US4761325A
Expired / Lapsed
US
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Multilayer ceramic circuit board
Assignee: Fujitsu Ltd
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Filing: 1985-08-02
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Granted: 1988-08-02
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Expires: 2005-08-02
Abstract
Abstract A method for producing a multilayer ceramic circuit board including the steps of forming a multilayer structure consisting of patterns of copper-based paste and glass-ceramic layers, the glass-ceramic layers consisting of a mixture of 10 percent to 75 percent by weight of α-alumina, 20 percent to 60 percent by weight of crystallizable or noncrystallizable glass which can be sintered at a temperature lower than the melting point of copper, and 5 percent to 70 percent by weight of quartz glass, based on the total weight of the glass-ceramic, blended with a binder containing a thermally depolymerizable resin; prefiring the multilayer structure in an inert atmosphere containing water vapor, the partial pressure of which is 0.005 to 0.3 atmosphere, at a temperature where the thermally depolymerizable resin is eliminated; and firing the multilayer structure in an inert atmosphere containing no water vapor at a temperature below the melting point of copper so as to sinter the glass-ceramic.
Inventors
- 👤 Kazuaki Kurihara
- 👤 Nobuo Kamehara
- 👤 Hiromitsu Yokoyama
- 👤 Hiromi Ogawa
- 👤 Kishio Yokouchi
- 👤 Yoshihiko Imanaka
- 👤 Koichi Niwa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:41
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/46; H05K3/4644; H05K3/4664; H05K3/4667; C; C03; C03C; C03C10/00; C03C10/0009; H05K1/00; H05K1/02; H05K1/03; H05K1/0306; H05K3/4611; H05K3/4626; H05K3/4629; H10; H10W; H10W70/00; H10W70/01; H10W70/05; H10W70/098; H10W70/60; H10W70/67; H10W70/69; H10W70/692; C03C2214/00; C03C2214/04; C03C2214/20; H05K1/09; H05K1/092; H05K2203/00; H05K2203/08; H05K2203/086; H05K2203/088; H05K2203/11; H05K2203/1126; H05K3/10; H05K3/12; H05K3/1283; H05K3/1291; Y; Y10; Y10S; Y10S428/00; Y10S428/901; Y10T; Y10T428/00; Y10T428/24; Y10T428/24273; Y10T428/24322; Y10T428/24802; Y10T428/24917; Y10T428/24926; Y10T428/25; Y10T428/252
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
101 words
A sinterable precursor material for a glass-ceramic insulating layer of a multilayer ceramic circuit board made up of copper conductors separated by glass-ceramic insulating layers, said material comprising a mixture of 10 percent to 75 percent by weight of α-alumina particles, 20 percent to 60 percent by weight of crystallizable or non-crystallizable glass which has a softening point in the range of approximately 750° C. to 900° C. and is sinterable at a temperature lower than the melting point of copper, and 5 percent to 70 percent by weight of quartz glass particles based on the total weight of the mixture.
Claim 2
Dependent Claim
101 words
A sinterable precursor material for a glass-ceramic insulating layer of a multilayer ceramic circuit board made up of copper conductors separated by glass-ceramic insulating layers, said material comprising a mixture of 10 percent to 75 percent by weight of α-alumina particles, 20 percent to 60 percent by weight of crystallizable or non-crystallizable glass which has a softening point in the range of approximately 750° C. to 900° C. and is sinterable at a temperature lower than the melting point of copper, and 5 percent to 70 percent by weight of quartz glass particles based on the total weight of the mixture.
Claim 3
Dependent Claim
17 words
A precursor material as set forth in claim 1 wherein said crystallizable glass comprises cordierite or spoduemene.
Claim 4
Dependent Claim
19 words
A precursor material as set forth in claim 1 wherein said non-crystallizable glass comprises borosilicate glass or aluminosilicate glass.
Claim 5
Dependent Claim
32 words
A precursor material as set forth in claim 1 comprising a mixture of approximately 34 weight percent of α-alumina, 33 weight percent of borosilicate glass and 33 weight percent of quartz glass.
Claim 6
Dependent Claim
31 words
A precursor material as set forth in claim 1 comprising a mixture of approximately 34 weight percent of α-alumina, 33 weight percent of β-spoduemene and 33 weight percent of quartz glass.
Claim 7
Dependent Claim
26 words
A green sheet for a glass-ceramic layer of a multilayer ceramic circuit board comprising an admixture of the precursor material of claim 1 and a binder.
Claim 8
Dependent Claim
26 words
A green sheet for a glass-ceramic layer of a multilayer ceramic circuit board comprising an admixture of the precursor material of claim 2 and a binder.
Claim 9
Dependent Claim
26 words
A green sheet for a glass-ceramic layer of a multilayer ceramic circuit board comprising an admixture of the precursor material of claim 3 and a binder.
Claim 10
Dependent Claim
26 words
A green sheet for a glass-ceramic layer of a multilayer ceramic circuit board comprising an admixture of the precursor material of claim 4 and a binder.
Claim 11
Dependent Claim
26 words
A green sheet for a glass-ceramic layer of a multilayer ceramic circuit board comprising an admixture of the precursor material of claim 5 and a binder.
Claim 12
Dependent Claim
21 words
A sinterable composite comprising a plurality of copper conductor layers separated by layers formed from the precursor material of claim 1.
Claim 13
Dependent Claim
21 words
A sinterable composite comprising a plurality of copper conductor layers separated by layers formed from the precursor material of claim 2.
Claim 14
Dependent Claim
21 words
A sinterable composite comprising a plurality of copper conductor layers separated by layers formed from the precursor material of claim 3.
Claim 15
Dependent Claim
21 words
A sinterable composite comprising a plurality of copper conductor layers separated by layers formed from the precursor material of claim 4.
Claim 16
Dependent Claim
21 words
A sinterable composite comprising a plurality of copper conductor layers separated by layers formed from the precursor material of claim 5.
Claim 17
Dependent Claim
30 words
A multilayer ceramic circuit board prepared by firing the composite of claim 11 in an inert atmosphere containing no water vapor at a temperature below the melting point of copper.
Claim 18
Dependent Claim
87 words
A ceramic circuit board comprising a layer of conductive material supported by a ceramic insulating layer, said board having been prepared by admixing the precursor material of claim 1 with a binder; forming a layer from the admixture; laying a conductive material on the layer to form a composite; subjecting the composite to conditions suitable for removing the binder; and thereafter firing the composite under temperature conditions suitable for causing the crystallizable or non-crystallizable glass to sinter without causing sintering of the α-alumina and quartz glass components.
Claim 19
Dependent Claim
138 words
A fired ceramic circuit board comprising a layer of a conductive material supported by a ceramic insulating layer, said insulating layer comprising 10 percent to 75 percent by weight of α-alumina particles, 20 percent to 60 percent of a sintered glass matrix composed of glass component which initially had a softening point in the range of approximately 750° C. to 900° C. and was sinterable at a temperature lower than about 1083° C., and 5 percent to 70 percent by weight of quartz glass particles, said circuit board having been fired in an inert atmosphere containing no water vapor and at a temperature above the sintering temperature of the glass component and below the sintering temperatures of α-alumina and quartz glass so as to produce a structure comprising α-alumina and quartz glass particles surrounded by said glass matrix.
Claim 20
Dependent Claim
138 words
A fired ceramic circuit board comprising a layer of a conductive material supported by a ceramic insulating layer, said insulating layer comprising 10 percent to 75 percent by weight of α-alumina particles, 20 percent to 60 percent of a sintered glass matrix composed of glass component which initially had a softening point in the range of approximately 750° C. to 900° C. and was sinterable at a temperature lower than about 1083° C., and 5 percent to 70 percent by weight of quartz glass particles, said circuit board having been fired in an inert atmosphere containing no water vapor and at a temperature above the sintering temperature of the glass component and below the sintering temperatures of α-alumina and quartz glass so as to produce a structure comprising α-alumina and quartz glass particles surrounded by said glass matrix.
Claim 21
Dependent Claim
57 words
A fired ceramic circuit board comprising a conductive layer supported by a ceramic insulating layer, said insulating layer comprising 10 percent to 75 percent by weight of α-alumina particles, 5 percent to 70 percent by weight quartz glass particles, and 20 to 60 percent by weight of a matrix of a sintered glass component surrounding said particles.
Claim 22
Dependent Claim
57 words
A fired ceramic circuit board comprising a conductive layer supported by a ceramic insulating layer, said insulating layer comprising 10 percent to 75 percent by weight of α-alumina particles, 5 percent to 70 percent by weight quartz glass particles, and 20 to 60 percent by weight of a matrix of a sintered glass component surrounding said particles.
Claim 23
Dependent Claim
24 words
A fired ceramic circuit board as set forth in claim 19 wherein said ceramic insulating layer contains less than about 100 ppm residual carbon.
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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) | 1991-08-02 | 1992-02-01 | 1992-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-02 | 1996-02-01 | 1996-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-02 | 2000-02-01 | 2000-08-02 | $7700.00 | Window Closed / Lapsed |