US4954200A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making drill back-up material for small bore drilling of circuit boards
Assignee: General Electric Co
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Filing: 1988-12-22
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Granted: 1990-09-04
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Expires: 2008-12-22
Abstract
Abstract Disclosed is an improved back-up sheet for backing a workpiece during a small bore drilling process. The sheet also possesses electrical properties making it an ideal candidate as a laminate (reinforcing layer or bonding sheet) in the construction of multi-layer printed wiring boards. The sheet or laminate comprises the cured residue of: (a) polyphenylene oxide; (b) a bisphenol A-type epoxy resin; and (c) an amine hardener for said epxoy resin, the weight ratio of a:b+c ranging from about 1:10 to 1:2.
Inventors
- 👤 Carl E. Trewiler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:37
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/0011; H05K3/0044; H05K3/0047; B; B23; B23B; B23B35/00; B23B35/005; H05K2203/00; H05K2203/02; H05K2203/0214; Y; Y10; Y10S; Y10S408/00; Y10S408/704; Y10T; Y10T156/00; Y10T156/11; Y10T156/1168; Y10T156/1179; Y10T156/1184; Y10T156/19; Y10T156/1961; Y10T156/1967; Y10T408/00; Y10T408/03
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
105 words
In a method for small bore drilling of a workpiece wherein back-up sheets are placed on both sides of said workpiece during said drilling, the improvement for making said back-up sheets for backing said workpiece during said small bore drilling process which comprises: (a) disposing the uncured ingredients for said sheet on the matte side of an electrodeposited metal foil; (b) pressing and heating the ingredients/foil formed in step (a) to at least partially cure said ingredients for forming said sheet; and (c) removing said metal foil from said sheet for said sheet to be used as a backing during said small bore drilling process.
Claim 2
Dependent Claim
105 words
In a method for small bore drilling of a workpiece wherein back-up sheets are placed on both sides of said workpiece during said drilling, the improvement for making said back-up sheets for backing said workpiece during said small bore drilling process which comprises: (a) disposing the uncured ingredients for said sheet on the matte side of an electrodeposited metal foil; (b) pressing and heating the ingredients/foil formed in step (a) to at least partially cure said ingredients for forming said sheet; and (c) removing said metal foil from said sheet for said sheet to be used as a backing during said small bore drilling process.
Claim 3
Dependent Claim
13 words
The method of claim 1 wherein said metal foil comprises electrodeposited copper foil.
Claim 4
Dependent Claim
40 words
The method of claim 1 wherein said uncured ingredients comprise polyphenylene oxide, bis-phenol A-type epoxy resin, and an amine hardener for said epoxy resin, wherein the weight ratio of polyphenylene oxide to epoxy resin/hardener ranges from about 1:10 to 1:2.
Claim 5
Dependent Claim
40 words
The method of claim 2 wherein said uncured ingredients comprise polyphenylene oxide, bis-phenol A-type epoxy resin, and an amine hardener for said epoxy resin, wherein the weight ratio of polyphenylene oxide to epoxy resin/hardener ranges from about 1:10 to 1:2.
Claim 6
Dependent Claim
25 words
The method of claim 3 wherein said epoxy resin comprises a diglycidyl ether of bis-phenol A/tetrabromobis-phenol A adduct and said hardener comprises a bismaleimide-triazene compound.
Claim 7
Dependent Claim
25 words
The method of claim 4 wherein said epoxy resin comprises a diglycidyl ether of bis-phenol A/tetrabromobis-phenol A adduct and said hardener comprises a bismaleimide-triazene compound.
References Cited (Backward Citations)
US3475513A
Cited
US3700341A
Cited
JPS57101319A
Cited
US4496695A
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US4354895A
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US4555414A
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EP0126494A1
Cited
US4567216A
Cited
US4737208A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-09-03 | 1994-03-05 | 1994-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-03 | 1998-03-05 | 1998-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-03 | 2002-03-05 | 2002-09-04 | $7700.00 | Window Closed / Lapsed |