US4443295A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of etching refractory metal film on semiconductor structures utilizing triethylamine and H2 O2
Assignee: National Semiconductor Corp
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Filing: 1983-06-13
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Granted: 1984-04-17
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Expires: 2003-06-13
Abstract
Abstract A method is disclosed of etching a refractory metal layer on a semiconductor structure comprising subjecting it to a mixture of a Lewis base and an oxidizing agent. In the preferred embodiment a method is described for etching a tungsten-titanium layer on a semiconductor structure by immersing it in a mixture of triethylamine and hydrogen peroxide.
Inventors
- 👤 Kenneth J. Radigan
- 👤 James M. Cleeves
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:41
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/10; C23F1/14; C23F1/32; C23F1/38; C23F1/16; C23F1/20; H; H10; H10P; H10P50/00; H10P50/60; H10P50/66; H10P50/663; H10P50/667
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
27 words
A method of etching a refractory metal layer on a semiconductor structure comprising subjecting the layer to a mixture of a Lewis base and an oxidizing agent.
Claim 2
Independent Claim
27 words
A method of etching a refractory metal layer on a semiconductor structure comprising subjecting the layer to a mixture of a Lewis base and an oxidizing agent.
Claim 3
Dependent Claim
13 words
A method as in claim 1 wherein the refractory metal layer comprises tungsten.
Claim 4
Dependent Claim
14 words
A method as in claim 2 wherein the refractory metal layer further comprises titanium.
Claim 5
Dependent Claim
12 words
A method as in claim 1 wherein the Lewis base comprises triethylamine.
Claim 6
Dependent Claim
13 words
A method as in claim 4 wherein the oxidizing agent comprises hydrogen peroxide.
Claim 7
Dependent Claim
13 words
A method as in claim 1 wherein the Lewis base comprises ethylene diamine.
Claim 8
Dependent Claim
13 words
A method as in claim 6 wherein the oxidizing agent comprises hydrogen peroxide.
Claim 9
Independent Claim
21 words
A method of etching a tungsten-titanium layer on semiconductor structure comprising subjecting it to a mixture of triethylamine and hydrogen peroxide.
Claim 10
Independent Claim
21 words
A method of etching a tungsten-titanium layer on semiconductor structure comprising subjecting it to a mixture of triethylamine and hydrogen peroxide.
References Cited (Backward Citations)
US3529350A
Cited
US3669776A
Cited
US3737306A
Cited
US3944496A
Cited
US3841931A
Cited
US4267012A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-04-17 | 1987-10-17 | 1988-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-17 | 1991-10-17 | 1992-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-17 | 1995-10-17 | 1996-04-17 | $7700.00 | Window Closed / Lapsed |