Patent US5196251A successfully refreshed from Google Patents.
US5196251A
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Ceramic substrate having a protective coating thereon and a method for protecting a ceramic substrate
Assignee: International Business Machines Corp
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Filing: 1991-04-30
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Granted: 1993-03-23
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Expires: 2011-04-30
Abstract
Abstract Disclosed is a ceramic substrate having a protective coating on at least one surface thereof which includes: a ceramic substrate having at least one electrically conductive via extending to a surface of the substrate; an electrically conductive I/O pad electrically connected to at least one of the vias; an I/O pin brazed to the I/O pad, the brazed pin having a braze fillet; and a protective layer of polymeric material fully encapsulating the I/O pad, wherein the layer of polymeric material protects the I/O pad from corrosion. Also disclosed is a method of protecting a ceramic substrate from corrosion, the ceramic substrate of the type having a plurality of electrically conductive vias extending to a surface of the substrate, a multilayer metallic I/O pad electrically connected to at least one of the vias, and an I/O pin brazed to the I/O pad, the brazed pin having a braze fillet, the method comprising the step of: encapsulating fully the I/O pad with a protective layer of polymeric material, wherein the layer of polymeric material protects the I/O pad from corrosion. In a preferred embodiment, the I/O pin is selectively exposed to plasma ashing to remove any errant polymeric material from the pin shank, thereby assuring electrical contact to the pin shank.
Inventors
- 👤 Nanik Bakhru
- 👤 Richard A. Bates
- 👤 George Czornyj
- 👤 Nunzio DiPaolo
- 👤 Ananda H. Kumar
- 👤 Suryanarayana Mukkavilli
- 👤 Heinz O. Steimel
- 👤 Rao R. Tummala
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:05
CPC Classifications
H; H10; H10W; H10W90/00; H10W90/701; H10W70/00; H10W70/099; H10W99/00; Y; Y10; Y10S; Y10S428/00; Y10S428/901; Y10T; Y10T428/00; Y10T428/23; Y10T428/239; Y10T428/24; Y10T428/24802; Y10T428/24917
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
113 words
A ceramic substrate having a protective coating on at least one surface thereof comprising: a ceramic substrate having at least one electrically conductive via extending to a surface of said substrate; an electrically conductive I/O pad electrically connected to said at least one via, wherein said I/O pad is susceptible to corrosion that is enhanced or aided by exposure to the atmosphere; an I/O pin brazed to said I/O pad, wherein said I/O pad is larger in cross-section than said I/O pin, said brazed pin having a braze fillet; and a protective layer of polymeric material fully encapsulating said I/O pad, wherein said layer of polymeric material protects said I/O pad from corrosion.
Claim 2
Dependent Claim
113 words
A ceramic substrate having a protective coating on at least one surface thereof comprising: a ceramic substrate having at least one electrically conductive via extending to a surface of said substrate; an electrically conductive I/O pad electrically connected to said at least one via, wherein said I/O pad is susceptible to corrosion that is enhanced or aided by exposure to the atmosphere; an I/O pin brazed to said I/O pad, wherein said I/O pad is larger in cross-section than said I/O pin, said brazed pin having a braze fillet; and a protective layer of polymeric material fully encapsulating said I/O pad, wherein said layer of polymeric material protects said I/O pad from corrosion.
Claim 3
Dependent Claim
21 words
The ceramic substrate of claim 1 wherein said polymeric material encapsulates at least a portion of said surface of said substrate.
Claim 4
Dependent Claim
19 words
The ceramic substrate of claim 1 wherein said polymeric material encapsulates at least a portion of said braze fillet.
Claim 5
Dependent Claim
16 words
The ceramic substrate of claim 1 wherein said surface is a bottom surface of said substrate.
Claim 6
Dependent Claim
15 words
The ceramic substrate of claim 1 wherein said ceramic substrate is a multilayer ceramic substrate.
Claim 7
Dependent Claim
18 words
The ceramic substrate of claim 1 wherein said electrically conductive I/O pad is a multilayer metallic I/O pad.
Claim 8
Dependent Claim
27 words
The ceramic substrate of claim 6 wherein said I/O pad comprises successive layers of chromium, copper, titanium and gold wherein said gold layer is the outermost layer.
Claim 9
Dependent Claim
15 words
The ceramic substrate of claim 1 wherein said protective polymeric material comprises a polyimide material.
Claim 10
Dependent Claim
24 words
The ceramic substrate of claim 4 wherein said polyimide material is selected from the group consisting of BPDA-PDA, BPDA-ODA, PMDA-ODA and BTDA-ODA type polyimides.
Claim 11
Dependent Claim
14 words
The ceramic substrate of claim 5 wherein said polyimide is a BPDA-PDA type polyimide.
Claim 12
Dependent Claim
163 words
A ceramic substrate having a protective coating on at least one surface thereof comprising: a ceramic substrate having at least one electrically conductive via extending to a surface of said substrate; an electrically conductive capture pad on said surface and in electrical contact with said at least one via; a stress relief layer of polymeric material on said surface and disposed over said electrically conductive capture pad; an electrically conductive I/O pad disposed over said stress relief layer of polymeric material and electrically connected to said at least one via through said capture pad, wherein said I/O pad is susceptible to corrosion that is enhanced or aided by exposure to the atmosphere; an I/O pin brazed to said I/O pad, wherein said I/O pad is larger in cross-section than said I/O pin, said brazed pin having a braze fillet; and a protective layer of polymeric material fully encapsulating said I/O pad, wherein said layer of polymeric material protects said I/O pad from corrosion.
Claim 13
Dependent Claim
163 words
A ceramic substrate having a protective coating on at least one surface thereof comprising: a ceramic substrate having at least one electrically conductive via extending to a surface of said substrate; an electrically conductive capture pad on said surface and in electrical contact with said at least one via; a stress relief layer of polymeric material on said surface and disposed over said electrically conductive capture pad; an electrically conductive I/O pad disposed over said stress relief layer of polymeric material and electrically connected to said at least one via through said capture pad, wherein said I/O pad is susceptible to corrosion that is enhanced or aided by exposure to the atmosphere; an I/O pin brazed to said I/O pad, wherein said I/O pad is larger in cross-section than said I/O pin, said brazed pin having a braze fillet; and a protective layer of polymeric material fully encapsulating said I/O pad, wherein said layer of polymeric material protects said I/O pad from corrosion.
Claim 14
Dependent Claim
21 words
The ceramic substrate of claim 11 wherein said polymeric material encapsulates at least a portion of said surface of said substrate.
Claim 15
Dependent Claim
19 words
The ceramic substrate of claim 11 wherein said polymeric material encapsulates at least a portion of said braze fillet.
Claim 16
Dependent Claim
16 words
The ceramic substrate of claim 11 wherein said surface is a bottom surface of said substrate.
Claim 17
Dependent Claim
15 words
The ceramic substrate of claim 11 wherein said ceramic substrate is a multilayer ceramic substrate.
Claim 18
Dependent Claim
18 words
The ceramic substrate of claim 11 wherein said electrically conductive I/O pad is a multilayer metallic I/O pad.
Claim 19
Dependent Claim
27 words
The ceramic substrate of claim 16 wherein said I/O pad comprises successive layers of chromium, copper, titanium and gold wherein said gold layer is the outermost layer.
Claim 20
Dependent Claim
15 words
The ceramic substrate of claim 11 wherein said protective polymeric material comprises a polyimide material.
Claim 21
Dependent Claim
24 words
The ceramic substrate of claim 18 wherein said polyimide material is selected from the group consisting of BPDA-PDA, BPDA-ODA, PMDA-ODA and BTDA-ODA type polyimides.
Claim 22
Dependent Claim
14 words
The ceramic substrate of claim 19 wherein said polyimide is a BPDA-PDA type polyimide.
Claim 23
Independent Claim
123 words
A method of protecting a ceramic substrate from corrosion, the ceramic substrate of the type having a plurality of electrically conductive vias extending to a surface of the substrate, a multilayer metallic I/O pad electrically connected to at least one of the vias, the I/O pad being susceptible to corrosion that is enhanced or aided by exposure to the atmosphere, and an I/O pin brazed to the I/O pad, the brazed pin having a braze fillet, the method comprising the step of: encapsulating fully the I/O pad with a protective layer of polymeric material, wherein said layer of polymeric material protects the I/O pad from corrosion; and plasma ashing the pin to remove any polymeric material which might be present on the pin.
Claim 24
Independent Claim
123 words
A method of protecting a ceramic substrate from corrosion, the ceramic substrate of the type having a plurality of electrically conductive vias extending to a surface of the substrate, a multilayer metallic I/O pad electrically connected to at least one of the vias, the I/O pad being susceptible to corrosion that is enhanced or aided by exposure to the atmosphere, and an I/O pin brazed to the I/O pad, the brazed pin having a braze fillet, the method comprising the step of: encapsulating fully the I/O pad with a protective layer of polymeric material, wherein said layer of polymeric material protects the I/O pad from corrosion; and plasma ashing the pin to remove any polymeric material which might be present on the pin.
Claim 25
Dependent Claim
29 words
The method of claim 21 wherein the step of encapsulating includes encapsulating at least a portion of the surface of the substrate with said protective layer of polymeric material.
Claim 26
Dependent Claim
27 words
The method of claim 21 wherein the step of encapsulating includes encapsulating at least a portion of the braze fillet with said protective layer of polymeric material.
Claim 27
Dependent Claim
14 words
The method of claim 21 wherein said protective polymeric material comprises a polyimide material.
Claim 28
Dependent Claim
23 words
The method of claim 24 wherein said polyimide material is selected from the group consisting of BPDA-PDA, BPDA-ODA, PMDA-ODA and BTDA-ODA type polyimides.
Claim 29
Dependent Claim
13 words
The method of claim 25 wherein said polyimide is a BPDA-PDA type polyimide.
Claim 30
Dependent Claim
18 words
The method of claim 21 wherein the multilayer metallic I/O pad is protected during said plasma ashing step.
Claim 31
Dependent Claim
25 words
The method of claim 27 wherein the multilayer metallic I/O pad is protected by a perforated mask placed over the pinned side of the substrate.
Claim 32
Dependent Claim
21 words
The method of claim 28 wherein the perforated metal mask is made of a material that is resistant to plasma ashing.
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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) | 1996-03-22 | 1996-09-21 | 1997-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-03-22 | 2000-09-21 | 2001-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-03-22 | 2004-09-21 | 2005-03-23 | $7700.00 | Window Closed / Lapsed |