EP0902473A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Improvements in or relating to leadframes
Assignee: Texas Instruments Inc
•
Filing: 1998-09-02
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Granted: —
•
Expires: 2018-09-02
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
EP
Data Source
google_patents
Last Synchronized
2026-11-06 01:29
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: 16
Claim 1
Independent Claim
63 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
arranged for accommodating bending and stretching beyond the
limit of simple elongation based upon inherent material
characteristics.
Claim 2
Dependent Claim
26 words
The leadframe according to Claim 1 wherein said geometry
arrangement contributes 50 to 500 % over the contribution of
said material elongation to the segment stretching.
Claim 3
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
arranged for accommodating bending and stretching beyond the
limit of simple elongation based upon inherent material
characteristics.
Claim 4
Dependent Claim
17 words
The leadframe according to Claim 3, wherein said second
plurality of leadframe segment has a curved geometry.
Claim 5
Dependent Claim
19 words
The leadframe according to any of Claims 3, wherein said
second plurality of leadframe segments has a toroidal geometry.
Claim 6
Dependent Claim
23 words
The leadframe according to any of Claims 3 to 5, wherein
said second plurality of leadframe segments can accommodate a
multiplicity of bends.
Claim 7
Dependent Claim
100 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, said second plurality having
been formed by bending and stretching beyond the limit of simple
elongation based upon inherent material characteristics; a circuit chip mounted on said chip mount pad; and a 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 encapsulating
package.
Claim 8
Dependent Claim
21 words
The semiconductor device according to Claim 7, wherein said
chip mount pad provides a direct thermal path to said circuit
chip.
Claim 9
Dependent Claim
22 words
The semiconductor device according to Claim 7, wherein said
chip mount pad serves as a heat convection surface for said
circuit chip.
Claim 10
Dependent Claim
47 words
The semiconductor device according to any of Claims 7 to 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 11
Dependent Claim
31 words
The semiconductor device according to any of Claims 7 to
10, in combination with a printed circuit board, and a heat
dissipating device in thermal contact with said exposed chip
pad.
Claim 12
Independent Claim
42 words
A method for the fabrication of said leadframe comprising: applying force to the chip mount pad while clamping the
leadframe; stretching the material of said second plurality of
leadframe segments; bending and straightening the designed-in geometry of said
plurality of leadframe segments.
Claim 13
Dependent Claim
15 words
The method according to Claim 12, wherein said bending can
includes shallow and steep angles.
Claim 14
Dependent Claim
62 words
A lead frame for a semiconductor device, the lead frame
having a substantially planar peripheral portion from which
extends inwardly a plurality of segments (14, 15) for connection
to a chip mount pad, characterised in that at least one of said
segments (15) is formed with an elevated portion extending out
of the plane of the peripheral portion of the lead frame.
Claim 15
Dependent Claim
82 words
A lead frame according to claim 14, wherein the elevated
portion is shaped and dimensioned to allow subsequent extension
of said at least one segment in the plane of the peripheral
portion of the lead frame by an amount in excess of the
extension that would have been possible within the elastic limit
of the material of which the at least one segment is formed, had
the at least one segment been formed co-planar with the
peripheral portion of the lead frame.
Claim 16
Dependent Claim
22 words
An apparatus according to claim 14 or 15 having any of the
additional features of any one of claims 1 to 6.
References Cited (Backward Citations)
No citation records indexed.
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