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US5665459A
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Low-temperature fired ceramic circuit substrate and thick-film paste for use in fabrication thereof
Assignee: Murata Manufacturing Co Ltd
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Filing: 1996-02-26
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Granted: 1997-09-09
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Expires: 2016-02-26
Abstract
Abstract A low-temperature fired ceramic circuit substrate fired at a temperature ranging between 800 DEG and 1,000 DEG C. includes a plurality of insulating layers each formed of a low-temperature fired ceramic, an Ag conductor layer formed internally of the substrate, an Au conductor layer formed on a surface of the substrate, and an Ag-Pd layer formed between the Ag and the Au conductor layers, the Ag-Pd layer being composed of 100 parts metal composition consisting of 70 to 95 parts Ag and 5 to 30 part Pd by weight, and 2 to 10 parts lead borosilicate glass by weight. As the result of the above composition of the ceramic circuit substrate, its fabrication process can be simplified, and a defect rate in a connection between the Ag and Au layers after repeated firing is rendered approximately zero, which ensures high reliability for the connection.
Inventors
- 👤 Junzo Fukuta
- 👤 Masashi Fukaya
- 👤 Hideaki Araki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 16:53
CPC Classifications
H; H10; H10W; H10W70/00; H10W70/60; H10W70/62; H10W70/66; H10W70/666; H05; H05K; H05K3/00; H05K3/40; H05K3/4038; H05K3/4053; H05K3/4061; H05K1/00; H05K1/02; H05K1/03; H05K1/0306; H05K1/09; H05K1/092; H05K2201/00; H05K2201/03; H05K2201/0332; H05K2201/0335; H05K2201/035; H05K3/22; H05K3/24; H05K3/245; H05K3/247; H05K3/248; H05K3/46; H05K3/4611; H05K3/4626; H05K3/4629; H10W72/00; H10W72/50; H10W72/551; H10W72/552; H10W72/5522; H10W72/851; H10W72/874; H10W72/884; H10W90/00; H10W90/701; H10W90/731; H10W90/734; H10W90/751; H10W90/754; Y; Y10; Y10S; Y10S428/00; Y10S428/901; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24917; Y10T428/24926
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
136 words
A low-temperature fired ceramic circuit substrate fired at a temperature ranging between 800° and 1,000° C. comprising: a plurality of insulating layers each formed by firing a mixture of CaO--SiO 2 --Al 2 O 3 --B 2 O 3 glass and Al 2 O 3 at a temperature ranging between 800° to 1,000° C.; an Ag thick-film conductor layer formed in the insulating layer and consisting essentially of Ag; an Au thick-film conductor layer formed on a surface of the substrate and consisting essentially of Au; and an Ag--Pd thick-film layer formed between the Ag and the Au thick-film conductor layers and consisting essentially of: (a) 100 parts metal composition consisting of 70 to 95 parts Ag and 5 to 30 parts Pd by weight; and (b) 2 to 10 parts lead borosilicate glass by weight.
Claim 2
Dependent Claim
136 words
A low-temperature fired ceramic circuit substrate fired at a temperature ranging between 800° and 1,000° C. comprising: a plurality of insulating layers each formed by firing a mixture of CaO--SiO 2 --Al 2 O 3 --B 2 O 3 glass and Al 2 O 3 at a temperature ranging between 800° to 1,000° C.; an Ag thick-film conductor layer formed in the insulating layer and consisting essentially of Ag; an Au thick-film conductor layer formed on a surface of the substrate and consisting essentially of Au; and an Ag--Pd thick-film layer formed between the Ag and the Au thick-film conductor layers and consisting essentially of: (a) 100 parts metal composition consisting of 70 to 95 parts Ag and 5 to 30 parts Pd by weight; and (b) 2 to 10 parts lead borosilicate glass by weight.
Claim 3
Dependent Claim
42 words
A substrate according to claim 1, wherein the Ag--Pd thick-film layer is fired on the surface of the insulating layers after the same has been co-fired with the internal Ag thick-film conductor layer, and then the Au thick-film conductor layer is fired.
Claim 4
Dependent Claim
32 words
A substrate according to claim 1, wherein the insulating layers, the Ag thick-film conductor layer and the intermediate Ag--Pd thick-film layer are co-fired, and then the Au thick-film conductor layer is fired.
Claim 5
Dependent Claim
41 words
A substrate according to claim 1, wherein the intermediate Ag--Pd thick-film layer covers Ag via conductors in a surface layer of the substrate and the Au thick-film conductor layer is formed on the Ag--Pd thick-film layer covering the Ag via conductors.
References Cited (Backward Citations)
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US4424251A
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US4464420A
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US4621066A
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US4795670A
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EP0247617A2
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JPH0569319A
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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) | 2000-09-08 | 2001-03-10 | 2001-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-09-08 | 2005-03-10 | 2005-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-09-08 | 2009-03-10 | 2009-09-09 | $7700.00 | Window Closed / Lapsed |