Patent US4073669A successfully refreshed from Google Patents.
US4073669A
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Plasma etching
Assignee: ITT Inc
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Filing: 1976-04-29
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Granted: 1978-02-14
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Expires: 1996-04-29
Abstract
Abstract Aluminum films on a semiconductor surface are etched in a carbon tetrachloride glow discharge. Typical etch rates are 2000-3000 A/min. The addition of 15% ammonia to the plasma prevents HCl formation when the etched material is exposed to air. This process provides a more easily controlled process for the manufacture of high density integrated circuits.
Inventors
- 👤 Rudolf A. H. Heinecke
- 👤 Geoffrey L. Ashcroft
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:49
CPC Classifications
H; H10; H10P; H10P72/00; H10P72/04; H10P72/0402; H10P72/0418; H10P72/0421; C; C23; C23F; C23F4/00; H01; H01J; H01J37/00; H01J37/32; H01J37/32009; H01J37/32082; H01J37/321; H01J37/32431; H01J37/32532; H01J37/32623; H10D; H10D64/00; H10D64/01; H10D64/011; H10P50/00; H10P50/20; H10P50/26; H10P50/262; H10P50/264; H10P50/266; H10P50/267
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
65 words
A method for selectively etching an aluminum film carried on a semiconductor substrate, comprising: selectively masking the aluminum film with a photoresist material; exposing the masked film to a radio-frequency glow discharge maintained in an atmosphere comprising carbon tetrachloride together with up to 15 volume percent ammonia; and stripping of the photoresist mask to obtain a finished semiconductor substrate carrying an aluminum conductor pattern thereon.
Claim 2
Independent Claim
65 words
A method for selectively etching an aluminum film carried on a semiconductor substrate, comprising: selectively masking the aluminum film with a photoresist material; exposing the masked film to a radio-frequency glow discharge maintained in an atmosphere comprising carbon tetrachloride together with up to 15 volume percent ammonia; and stripping of the photoresist mask to obtain a finished semiconductor substrate carrying an aluminum conductor pattern thereon.
Claim 3
Dependent Claim
21 words
A method according to claim 1 wherein the carbon tetrachloride atmosphere is maintained at a pressure between 0.03 and 0.3 torr.
Claim 4
Dependent Claim
37 words
A method according to claim 2 wherein the plasma etching stage is performed with the masked substrate mounted on a D.C. isolated conductive plate positioned in the plasma, and wherein said plate is capacitively coupled to earth.
Claim 5
Dependent Claim
12 words
A method according to claim 3 wherein the semiconductor material is silicon.
Claim 6
Dependent Claim
21 words
A method according to claim 4 wherein the aluminum is etched at a rate of 2,000 to 3,000 A per minute.
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) | 1981-02-13 | 1981-08-15 | 1982-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-13 | 1985-08-15 | 1986-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-13 | 1989-08-15 | 1990-02-14 | $7700.00 | Window Closed / Lapsed |