US4685606A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Oxide-free extruded thermal joint
Assignee: International Business Machines Corp
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Filing: 1986-05-09
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Granted: 1987-08-11
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Expires: 2006-05-09
Abstract
Abstract A method of joining a thermally conductive element to an electric circuit chip for cooling the chip includes initial steps of forming an oxide-free preform of a fusible metal alloy by extrusion of alloy between two mold blocks or plates. During the extrusion, the oxide coating is left behind so that the extruded alloy is essentially free of oxide. The extrusion takes place at a temperature elevated to approximately the liquidus temperature of the alloy. The preform, which may be in the form of a pill or section of thin foil, is placed between interfacing surfaces of the thermally conductive element and the chip, and is then extruded along the interfacing surfaces under pressure and elevated temperature to form a thermally conductive, oxide-free bonding layer of superior thermal conductivity.
Inventors
- 👤 Ephraim B. Flint
- 👤 Peter A. Gruber
- 👤 Ronald F. Marks
- 👤 Graham Olive
- 👤 Arthur R. Zingher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:06
CPC Classifications
H; H10; H10W; H10W40/00; H10W40/20; H10W40/25; H10W40/258; H10W40/40; H10W40/47; H10W40/70; H10W40/77; H10W72/00; H10W72/071; H10W72/072; H10W72/07251; H10W72/20
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
129 words
A method of attachment of a heat-conductive element to an electric circuit chip comprising the steps of: placing a charge of a thermally conductive alloy in a chamber assembly; heating the alloy to approximately the liquidus temperature thereof to facilitate extrusion of the alloy; pressing the alloy within said chamber assembly to extrude a portion of the alloy away from the site of said charge, any oxide present on a surface of the charge remaining in the vicinity of the charge during extrusion of the alloy, an extruded portion being free of the oxide; positioning said extruded portion between said heat-conductive element and said chip; and forcing said heat-conductive element against said chip to extrude the alloy of said portion along an interface between said element and said chip.
Claim 2
Independent Claim
129 words
A method of attachment of a heat-conductive element to an electric circuit chip comprising the steps of: placing a charge of a thermally conductive alloy in a chamber assembly; heating the alloy to approximately the liquidus temperature thereof to facilitate extrusion of the alloy; pressing the alloy within said chamber assembly to extrude a portion of the alloy away from the site of said charge, any oxide present on a surface of the charge remaining in the vicinity of the charge during extrusion of the alloy, an extruded portion being free of the oxide; positioning said extruded portion between said heat-conductive element and said chip; and forcing said heat-conductive element against said chip to extrude the alloy of said portion along an interface between said element and said chip.
Claim 3
Dependent Claim
31 words
A method according to claim 1 wherein said step of forcing is accomplished at a temperature elevated to approximately the liquidus temperature of said alloy to facilitate extrusion of the alloy.
Claim 4
Dependent Claim
25 words
A method according to claim 2 further comprising a step of cooling said chip and said heat-conductive element upon completion of said step of forcing.
Claim 5
Dependent Claim
34 words
A method according to claim 1 wherein said extruded portion is in the form of a foil, and wherein said step of forcing is accomplished in a vacuum oven to avoid entrapment of air.
Claim 6
Dependent Claim
24 words
A method according to claim 4 further comprising a step of cutting a section of said foil for use in said step of positioning.
Claim 7
Dependent Claim
64 words
A method according to claim 1 wherein said chamber assembly includes a chamber for holding said charge and a cavity communicating with said chamber for receiving said extruded portion, said step of pressing forming a pill of oxide-free extruded alloy within said cavity, any oxide present on a surface of the charge remaining in said chamber during extrusion of the alloy into said cavity.
Claim 8
Dependent Claim
23 words
A method according to claim 6 further comprising a step of extracting said pill from said cavity prior to said step of positioning.
Claim 9
Dependent Claim
42 words
A method according to claim 1 wherein said extruded portion is in the form of a pill having a smooth convex surface, and wherein said step of forcing is accomplished in an air oven, the smooth convex shape avoiding entrapment of air.
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) | 1990-08-10 | 1991-02-09 | 1991-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-10 | 1995-02-09 | 1995-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-10 | 1999-02-09 | 1999-08-11 | $7700.00 | Window Closed / Lapsed |