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US3986897A
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Aluminum treatment to prevent hillocking
Assignee: Motorola Solutions Inc
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Filing: 1974-09-30
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Granted: 1976-10-19
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Expires: 1994-09-30
Abstract
Abstract A method of surface treating aluminum, particularly aluminum metallization for semiconductors, which includes subjecting the aluminum surface to be treated with fuming nitric acid for one to ten minutes at room temperature. Following cleaning, the surface is subjected to boiling water for 5 to 15 minutes. The foregoing treatment appears to form a boehmite (AlO(OH)) layer on the surface of the aluminum, thereby substantially eliminating hillocking.
Inventors
- 👤 Larry D. McMillan
- 👤 Richard E. Shipley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 21:48
CPC Classifications
H; H10; H10P; H10P95/00; C; C23; C23C; C23C22/00; C23C22/05; C23C22/68; H10P14/00; H10P14/60; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6314; Y; Y10; Y10S; Y10S438/00; Y10S438/937
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
75 words
In a method of manufacturing semiconductors including the steps of forming semiconductor junction regions in a surface of a semiconductor substrate; covering the surface with a dielectric layer; opening windows therein; and depositing aluminum metallization thereover; a process for eliminating hillocking of said aluminum metallization comprising the steps of: subjecting the aluminum metallization to fuming nitric acid for one to ten minutes; and subjecting the treated surface to boiling water for five to fifteen minutes.
Claim 2
Dependent Claim
75 words
In a method of manufacturing semiconductors including the steps of forming semiconductor junction regions in a surface of a semiconductor substrate; covering the surface with a dielectric layer; opening windows therein; and depositing aluminum metallization thereover; a process for eliminating hillocking of said aluminum metallization comprising the steps of: subjecting the aluminum metallization to fuming nitric acid for one to ten minutes; and subjecting the treated surface to boiling water for five to fifteen minutes.
Claim 3
Dependent Claim
18 words
A method as recited in claim 1 wherein said surface is cleaned prior to the boiling water step.
Claim 4
Dependent Claim
26 words
A method as recited in claim 1 wherein said aluminum is selected from the group consisting essentially of aluminum and alloys thereof containing silicon and copper.
Claim 5
Dependent Claim
21 words
A method as recited in claim 1 wherein said surface is treated with nitric acid for a period of three minutes.
Claim 6
Dependent Claim
23 words
A method as recited in claim 1 wherein said fuming nitric acid has a concentration of more than 80 percent HNO 3 .
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) | 1979-10-19 | 1980-04-19 | 1980-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-19 | 1984-04-19 | 1984-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-19 | 1988-04-19 | 1988-10-19 | $7700.00 | Window Closed / Lapsed |