Patent US4078711A successfully refreshed from Google Patents.
US4078711A
Expired / Lapsed
US
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Metallurgical method for die attaching silicon on sapphire devices to obtain heat resistant bond
Assignee: Boeing North American Inc
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Filing: 1977-04-14
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Granted: 1978-03-14
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Expires: 1997-04-14
Abstract
Abstract A method for attaching a silicon-on-sapphire (SOS) device to a gold-plated surface of a package for the device. A layer of a metal adherent to both sapphire and gold such as, for example, tungsten, is deposited on the back side of a wafer of the devices. A layer of gold is then deposited on the tungsten layer. A preform of an alloy compatible with gold, such as gold-germanium, interposed between and in contact with the die and the package, is heated and then cooled to bond the die to the surface of the package.
Inventors
- 👤 Herbert A. Bell
- 👤 Micheal E. McCoy
- 👤 Francis J. Woolston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:25
CPC Classifications
B; B23; B23K; B23K1/00; B23K1/19; B23K35/00; B23K35/001; H; H10; H10W; H10W70/00; H10W70/60; H10W70/67; H10W70/69; H10W70/692; H10W72/00; H10W72/30; H10W72/071; H10W72/073; H10W72/07331; H10W72/07336; H10W72/07337; H10W72/351; H10W72/352; H10W72/353; H10W72/354; H10W72/50; H10W72/59; H10W72/90; H10W72/951; H10W72/952
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
164 words
A method of forming a heat-resistant bond between a sapphire surface of an SOS device and a metallic surface of a device package for said device wherein said metallic surfaces is of a first metal, said method comprising: depositing a layer of a second metal on the sapphire surface of an SOS wafer, wherein said second metal is adherent to both sapphire and said first metal; depositing a layer of said first metal on said layer of said second metal; positioning the metal layers on said sapphire surface of said SOS device adjacent said metallic surface of said device package; interposing a preform of an alloy between said metallic surface and said metal layers on said sapphire surface wherein said alloy is compatible with said first metal for bonding; heating and then cooling said preform, said device package metallic surface, and said layer of said first metal on said sapphire surface of said SOS devices to bond said sapphire surface to each device package.
Claim 2
Independent Claim
164 words
A method of forming a heat-resistant bond between a sapphire surface of an SOS device and a metallic surface of a device package for said device wherein said metallic surfaces is of a first metal, said method comprising: depositing a layer of a second metal on the sapphire surface of an SOS wafer, wherein said second metal is adherent to both sapphire and said first metal; depositing a layer of said first metal on said layer of said second metal; positioning the metal layers on said sapphire surface of said SOS device adjacent said metallic surface of said device package; interposing a preform of an alloy between said metallic surface and said metal layers on said sapphire surface wherein said alloy is compatible with said first metal for bonding; heating and then cooling said preform, said device package metallic surface, and said layer of said first metal on said sapphire surface of said SOS devices to bond said sapphire surface to each device package.
Claim 3
Dependent Claim
12 words
The method recited in claim 1 wherein said first metal is gold.
Claim 4
Dependent Claim
20 words
The method recited in claim 2 wherein said second metal is selected from the group consisting of tungsten and titanium,
Claim 5
Dependent Claim
23 words
The method recited in claim 3 wherein said layers of said first and second metals are deposited by sputtering in a vacuum chamber.
Claim 6
Dependent Claim
31 words
The method recited in claim 3 wherein said layer of said first metal is about 100 microinches thick and wherein said layer of said second metal is about 1000 angstroms thick.
Claim 7
Dependent Claim
19 words
The method recited in claim 3 wherein said alloy is selected from the group consisting of gold-germanium and gold-silicon.
Claim 8
Dependent Claim
13 words
The method recited in claim 6 wherein said alloy is a eutectic alloy.
Claim 9
Dependent Claim
25 words
The method recited in claim 1 wherein said step of heating said preform heats said metallic surface of said device package to about 390° C.
Claim 10
Dependent Claim
24 words
The method recited in claim 1 wherein said step of heating and then cooling said preform is accomplished in an atmosphere of inert gas.
Claim 11
Dependent Claim
12 words
The method recited in claim 9 wherein said inert gas is nitrogen.
Claim 12
Dependent Claim
23 words
The method recited in claim 1 wherein said metallic surface and said layer of first metal are fused together during said heating step.
Claim 13
Dependent Claim
17 words
The method recited in claim 4 wherein said sputtering is accomplished using a planar magnetron sputtering system.
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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) | 1981-03-13 | 1981-09-12 | 1982-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-13 | 1985-09-12 | 1986-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-13 | 1989-09-12 | 1990-03-14 | $7700.00 | Window Closed / Lapsed |