US4597988A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing printed circuit board thru-holes
Assignee: MacDermid Acumen Inc
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Filing: 1985-07-26
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Granted: 1986-07-01
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Expires: 2005-07-26
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
2026-11-02 03:01
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: 14
Claim 1
Independent Claim
99 words
A process for depositing a conductive metal layer on the surfaces of a thru-hole formed in a multilayer printed circuit board substrate comprised of a conductive metal and epoxy resin laminate having one or more conductive metal innerlayers, comprising the steps of: (a) subjecting said thru-hole to a desmearing process; (b) thereafter contacting said thru-hole surfaces with a solvent capable of removing resin residue from said surfaces; (c) thereafter contacting said thru-hole surfaces with an alkaline solution comprising potassium permanganate having a pH in excess of 13; and (d) thereafter depositing a conductive metal layer on said thru-hole surfaces.
Claim 2
Dependent Claim
99 words
A process for depositing a conductive metal layer on the surfaces of a thru-hole formed in a multilayer printed circuit board substrate comprised of a conductive metal and epoxy resin laminate having one or more conductive metal innerlayers, comprising the steps of: (a) subjecting said thru-hole to a desmearing process; (b) thereafter contacting said thru-hole surfaces with a solvent capable of removing resin residue from said surfaces; (c) thereafter contacting said thru-hole surfaces with an alkaline solution comprising potassium permanganate having a pH in excess of 13; and (d) thereafter depositing a conductive metal layer on said thru-hole surfaces.
Claim 3
Dependent Claim
22 words
The process according to claim 1 wherein said desmearing process comprises contact of said thru-hole surfaces with a solution comprising sulfuric acid.
Claim 4
Dependent Claim
22 words
The process according to claim 1 wherein said desmearing process comprises contact of said thru-hole surfaces with a solution comprising chromic acid.
Claim 5
Dependent Claim
15 words
The process according to claim 1 wherein said desmearing process comprises a mechanical desmearing process.
Claim 6
Dependent Claim
15 words
The process according to claim 1 wherein said desmearing process comprises a plasma etching process.
Claim 7
Dependent Claim
11 words
The process according to claim 1 wherein said solvent comprises m-pyrol.
Claim 8
Dependent Claim
96 words
A process for treating the surfaces of a thru-hole formed in a multilayer printed circuit board substrate comprised of a conductive metal and epoxy resin laminate having one or more conductive metal innerlayers so as to condition said surfaces for subsequent deposition of a conductive metal coating thereon, comprising the steps of: (a) subjecting said thru-hole to a desmearing process; (b) thereafter contacting said thru-hole surfaces with a solvent capable of removing resin residue from said surfaces; and (c) thereafter contacting said thru-hole surfaces with an alkaline permanganate solution having a pH in excess of 13.
Claim 9
Dependent Claim
96 words
A process for treating the surfaces of a thru-hole formed in a multilayer printed circuit board substrate comprised of a conductive metal and epoxy resin laminate having one or more conductive metal innerlayers so as to condition said surfaces for subsequent deposition of a conductive metal coating thereon, comprising the steps of: (a) subjecting said thru-hole to a desmearing process; (b) thereafter contacting said thru-hole surfaces with a solvent capable of removing resin residue from said surfaces; and (c) thereafter contacting said thru-hole surfaces with an alkaline permanganate solution having a pH in excess of 13.
Claim 10
Dependent Claim
34 words
The process according to claim 7 wherein said desmearing process comprises contact of said thru-hole surfaces with a solution comprised of a material selected from the group consisting of sulfuric acid and chromic acid.
Claim 11
Dependent Claim
15 words
The process according to claim 7 wherein said desmearing process comprises a plasma etching process.
Claim 12
Dependent Claim
11 words
The process according to claim 7 wherein said solvent comprises m-pyrol.
Claim 13
Dependent Claim
15 words
The process according to claim 7 wherein said conductive metal of said laminate is copper.
Claim 14
Dependent Claim
17 words
The process according to claim 11 wherein said conductive metal coating is an electroless copper metal coating.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-06-30 | 1989-12-30 | 1990-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-30 | 1993-12-30 | 1994-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-30 | 1997-12-30 | 1998-07-01 | $7700.00 | Window Closed / Lapsed |