Patent US2029216A successfully refreshed from Google Patents.
Patent US4735681A successfully refreshed from Google Patents.
US4735681A
Expired / Lapsed
US
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Fabrication method for sub-micron trench
Assignee: NXP USA Inc
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Filing: 1986-08-15
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Granted: 1988-04-05
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Expires: 2006-08-15
Abstract
Abstract A method for the construction of self aligned submicron trenches by forming projecting ridges on a surface, forming a mask over the surface and then etching back the ridges to form gaps in the mask which act as guides for the etching of trenches in the substrate below.
Inventors
- 👤 Antonio R. Alvarez
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:21
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/69; H10P50/691; H10P50/693; H10P50/695; H10P50/696; Y; Y10; Y10S; Y10S438/00; Y10S438/942; Y10S438/947
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
149 words
A method for the construction of self aligned submicron trenches in a substrate comprising the steps of: placing a first masking material on a substrate said first masking material having at least one side extending to said substrate; forming a spacer material over said first masking material and said substrate; removing a quantity of said spacer material by anisotropically etching it and thereby leaving a quantity of said spacer material along said at least one side of the first masking material; selectively removing said first masking material thereby leaving said spacer material in a projecting ridge; covering said projecting ridge of said spacer material and said substrate with a second masking material; planarizing the second masking material and exposing said projecting ridge; etching the projecting ridge thereby forming a gap in said second masking material; and using said gap as a mask opening, etching a trench in said substrate.
Claim 2
Independent Claim
149 words
A method for the construction of self aligned submicron trenches in a substrate comprising the steps of: placing a first masking material on a substrate said first masking material having at least one side extending to said substrate; forming a spacer material over said first masking material and said substrate; removing a quantity of said spacer material by anisotropically etching it and thereby leaving a quantity of said spacer material along said at least one side of the first masking material; selectively removing said first masking material thereby leaving said spacer material in a projecting ridge; covering said projecting ridge of said spacer material and said substrate with a second masking material; planarizing the second masking material and exposing said projecting ridge; etching the projecting ridge thereby forming a gap in said second masking material; and using said gap as a mask opening, etching a trench in said substrate.
Claim 3
Dependent Claim
28 words
The method of claim 1 wherein the step of planarizing includes spinning on a planarizing material and etching back until said projecting ridge of spacer material is exposed.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-04-05 | 1991-10-05 | 1992-04-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-05 | 1995-10-05 | 1996-04-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-05 | 1999-10-05 | 2000-04-05 | $7700.00 | Window Closed / Lapsed |