Patent US3087838A successfully refreshed from Google Patents.
US4987677A
Expired / Lapsed
US
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Bonded ceramic metal composite substrate, circuit board constructed therewith and methods for production thereof
Assignee: Toshiba Corp
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Filing: 1990-02-26
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Granted: 1991-01-29
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Expires: 2010-02-26
Abstract
Abstract A bonded ceramic-metal composite substrate comprising a ceramic substrate having opposite surfaces and a copper sheet having a face directly bonded to one of the surfaces of the ceramic substrate, wherein the median surface roughness (R a ) of the outer surface of the copper sheet is not greater than 3 μm, and the maximum surface roughness (R max ) of the outer surface of the copper sheet is not greater than 18 μm. The invention improves the manufacturing reliability of various electronic devices such as semiconductor modules.
Inventors
- 👤 Tadashi Tanaka
- 👤 Kazuo Matsumura
- 👤 Hiroshi Komorita
- 👤 Nobuyuki Mizunoya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:49
CPC Classifications
H; H10; H10W; H10W40/00; H10W40/20; H10W40/25; H10W40/255; H05; H05K; H05K3/00; H05K3/38; H10W70/00; H10W70/01; H10W70/04; H10W70/047; H10W70/60; H10W70/62; H10W70/66; H10W72/00; H10W72/50; H05K1/00; H05K1/02; H05K1/03; H05K1/0306; H05K2201/00; H05K2201/03; H05K2201/0332; H05K2201/0335; H05K2201/0355; H05K2201/09; H05K2201/09009; H05K2201/09118; H10W72/531; H10W72/5363; H10W72/551; H10W72/552; H10W72/5524; H10W90/00; H10W90/701; H10W90/751; H10W90/754; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117; Y10T29/49124; Y10T29/4913; Y10T29/49155; Y10T428/00; Y10T428/12; Y10T428/12472; Y10T428/12993
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
118 words
A method of producing a bonded ceramic metal composite substrate comprising the steps of applying a copper member to a desired position on a surface of a ceramic substrate and heating the resulting assembly to a temperature below the melting point of copper but above the eutectic temperature of copper and oxygen to directly bond the copper membe to the substrate, wherein said copper member is selected to have an initial surface roughness such that the median surface roughness (R a ) of said copper member after said heating step is not greater than 3 μm, and the maximum surface roughness (R max ) of said copper member after said heating step is not greater than 18 μm.
Claim 2
Independent Claim
118 words
A method of producing a bonded ceramic metal composite substrate comprising the steps of applying a copper member to a desired position on a surface of a ceramic substrate and heating the resulting assembly to a temperature below the melting point of copper but above the eutectic temperature of copper and oxygen to directly bond the copper membe to the substrate, wherein said copper member is selected to have an initial surface roughness such that the median surface roughness (R a ) of said copper member after said heating step is not greater than 3 μm, and the maximum surface roughness (R max ) of said copper member after said heating step is not greater than 18 μm.
Claim 3
Dependent Claim
50 words
A method according to claim 1, wherein the median surface roughness (R a ) of the copper member after said heating step is not greater than 1 μm, and the maximum surface roughness (R max ) of the copper member after said heating step is not greater than 8 μm.
Claim 4
Dependent Claim
27 words
A method according to claim 1, wherein said copper member is pre-formed to the shape of a desired circuit pattern prior to application to said ceramic substrate.
Claim 5
Dependent Claim
49 words
A method according to claim 1, wherein said member is applied to said substrate in the form of a continuous sheet, said method further comprising the step of subjecting the copper member to an etching operation to form it to a desired circuit pattern after bonding to said substrate.
Claim 6
Dependent Claim
20 words
A method according to claim 4, further comprising the step of subjecting the etched copper member to a polishing operation.
Claim 7
Dependent Claim
15 words
A method according to claim 5, wherein said polishing operation is a chemical polishing operation.
Claim 8
Independent Claim
174 words
A method of producing a circuit board comprising the steps of: (a) producing a bonded ceramic metal composite substrate by applying a copper member to a desired position on the surface of a ceramic substrate and heating the resulting assembly to a temperature below the melting point of copper but above the eutectic temperature of copper and oxygen to directly bond the copper member to the substrate, said copper member having a free face comprising at least one mounting area and at least one electrode area, wherein said copper member is selected to have an initial surface roughness such that the median surface roughness (R a ) of said copper member after said heating step is not greater than 3 μm, and the maximum surface roughness (R max ) is not greater than 18 μm; (b) mounting at least one electrical element on said at least one mounting area of the copper sheet, and (c) electrically connecting a bonding wire to said at least one electrical element and said at least one electrode area.
Claim 9
Independent Claim
174 words
A method of producing a circuit board comprising the steps of: (a) producing a bonded ceramic metal composite substrate by applying a copper member to a desired position on the surface of a ceramic substrate and heating the resulting assembly to a temperature below the melting point of copper but above the eutectic temperature of copper and oxygen to directly bond the copper member to the substrate, said copper member having a free face comprising at least one mounting area and at least one electrode area, wherein said copper member is selected to have an initial surface roughness such that the median surface roughness (R a ) of said copper member after said heating step is not greater than 3 μm, and the maximum surface roughness (R max ) is not greater than 18 μm; (b) mounting at least one electrical element on said at least one mounting area of the copper sheet, and (c) electrically connecting a bonding wire to said at least one electrical element and said at least one electrode area.
Claim 10
Dependent Claim
38 words
A method according to claim 7, wherein the median surface roughness (R a ) of the copper member is not greater than 1 μm, and the maximum surface roughness (R max ) is not greater than 8 μm.
Claim 11
Dependent Claim
27 words
A method according to claim 7, wherein said copper member is pre-formed to the shape of a desired circuit pattern prior to application to said ceramic substrate.
Claim 12
Dependent Claim
47 words
A method according to claim 7, wherein said member is applied to said substrate in the form of a continuous sheet, futher comprising the step of subjecting the copper member to an etching operation to form it to a desired circuit pattern after bonding to said substrate.
Claim 13
Dependent Claim
20 words
A method according to claim 10, further comprising the step of subjecting the etched copper member to a polishing operation.
Claim 14
Dependent Claim
15 words
A method according to claim 11, wherein said polishing operation is a chemical polishing operation.
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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) | 1994-01-28 | 1994-07-30 | 1995-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-28 | 1998-07-30 | 1999-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-28 | 2002-07-30 | 2003-01-29 | $7700.00 | Window Closed / Lapsed |