US5221859A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Lead frame for semiconductor device
Assignee: Hitachi Ltd
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Filing: 1991-02-26
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Granted: 1993-06-22
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Expires: 2011-02-26
Abstract
Abstract A lead frame of a plastic encapsulated type semiconductor device is provided with a coating film which has a solderability higher than a solderability of a basic metal of the lead frame, and the coating film has a corrosion potential higher than a corrosion potential of the basic metal. The coating film protects the basic metal from corrosion caused by the plastic encapsulated member. The coating film of the lead frame made of a Fe-Ni alloy is an alloy comprising metal selected from Mo, W, Au, Cr, Cu, metals of the platinum group and a metal selected from Fe, Co, and Ni.
Inventors
- 👤 Shiro Kobayashi
- 👤 Narutoshi Kazama
- 👤 Masahiko Itoh
- 👤 Noriyuki Ohnaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 10:05
CPC Classifications
H; H10; H10W; H10W70/00; H10W70/40; H10W70/456; H10W70/457; H04; H04M; H04M3/00; H04M3/42; H04M3/436; H04M3/4365; H10W70/411; H10W70/415; H05; H05K; H05K3/00; H05K3/30; H05K3/32; H05K3/34; H05K3/341; H05K3/3421; H10W72/00; H10W72/50; H10W72/551; H10W72/552; H10W72/5522; H10W72/5524; H10W72/5525; H10W72/59; H10W72/851; H10W72/874; H10W72/884; H10W72/90; H10W72/951; H10W72/952; H10W74/00; H10W90/00; H10W90/701; H10W90/731; H10W90/736; H10W90/751; H10W90/756
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
75 words
A lead frame for mounting a semiconductor chip comprising: an alloy layer covering a portion of said lead frame, wherein said alloy layer comprises a first metal selected from the group consisting of Mo, W, Au, Ag, Cu, Pt, Pd, Cr, Rh, Ru, Ir, and Os, and a second metal selected from the group consisting of Fe, Ni, and Co, and wherein said first metal is less than 30% by weight of said alloy layer.
Claim 2
Dependent Claim
75 words
A lead frame for mounting a semiconductor chip comprising: an alloy layer covering a portion of said lead frame, wherein said alloy layer comprises a first metal selected from the group consisting of Mo, W, Au, Ag, Cu, Pt, Pd, Cr, Rh, Ru, Ir, and Os, and a second metal selected from the group consisting of Fe, Ni, and Co, and wherein said first metal is less than 30% by weight of said alloy layer.
Claim 3
Dependent Claim
50 words
A lead frame for mounting a semiconductor chip comprising: an oxide film covering a portion of said lead frame, wherein said oxide film comprises a complex oxide, a metal selected from the group consisting of Mo, W, and Cr, and an oxide of a basic metal of said lead frame.
Claim 4
Dependent Claim
50 words
A lead frame for mounting a semiconductor chip comprising: an oxide film covering a portion of said lead frame, wherein said oxide film comprises a complex oxide, a metal selected from the group consisting of Mo, W, and Cr, and an oxide of a basic metal of said lead frame.
Claim 5
Dependent Claim
76 words
A lead frame comprising: an alloy layer covering a surface of a basic metal of said lead frame, wherein said alloy layer includes a first metal selected from the group consisting of Mo, W, Au, Ag, Cr, Cu, Pt, Pd, Rh, Ru, Ir, and Os and a second metal at least selected from the group consisting of Fe, Co, and Ni, and wherein said first metal is less than 30% by weight of said alloy layer.
Claim 6
Dependent Claim
76 words
A lead frame comprising: an alloy layer covering a surface of a basic metal of said lead frame, wherein said alloy layer includes a first metal selected from the group consisting of Mo, W, Au, Ag, Cr, Cu, Pt, Pd, Rh, Ru, Ir, and Os and a second metal at least selected from the group consisting of Fe, Co, and Ni, and wherein said first metal is less than 30% by weight of said alloy layer.
Claim 7
Dependent Claim
109 words
A lead frame comprising: a basic metal, an alloy layer covering a surface of said basic metal, wherein said alloy layer include a first metal selected from the group consisting of Mo, W, Au, Ag, Cr, Cu, Pt, Pd, Rh, Ru, Ir, and Os, a second metal selected from the group consisting of Fe, Ni and Co, and a third metal selected from the group consisting of Sn and Zn, and wherein said first metal is less than 30% by weight of said alloy layer, said third metal being less than 30% by weight of said alloy layer, and said second metal being a residual of said alloy layer.
Claim 8
Dependent Claim
109 words
A lead frame comprising: a basic metal, an alloy layer covering a surface of said basic metal, wherein said alloy layer include a first metal selected from the group consisting of Mo, W, Au, Ag, Cr, Cu, Pt, Pd, Rh, Ru, Ir, and Os, a second metal selected from the group consisting of Fe, Ni and Co, and a third metal selected from the group consisting of Sn and Zn, and wherein said first metal is less than 30% by weight of said alloy layer, said third metal being less than 30% by weight of said alloy layer, and said second metal being a residual of said alloy layer.
References Cited (Backward Citations)
US3839660A
Cited
US4785137A
Cited
JPS6349382A
Cited
JPS63169056A
Cited
US5010388A
Cited
US4894752A
Cited
US4942454A
Cited
US4974052A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-06-21 | 1996-12-21 | 1997-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-21 | 2000-12-21 | 2001-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-21 | 2004-12-21 | 2005-06-22 | $7700.00 | Window Closed / Lapsed |