US4757934A
Expired / Lapsed
US
⏱️ 0.0 years remaining
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 02:09
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.
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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) | 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 |