Patent US228081A successfully refreshed from Google Patents.
Patent US4756930A successfully refreshed from Google Patents.
US4756930A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing printed circuit board thru-holes
Assignee: MacDermid Acumen Inc
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Filing: 1986-06-23
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Granted: 1988-07-12
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Expires: 2006-06-23
Abstract
Abstract The thru-holes of a multilayer printed circuit board, comprised of a laminate of epoxy resin and metal innerlayers, are provided with a conductive metal coating by a process in which the holes are first subjected to a desmearing process to remove smear from the copper innerlayers, followed by treatment of the hole surfaces with a solvent for the resin, treatment of the hole surfaces with a highly alkaline permanganate solution, and deposition of a conductive metal layer on the hole surfaces.
Inventors
- 👤 Peter E. Kukanskis
- 👤 Harold L. Rhodenizer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:54
CPC Classifications
C; C23; C23C; C23C18/00; C23C18/16; C23C18/18; C23C18/20; C23C18/22; H; H05; H05K; H05K3/00; H05K3/0011; H05K3/0055; H05K2203/00; H05K2203/02; H05K2203/025; H05K2203/07; H05K2203/0779; H05K2203/0783; H05K2203/0786; H05K2203/0789; H05K2203/0793; H05K2203/0796; H05K2203/09; H05K2203/095; H05K3/40; H05K3/42; H05K3/429
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
119 words
A process for treating the surfaces of a thru-hole formed in a multilayer printed circuit board substrate, said substrate comprised of a conductive metal and insulating resin laminate having one or more conductive metal innerlayers, so as to condition said thru-hole surfaces for subsequent deposition of a conductive metal coating thereon, comprising the steps of: (a) subjecting said thru-hole to a desmearing process to remove resin material from exposed metal innerlayer surfaces in said thru-hole brought about by formation of the thru-hole; (b) thereafter contacting said thru-hole surfaces with a solvent which is capable of being absorbed by the resin; and (c) thereafter contacting said thru-hole surfaces with an alkaline permanganate solution having a pH in excess of 13.
Claim 2
Dependent Claim
119 words
A process for treating the surfaces of a thru-hole formed in a multilayer printed circuit board substrate, said substrate comprised of a conductive metal and insulating resin laminate having one or more conductive metal innerlayers, so as to condition said thru-hole surfaces for subsequent deposition of a conductive metal coating thereon, comprising the steps of: (a) subjecting said thru-hole to a desmearing process to remove resin material from exposed metal innerlayer surfaces in said thru-hole brought about by formation of the thru-hole; (b) thereafter contacting said thru-hole surfaces with a solvent which is capable of being absorbed by the resin; and (c) thereafter contacting said thru-hole surfaces with an alkaline permanganate solution having a pH in excess of 13.
Claim 3
Dependent Claim
139 words
A process for providing a full, smooth, adherent layer of conductive metal on the surfaces of a thru-hole formed in a multilayer printed circuit board substrate, said substrate being comprised of a conductive metal and insulating resin laminate having one or more innerlayes of said conductive metal, and wherein said thru-holes formed in said multilayer printed circuit board substrate have been previously subjected to a desmearing process to remove resin material fromexpose dmetal innerlayer surfaces in said thru-hole brought about by formation of the thru-hole, said process comprising the steps of: (a) contacting said thru-hole surfaces with a solvent which is capable of being absorbed by said resin; (b) thereafter contacting said thru-hole surfaces with an alkaline permanganate solution having a pH in excess of 13; and (c) thereafter electrolessly depositing a conductive metal layer onto said thru-hole surfaces.
Claim 4
Dependent Claim
139 words
A process for providing a full, smooth, adherent layer of conductive metal on the surfaces of a thru-hole formed in a multilayer printed circuit board substrate, said substrate being comprised of a conductive metal and insulating resin laminate having one or more innerlayes of said conductive metal, and wherein said thru-holes formed in said multilayer printed circuit board substrate have been previously subjected to a desmearing process to remove resin material fromexpose dmetal innerlayer surfaces in said thru-hole brought about by formation of the thru-hole, said process comprising the steps of: (a) contacting said thru-hole surfaces with a solvent which is capable of being absorbed by said resin; (b) thereafter contacting said thru-hole surfaces with an alkaline permanganate solution having a pH in excess of 13; and (c) thereafter electrolessly depositing a conductive metal layer onto said thru-hole surfaces.
Claim 5
Dependent Claim
26 words
The process according to either of claims 1 or 2 wherein said desmearing process comprises contact of said thru-hole surfaces with a solution comprising sulfuric acid.
Claim 6
Dependent Claim
26 words
The process according to either of claims 1 or 2 wherein said desmearing process comprises contact of said thru-hole surfaces with a solution comprising chromic acid.
Claim 7
Dependent Claim
19 words
The process according to either of claims 1 or 2 wherein said desmearing process comprises a mechanical desmearing process.
Claim 8
Dependent Claim
15 words
The process according to either of claims 1 or 2 wherein said solvent comprises m-pyrol.
Claim 9
Dependent Claim
15 words
The process according to either of claims 2 or 3 wherein said solvent comprises dimethylformamide.
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) | 1991-07-12 | 1992-01-11 | 1992-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-12 | 1996-01-11 | 1996-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-12 | 2000-01-11 | 2000-07-12 | $7700.00 | Window Closed / Lapsed |