US4504427A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solder preform stabilization for lead frames
Assignee: Nokia Bell Labs
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Filing: 1983-06-17
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Granted: 1985-03-12
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Expires: 2003-06-17
Abstract
Abstract Fabricating spacer bars or dam bars in conventional lead frames of a low melting material, e.g. solder, permits facile removal of the bar after molding. The low melting bars can be removed by furnace heating, localized radiant energy heating, exposure to rapid thermal annealing (RTA), hot air or hot liquid leveling, etc.
Inventors
- 👤 Harold W. Moyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 07:58
CPC Classifications
B; B29; B29C; B29C33/00; B29C33/12; B29C70/00; B29C70/68; B29C70/72; H; H10; H10W; H10W74/00; H10W74/01; B29L; B29L2031/00; B29L2031/34; B29L2031/3406; H05; H05K; H05K3/00; H05K3/30; H05K3/32; H05K3/34; H05K3/341; H05K3/3421; H05K3/3426; H05K3/3465
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
95 words
Method for mold encapsulating an electrical device wherein the device has a plurality of electrical leads arranged to extend beyond the molded encapsulant and wherein a spacer element is applied to the leads to maintain the leads in a desired spatial relationship during the mold encapsulating process the invention characterized in that the spacer element is formed of a material that melts preferentially with respect to the material of the metal leads and the invention further characterized by melting the spacer element without melting the electrical leads or the encapsulant after the mold encapsulating process.
Claim 2
Dependent Claim
95 words
Method for mold encapsulating an electrical device wherein the device has a plurality of electrical leads arranged to extend beyond the molded encapsulant and wherein a spacer element is applied to the leads to maintain the leads in a desired spatial relationship during the mold encapsulating process the invention characterized in that the spacer element is formed of a material that melts preferentially with respect to the material of the metal leads and the invention further characterized by melting the spacer element without melting the electrical leads or the encapsulant after the mold encapsulating process.
Claim 3
Dependent Claim
14 words
The method of claim 1 in which the spacer bars are comprised of solder.
Claim 4
Dependent Claim
21 words
The method of claim 1 in which heat is applied by a beam of radiant energy to melt the spacer bars.
Claim 5
Dependent Claim
18 words
The method of claim 2 in which the spacer bars are removed by hot air or liquid leveling.
Claim 6
Dependent Claim
15 words
The method of claim 1 in which the spacer element is composed of conductive material.
References Cited (Backward Citations)
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Cited
US3076051A
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US3494023A
Cited
US3429030A
Cited
US3418089A
Cited
US3529054A
Cited
US3810300A
Cited
US4137546A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-03-11 | 1988-09-10 | 1989-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-03-11 | 1992-09-10 | 1993-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-03-11 | 1996-09-10 | 1997-03-12 | $7700.00 | Window Closed / Lapsed |