US4818727A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of improving the corrosion resistance of aluminum contacts on semiconductors
Assignee: STMicroelectronics lnc USA
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Filing: 1987-06-23
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Granted: 1989-04-04
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Expires: 2007-06-23
Abstract
Abstract A method for improving the corrosion resistance of aluminum in a semiconductor device. The step includes providing a semiconductor device having aluminum containing contact pads; attaching a leadframe to the contact pads; and applying sufficient zinc chromate in solution to the contact pads for a sufficient time and at a sufficient temperature to render said aluminum substantially resistant to corrosion.
Inventors
- 👤 Timothy E. Turner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 20:40
CPC Classifications
H; H10; H10W; H10W72/00; H10W72/01; H10W72/012; H10W20/00; H10W20/01; H10W20/031; H10W20/064; H10W20/065; H10W72/20; H10W72/251; H10W72/50; H10W72/551; H10W72/552; H10W72/5524; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117; Y10T29/49121
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
63 words
A method for producing a semiconductor article which comprises providing a semiconductor device having aluminum containing contact pads; electrically attaching a leadframe to said contact pads; and applying sufficient zinc chromate in solution to said contact pads for a sufficient time and at a sufficient temperature to render said aluminum substantially resistant to corrosion from an atmosphere containing moisture and an ionic species.
Claim 2
Independent Claim
63 words
A method for producing a semiconductor article which comprises providing a semiconductor device having aluminum containing contact pads; electrically attaching a leadframe to said contact pads; and applying sufficient zinc chromate in solution to said contact pads for a sufficient time and at a sufficient temperature to render said aluminum substantially resistant to corrosion from an atmosphere containing moisture and an ionic species.
Claim 3
Dependent Claim
33 words
The method of claim 1 wherein said zinc chromate in solution comprises an aqueous solution containing from about 0.1% to about 20% zinc chromate based on the weight of the solution component parts.
Claim 4
Dependent Claim
20 words
The method of claim 1 wherein said zinc chromate in solution comprises a saturated solution of zinc chromate in water.
Claim 5
Dependent Claim
27 words
The method of claim 1 wherein said application is conducted wherein said solution is maintained at a temperature of from about 50° C. to about 100° C.
Claim 6
Dependent Claim
18 words
The method of claim 1 wherein said application is conducted for from about 10 to about 60 minutes.
Claim 7
Dependent Claim
22 words
The method of claim 1 wherein said aluminum containing contact pad is an alloy containing at least about 90% by weight aluminum.
Claim 8
Dependent Claim
18 words
The method of claim 6 wherein said alloy contains from about 0.5% to about 7% by weight copper.
Claim 9
Dependent Claim
18 words
The method of claim 6 wherein said alloy contains from about 0.5% to about 1% by weight silicon.
Claim 10
Dependent Claim
70 words
The method of claim 1 wherein said zinc chromate in solution comprises an aqueous solution containing from about 0.1% to about 20% zinc chromate based on the weight of the solution component parts; and wherein said application is conducted wherein said solution is maintained at a temperature of from about 50° C. to about 100° C.; and wherein said application is conducted for from about 10 to about 60 minutes.
Claim 11
Independent Claim
51 words
A method for producing an aluminum containing member having improved corrosion resistance which comprises providing an aluminum containing article and applying sufficient zinc chromate in solution to said article for and at a temperature to render said aluminum substantially resistant to corrosion from an atmosphere containing moisture and an ionic species.
Claim 12
Independent Claim
51 words
A method for producing an aluminum containing member having improved corrosion resistance which comprises providing an aluminum containing article and applying sufficient zinc chromate in solution to said article for and at a temperature to render said aluminum substantially resistant to corrosion from an atmosphere containing moisture and an ionic species.
Claim 13
Dependent Claim
33 words
The method of claim 10 wherein said zinc chromate in solution comprises an aqueous solution containing from about 0.1% to about 20% zinc chromate based on the weight of the solution component parts.
Claim 14
Dependent Claim
20 words
The method of claim 10 wherein said zinc chromate in solution comprises a saturated solution of zinc chromate in water.
Claim 15
Dependent Claim
21 words
The method of claim 10 wherein said aluminum containing article is an alloy containing at least about 90% by weight aluminum.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-04-03 | 1992-10-03 | 1993-04-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-03 | 1996-10-03 | 1997-04-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-03 | 2000-10-03 | 2001-04-04 | $7700.00 | Window Closed / Lapsed |