Patent US5541446A successfully refreshed from Google Patents.
US5541446A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Integrated circuit package with improved heat dissipation
Assignee: Analog Devices Inc
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Filing: 1995-09-26
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Granted: 1996-07-30
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Expires: 2015-09-26
Abstract
Abstract A leadframe that exhibits improved thermal dissipation and that can be incorporated into standard integrated circuit (IC) packages is provided by widening the inner lead portions with respect to the outer lead portions and extending them along a major surface of the IC. In the preferred embodiment, the wide inner lead portions cover at least 80 percent of the IC surface and also support the IC, eliminating the need for a leadframe paddle. The wide inner lead portions are more efficient at conducting heat away from the IC than prior "standard" width inner lead portions because of the increased thermal contact area between them and the IC. Heat from the IC is conducted to the outside of the package via the leads and into the circuit board on which the IC package is mounted. Added thermal dissipation is achieved by making the inner portion of a ground lead wider than the inner portion of any other lead. In addition, existing IC package designs that utilize the present leadframe structure can accomodate larger ICs than before because the present leadframe structure has no leadframe paddle to limit the IC size.
Inventors
- 👤 Oliver J. Kierse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:33
CPC Classifications
H; H10; H10W; H10W70/00; H10W70/40; H10W70/411; H10W70/415; H10W70/461; H10W72/00; 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: 32
Claim 1
Independent Claim
130 words
A thermally enhanced leadframe structure for supporting an integrated circuit (IC) having first, second, third and fourth lateral sides, comprising: a plurality of electrically and thermally conductive leads with all of said leads having outer portions that are arranged on only two opposing sides of said IC, when said IC is positioned on the leadframe structure, and respective inner portions that extend along a major surface of said IC, cover a substantial majority of said IC surface and are in thermal communication with said IC surface, said plurality of leads comprising first, second, third and fourth sets of leads that initially intersect said IC at said first, second, third and fourth lateral IC sides, respectively, and at least one tie-bar for holding said leads and for maintaining their relative positions.
Claim 2
Dependent Claim
130 words
A thermally enhanced leadframe structure for supporting an integrated circuit (IC) having first, second, third and fourth lateral sides, comprising: a plurality of electrically and thermally conductive leads with all of said leads having outer portions that are arranged on only two opposing sides of said IC, when said IC is positioned on the leadframe structure, and respective inner portions that extend along a major surface of said IC, cover a substantial majority of said IC surface and are in thermal communication with said IC surface, said plurality of leads comprising first, second, third and fourth sets of leads that initially intersect said IC at said first, second, third and fourth lateral IC sides, respectively, and at least one tie-bar for holding said leads and for maintaining their relative positions.
Claim 3
Dependent Claim
19 words
The structure of claim 1, wherein said inner lead portions cover at least 80 percent of said IC surface.
Claim 4
Dependent Claim
24 words
The structure of claim 1, further comprising a thermally conductive and electrically insulating adhesive for securely holding said IC to said inner lead portions.
Claim 5
Dependent Claim
39 words
The structure of claim 1, wherein at least one of said leads is a ground lead with an inner lead portion that extends over a substantially larger area of said IC surface than any other individual inner lead portion.
Claim 6
Dependent Claim
22 words
The structure of claim 1, wherein the gap between adjacent inner lead portions is no greater than the thickness of said leads.
Claim 7
Dependent Claim
16 words
The structure of claim 3, wherein said adhesive comprises a thermally conductive and electrically insulating tape.
Claim 8
Dependent Claim
130 words
A thermally enhanced leadframe structure for supporting an integrated circuit (IC) having first, second, third and fourth lateral sides, comprising: a plurality of electrically and thermally conducting leads with all of said leads having outer portions that are arranged on only two, opposing sides of said IC, when said IC is positioned on the leadframe structure, and respective inner portions that extend along a major surface of said IC, are substantially wider than their respective outer portions, and are in thermal communication with said IC surface, said plurality of leads comprising first, second, third and fourth sets of leads that initially intersect said IC at said first, second, third and fourth lateral IC sides, respectively, and at least one tie-bar for holding said leads and for maintaining their relative positions.
Claim 9
Dependent Claim
130 words
A thermally enhanced leadframe structure for supporting an integrated circuit (IC) having first, second, third and fourth lateral sides, comprising: a plurality of electrically and thermally conducting leads with all of said leads having outer portions that are arranged on only two, opposing sides of said IC, when said IC is positioned on the leadframe structure, and respective inner portions that extend along a major surface of said IC, are substantially wider than their respective outer portions, and are in thermal communication with said IC surface, said plurality of leads comprising first, second, third and fourth sets of leads that initially intersect said IC at said first, second, third and fourth lateral IC sides, respectively, and at least one tie-bar for holding said leads and for maintaining their relative positions.
Claim 10
Dependent Claim
19 words
The structure of claim 7, wherein said inner lead portions cover at least 80 percent of said IC surface.
Claim 11
Dependent Claim
24 words
The structure of claim 7, further comprising a thermally conductive and electrically insulating adhesive for securely holding said IC to said inner lead portions.
Claim 12
Dependent Claim
32 words
The structure of claim 7, wherein at least one of said leads is a ground lead with an inner lead portion that is substantially wider than any other individual inner lead portion.
Claim 13
Dependent Claim
22 words
The structure of claim 7, wherein the gap between adjacent inner lead portions is no greater than the thickness of said leads.
Claim 14
Dependent Claim
16 words
The structure of claim 9, wherein said adhesive comprises a thermally conductive and electrically insulating tape.
Claim 15
Dependent Claim
130 words
A thermally enhanced integrated circuit (IC) package, comprising: an integrated circuit (IC) having first, second, third and fourth lateral sides, a plurality of electrically and thermally conductive leads with all of said leads having outer portions that are arranged on only two opposing sides of said IC package, and respective inner portions that extend along a major surface of said IC, cover a substantial majority of said IC surface and are in thermal communication with said IC surface, said leads in electrical communication with bonding pads on said IC, said plurality of leads comprising first, second, third and fourth sets of leads that initially intersect said IC at said first, second, third and fourth lateral IC sides, respectively, and a moulding compound encapsulating said IC and said inner lead portions.
Claim 16
Dependent Claim
130 words
A thermally enhanced integrated circuit (IC) package, comprising: an integrated circuit (IC) having first, second, third and fourth lateral sides, a plurality of electrically and thermally conductive leads with all of said leads having outer portions that are arranged on only two opposing sides of said IC package, and respective inner portions that extend along a major surface of said IC, cover a substantial majority of said IC surface and are in thermal communication with said IC surface, said leads in electrical communication with bonding pads on said IC, said plurality of leads comprising first, second, third and fourth sets of leads that initially intersect said IC at said first, second, third and fourth lateral IC sides, respectively, and a moulding compound encapsulating said IC and said inner lead portions.
Claim 17
Dependent Claim
19 words
The package of claim 13, wherein said inner lead portions cover at least 80 percent of said IC surface.
Claim 18
Dependent Claim
39 words
The package of claim 13, wherein at least some of said inner lead portions include at least one perforation, with said moulding compound extending through said perforation to more securely anchor said inner lead portions to said moulding compound.
Claim 19
Dependent Claim
42 words
The package of claim 13, wherein at least some of said inner lead portions include at least one indentation along its perimeter, with said moulding compound extending into said indentation to more securely anchor said inner lead portions to said moulding compound.
Claim 20
Dependent Claim
23 words
The package of claim 13, further comprising a thermally conductive and electrically insulating adhesive securely holding said IC to said inner lead portions.
Claim 21
Dependent Claim
39 words
The package of claim 13, wherein at least one of said leads is a ground lead with an inner lead portion that extends along a substantially larger area of said IC surface than any other individual inner lead portion.
Claim 22
Dependent Claim
22 words
The package of claim 13, wherein the gap between adjacent inner lead portions is no greater than the thickness of said leads.
Claim 23
Dependent Claim
16 words
The package of claim 17, wherein said adhesive comprises a thermally conductive and electrically insulating tape.
Claim 24
Dependent Claim
130 words
A thermally enhanced integrated circuit (IC) package, comprising: an integrated circuit (IC) having first, second, third and fourth lateral sides, a plurality of electrically and thermally conductive leads with all of said leads having outer portions that are arranged on only two opposing sides of said IC package, and respective inner portions that extend along a major surface of said IC, are substantially wider than their respective outer portions, and are in thermal communication with said IC surface, said leads in electrical communication with bonding pads on said IC, said plurality of leads comprising first, second, third and fourth sets of leads that initially intersect said IC at said first, second third and fourth lateral IC sides, respectively, and a moulding compound encapsulating said IC and said inner lead portions.
Claim 25
Dependent Claim
130 words
A thermally enhanced integrated circuit (IC) package, comprising: an integrated circuit (IC) having first, second, third and fourth lateral sides, a plurality of electrically and thermally conductive leads with all of said leads having outer portions that are arranged on only two opposing sides of said IC package, and respective inner portions that extend along a major surface of said IC, are substantially wider than their respective outer portions, and are in thermal communication with said IC surface, said leads in electrical communication with bonding pads on said IC, said plurality of leads comprising first, second, third and fourth sets of leads that initially intersect said IC at said first, second third and fourth lateral IC sides, respectively, and a moulding compound encapsulating said IC and said inner lead portions.
Claim 26
Dependent Claim
19 words
The package of claim 21, wherein said inner lead portions cover at least 80 percent of said IC surface.
Claim 27
Dependent Claim
43 words
The package of claim 21, wherein at least some of said inner lead portions include at least one perforation outside of said IC, with said moulding compound extending through said perforation to more securely anchor said inner lead portions to said moulding compound.
Claim 28
Dependent Claim
42 words
The package of claim 21, wherein at least some of said inner lead portions include at least one indentation along its perimeter, with said moulding compound extending into said indentation to more securely anchor said inner lead portions to said moulding compound.
Claim 29
Dependent Claim
23 words
The package of claim 21, further comprising a thermally conductive and electrically insulating adhesive securely holding said IC to said inner lead portions.
Claim 30
Dependent Claim
32 words
The package of claim 21, wherein at least one of said leads is a ground lead with an inner lead portion that is substantially wider than any other individual inner lead portion.
Claim 31
Dependent Claim
22 words
The package of claim 21, wherein the gap between adjacent inner lead portions is no greater than the thickness of said leads.
Claim 32
Dependent Claim
16 words
The package of claim 25, wherein said adhesive comprises a thermally conductive and electrically insulating tape.
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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) | 1999-07-30 | 2000-01-29 | 2000-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-07-30 | 2004-01-29 | 2004-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-07-30 | 2008-01-29 | 2008-07-30 | $7700.00 | Window Closed / Lapsed |