Patent US4757934A successfully refreshed from Google Patents.
US4757934A
Expired / Lapsed
US
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Low stress heat sinking for semiconductors
Assignee: Motorola Solutions Inc
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Filing: 1987-02-06
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Granted: 1988-07-19
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Expires: 2007-02-06
Abstract
Abstract A semiconductor die is mounted on a metal substrate via intermediate layers which permit the die to be readily soldered to the combination while yet reducing thermal stresses. A dielectric layer is formed over the substrate, followed by another layer of a selected metal, either molybdenum or tungsten. Atop the metal layer is another layer comprising a mixture of solder and the selected metal. A layer of only solder is formed over the mixture, and the semiconductor die is bonded thereto by means of the layer of solder.
Inventors
- 👤 Bernard Greenstein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:17
CPC Classifications
B; B23; B23K; B23K1/00; B23K1/19; B23K31/00; B23K31/02; B23K35/00; B23K35/001; B23K35/002; H; H10; H10W; H10W40/00; H10W40/20; H10W40/25; H10W40/255; H10W72/00; H10W72/01; H10W72/013; B23K2035/008; H10W72/071; H10W72/073; H10W72/07331; H10W72/07336; H10W72/07337; H10W72/30; H10W72/321; H10W72/322; H10W72/351; H10W72/352; H10W72/353; H10W72/50; H10W72/59; H10W90/00; H10W90/701; H10W90/731; H10W90/736
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
71 words
A method of bonding a semiconductor die to a metal substrate, comprising: (a) depositing a dielectric layer on the substrate; (b) depositing an initial layer of metal on the dielectric layer, said metal being selected from the group consisting of molybdenum and tungsten; (c) depositing a mixture of the selected metal, plus solder, on the initial layer; (d) depositing solder over the mixture; and (e) bonding the die to the solder.
Claim 2
Independent Claim
71 words
A method of bonding a semiconductor die to a metal substrate, comprising: (a) depositing a dielectric layer on the substrate; (b) depositing an initial layer of metal on the dielectric layer, said metal being selected from the group consisting of molybdenum and tungsten; (c) depositing a mixture of the selected metal, plus solder, on the initial layer; (d) depositing solder over the mixture; and (e) bonding the die to the solder.
Claim 3
Dependent Claim
26 words
A method as set forth in claim 1 wherein the metal and solder deposits recited in steps (b), (c) and (d) are effected by plasma spraying.
Claim 4
Dependent Claim
66 words
A method as set forth in claim 2 wherein steps (b), (c) and (d) are effected by plasma spraying the selected metal onto the dielectric layer, phasing in solder with the selected metal so as to spray a mixture of the selected metal and the solder, and phasing out the selected metal from the spray so that a layer of solder is deposited over the mixture.
Claim 5
Dependent Claim
23 words
A method as set forth in claim 1 or 3 wherein the dielectric layer is applied directly onto the substrate by plasma spraying.
Claim 6
Independent Claim
100 words
A method of bonding a semiconductor die to an aluminum substrate, comprising: (a) plasma spraying a layer of alumina onto the substrate; (b) plasma spraying a deposit onto the alumina by first spraying a metal selected from the group consisting of molybdenum and tungsten, then phasing out the selected metal from the spray while phasing in solder to the spray such that a mixture of the selected metal and solder is deposited over a layer of the selected metal, and then a layer of solder is deposited over the mixture; and (c) bonding the die atop the layer of solder.
Claim 7
Independent Claim
100 words
A method of bonding a semiconductor die to an aluminum substrate, comprising: (a) plasma spraying a layer of alumina onto the substrate; (b) plasma spraying a deposit onto the alumina by first spraying a metal selected from the group consisting of molybdenum and tungsten, then phasing out the selected metal from the spray while phasing in solder to the spray such that a mixture of the selected metal and solder is deposited over a layer of the selected metal, and then a layer of solder is deposited over the mixture; and (c) bonding the die atop the layer of solder.
Claim 8
Dependent Claim
77 words
A semiconductor and heat sink arrangement comprising: a metal substrate forming at least part of a heat sink; a dielectric layer deposited on the substrate; a layer of metal deposited on the dielectric, said metal being selected from the group consisting of molybdenum and tungsten; a mixture of solder and the selected metal deposited on the layer of metal; a layer of solder deposited on the mixture; and a semiconductor die bonded atop the layer of solder.
Claim 9
Dependent Claim
77 words
A semiconductor and heat sink arrangement comprising: a metal substrate forming at least part of a heat sink; a dielectric layer deposited on the substrate; a layer of metal deposited on the dielectric, said metal being selected from the group consisting of molybdenum and tungsten; a mixture of solder and the selected metal deposited on the layer of metal; a layer of solder deposited on the mixture; and a semiconductor die bonded atop the layer of solder.
Claim 10
Dependent Claim
25 words
An arrangement as set forth in claim 6 wherein the metal substrate is made of aluminum and wherein the dielectric layer is made of alumina.
References Cited (Backward Citations)
FR647956A
Cited
US2662997A
Cited
US2763822A
Cited
US2922092A
Cited
US3209218A
Cited
US3010057A
Cited
US3248681A
Cited
US3339267A
Cited
US3331995A
Cited
US3387191A
Cited
US3399332A
Cited
US3303432A
Cited
US3600144A
Cited
US3839727A
Cited
US4074342A
Cited
US4224636A
Cited
US4542401A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-07-19 | 1992-01-18 | 1992-07-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-19 | 1996-01-18 | 1996-07-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-19 | 2000-01-18 | 2000-07-19 | $7700.00 | Window Closed / Lapsed |