US4996171A
Expired / Lapsed
US
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Silver-filled glass
Assignee: Johnson Matthey PLC
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Filing: 1988-12-22
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Granted: 1991-02-26
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Expires: 2008-12-22
Abstract
Abstract Silver-filled glass pastes useful for the attachment of silicon semi-conductor devices (dies) to substrates comprise particulate silver and a lead phosphate glass, together with conventional organic components. The pastes have low bonding temperatures, and give good adhesion at firing temperatures of 350° to 460° C.
Inventors
- 👤 Nigel M. Davey
- 👤 Gordon G. Ferrier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:58
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/40; H10W72/00; H10W72/30; H10W72/071; H10W72/073; H10W72/07331; H10W72/07337
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
68 words
In a silver-filled glass bonding paste for the electronics industry, the improvement wherein a lead phosphate glass consisting essentially of lead oxide, phosphorus oxide and at least one further oxide selected from the oxides of magnesium, calcium, strontium, barium, cadmium, boron, silicon and vanadium and wherein said lead phosphate glass has a softening temperature in the range of 150°-400 ° C. is the glass component of the paste.
Claim 2
Dependent Claim
68 words
In a silver-filled glass bonding paste for the electronics industry, the improvement wherein a lead phosphate glass consisting essentially of lead oxide, phosphorus oxide and at least one further oxide selected from the oxides of magnesium, calcium, strontium, barium, cadmium, boron, silicon and vanadium and wherein said lead phosphate glass has a softening temperature in the range of 150°-400 ° C. is the glass component of the paste.
Claim 3
Dependent Claim
12 words
The paste of claim 1, wherein the further oxide is vanadium pentoxide.
Claim 4
Dependent Claim
15 words
The paste of claim 1, wherein the lead phosphate glass is free of alkali metal.
Claim 5
Dependent Claim
18 words
The paste of claim 1, wherein the silver comprises silver flakes of average maximum dimension about 10 μm.
Claim 6
Dependent Claim
46 words
The paste of claim 1, wherein the lead phosphate glass consists essentially of 50 to 60 mole % of PbO, 10 to 20 mole % P 2 O 5 and 20 to 30 mole % V 2 O 5 , the total being 100 mole %.
References Cited (Backward Citations)
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Cited
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US4436785A
Cited
US4459166A
Cited
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Cited
US4761224A
Cited
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Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-02-25 | 1994-08-27 | 1995-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-25 | 1998-08-27 | 1999-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-02-25 | 2002-08-27 | 2003-02-26 | $7700.00 | Window Closed / Lapsed |