US4082604A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor process
Assignee: Motorola Solutions Inc
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Filing: 1976-01-05
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Granted: 1978-04-04
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Expires: 1996-01-05
Abstract
Abstract A process for improving the continuity of overlayers above an aluminum metallization stripe on a semiconductor device which includes the step of forming a conversion coating on the surface of the aluminium metallization. The conversion coating has a higher etch rate than the aluminum per se, and hence after selective masking, a tapered or sloped edge is produced on the aluminum stripe which is more easily continuously overlayed by the further necessary layers.
Inventors
- 👤 Richard R. Yanez
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:01
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/60; H10P50/66; H10P50/663; H10P50/667; C; C23; C23C; C23C22/00; C23C22/05; C23C22/06; C23C22/48; C23C22/56; H10P14/00; H10P14/60; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6314; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/062
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
93 words
In a process for producing a semiconductor integrated circuit the steps comprising: (a) depositing an aluminum metallization layer over an insulating layer of a semiconductor substrate, (b) forming a conversion coating on the surface of the aluminum metallization layer by immersing the semiconductor substrate in fuming nitric acid and then subjecting the wafer to boiling water, (c) selectively masking said aluminum metallization layer, and (d) etching said aluminum metallization whereby said conversion coating etches more rapidly than the unconverted portion of the layer and forms a sloping etch on the unremoved aluminum layer.
Claim 2
Dependent Claim
93 words
In a process for producing a semiconductor integrated circuit the steps comprising: (a) depositing an aluminum metallization layer over an insulating layer of a semiconductor substrate, (b) forming a conversion coating on the surface of the aluminum metallization layer by immersing the semiconductor substrate in fuming nitric acid and then subjecting the wafer to boiling water, (c) selectively masking said aluminum metallization layer, and (d) etching said aluminum metallization whereby said conversion coating etches more rapidly than the unconverted portion of the layer and forms a sloping etch on the unremoved aluminum layer.
Claim 3
Dependent Claim
22 words
In a process as recited in claim 1 wherein said fuming nitric acid is maintained at a temperature of approximately 80° C.
Claim 4
Dependent Claim
104 words
In a process for producing a semiconductor integrated circuit the steps comprising: (a) depositing an aluminum conductor layer over an insulating layer on a semiconductor substrate. (b) forming a conversion coating on the surface of the aluminum layer by immersing the semiconductor substrate in fuming nitric acid and then subjecting the wafer to boiling water, which coating has a more rapid etch rate than the conductor layer, (c) selectively masking said conductor layer, and (d) etching said conductor layer whereby said coating etches more rapidly than the uncovered portion of the layer and forms a sloping etch on the unremoved portion of the layer.
Claim 5
Dependent Claim
104 words
In a process for producing a semiconductor integrated circuit the steps comprising: (a) depositing an aluminum conductor layer over an insulating layer on a semiconductor substrate. (b) forming a conversion coating on the surface of the aluminum layer by immersing the semiconductor substrate in fuming nitric acid and then subjecting the wafer to boiling water, which coating has a more rapid etch rate than the conductor layer, (c) selectively masking said conductor layer, and (d) etching said conductor layer whereby said coating etches more rapidly than the uncovered portion of the layer and forms a sloping etch on the unremoved portion of the layer.
References Cited (Backward Citations)
US3825454A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-04-03 | 1981-10-03 | 1982-04-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-04-03 | 1985-10-03 | 1986-04-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-04-03 | 1989-10-03 | 1990-04-04 | $7700.00 | Window Closed / Lapsed |