Patent US5691567A successfully refreshed from Google Patents.
US5691567A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Structure for attaching a lead frame to a heat spreader/heat slug structure
Assignee: National Semiconductor Corp
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Filing: 1995-09-19
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Granted: 1997-11-25
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Expires: 2015-09-19
Abstract
Abstract A method and structure for attaching a lead frame to a heat sink are provided. In one embodiment, a layer of thermally conductive, electrically insulating epoxy is formed on a heat sink and the epoxy layer is fully cured. A thermoplastic adhesive layer is formed on the epoxy layer, and the heat sink is clamped to the lead frame such that the thermoplastic layer contacts the lead frame. The thermoplastic layer is heated to its melting point and then cooled, thereby joining the heat sink and the lead frame. In a variation, a partially cured B-stage epoxy layer is used to replace the thermoplastic layer. The B-stage epoxy layer is fully cured to connect the lead frame to the heat sink.
Inventors
- 👤 Randy H. Y. Lo
- 👤 Boonmi Mekdhanasarn
- 👤 Daniel P. Tracy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:18
CPC Classifications
H; H10; H10W; H10W40/00; H10W40/70; H10W40/77; H10W40/778; H10W72/00; H10W72/071; H10W72/073; H10W72/07331; H10W72/07337; H10W72/07338; H10W72/07339; H10W72/30; H10W72/351; H10W72/352; H10W72/353; H10W72/354; H10W72/381; H10W72/50; H10W72/541; H10W72/5449; H10W72/851; H10W72/874; H10W72/884; H10W74/00; H10W90/00; H10W90/701; H10W90/731; H10W90/736; H10W90/751; H10W90/756
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
49 words
A semiconductor device comprising: a heat sink; a fully cured layer of thermally conductive, electrically insulating epoxy connected to a portion of the heat sink; a layer of thermally conductive, electrically insulating thermoplastic connected to the layer of epoxy; and a lead frame connected to the layer of thermoplastic.
Claim 2
Dependent Claim
49 words
A semiconductor device comprising: a heat sink; a fully cured layer of thermally conductive, electrically insulating epoxy connected to a portion of the heat sink; a layer of thermally conductive, electrically insulating thermoplastic connected to the layer of epoxy; and a lead frame connected to the layer of thermoplastic.
Claim 3
Dependent Claim
49 words
A semiconductor device comprising: a lead frame; a fully cured layer of thermally conductive, electrically insulating epoxy connected to a portion of the lead frame; a layer of thermally conductive, electrically insulating thermoplastic connected to the layer of epoxy; and a heat sink connected to the layer of thermoplastic.
Claim 4
Dependent Claim
49 words
A semiconductor device comprising: a lead frame; a fully cured layer of thermally conductive, electrically insulating epoxy connected to a portion of the lead frame; a layer of thermally conductive, electrically insulating thermoplastic connected to the layer of epoxy; and a heat sink connected to the layer of thermoplastic.
Claim 5
Dependent Claim
46 words
A heat sink structure comprising: a thermally conductive heat sink; a fully cured first layer of thermally conductive, electrically insulating epoxy connected to the heat sink; and a partially cured second layer of thermally conductive, electrically insulating B-stage epoxy connected to the first layer of epoxy.
Claim 6
Dependent Claim
46 words
A heat sink structure comprising: a thermally conductive heat sink; a fully cured first layer of thermally conductive, electrically insulating epoxy connected to the heat sink; and a partially cured second layer of thermally conductive, electrically insulating B-stage epoxy connected to the first layer of epoxy.
Claim 7
Dependent Claim
44 words
A lead frame structure comprising: a lead frame; a fully cured first layer of thermally conductive, electrically insulating epoxy connected to the lead frame; and a partially cured second layer of thermally conductive, electrically insulating B-stage epoxy connected to the first layer of epoxy.
Claim 8
Dependent Claim
44 words
A lead frame structure comprising: a lead frame; a fully cured first layer of thermally conductive, electrically insulating epoxy connected to the lead frame; and a partially cured second layer of thermally conductive, electrically insulating B-stage epoxy connected to the first layer of epoxy.
Claim 9
Dependent Claim
40 words
A heat sink structure comprising: a thermally conductive heat sink; a fully cured layer of thermally conductive, electrically insulating epoxy connected to the heat sink; and a layer of thermally conductive, electrically insulating thermoplastic connected to the layer of epoxy.
Claim 10
Dependent Claim
40 words
A heat sink structure comprising: a thermally conductive heat sink; a fully cured layer of thermally conductive, electrically insulating epoxy connected to the heat sink; and a layer of thermally conductive, electrically insulating thermoplastic connected to the layer of epoxy.
Claim 11
Dependent Claim
38 words
A lead frame structure comprising: a lead frame; a fully cured layer of thermally conductive, electrically insulating epoxy connected to the lead frame; and a layer of thermally conductive, electrically insulating thermoplastic connected to the layer of epoxy.
Claim 12
Dependent Claim
38 words
A lead frame structure comprising: a lead frame; a fully cured layer of thermally conductive, electrically insulating epoxy connected to the lead frame; and a layer of thermally conductive, electrically insulating thermoplastic connected to the layer of epoxy.
Claim 13
Dependent Claim
90 words
A heat sink-lead frame structure for a semiconductor device comprising: a thermally conductive heat sink having a layer of fully cured thermally conductive, electrically insulating epoxy formed thereon; and a lead frame having a layer of thermally conductive, electrically insulating thermoplastic formed thereon, wherein the heat sink and the layer of fully cured epoxy are stored separate from the lead frame and the layer of thermoplastic prior to a subsequent joining of the layer of fully cured epoxy and the layer of thermoplastic to form the heat sink-lead frame structure.
Claim 14
Dependent Claim
90 words
A heat sink-lead frame structure for a semiconductor device comprising: a thermally conductive heat sink having a layer of fully cured thermally conductive, electrically insulating epoxy formed thereon; and a lead frame having a layer of thermally conductive, electrically insulating thermoplastic formed thereon, wherein the heat sink and the layer of fully cured epoxy are stored separate from the lead frame and the layer of thermoplastic prior to a subsequent joining of the layer of fully cured epoxy and the layer of thermoplastic to form the heat sink-lead frame structure.
Claim 15
Dependent Claim
90 words
A heat sink-lead frame structure for a semiconductor device comprising: a lead frame having a layer of fully cured thermally conductive, electrically insulating epoxy formed thereon; and a thermally conductive heat sink having a layer of thermally conductive, electrically insulating thermoplastic formed thereon, wherein the lead frame and the layer of fully cured epoxy are stored separate from the heat sink and the layer of thermoplastic prior to a subsequent joining of the layer of fully cured epoxy and the layer of thermoplastic to form the heat sink-lead frame structure.
Claim 16
Dependent Claim
90 words
A heat sink-lead frame structure for a semiconductor device comprising: a lead frame having a layer of fully cured thermally conductive, electrically insulating epoxy formed thereon; and a thermally conductive heat sink having a layer of thermally conductive, electrically insulating thermoplastic formed thereon, wherein the lead frame and the layer of fully cured epoxy are stored separate from the heat sink and the layer of thermoplastic prior to a subsequent joining of the layer of fully cured epoxy and the layer of thermoplastic to form the heat sink-lead frame structure.
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) | 2000-11-24 | 2001-05-26 | 2001-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-11-24 | 2005-05-26 | 2005-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-11-24 | 2009-05-26 | 2009-11-25 | $7700.00 | Window Closed / Lapsed |