Patent US4776978A successfully refreshed from Google Patents.
US4776978A
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Method of controlling the sintering of metal particles
Assignee: International Business Machines Corp
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Filing: 1987-04-27
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Granted: 1988-10-11
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Expires: 2007-04-27
Abstract
Abstract Sintering of metal particles at their normal sintering temperature is inhibited by coating the metal particles with an organic material such as polyvinyl butyral, polyvinyl formvar, polyvinyl alcohol, polyacrylonitrile epoxies, urethanes and cross-linked polyvinyl butyral. The organic coating serves as a barrier preventing physical contact between metal particles during the initial phase of the sintering cycle and degrades into a carbonaceous coating followed by volatilization during the intermediate phase of the cycle permitting coalescence of the metal particles into a dense mass along with the coalescence of the glass-ceramic particles. Co-sintering of the metal particles and the glass-ceramic particles with the aid of the organic coating results in a hermetic multi-layer glass ceramic substrate free of dimensional stability problems without deleteriously affecting the electrical conductivity of the metal conductor pattern.
Inventors
- 👤 Lester W. Herron
- 👤 Raj N. Master
- 👤 Robert W. Nufer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:22
CPC Classifications
H; H10; H10W; H10W70/00; H10W70/01; H10W70/05; H10W70/098; B; B22; B22F; B22F1/00; B22F1/10; B22F3/00; B22F3/10; B22F3/1017; B22F3/1021; C; C04; C04B; C04B41/00; C04B41/45; C04B41/50; C04B41/51; C04B41/80; C04B41/81; C04B41/85; C04B41/88; H05; H05K; H05K1/00; H05K1/02; H05K1/09; H05K1/092; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2998
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
104 words
A conductor forming composition suitable for forming thick film conductors in a multilayer ceramic substrate for an integrated circuit device package by subjecting said composition to a sintering cycle, said composition comprising: a base of low melting point and high electrical conductivity metal particles; and an organic coating over said metal particles capable of decomposing in a non-oxidizing environment at a low temperature corresponding to the initial phase of said sintering cycle and thereby providing a carbonaceous residue for preventing sintering of the metal particles until subjected to an oxidizing environment at a high temperature corresponding to the intermediate phase of the sintering cycle.
Claim 2
Dependent Claim
104 words
A conductor forming composition suitable for forming thick film conductors in a multilayer ceramic substrate for an integrated circuit device package by subjecting said composition to a sintering cycle, said composition comprising: a base of low melting point and high electrical conductivity metal particles; and an organic coating over said metal particles capable of decomposing in a non-oxidizing environment at a low temperature corresponding to the initial phase of said sintering cycle and thereby providing a carbonaceous residue for preventing sintering of the metal particles until subjected to an oxidizing environment at a high temperature corresponding to the intermediate phase of the sintering cycle.
Claim 3
Dependent Claim
31 words
The composition as recited in claim 1 wherein said organic coating is selected from a group consisting of polyvinyl butyral, polyvinyl formvar, polyvinyl alcohol, polyacrylonitrile, epoxies, urethanes and cross-linked polyvinyl butyral.
Claim 4
Dependent Claim
27 words
The composition as recited in claim 2 wherein said metal is selected from a group consisting of copper, nickel, platinum, palladium, silver and gold and alloys thereof.
Claim 5
Dependent Claim
35 words
A conductor forming composition suitable for forming a conductor on a ceramic substrate by subjecting said composition to a sintering cycle, said composition comprising copper particle base and polyvinyl butyral coating over said copper particle.
Claim 6
Dependent Claim
35 words
A conductor forming composition suitable for forming a conductor on a ceramic substrate by subjecting said composition to a sintering cycle, said composition comprising copper particle base and polyvinyl butyral coating over said copper particle.
Claim 7
Dependent Claim
20 words
The composition as recited in claim 4 wherein the polyvinyl butyral is about 0.3-0.6 wt. percent of said copper particle.
Claim 8
Dependent Claim
83 words
A conductor forming composition suitable for forming a thick film conductor on a ceramic substrate by subjecting said composition to a sintering cycle, said composition comprising: a particle base of a low melting point and high electrical conductivity material selected from the group consisting of copper, nickel, platinum, palladium, silver, gold and alloys thereof; and an organic coating over said particles, said coating being selected from a group consisting of polyvinyl butyral, polyvinyl formvar, polyvinyl alcohol, polyacrylonitrile, epoxies, urethanes and cross-linked polyvinyl butyral.
Claim 9
Dependent Claim
83 words
A conductor forming composition suitable for forming a thick film conductor on a ceramic substrate by subjecting said composition to a sintering cycle, said composition comprising: a particle base of a low melting point and high electrical conductivity material selected from the group consisting of copper, nickel, platinum, palladium, silver, gold and alloys thereof; and an organic coating over said particles, said coating being selected from a group consisting of polyvinyl butyral, polyvinyl formvar, polyvinyl alcohol, polyacrylonitrile, epoxies, urethanes and cross-linked polyvinyl butyral.
Claim 10
Dependent Claim
25 words
The composition as in claim 6 wherein the polyvinyl butyral coating has a weight percent in the range of about 0.3-0.6 of said copper particle.
References Cited (Backward Citations)
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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) | 1991-10-11 | 1992-04-11 | 1992-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-11 | 1996-04-11 | 1996-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-11 | 2000-04-11 | 2000-10-11 | $7700.00 | Window Closed / Lapsed |