US4615764A
Expired / Lapsed
US
⏱️ 0.0 years remaining
SF6/nitriding gas/oxidizer plasma etch system
Assignee: Honeywell International Inc
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Filing: 1984-11-05
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Granted: 1986-10-07
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Expires: 2004-11-05
Abstract
Abstract A gaseous mixture of SF 6 , a nitriding gas component and an oxidizer gas component is disclosed as an effective SiO 2 etchant having enhanced selectively for use in either the plasma or reactive ion etch process. By adding an oxidizing gas to the SF 6 nitriding gas plasma etchant, the selectively for SiO 2 over silicon or polysilicon is marked improved. The optional addition of an inert diluent gas did not substantially change these results.
Inventors
- 👤 Stephen M. Bobbio
- 👤 Marie C. Flanigan
- 👤 Kenneth M. Thrun
- 👤 Ralph L. DePrenda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:36
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
87 words
Method of enhancing the selectivity in etching silicon dioxide preferentially over silicon or polysilicon in an article containing a layer of silicon dioxide on an underlayer of silicon or polysilicon in which said article is exposed to a low pressure plasma gas mixture discharge and wherein the plasma comprises SF 6 and a nitriding component in the gaseous phase, the improvement comprising adding an oxidizer as a component of the plasma gas mixture and continuing said exposure of said article until the silicon dioxide layer is penetrated.
Claim 2
Dependent Claim
87 words
Method of enhancing the selectivity in etching silicon dioxide preferentially over silicon or polysilicon in an article containing a layer of silicon dioxide on an underlayer of silicon or polysilicon in which said article is exposed to a low pressure plasma gas mixture discharge and wherein the plasma comprises SF 6 and a nitriding component in the gaseous phase, the improvement comprising adding an oxidizer as a component of the plasma gas mixture and continuing said exposure of said article until the silicon dioxide layer is penetrated.
Claim 3
Dependent Claim
12 words
The method of claim 1 wherein the oxidizing component is carbon dioxide.
Claim 4
Dependent Claim
11 words
The method of claim 1 wherein the oxidizer is sulfur dioxide.
Claim 5
Dependent Claim
11 words
The method of claim 1 wherein the oxidizer is nitric oxide.
Claim 6
Dependent Claim
10 words
The method of claim 1 wherein the oxidizer is oxygen.
Claim 7
Dependent Claim
13 words
The method of claim 1 wherein the oxidizer is H 2 O vapor.
Claim 8
Dependent Claim
16 words
The method of claim 1 in which the gas mixture is diluted with an inert gas.
Claim 9
Dependent Claim
32 words
The method of claim 1 wherein the plasma gas mixture incorporates in a proportion by partial pressures of the SF 6 component to the oxidizer of from about 1:25 to about 3:1.
Claim 10
Dependent Claim
35 words
The method of claim 8 wherein the nitriding component is ammonia and the oxidizer is carbon dioxide and the proportion by partial pressure of SF 6 to oxidizing gas is about 1:15 to about 2:1.
Claim 11
Dependent Claim
56 words
A plasma etch gas for selectively etching silicon dioxide against silicon comprising a mixture of SF 6 , a nitriding gas and an oxidizing gas in partial pressure ratio of SF 6 to nitriding gas of from about 17:3 to about 1:4 and for SF 6 to oxidizing gas of from about 1:25 to about 3:1.
Claim 12
Dependent Claim
56 words
A plasma etch gas for selectively etching silicon dioxide against silicon comprising a mixture of SF 6 , a nitriding gas and an oxidizing gas in partial pressure ratio of SF 6 to nitriding gas of from about 17:3 to about 1:4 and for SF 6 to oxidizing gas of from about 1:25 to about 3:1.
Claim 13
Dependent Claim
26 words
A plasma etch gas according to claim 10 containing the oxidizing gas in a proportion to SF 6 by partial pressure of 1:15 to about 2:1.
References Cited (Backward Citations)
US3679502A
Cited
US3940506A
Cited
US3971684A
Cited
US3923568A
Cited
US4052251A
Cited
US4330384A
Cited
US4213818A
Cited
US4214946A
Cited
US4283249A
Cited
US4310380A
Cited
US4314875A
Cited
US4324611A
Cited
US4381967A
Cited
US4465552A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-10-06 | 1990-04-07 | 1990-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-10-06 | 1994-04-07 | 1994-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-10-06 | 1998-04-07 | 1998-10-07 | $7700.00 | Window Closed / Lapsed |