Patent US5277756A successfully refreshed from Google Patents.
US5277756A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Post fabrication processing of semiconductor chips
Assignee: Hewlett Packard Development Co LP
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Filing: 1992-06-15
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Granted: 1994-01-11
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Expires: 2012-06-15
Abstract
Abstract A method for for processing semiconductor chips which deters the formation of "tin whiskers" and which removes excess substrate material from the passive side of a semiconductor device is presented. The deterrence of tin whiskers is accomplished by controlling the size of the bead of flowable metal on the conductive bump. The removal of excess material from the passive side of the semiconductor device is accomplished by chemical reaction after the formation of the conductive bump.
Inventors
- 👤 John B. Dion
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:48
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/10; C23F1/14; C23F1/32; C23F1/38; H; H10; H10W; H10W72/00; H10W72/20; H10W72/01; H10W72/012; H10W72/01251; H10W72/01255; H10W72/019; H10W72/01951; H10W72/01953; H10W72/01955; H10W72/221; H10W72/222; H10W72/231; H10W72/234; H10W72/251; H10W72/29
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
31 words
A method for removing a barrier metal layer from a semiconductor device comprising the step of exposing the said semiconductor device to a solution containing a peroxide and oxidized ammonium persulfate.
Claim 2
Independent Claim
31 words
A method for removing a barrier metal layer from a semiconductor device comprising the step of exposing the said semiconductor device to a solution containing a peroxide and oxidized ammonium persulfate.
Claim 3
Dependent Claim
28 words
A method for removing a barrier metal layer from a semiconductor device as in claim 1, said oxidized ammonium persulfate being approximately 7% of the solution by weight.
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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) | 1997-01-10 | 1997-07-12 | 1998-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-01-10 | 2001-07-12 | 2002-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-01-10 | 2005-07-12 | 2006-01-11 | $7700.00 | Window Closed / Lapsed |