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Patent US5134459A successfully refreshed from Google Patents.
US5134459A
Expired / Lapsed
US
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Lead frame for semiconductor device
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1990-04-26
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Granted: 1992-07-28
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Expires: 2010-04-26
Abstract
Abstract A lead frame for a high-density, sealed type of semiconductor device having many input/output pins and capable of high-speed operation is made of a magnetic material with a covering layer of a non-magnetic metal. The covering layer covers a top surface, a bottom surface, both side surfaces and an inner end face of a portion of the leads of the lead frame which is to be sealed in a semiconductor package. The covering layer has a thickness of 1 micron or more at both side surfaces of each lead. Therefore, the inductance at the leads can be reduced remarkably. Thus, the semiconductor can be operated at a high speed with improved reliability.
Inventors
- 👤 Takao Maeda
- 👤 Tomohiko Ihara
- 👤 Masaharu Yasuhara
- 👤 Shosaku Yamanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:47
CPC Classifications
H; H10; H10W; H10W70/00; H10W70/40; H10W70/456; H10W70/457; H10W72/00; H10W72/50; H10W72/531; H10W72/536; H10W72/5363; H10W72/551; H10W72/552; H10W72/5522; H10W72/59; H10W72/851; H10W72/874; H10W72/884; H10W74/00; H10W90/00; H10W90/701; H10W90/731; H10W90/736; H10W90/751; H10W90/756
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
83 words
A lead frame comprising a plate of a magnetic material defining leads each having top and bottom and side surfaces, and covering layers provided over the entire said top and bottom and both side surfaces of a portion of each of said leads which is to be sealed in a semiconductor package, said covering layers being made of a non-magnetic metal, and said layers being at least 1 micron thick at said side surfaces, thereby reducing the self-inductance of each of said leads.
Claim 2
Dependent Claim
83 words
A lead frame comprising a plate of a magnetic material defining leads each having top and bottom and side surfaces, and covering layers provided over the entire said top and bottom and both side surfaces of a portion of each of said leads which is to be sealed in a semiconductor package, said covering layers being made of a non-magnetic metal, and said layers being at least 1 micron thick at said side surfaces, thereby reducing the self-inductance of each of said leads.
Claim 3
Dependent Claim
17 words
A lead frame as claimed in claim 1, wherein said metal is aluminum or an aluminum alloy.
Claim 4
Dependent Claim
17 words
A lead frame as claimed in claim 1, wherein said metal is copper or a copper alloy.
Claim 5
Dependent Claim
17 words
A lead frame as claimed in claim 1, wherein said metal is gold or a gold alloy.
Claim 6
Dependent Claim
17 words
A lead frame as claimed in claim 1, wherein said metal is silver or a silver alloy.
Claim 7
Dependent Claim
17 words
A lead frame as claimed in claim 1, wherein said metal is zinc or a zinc alloy.
Claim 8
Dependent Claim
17 words
A lead frame as claimed in claim 1, wherein said metal is lead or a lead alloy.
Claim 9
Dependent Claim
17 words
A lead frame as claimed in claim 1, wherein said metal is tin or a tin alloy.
Claim 10
Dependent Claim
38 words
A lead frame as claimed in claim 1, wherein said magnetic material is an iron-nickel alloy of 38-55 percent by weight nickel or an iron-nickel-cobalt alloy of 25-35 percent by weight nickel and 15-25 percent by weight cobalt.
Claim 11
Dependent Claim
24 words
A lead frame as claimed in claim 1, wherein the length of said portion of each of said leads is at least 10 mm.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-07-28 | 1996-01-27 | 1996-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-07-28 | 2000-01-27 | 2000-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-07-28 | 2004-01-27 | 2004-07-28 | $7700.00 | Window Closed / Lapsed |