Patent EP0177686A2 successfully refreshed from Google Patents.
EP0177686A2
Expired / Lapsed
EP
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Process for bonding metals to electrophoretically deposited coatings, and printed circuit with plated through holes produced thereby
Assignee: Kollmorgen Corp
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Filing: 1985-07-16
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Granted: —
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Expires: 2005-07-16
Abstract
Abstract An economical process for producing metal plated through holes in metal core circuit boards is claimed which permits the formation of small holes and fine conductor lines. A metal sheet, which will become the core of a metal core circuit board, is provided with insulation layers on both sides, and through holes are provided through the insulation layers. The process involves incorporating fillers in a resinous coating solution which is electrophoretically applied to the hole walls to form an insulating layer of uniform thickness thereon. An increased diameter in the metal hole portion of each hole acts to restrict flow of the filled resinous solution during cure resulting in a straight hole wall. The coating is adhesion promoted and a metal layer is deposited thereon.
Inventors
- 👤 James J. Arachtingi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 14:27
CPC Classifications
H; H05; H05K; H05K1/00; H05K1/02; H05K1/03; H05K1/05; H05K1/056; C; C25; C25D; C25D13/00; H05K3/00; H05K3/44; H05K3/445; H05K2201/00; H05K2201/02; H05K2201/0203; H05K2201/0206; H05K2201/0209; H05K2201/09; H05K2201/09209; H05K2201/095; H05K2201/09581; H05K2203/00; H05K2203/03; H05K2203/0315; H05K2203/0323; H05K2203/11; H05K2203/1184; H05K2203/13; H05K2203/1333; H05K2203/135; H05K2203/14; H05K2203/1438; H05K3/38; H05K3/382; H05K3/385; H05K3/40; H05K3/42; H05K3/422; H05K3/425; H05K3/427; Y; Y10; Y10S; Y10S428/00; Y10S428/901; Y10T; Y10T428/00; Y10T428/24; Y10T428/24273; Y10T428/24802; Y10T428/24917
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
255 words
A process for producing a printed circuit network on an insulating metal substrate comprising the steps of providing the surface of a metal panel with one or more insulating top layers to form a metal core substrate; providing said substrate with one or more holes for through connections; etching the hole walls defined by the core to enlarge the hole diameter by a predetermined amount only in the portion of the hole(s) extending through said metal core; electrophoretically depositing a resinous coating from a solution thereof on the etched portion of said hole wall(s); curing the resinous coating; and forming the printed circuit network on the surface of the insulating layers and in the wall(s) of said hole(s), characterized in that the resin solution comprises a solid filler in a concentration from 1 to 25 % by weight of the cured resinous coating, having an average particle size not exceeding 5 microns, said filler being non-reactive with and uniformly dispersed in the resin solution, and capable of improving the adhesion of a metal layer to the electrophoretically deposited, cured and adhesion promoted resinous coating surface; said coating layer containing the filler having a volume resistivity greater than 10 4 Megohm-cm; and that it further comprises the steps of adhesion promoting the surface of the cured resinous coating layer containing said filler thus creating a hydrophilic, micro-etched surface; depositing a metal layer on the resinous coating of the hole wall(s) and on the insulating top layers or selected parts thereof; and forming said printed circuit network.
Claim 2
Dependent Claim
255 words
A process for producing a printed circuit network on an insulating metal substrate comprising the steps of providing the surface of a metal panel with one or more insulating top layers to form a metal core substrate; providing said substrate with one or more holes for through connections; etching the hole walls defined by the core to enlarge the hole diameter by a predetermined amount only in the portion of the hole(s) extending through said metal core; electrophoretically depositing a resinous coating from a solution thereof on the etched portion of said hole wall(s); curing the resinous coating; and forming the printed circuit network on the surface of the insulating layers and in the wall(s) of said hole(s), characterized in that the resin solution comprises a solid filler in a concentration from 1 to 25 % by weight of the cured resinous coating, having an average particle size not exceeding 5 microns, said filler being non-reactive with and uniformly dispersed in the resin solution, and capable of improving the adhesion of a metal layer to the electrophoretically deposited, cured and adhesion promoted resinous coating surface; said coating layer containing the filler having a volume resistivity greater than 10 4 Megohm-cm; and that it further comprises the steps of adhesion promoting the surface of the cured resinous coating layer containing said filler thus creating a hydrophilic, micro-etched surface; depositing a metal layer on the resinous coating of the hole wall(s) and on the insulating top layers or selected parts thereof; and forming said printed circuit network.
Claim 3
Dependent Claim
23 words
The process as claimed in claim 1 characterized in that the particle size of the filler is finer than 1 micron in diameter.
Claim 4
Dependent Claim
25 words
The process as claimed in claim 1, characterized in that the solid filler comprises from 3% to 10% by weight of the cured resinous coating.
Claim 5
Dependent Claim
34 words
The process as claimed in claim 1, characterized in that the filler is added to the solution of the cathodic coating composition as a concentrate dispersed in a small portion of said coating solution.
Claim 6
Dependent Claim
32 words
The process as claimed in claim 1, characterized in that the solid filler is selected from the group consisting of clays, silicas, aluminas, silicates, earths, barium sulfate, zinc oxide and titanium dioxide.
Claim 7
Dependent Claim
30 words
The process as claimed in claim 1, characterized in that the thickness of the electrophoretically deposited coating, after curing, is at least 0,025 mm and preferably 0,035 to 0,12 mm.
Claim 8
Dependent Claim
21 words
The process as claimed in claim 1, characterized in that the adhesion promotion is accomplished by oxidation of the cured coating.
Claim 9
Dependent Claim
25 words
The process as claimed in claim 7, characterized in that the oxidation is accomplished by an aqueous oxidizing solution preferably comprising a hexavalent chromium compound.
Claim 10
Dependent Claim
33 words
The process as claimed in claim 1, characterized in that the adhesion promotion is accomplished by pretreatment with an acid solution followed by an oxidizing solution, said second oxidizing solution comprising hexavalent chromium.
Claim 11
Dependent Claim
36 words
The process as claimed in claim 1, characterized in that the metal layer deposited on the adhesion promoted surface of the resinous coating adheres to said coating with a peel strength of at least 0,1 N/mm.
Claim 12
Dependent Claim
33 words
The process as claimed in claim 1, characterized in that the solution comprises a thermosetting resin selected from the group consisting of epoxy, acrylic, alkyd, epoxy-acrylate, polyimide, polyester, polyamide-imide resins and combinations thereof.
Claim 13
Dependent Claim
29 words
The process as claimed in claim 1, characterized in that the solution comprises a thermoplastic resin selected from the group consisting of acrylates, polysulfones, polyetherether ketones and combinations thereof.
Claim 14
Dependent Claim
138 words
A printed circuit article comprising a metal core; insulating layers superimposed on the surfaces of the metal core; at least one hole through the insulating layers and the metal core, the hole diameter defined by the metal core being greater than the hole diameter defined by the insulating layers; the metal wall(s) of said hole(s) being coated with an electrophoretically deposited resinous coating, said resinous coating comprising a thermosetting resin and an insulating filler dispersed therein; a metal conductor pattern adhered with a peel strength of at least 0,1 N/mm on the surface of the insulating layer, on the resinous coating and the insulating layer forming the surface of the hole wall(s), the metal conductor pattern being continuous and free of blisters, the resistance between the metal conductor pattern and the metal core being 10 gigaohm or greater.
Claim 15
Dependent Claim
138 words
A printed circuit article comprising a metal core; insulating layers superimposed on the surfaces of the metal core; at least one hole through the insulating layers and the metal core, the hole diameter defined by the metal core being greater than the hole diameter defined by the insulating layers; the metal wall(s) of said hole(s) being coated with an electrophoretically deposited resinous coating, said resinous coating comprising a thermosetting resin and an insulating filler dispersed therein; a metal conductor pattern adhered with a peel strength of at least 0,1 N/mm on the surface of the insulating layer, on the resinous coating and the insulating layer forming the surface of the hole wall(s), the metal conductor pattern being continuous and free of blisters, the resistance between the metal conductor pattern and the metal core being 10 gigaohm or greater.
References Cited (Backward Citations)
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