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Printed Circuit Base

IP.com Disclosure Number: IPCOM000093470D
Original Publication Date: 1967-Oct-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Marshall, JH: AUTHOR

Abstract

The method results in a printed circuit base of the type in which certain portions such as the walls of apertures are simply coated by a conductive coating. The process consists of impregnating a fibrous insulating material with a methylethyl ketone solution containing palladium chloride. The suspension mixture coats the fibers of the material with a sensitizer coating of palladium chloride after the MEK, methylethyl ketone, evaporates. After drying, the fibrous material is roller-coated with epoxy resin and further dried. The epoxy-coated fibrous material is then copper clad to form a copper clad laminate into which holes are drilled. Subsequently, the laminate is immersed in an electroless copper solution so that the holes and surfaces not copper clad become coated with the copper conductor.

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Printed Circuit Base

The method results in a printed circuit base of the type in which certain portions such as the walls of apertures are simply coated by a conductive coating. The process consists of impregnating a fibrous insulating material with a methylethyl ketone solution containing palladium chloride. The suspension mixture coats the fibers of the material with a sensitizer coating of palladium chloride after the MEK, methylethyl ketone, evaporates. After drying, the fibrous material is roller-coated with epoxy resin and further dried. The epoxy-coated fibrous material is then copper clad to form a copper clad laminate into which holes are drilled. Subsequently, the laminate is immersed in an electroless copper solution so that the holes and surfaces not copper clad become coated with the copper conductor. The resulting adhesion of the copper to the unclad portions of the laminate is superior to the adhesion obtained with other known methods. The MEK, which is used as the vehicle to dissolve and suspend the palladium salts, is neutral in reaction in comparison to the previously required acid or alkaline solutions of tin and palladium. These active solutions of tin and palladium preclude their use on some types of fibers. Other organic solvents especially of the ketone family work well but best results are obtained with MEK. Also, gold and platinum salts work as well as palladium.

This method can be further improved by utilizing a phenolic resin instead of...