 5
Dependent Claim
39 words
The method of claim 3 wherein a conformal nitride layer is formed over the structure following the formation of the oxide layer in said at least one opening, the sidewall spacers being formed by etching said conformal nitride layer.
Claim 6
Dependent Claim
28 words
The method of claim 4 wherein the dielectric lens is formed by thermally oxidizing the semiconductor material disposed between the sidewall spacers in the at least one opening.
Claim 7
Independent Claim
134 words
A method of forming a multiple trench semiconductor structure comprising the steps of: providing a silicon substrate; forming a blanket buried layer in said silicon substrate; forming an epitaxial silicon layer on said substrate; forming a dielectric layer on said epitaxial silicon layer; forming at least one opening in said dielectric layer, said at least one opening extending into said epitaxial silicon layer; and in the following order: forming an oxide layer on the bottom and sidewalls of said at least one opening; forming sidewall spacers in said at least one opening; thermally oxidizing said epitaxial silicon layer disposed between said sidewall spacers in said at least one opening to form an oxide lens; removing said sidewall spacers; and forming trenches in said at least one opening where said sidewall spacers were formerly disposed.
Claim 8
Independent Claim
134 words
A method of forming a multiple trench semiconductor structure comprising the steps of: providing a silicon substrate; forming a blanket buried layer in said silicon substrate; forming an epitaxial silicon layer on said substrate; forming a dielectric layer on said epitaxial silicon layer; forming at least one opening in said dielectric layer, said at least one opening extending into said epitaxial silicon layer; and in the following order: forming an oxide layer on the bottom and sidewalls of said at least one opening; forming sidewall spacers in said at least one opening; thermally oxidizing said epitaxial silicon layer disposed between said sidewall spacers in said at least one opening to form an oxide lens; removing said sidewall spacers; and forming trenches in said at least one opening where said sidewall spacers were formerly disposed.
Claim 9
Dependent Claim
37 words
The method of claim 6 wherein the dielectric layer comprises an oxide layer formed on the epitaxial silicon layer, a nitride layer formed on the oxide layer and a second oxide layer formed on the nitride layer.
Claim 10
Dependent Claim
39 words
The method of claim 6 wherein a conformal nitride layer is formed over the structure following the formation of the oxide layer in said at least one opening, the sidewall spacers being formed by etching said conformal nitride layer.
Claim 11
Dependent Claim
36 words
The method of claim 6 wherein a trench liner layer is formed in the trenches, said trench liner layer comprising an oxide layer disposed in said trench and a nitride layer disposed on said oxide layer.
Claim 12
Dependent Claim
14 words
The method of claim 9 wherein the trenches are filled by forming polysilicon therein.
Claim 13
Independent Claim
173 words
A method of forming a multiple trench semiconductor structure comprising the steps of: providing a silicon substrate; implanting a blanket buried layer in said substrate; forming an epitaxial silicon layer on said substrate; forming a thermal oxide layer on said epitaxial silicon layer; forming a nitride layer on said thermal oxide layer; forming an oxide layer on said nitride layer; forming a mask on said oxide layer to define at least one opening; etching at least one opening through said thermal oxide, nitride and oxide layers into said epitaxial silicon layer; and in the following order: forming a thermal oxide layer in said at least one opening; forming a conformal nitride layer on the semiconductor structure; etching said conformal nitride layer to form sidewall spacers in said at least one opening; thermally oxidizing the epitaxial silicon layer disposed between said sidewall spacers in said at least one opening to form an oxide lens; removing said sidewall spacers; and forming trenches in said at least one opening where said sidewall spacers were formerly disposed.
Claim 14
Independent Claim
173 words
A method of forming a multiple trench semiconductor structure comprising the steps of: providing a silicon substrate; implanting a blanket buried layer in said substrate; forming an epitaxial silicon layer on said substrate; forming a thermal oxide layer on said epitaxial silicon layer; forming a nitride layer on said thermal oxide layer; forming an oxide layer on said nitride layer; forming a mask on said oxide layer to define at least one opening; etching at least one opening through said thermal oxide, nitride and oxide layers into said epitaxial silicon layer; and in the following order: forming a thermal oxide layer in said at least one opening; forming a conformal nitride layer on the semiconductor structure; etching said conformal nitride layer to form sidewall spacers in said at least one opening; thermally oxidizing the epitaxial silicon layer disposed between said sidewall spacers in said at least one opening to form an oxide lens; removing said sidewall spacers; and forming trenches in said at least one opening where said sidewall spacers were formerly disposed.
Claim 15
Dependent Claim
36 words
The method of claim 11 wherein a trench liner layer is formed in the trenches, said trench liner layer comprising an oxide layer disposed in said trench and a nitride layer disposed on said oxide layer.
Claim 16
Dependent Claim
14 words
The method of claim 12 wherein the trenches are filled by forming polysilicon therein.
Claim 17
Dependent Claim
14 words
The method of claim 12 wherein the trenches are filled by forming oxide therein.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-04-01 | 1994-10-01 | 1995-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-04-01 | 1998-10-01 | 1999-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-04-01 | 2002-10-01 | 2003-04-02 | $7700.00 | Window Closed / Lapsed |