US5119167A
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: 1988-10-21
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Granted: 1992-06-02
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Expires: 2008-10-21
Abstract
Abstract A method for improving the corrosion resistance of aluminum in a semiconductor device. The step includes providing a semiconductor device having aluminus 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
2026-11-09 01:31
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/064; H10W20/065; H10W20/069; H10W72/00; H10W72/01; H10W72/012; H10W72/20; H10W72/251
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
63 words
A semiconductor article produced by a method 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
Dependent Claim
63 words
A semiconductor article produced by a method 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 article 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 article of claim 1 wherein said zinc chromate in solution comprises a saturated solution of zinc chromate in water.
Claim 5
Dependent Claim
26 words
The article of claim 1 wherein said application is conducted wherein said solution is maintained at a temperature of from about 50° C. to bout 100°C.
Claim 6
Dependent Claim
18 words
The article of claim 1 wherein said application is conducted for from about 10 to about 60 minutes.
Claim 7
Dependent Claim
22 words
The article 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 article of claim 6 wherein said alloy contains from about 0.5% to about 7% by weight copper.
Claim 9
Dependent Claim
18 words
The article of claim 6 wherein said alloy contains from about 0.5% to about 1% by weight silicon.
Claim 10
Dependent Claim
70 words
The article 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 bout 50° C. to about 100° C.; and wherein said application is conducted for from about 10 to bout 60 minutes.
Claim 11
Dependent Claim
52 words
A semiconductor article which comprises a semiconductor device having aluminum containing contact pads and a leadframe having leads which are electrically attached to a portion of said contact pads, the portion of the contact pads not underlying said leads having a surface which is the reaction product of aluminum and zinc chromate.
Claim 12
Dependent Claim
52 words
A semiconductor article which comprises a semiconductor device having aluminum containing contact pads and a leadframe having leads which are electrically attached to a portion of said contact pads, the portion of the contact pads not underlying said leads having a surface which is the reaction product of aluminum and zinc chromate.
Claim 13
Dependent Claim
26 words
The article of claim 10 wherein said leadframe comprises aluminum and the outer surface of said leadframe comprises the reaction product of aluminum and zinc chromate.
Claim 14
Dependent Claim
22 words
The article of claim 10 wherein said aluminum containing contact pads comprise an alloy containing at least abut 90% by weight aluminum.
Claim 15
Dependent Claim
18 words
The article of claim 12 wherein said alloy contains from about 0.5% to about 7% by weight copper.
Claim 16
Dependent Claim
18 words
The article of claim 12 wherein said alloy contains from about 0.5% to about 1% by weight silicon.
References Cited (Backward Citations)
US2695876A
Cited
US2816850A
Cited
US2989424A
Cited
US3191401A
Cited
US3535168A
Cited
US4003760A
Cited
GB1532230A
Cited
US4135292A
Cited
US4183758A
Cited
US4614963A
Cited
US4341564A
Cited
US4387006A
Cited
JPS58174436A
Cited
US4572928A
Cited
US4845543A
Cited
JPS60131975A
Cited
US4597714A
Cited
US4627151A
Cited
US4685998A
Cited
US4818727A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-06-02 | 1995-12-02 | 1996-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-06-02 | 1999-12-02 | 2000-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-06-02 | 2003-12-02 | 2004-06-02 | $7700.00 | Window Closed / Lapsed |