Patent US6072230A successfully refreshed from Google Patents.
US6072230A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exposed leadframe for semiconductor packages and bend forming method of fabrication
Assignee: Texas Instruments Inc
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Filing: 1997-09-09
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Granted: 2000-06-06
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Expires: 2017-09-09
Abstract
Abstract The invention relates to a single piece leadframe that can be used in current semiconductor device production. The leadframe has a plurality of segments in a horizontal plane, a chip mount pad in a different horizontal plane, and another plurality of segments connecting said chip mount pad with said leadframe. The latter plurality of segments has a geometry designed so as to tolerate bending and stretching beyond the limit of simple elongation based upon the inherent material characteristics. The chip mount pad of said leadframe provides direct thermal contact to an external heat conductor or heat sink by being designed so as to extend through the encapsulating package. The exposed chip pad can also be used electrically as a ground connection.
Inventors
- 👤 Buford H. Carter, Jr.
- 👤 Jesse E. Clark
- 👤 David R. Kee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:10
CPC Classifications
H; H10; H10W; H10W70/00; H10W70/40; H10W70/421; H10W70/424; H10W70/427; H10W70/01; H10W70/04; H10W70/048; H10W70/411; H10W70/433; H10W70/461; H10W90/00; H10W90/811; H10W72/00; H10W72/50; H10W72/541; H10W72/5449; H10W72/90; H10W72/931; H10W72/932; H10W74/00; H10W90/701; H10W90/751; H10W90/756
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
74 words
A leadframe for use with semiconductor circuits, comprising: a first plurality of leadframe segments in a first horizontal plane; a chip mount pad in a second horizontal plane; and a second plurality of leadframe segments connecting said chip mount pad with said leadframe, having a geometry designed to accommodate elongation in a direction that lies substantially within the plane of said second segments, beyond the limit of simple elongation based upon inherent material characteristics.
Claim 2
Dependent Claim
74 words
A leadframe for use with semiconductor circuits, comprising: a first plurality of leadframe segments in a first horizontal plane; a chip mount pad in a second horizontal plane; and a second plurality of leadframe segments connecting said chip mount pad with said leadframe, having a geometry designed to accommodate elongation in a direction that lies substantially within the plane of said second segments, beyond the limit of simple elongation based upon inherent material characteristics.
Claim 3
Dependent Claim
25 words
The leadframe according to claim 1 wherein said geometry design contributes 50 to 500% over the contribution of said material elongation to the segment stretching.
Claim 4
Dependent Claim
16 words
The leadframe according to claim 1 wherein said second plurality of leadframe segment has curved geometry.
Claim 5
Dependent Claim
16 words
The leadframe according to claim 1 wherein said second plurality of leadframe segments has toroidal geometry.
Claim 6
Dependent Claim
19 words
The leadframe according to claim 1 wherein said second plurality of leadframe segments can accommodate a multiplicity of bendings.
Claim 7
Dependent Claim
30 words
A leadframe as in claim 1 wherein the mechanical stability and rigidity of the chip mount pad is maintained by said second segments, during and after said bending and stretching.
Claim 8
Dependent Claim
34 words
A leadframe as in claim 1 wherein the portions location of boundable and stretchable of said second segments allow bond wire lengths, between the leadframe finger tips and the chip, to remain substantially unchanged.
Claim 9
Dependent Claim
73 words
A leadframe for use with semiconductor circuits, comprising: a first plurality of leadframe segments in a first horizontal plane; a chip mount pad in a second horizontal plane; and a second plurality of leadframe segments connecting said chip mount pad with selected members of said first plurality of leadframe segments, said second plurality having a geometry designed to accommodate bending and stretching beyond the limit of simple elongation based upon inherent material characteristics.
Claim 10
Dependent Claim
73 words
A leadframe for use with semiconductor circuits, comprising: a first plurality of leadframe segments in a first horizontal plane; a chip mount pad in a second horizontal plane; and a second plurality of leadframe segments connecting said chip mount pad with selected members of said first plurality of leadframe segments, said second plurality having a geometry designed to accommodate bending and stretching beyond the limit of simple elongation based upon inherent material characteristics.
Claim 11
Dependent Claim
111 words
A semiconductor device comprising: a first plurality of leadframe segments in a first horizontal plane; a chip mount pad in a second horizontal plane; a second plurality of leadframe segments connecting said chip mount pad with said leadframe having been formed by bending and stretching substantially within the plane of said second segments, beyond the limit of simple elongation based upon inherent material characteristics; a circuit chip mounted on said chip mount pad; and an encompassing package encapsulating a portion of the leadframe leads, the circuit chip, and a portion of said chip mount pad, said chip mount pad extending to and through said package, to provide an exposed chip pad.
Claim 12
Dependent Claim
111 words
A semiconductor device comprising: a first plurality of leadframe segments in a first horizontal plane; a chip mount pad in a second horizontal plane; a second plurality of leadframe segments connecting said chip mount pad with said leadframe having been formed by bending and stretching substantially within the plane of said second segments, beyond the limit of simple elongation based upon inherent material characteristics; a circuit chip mounted on said chip mount pad; and an encompassing package encapsulating a portion of the leadframe leads, the circuit chip, and a portion of said chip mount pad, said chip mount pad extending to and through said package, to provide an exposed chip pad.
Claim 13
Dependent Claim
21 words
The semiconductor device according to claim 9 wherein said chip mount pad provides a direct thermal path to said circuit chip.
Claim 14
Dependent Claim
22 words
The semiconductor device according to claim 9 wherein said chip mount pad serves as a heat convection surface for said circuit chip.
Claim 15
Dependent Claim
43 words
The semiconductor device according to claim 9 wherein the leadframe leads outside of the encapsulating package are formed to place the chip pad extending through the top side of the semiconductor device package when the package is mounted on a printed wiring board.
Claim 16
Dependent Claim
27 words
The semiconductor device according to claim 9, in combination with a printed circuit board, and a heat dissipating device in thermal contact with said exposed chip pad.
Claim 17
Dependent Claim
30 words
A leadframe as in claim 9 wherein the mechanical stability and rigidity of the chip mount pad is maintained by said second segments, during and after said bending and stretching.
Claim 18
Dependent Claim
34 words
A leadframe as in claim 9 wherein the portions location of boundable and stretchable of said second segments allow bond wire lengths, between the leadframe finger tips and the chip, to remain substantially unchanged.
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) | 2003-06-06 | 2003-12-06 | 2004-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-06-06 | 2007-12-06 | 2008-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-06-06 | 2011-12-06 | 2012-06-06 | $7700.00 | Window Closed / Lapsed |