US4034469A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making conduction-cooled circuit package
Assignee: International Business Machines Corp
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Filing: 1976-09-03
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Granted: 1977-07-12
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Expires: 1996-09-03
Abstract
Abstract A circuit package exhibiting an excellent heat transfer path from a semiconductor chip or other heat-generating device to the heat-sink can or cover of the package. A heat-conducting pad is metallurgically bonded to either said cover or a surface of said device; the pad is also separably attached, but metallurgically unbonded, to the other. In one preferred embodiment, a readily deformable metal or alloy, such as indium, is metallurgically bonded to a limited central region of the heat sink cover. The deformable metal is separably attached to a major surface of the chip so that there is no stress between the chip or its joints and the solder during the electrical operation of the chip when it generates heat. The preferred method of fabrication involves the mechanical deformation of a mass of solder against the back side of the chip, after the solder has been metallurgically bonded to heat sink. The process may be accomplished either at high or low temperatures, depending upon the solder composition and the relative strength of the leads which join the chip to conductive lands on its supportive substrate.
Inventors
- 👤 Nicholas George Koopman
- 👤 Paul Anthony Totta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:08
CPC Classifications
H; H10; H10W; H10W40/00; H10W40/70; H10W40/77; H10W40/20; H10W40/25; H10W40/258; H10W72/00; H10W72/30; H10W72/20; H10W72/251; H10W72/252; H10W72/351; H10W72/352; H10W72/851; H10W72/874; H10W72/877; H10W72/879; H10W90/00; H10W90/701; H10W90/721; H10W90/724; H10W90/731; H10W90/736; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
81 words
In the method of fabricating circuit package in which a heat-generating component is cooled by conduction of heat to a heat-sink component, the improvement comprising: metallurgically bonding of a deformable mass of metal to a major surface of either one or the other of said components; positioning said metal adjacent to a major surface of the other of said components; and compressing said metal against said major surface of the other of said components to form an unbonded, separable interface therebetween.
Claim 2
Dependent Claim
81 words
In the method of fabricating circuit package in which a heat-generating component is cooled by conduction of heat to a heat-sink component, the improvement comprising: metallurgically bonding of a deformable mass of metal to a major surface of either one or the other of said components; positioning said metal adjacent to a major surface of the other of said components; and compressing said metal against said major surface of the other of said components to form an unbonded, separable interface therebetween.
Claim 3
Dependent Claim
20 words
A method as in claim 1 wherein said metal is selected from the group consisting of indium and indium alloys.
Claim 4
Dependent Claim
63 words
In the method of fabricating a circuit package in which a semiconductor chip is cooled by a heat-sink cover, the improvement comprising: metallurgically bonding a deformable mass of metal to a central region of said heat-sink cover; positioning said metal adjacent to a major surface of said chip; and compressing said deformable metal against said chip to form an unbonded, separable interface therebetween.
Claim 5
Dependent Claim
63 words
In the method of fabricating a circuit package in which a semiconductor chip is cooled by a heat-sink cover, the improvement comprising: metallurgically bonding a deformable mass of metal to a central region of said heat-sink cover; positioning said metal adjacent to a major surface of said chip; and compressing said deformable metal against said chip to form an unbonded, separable interface therebetween.
Claim 6
Dependent Claim
57 words
A method as in claim 3 wherein said heat-sink cover is a material with which said deformable metal will not form a metallurgical bond; and said bonding step includes: bonding another metal which forms a metallurgical bond with said deformable metal on said central region of said heat-sink; and bonding said deformable metal to said other metal.
Claim 7
Dependent Claim
21 words
A method as in claim 3 wherein said deformable metal is selected from the group consisting of indium and indium alloy.
Claim 8
Dependent Claim
29 words
A method as in claim 5 wherein said compressing step is accomplished at an elevated temperature, whereby the yield stress of said deformable metal is reduced during said compressing.
Claim 9
Dependent Claim
65 words
In the method of fabricating a circuit package in which a semiconductor chip is cooled off by a heat-sink cover, the improvement comprising: metallurgically bonding a deformable mass of metal to a major surface of said chip; positioning said metal adjacent to a central region of said heat-sink cover; and compressing said deformable metal against said heat-sink cover to form an unbonded, separable interface therebetween.
Claim 10
Dependent Claim
65 words
In the method of fabricating a circuit package in which a semiconductor chip is cooled off by a heat-sink cover, the improvement comprising: metallurgically bonding a deformable mass of metal to a major surface of said chip; positioning said metal adjacent to a central region of said heat-sink cover; and compressing said deformable metal against said heat-sink cover to form an unbonded, separable interface therebetween.
Claim 11
Dependent Claim
56 words
A method as in claim 7 wherein said chip is a material with which said deformable metal will not form a metallurgical bond; and said bonding step includes: bonding another metal which forms a metallurgical bond with said deformable metal on said major surface of said chip; and bonding said deformable metal to said other metal.
Claim 12
Dependent Claim
21 words
A method as in claim 7 wherein said deformable metal is selected from the group consisting of indium and indium alloy.
Claim 13
Dependent Claim
29 words
A method as in claim 9 wherein said compressing step is accomplished at an elevated temperature, whereby the yield stress of said deformable metal is reduced during said compressing.
Claim 14
Dependent Claim
106 words
In the method of fabricating a circuit package in which a semiconductor chip is cooled by a heat-sink cover, the improvement comprising: metallurgically bonding a deformable mass of metal to a central region of said heat-sink cover; providing a component which has a first major surface conforming to a major surface of said chip; metallurgically bonding a second major surface of said component to said metal; positioning said first major surface of said component adjacent to said major surface of said chip; and pressing said component against said chip, thereby compressing said deformable metal and forming an unbonded, separable interface between said component and said chip.
Claim 15
Dependent Claim
106 words
In the method of fabricating a circuit package in which a semiconductor chip is cooled by a heat-sink cover, the improvement comprising: metallurgically bonding a deformable mass of metal to a central region of said heat-sink cover; providing a component which has a first major surface conforming to a major surface of said chip; metallurgically bonding a second major surface of said component to said metal; positioning said first major surface of said component adjacent to said major surface of said chip; and pressing said component against said chip, thereby compressing said deformable metal and forming an unbonded, separable interface between said component and said chip.
Claim 16
Dependent Claim
57 words
A method as in claim 11 wherein said heat-sink cover is a material with which said deformable metal will not form a metallurgical bond; and said bonding step includes: bonding another metal which forms a metallurgical bond with said deformable metal on said central region of said heat-sink; and bonding said deformable metal to said other metal.
Claim 17
Dependent Claim
21 words
A method as in claim 11 wherein said deformable metal is selected from the group consisting of indium and indium alloy.
Claim 18
Dependent Claim
112 words
In the method of fabricating a circuit package in which a semiconductor chip is cooled by a heat-sink cover, the improvement comprising: metallurgically bonding a plurality of deformable metal pads, each to a separate location of said heat-sink cover; providing a component which has a first major surface conforming to a major surface of said chip; metallurgically bonding a second major surface of said component to said plurality of metal pads; positioning said first major surface of said component adjacent to said major surface of said chip; and pressing said component against said chip, thereby compressing said deformable metal pads and forming an unbonded, separable interface between said component and said chip.
Claim 19
Dependent Claim
112 words
In the method of fabricating a circuit package in which a semiconductor chip is cooled by a heat-sink cover, the improvement comprising: metallurgically bonding a plurality of deformable metal pads, each to a separate location of said heat-sink cover; providing a component which has a first major surface conforming to a major surface of said chip; metallurgically bonding a second major surface of said component to said plurality of metal pads; positioning said first major surface of said component adjacent to said major surface of said chip; and pressing said component against said chip, thereby compressing said deformable metal pads and forming an unbonded, separable interface between said component and said chip.
Claim 20
Dependent Claim
66 words
A method as in claim 14 wherein said heat-sink cover is a material with which said deformable metal pads will not form a metallurgical bond; and said bonding step includes: prior to bonding said pads, bonding a plurality of films of another metal which forms a metallurgical bond with said deformable metal, each of said film being bonded to said separate locations of said heat-sink cover.
Claim 21
Dependent Claim
21 words
A method as in claim 14 wherein said deformable metal is selected from the group consisting of indium and indium alloy.
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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) | 1980-07-11 | 1981-01-10 | 1981-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-11 | 1985-01-10 | 1985-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-11 | 1989-01-10 | 1989-07-12 | $7700.00 | Window Closed / Lapsed |