Patent US4654114A successfully refreshed from Google Patents.
US4654114A
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Dry etching method for selectively etching silicon nitride existing on silicon dioxide
Assignee: Sony Corp
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Filing: 1985-12-16
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Granted: 1987-03-31
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Expires: 2005-12-16
Abstract
Abstract A dry etching method for selectively etching a silicon nitride having the generic formula Si x N y existing over a base of SiO 2 utilizing, as the etchant gas, a mixture of a fluorohydrocarbon in which the atomic ratio of F/C is smaller than 3:1, the mixture containing 30-70% of CO 2 on a flow rate basis. The presence of such a large amount of CO 2 in the etchant in combination with the particular fluorohydrocarbons is effective for enhancing the selective ratio of etching between Si x N y and SiO 2 and also for preventing formation of obstructive polymers of fluorocarbons.
Inventors
- 👤 Shingo Kadomura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:37
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
67 words
In a dry etching method for selective etching of a silicon nitride existing on a surface of SiO 2 with an etchant gas containing a fluorohydrocarbon, the improvement which comprises: employing as said etchant gas a mixture of a fluorohydrocarbon having an atomic ratio of F to C less than 3:1 and CO 2 in an amount of 30-70% of said mixture on a flow rate basis.
Claim 2
Dependent Claim
67 words
In a dry etching method for selective etching of a silicon nitride existing on a surface of SiO 2 with an etchant gas containing a fluorohydrocarbon, the improvement which comprises: employing as said etchant gas a mixture of a fluorohydrocarbon having an atomic ratio of F to C less than 3:1 and CO 2 in an amount of 30-70% of said mixture on a flow rate basis.
Claim 3
Dependent Claim
17 words
A dry etching method according to claim 1 wherein said fluorohydrocarbon is CH 2 F 2 .
Claim 4
Dependent Claim
17 words
A dry etching method according to claim 1 wherein said fluorohydrocarbon is CH 2 F 2 .
Claim 5
Dependent Claim
18 words
A dry etching method according to claim 1 wherein said silicon nitride is Si 3 N 4 .
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) | 1990-03-30 | 1990-09-29 | 1991-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-30 | 1994-09-29 | 1995-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-30 | 1998-09-29 | 1999-03-31 | $7700.00 | Window Closed / Lapsed |