US5074969A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Composition and coating to prevent current induced electrochemical dendrite formation between conductors on dielectric substrate
Assignee: International Business Machines Corp
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Filing: 1991-03-07
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Granted: 1991-12-24
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Expires: 2011-03-07
Abstract
Abstract The present invention comprises the use of a copper/nickel containing alloy composition or application of a protective nickel alloy coating to copper current-carrying leads to prevent electrolytic migration between tape automated bonding (TAB) package leads.
Inventors
- 👤 William D. Brewer
- 👤 Kurt R. Grebe
- 👤 Raymond R. Horton
- 👤 Linda C. Matthew
- 👤 Ismail C. Noyan
- 👤 Michael J. Palmer
- 👤 Sampath Purushothaman
- 👤 David L. Rath
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:54
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/22; H05K3/24; H05K3/244; H05K1/00; H05K1/02; H05K1/09; H10; H10W; H10W70/00; H10W70/01; H10W70/05; H10W70/60; H10W70/62; H10W70/66; H05K1/03; H05K1/0393
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
135 words
In a tape automated bonding frame comprising a substrate having coated inner and outer leads secured thereto, a continuous method for rendering said coated inner an outer leads wettable by solder, comprising: coating inner and outer current carrying leads situated on a substrate, said leads comprising a corrosible metal capable of providing a source of ions which under electrolytic conditions form dendrites with adjacent leads, with a noble metal deposited on the top and sides of said leads; selectively applying a resist coating on said noble metal coating at predetermined sites along the length and width of said inner and outer leads; applying a nickel-containing coating that covers said noble metal coating but does not coat the sites covered by said resist; stripping said resist from said sites thereby exposing said sites suitable for soldering.
Claim 2
Dependent Claim
135 words
In a tape automated bonding frame comprising a substrate having coated inner and outer leads secured thereto, a continuous method for rendering said coated inner an outer leads wettable by solder, comprising: coating inner and outer current carrying leads situated on a substrate, said leads comprising a corrosible metal capable of providing a source of ions which under electrolytic conditions form dendrites with adjacent leads, with a noble metal deposited on the top and sides of said leads; selectively applying a resist coating on said noble metal coating at predetermined sites along the length and width of said inner and outer leads; applying a nickel-containing coating that covers said noble metal coating but does not coat the sites covered by said resist; stripping said resist from said sites thereby exposing said sites suitable for soldering.
Claim 3
Dependent Claim
21 words
The method defined in claim 1 wherein said substrate is polyimide and said corrosible metal is copper or a copper alloy.
Claim 4
Dependent Claim
25 words
The method defined in claim 1 wherein said resist is applied to said noble metal coating using a rotating drum having a raised pattern thereon.
Claim 5
Dependent Claim
40 words
The method defined in claim 3 wherein said raised pattern consists of two figures which match the configuration of the ILB and the OLB in that one of said figures is located within the confines of the other said figure.
Claim 6
Dependent Claim
14 words
The method defined in claim 4 wherein said pattern figures are rectangular in shape.
Claim 7
Dependent Claim
22 words
The method defined in claim 4 wherein said noble metal is selected from the group consisting of Au, Pt, Pd or Rh.
Claim 8
Dependent Claim
12 words
The method defined in claim 6 wherein said noble metal is Au.
Claim 9
Dependent Claim
16 words
The method defined in claim 6 wherein said nickel-containing coating is electroplated onto said gold coating.
References Cited (Backward Citations)
US4810620A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-12-23 | 1995-06-24 | 1995-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-23 | 1999-06-24 | 1999-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-23 | 2003-06-24 | 2003-12-24 | $7700.00 | Window Closed / Lapsed |