US5627407A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic package with reduced bending stress
Assignee: Nokia of America Corp
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Filing: 1995-04-28
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Granted: 1997-05-06
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Expires: 2015-04-28
Abstract
Abstract In accordance with the invention, electronic packages comprising a layer of molded plastic on one side of an insulating substrate are provided with a surrogate layer on the side of the substrate opposite the molded plastic to reduce bending stress. The surrogate layer is preferably thin, has a high coefficient of thermal expansion and is resistant to high tensile stress. Advantageously, the surrogate layer is processed concurrently with the molding of the plastic. Preferred surrogate layers are low temperature thermoplastic sheets, such as acetal plastic sheets, that soften at the molding temperature sufficiently to bond to the substrate. Alternatively, they can be higher temperature rigid materials, such as glass fiber composites, bonded to the substrate with an adhesive layer that cures during molding.
Inventors
- 👤 Ephraim Suhir
- 👤 John D. Weld
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 21:31
CPC Classifications
H; H10; H10W; H10W70/00; H10W70/60; H10W70/67; H10W70/69; H10W70/695
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
106 words
In a package for electronic components comprising a body of molded plastic on one side of insulating substrate, said body of molded plastic having a molding temperature and containing one or more electronic components, and said insulating substrate subject to bending stress caused by thermal expansion mismatch with said molded plastic, the improvement wherein: said substrate is provided with a surrogate layer on the side opposite said molded plastic body, said surrogate layer having a thickness less than 2 mm, and a coefficient of thermal expansion greater than 40×10 -6 /°C. for reducing the bending stress on said substrate at a temperature below said molding temperature.
Claim 2
Dependent Claim
106 words
In a package for electronic components comprising a body of molded plastic on one side of insulating substrate, said body of molded plastic having a molding temperature and containing one or more electronic components, and said insulating substrate subject to bending stress caused by thermal expansion mismatch with said molded plastic, the improvement wherein: said substrate is provided with a surrogate layer on the side opposite said molded plastic body, said surrogate layer having a thickness less than 2 mm, and a coefficient of thermal expansion greater than 40×10 -6 /°C. for reducing the bending stress on said substrate at a temperature below said molding temperature.
Claim 3
Dependent Claim
18 words
The improved package of claim 1 wherein said surrogate layer has a thickness in the range 0.25-1.00 mm.
Claim 4
Dependent Claim
37 words
The improved package of claim 1 wherein said surrogate layer has a coefficient of thermal expansion in the range 50×10 -6 /°C. to 80×10 -6 /°C., and wherein the temperature below the molding temperature includes room temperature.
Claim 5
Dependent Claim
13 words
The improved package of claim 1 wherein said surrogate layer comprises thermoplastic resin.
Claim 6
Dependent Claim
14 words
The improved package of claim 1 wherein said surrogate layer comprises fiber-reinforced thermoplastic resin.
Claim 7
Dependent Claim
14 words
The improved package of claim 1 wherein said surrogate layer comprises glass-reinforced acetal resin.
Claim 8
Dependent Claim
29 words
The improved package of claim 1 wherein said body of plastic comprises thermosetting epoxy molding compound; said insulating substrate comprises ceramic and said surrogate layer comprises fiber-reinforced thermoplastic resin.
Claim 9
Dependent Claim
22 words
The improved package of claim 7 wherein said insulating substrate comprises ferrite and said fiber-reinforced thermoplastic resin comprises glass-fiber reinforced acetal resin.
Claim 10
Dependent Claim
21 words
The improved package of claim 1 wherein said surrogate layer is resistant to tensile stresses higher than 10,000 Kgf/cm 2 .
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2000-05-05 | 2000-11-04 | 2001-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-05-05 | 2004-11-04 | 2005-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-05-05 | 2008-11-04 | 2009-05-06 | $7700.00 | Window Closed / Lapsed |