US5318665A
Expired / Lapsed
US
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Method for etching polysilicon film
Assignee: NEC Electronics Corp
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Filing: 1992-04-07
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Granted: 1994-06-07
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Expires: 2012-04-07
Abstract
Abstract In etching a polysilicon film having a large step difference by means of the RIE method, use is made of a mixed gas of HBr and Ar (10 to 25%) or a mixed gas of HBr, Ar (5 to 25 %), and O 2 (0.2 to 2%). With this arrangement, it is possible to eliminate the residuals in the step part, and etch the polysilicon film with high anisotropy with little etching of the underlying oxide film.
Inventors
- 👤 Kirokazu Oikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:18
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267; H10P50/268
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
66 words
A method for etching a polysilicon film formed via an insulating film on the surface of a semiconductor substrate which underwent an impurity diffusion process by a reactive ion etching method that carries out ion etching in a reaction chamber having the atmosphere of an etching gas of a total gas flow, characterized in that said etching gas contains at least hydrogen bromide argon, and argon.
Claim 2
Independent Claim
66 words
A method for etching a polysilicon film formed via an insulating film on the surface of a semiconductor substrate which underwent an impurity diffusion process by a reactive ion etching method that carries out ion etching in a reaction chamber having the atmosphere of an etching gas of a total gas flow, characterized in that said etching gas contains at least hydrogen bromide argon, and argon.
Claim 3
Dependent Claim
59 words
An etching method for a polysilicon film as claimed in claim 1, wherein the ratio of gas flow of said argon is set to be in the range of 5 to 25% of said total gas flow and the ratio of said oxygen is set to be in the range of 0.2 to 2% of said total gas flow.
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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) | 1997-06-06 | 1997-12-06 | 1998-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-06-06 | 2001-12-06 | 2002-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-06-06 | 2005-12-06 | 2006-06-07 | $7700.00 | Window Closed / Lapsed |