US5693572A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ball grid array integrated circuit package with high thermal conductivity
Assignee: STMicroelectronics lnc USA
•
Filing: 1996-01-18
•
Granted: 1997-12-02
•
Expires: 2016-01-18
Abstract
Abstract An integrated circuit package with a path of high thermal conductivity is disclosed. A thermally conductive slug, formed of a material such as copper, is attached to an underside portion of a substrate, such as a printed circuit board or a ceramic substrate, through which an opening has been formed. An integrated circuit chip is mounted to one side of the slug exposed in the opening. An opposing surface of the slug lies below the plane of the underside of the substrate. The chip is wire bonded to the substrate, and is encapsulated in the conventional manner. Solder balls are attached to a portion of the underside of the substrate not covered by the slug in a ball-grid-array manner, for mounting to a circuit board. Upon mounting to the circuit board, a path of high thermal conductivity is provided between the chip and the circuit board, through the slug and the solder balls.
Inventors
- 👤 Robert H. Bond
- 👤 Michael J. Hundt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:22
CPC Classifications
H; H10; H10W; H10W70/00; H10W70/60; H10W70/62; H10W70/63; H10W70/635; H05; H05K; H05K3/00; H05K3/30; H05K3/303; H05K3/32; H05K3/34; H05K3/341; H05K3/3431; H05K3/3436; H10W40/00; H10W40/20; H10W40/22; H10W40/226; H10W40/228; H10W40/70; H10W40/77; H10W40/778; H10W74/00; H10W74/10; H10W74/111; H10W74/114; H10W74/117; H10W90/00; H10W90/701; H05K1/00; H05K1/02; H05K1/0201; H05K1/0203; H05K2201/00; H05K2201/09; H05K2201/09209; H05K2201/09654; H05K2201/09781; H05K2201/10; H05K2201/10613; H05K2201/10621; H05K2201/10734; H05K2201/10954; H05K2201/10969; H05K2203/00; H05K2203/04; H05K2203/041; H05K2203/0465; H10W70/67; H10W70/68; H10W70/682; H10W70/685; H10W72/00; H10W72/071; H10W72/075; H10W72/07551; H10W72/07554; H10W72/50; H10W72/541; H10W72/547; H10W74/131; H10W74/142; H10W90/731; H10W90/737; H10W90/751; H10W90/754; Y; Y02; Y02P; Y02P70/00; Y02P70/50; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117; Y10T29/49124; Y10T29/4913; Y10T29/49144
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
202 words
A method of mounting a packaged integrated circuit on a circuit board, comprising the steps of: attaching a portion of a thermally conductive slug having first and second surfaces onto a substrate having first and second surfaces, wherein the conductive slug is attached to a first surface of the substrate, and wherein the first surface of the slug lies below the plane of the first surface of the substrate; mounting an integrated circuit chip to a portion of the second surface of the thermally conductive slug; encapsulating the integrated circuit chip; attaching a plurality of solder connectors to the first surface of the substrate, whereby the packaged integrated circuit comprises the thermally conductive slug, the substrate, the integrated circuit chip, and the solder connectors; placing the packaged integrated circuit on a surface of the circuit board; and conducting a reflow procedure such that the thermally conductive slug comes into contact with the surface of the circuit board and defines a stand-off distance between the surface of the circuit board and the first surface of the substrate, the solder connectors being reformed within the stand-off distance such that the thermally conductive slug conducts heat from the integrated circuit chip to the circuit board.
Claim 2
Independent Claim
202 words
A method of mounting a packaged integrated circuit on a circuit board, comprising the steps of: attaching a portion of a thermally conductive slug having first and second surfaces onto a substrate having first and second surfaces, wherein the conductive slug is attached to a first surface of the substrate, and wherein the first surface of the slug lies below the plane of the first surface of the substrate; mounting an integrated circuit chip to a portion of the second surface of the thermally conductive slug; encapsulating the integrated circuit chip; attaching a plurality of solder connectors to the first surface of the substrate, whereby the packaged integrated circuit comprises the thermally conductive slug, the substrate, the integrated circuit chip, and the solder connectors; placing the packaged integrated circuit on a surface of the circuit board; and conducting a reflow procedure such that the thermally conductive slug comes into contact with the surface of the circuit board and defines a stand-off distance between the surface of the circuit board and the first surface of the substrate, the solder connectors being reformed within the stand-off distance such that the thermally conductive slug conducts heat from the integrated circuit chip to the circuit board.
Claim 3
Dependent Claim
85 words
The method of claim 1, wherein the second surface of the thermally conductive slug has a first and second level, and wherein the step of attaching the thermally conductive slug to the first surface of the substrate further comprises the step of inserting the thermally conductive slug into the substrate wherein the first level of the second surface is attached to the first surface of the substrate and the second level of the second surface is substantially planar with the second surface of the substrate.
Claim 4
Dependent Claim
15 words
The method of claim 1 wherein the reflow procedure comprises an infra-red solder reflow procedure.
Claim 5
Dependent Claim
20 words
The method of claim 1 wherein the encapsulating step comprises: transfer molding a plastic compound over the integrated circuit chip.
Claim 6
Dependent Claim
26 words
The method of claim 1 wherein the encapsulating step comprises the step of: dispensing a plastic over the integrated circuit chip; and curing the dispensed plastic.
Claim 7
Dependent Claim
19 words
The method of claim 1, further comprising the step of: plating the first surface of the thermally conductive slug.
Claim 8
Dependent Claim
32 words
The method of claim 1, further comprising the step of: bonding a plurality of wire bonds to a top surface of the integrated circuit chip and the second surface of the substrate.
Claim 9
Dependent Claim
13 words
The method of claim 7 wherein the step of bonding comprises ultrasonic bonding.
Claim 10
Dependent Claim
12 words
The method of claim 7 wherein the step of bonding comprises thermocompression.
Claim 11
Dependent Claim
13 words
The method of claim 1 wherein the thermally conductive slug also conducts electricity.
Claim 12
Dependent Claim
14 words
The method of claim 1 wherein the thermally conductive slug is comprised of copper.
References Cited (Backward Citations)
JPS63120431A
Cited
FR2609841A1
Cited
JPS63293965A
Cited
JPH0258358A
Cited
US5081067A
Cited
US5266834A
Cited
US5041396A
Cited
US5012386A
Cited
JPH03198368A
Cited
US5202288A
Cited
US5403776A
Cited
US5120678A
Cited
US5216278A
Cited
US5157480A
Cited
US5102829A
Cited
US5172301A
Cited
US5444025A
Cited
US5311402A
Cited
US5222014A
Cited
US5285352A
Cited
US5438478A
Cited
US5291062A
Cited
US5474958A
Cited
US5362679A
Cited
US5455456A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-12-01 | 2001-06-02 | 2001-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-12-01 | 2005-06-02 | 2005-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-12-01 | 2009-06-02 | 2009-12-02 | $7700.00 | Window Closed / Lapsed |