US5360991A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Integrated circuit devices with solderable lead frame
Assignee: Nokia Bell Labs
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Filing: 1993-07-29
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Granted: 1994-11-01
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Expires: 2013-07-29
Abstract
Abstract A packaged device with a lead frame, a lead frame and an article of manufacture comprising a base metal, a layer of nickel on the base metal, and a protective composite of metal layers on the nickel. The composite includes, in succession from the nickel layer, a layer of palladium or soft gold strike, a layer of palladium-nickel alloy, a layer of palladium and a layer of gold. The palladium or soft gold strike layer acts primarily as a bonding (an adhesive) layer between the Ni and Pd-Ni alloy layers and as a layer that enhances reduction in porosity of subsequent layers, Pd-Ni alloy layer acts as a trap for base metal ions, Pd layer acts as a trap for Ni ions from the Pd-Ni alloy layer, and the outer gold layer synergistically enhances the quality to the Pd layer. The various layers are in thickness sufficient to effectively accomplish each of their designated roles, depending on the processing and use conditions. Pd on soft Au strike layer may be 1-5 microinches thick, Pd-Ni alloy layer from 4 to 100 microinches, Pd layer from 1 to 100 microinches and the outer gold layer from 1 to 100 microinches in thickness.
Inventors
- 👤 Joseph A. Abys
- 👤 Igor V. Kadija
- 👤 Edward J. Kudrak, Jr.
- 👤 Joseph J. Maisano, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:42
CPC Classifications
C; C23; C23C; C23C28/00; C23C28/02; C23C28/021; C23C28/023; H; H10; H10W; H10W70/00; H10W70/40; H10W70/456; H10W70/457; H10W72/00; H10W72/50; H10W72/071; H10W72/075; H10W72/531; H10W72/536; 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; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/9265; Y10S428/929; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12771; Y10T428/12861; Y10T428/12875; Y10T428/12889
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
172 words
An IC package comprising at least one IC unit, and leads sealed within a protective package, in which said leads comprise a base metal, a layer of nickel on the base metal, and a composite of metal layers on top of nickel, said composite including, in succession from nickel, a palladium or soft gold strike layer, a palladium-nickel alloy layer having 10 to 90 weight percent nickel, by weight, a palladium layer, and a gold layer, in which said palladium or soft gold strike layer is deposited in a thickness sufficient to bond palladium-nickel alloy layer to the nickel layer, said palladium-nickel alloy layer is deposited in a thickness sufficient to at least slow down diffusion of base metal to the surface of the leads, said palladium layer is deposited in a thickness sufficient to at least slow down diffusion of nickel to the surface of the lead, and said outer gold layer is deposited in a thickness sufficient to further bar diffusion of any nickel to the surface of the lead.
Claim 2
Dependent Claim
172 words
An IC package comprising at least one IC unit, and leads sealed within a protective package, in which said leads comprise a base metal, a layer of nickel on the base metal, and a composite of metal layers on top of nickel, said composite including, in succession from nickel, a palladium or soft gold strike layer, a palladium-nickel alloy layer having 10 to 90 weight percent nickel, by weight, a palladium layer, and a gold layer, in which said palladium or soft gold strike layer is deposited in a thickness sufficient to bond palladium-nickel alloy layer to the nickel layer, said palladium-nickel alloy layer is deposited in a thickness sufficient to at least slow down diffusion of base metal to the surface of the leads, said palladium layer is deposited in a thickness sufficient to at least slow down diffusion of nickel to the surface of the lead, and said outer gold layer is deposited in a thickness sufficient to further bar diffusion of any nickel to the surface of the lead.
Claim 3
Dependent Claim
22 words
The IC package of claim 1, in which said composite is deposited in a total thickness ranging from 10 to 300 microinches.
Claim 4
Dependent Claim
20 words
The IC package of claim 1, in which said composite is deposited in a minimum total thickness of 10 microinches.
Claim 5
Dependent Claim
55 words
The IC package of claim 1, in which said palladium or soft gold strike layer is at least 1 microinch in thickness, said palladium-nickel alloy layer is at least 4 microinches in thickness, said palladium layer is at least one microinch in thickness, and said outer gold layer is at least one microinch in thickness.
Claim 6
Dependent Claim
62 words
The IC package of claim 1, in which for use at temperatures at 250° C. and less, said palladium strike layer is at least 3 microinches in thickness, said palladium-nickel alloy layer is at least 4 microinches in thickness, said palladium layer is at least 3 microinches in thickness, and said outer gold layer is at least one microinch is in thickness.
Claim 7
Dependent Claim
60 words
The IC package of claim 1, in which for use at temperatures of 450° C. and greater said palladium or soft gold strike layer is within a range of from 1 to 5 microinches, and said palladium-nickel alloy layer, said palladium layer and said outer gold layer have a thickness falling within a range of at least 20-30 microinches each.
Claim 8
Dependent Claim
22 words
The IC package of claim 1, in which said base metal comprises copper and said Pd-Ni alloy contains 20 weight percent nickel.
Claim 9
Dependent Claim
16 words
The IC package of claim 1, in which said outer gold layer comprises soft gold strike.
Claim 10
Dependent Claim
178 words
A lead frame for providing an electrical contact to an integrated circuit unit, comprising a plurality of leads electrically connected to the integrated circuit, each lead comprising a base metal, a nickel layer on the base metal, and a composite of metal layers deposited on the nickel layer, wherein said composite comprises in succession from the nickel layer a palladium or soft gold strike layer, a palladium-nickel alloy layer having from 10 to 90% nickel, by weight, a palladium layer, and a gold layer, in which said palladium or soft gold strike layer is deposited in a thickness sufficient to bond palladium-nickel alloy layer to the nickel layer, said palladium-nickel alloy layer is deposited in a thickness sufficient to at least slow down diffusion of the base metal to the surface of the leads, said palladium layer is deposited in a thickness sufficient to at least slow down diffusion of nickel to the surface of the lead, and said gold layers in a thickness sufficient to further bar diffusion of any nickel to the surface of the lead.
Claim 11
Dependent Claim
178 words
A lead frame for providing an electrical contact to an integrated circuit unit, comprising a plurality of leads electrically connected to the integrated circuit, each lead comprising a base metal, a nickel layer on the base metal, and a composite of metal layers deposited on the nickel layer, wherein said composite comprises in succession from the nickel layer a palladium or soft gold strike layer, a palladium-nickel alloy layer having from 10 to 90% nickel, by weight, a palladium layer, and a gold layer, in which said palladium or soft gold strike layer is deposited in a thickness sufficient to bond palladium-nickel alloy layer to the nickel layer, said palladium-nickel alloy layer is deposited in a thickness sufficient to at least slow down diffusion of the base metal to the surface of the leads, said palladium layer is deposited in a thickness sufficient to at least slow down diffusion of nickel to the surface of the lead, and said gold layers in a thickness sufficient to further bar diffusion of any nickel to the surface of the lead.
Claim 12
Dependent Claim
22 words
The lead frame of claim 9, in which said composite is deposited in a total thickness ranging from 10 to 300 microinches.
Claim 13
Dependent Claim
22 words
The lead frame of claim 9, in which said composite is deposited in a minimum total thickness of at least 10 microinches.
Claim 14
Dependent Claim
55 words
The lead frame of claim 9, in which said palladium or soft gold strike layer is at least 1 microinch in thickness, said palladium-nickel alloy layer is at least 4 microinches in thickness, said palladium layer is at least one microinch in thickness, and said outer gold layer is at least one microinch in thickness.
Claim 15
Dependent Claim
62 words
The lead frame of claim 9, in which for use at temperatures at 250° C. and less, said palladium strike layer is at least 3 microinches in thickness, said palladium-nickel alloy layer is at least 4 microinches in thickness, said palladium layer is at least 3 microinches in thickness, and said outer gold layer is at least one microinch is in thickness.
Claim 16
Dependent Claim
60 words
The lead frame of claim 9, in which for use at temperatures of 450° C. and greater said palladium or soft gold strike layer is within a range of from 1 to 5 microinches, and said palladium-nickel alloy layer, said palladium layer and said outer gold layer have a thickness falling within a range of at least 20-30 microinches each.
Claim 17
Dependent Claim
22 words
The lead frame of claim 9, in which said base metal comprises copper and said Pd-Ni alloy contains 20 weight percent nickel.
Claim 18
Dependent Claim
16 words
The lead frame of claim 9, in which said outer gold layer comprises soft gold strike.
Claim 19
Dependent Claim
92 words
An article of manufacture comprising a base metal, a layer of nickel upon the base metal, and a composite of layers on the nickel layer, said composite including, in succession from the nickel layer, a palladium or soft gold strike layer, a palladium-nickel alloy layer having from 10 to 90% nickel by weight, a palladium layer and a gold layer, said palladium-nickel alloy being at least 4 microinches thick, and said palladium or gold strike layer, said palladium layer and said outer gold layer being at least one microinch each in thickness.
Claim 20
Dependent Claim
92 words
An article of manufacture comprising a base metal, a layer of nickel upon the base metal, and a composite of layers on the nickel layer, said composite including, in succession from the nickel layer, a palladium or soft gold strike layer, a palladium-nickel alloy layer having from 10 to 90% nickel by weight, a palladium layer and a gold layer, said palladium-nickel alloy being at least 4 microinches thick, and said palladium or gold strike layer, said palladium layer and said outer gold layer being at least one microinch each in thickness.
Claim 21
Dependent Claim
21 words
The article of claim 17, in which said composite is deposited in a total thickness ranging from 10 to 300 microinches.
Claim 22
Dependent Claim
19 words
The article of claim 17, in which said composite is deposited in a minimum total thickness of 10 microinches.
Claim 23
Dependent Claim
54 words
The article of claim 17, in which said palladium or soft gold strike layer is at least 1 microinch in thickness, said palladium-nickel alloy layer is at least 4 microinches in thickness, said palladium layer is at least one microinch in thickness, and said outer gold layer is at least one microinch in thickness.
Claim 24
Dependent Claim
63 words
The article of claim 17, in which for use at temperatures at 250° C. and less, said palladium or soft gold strike layer is at least 3 microinches in thickness, said palladium-nickel alloy layer is at least 4 microinches in thickness, said palladium layer is at least 3 microinches in thickness, and said outer gold layer is at least one microinch in thickness.
Claim 25
Dependent Claim
58 words
The article of claim 17, in which for use at temperatures of 450° C. and greater, said palladium or soft gold strike layer is within a range of from 1 to 5 microinches, and said palladium-nickel alloy layer, said palladium layer and said gold layer have a thickness falling within a range of at least 20-30 microinches each.
Claim 26
Dependent Claim
21 words
The article of claim 17, in which said base metal comprises copper and said Pd-Ni alloy contains 20 weight percent nickel.
Claim 27
Dependent Claim
15 words
The article of claim 17, in which said outer gold layer comprises soft gold strike.
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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) | 1997-10-31 | 1998-05-02 | 1998-11-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-10-31 | 2002-05-02 | 2002-11-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-10-31 | 2006-05-02 | 2006-11-01 | $7700.00 | Window Closed / Lapsed |