Macdermid, Incorporated

Harold L Rhodenizer

Peter E Kukanskis

John J Grunwald

Eugene D D'Ottavio

Michael S Lombardo

Printed circuit boards containing thru-holes requiring metallization are manufactured by first applying to the board material an alkaline strippable resist in a predetermined desired pattern, thereafter applying material catalytic to subsequent metallization, thereafter treating the board with an aqueous alkaline solution to remove catalytic material from resist surfaces without adversely affecting the catalyst at non-resist areas, and then metallizing the non-resist areas. The ability to preliminarily apply the resist pattern before catalyst application, metallization, etc., yet prevent metallization of the resist, enables the manufacturing process to proceed straight through the activation, metallization, etc. steps without need for interruption for resist application.

Method for manufacture of printed circuit boards

Disclosed are an improved activation composition for preparing substrates for metallization in an electroless plating bath. Also disclosed is an improved process for activating substrates prior to metallization and an improved process for metallizing employing the improved activating process. Electroless deposition, which involves chemically reducing ions of the metal to be plated from a plating bath and onto an activated substrate surface, is improved by employing an organic acid in the activating bath which activates the substrate surface. Preferred activating baths contain palladium halide ions to provide a catalytic surface on the substrate, stannous halide ions to provide a protective sol, a source of additional halide ions, and an organic acid such as citric or tartaric acids. The composition and process enable the elimination of a typically-required acceleration step, but yet provide consistently high quality results especially with substrates having through holes requiring coating, such as printed circuit boards requiring a plating of copper.

Catalyst solutions for activating non-conductive substrates and

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.

Process for preparing printed circuit board thru-holes

A process is disclosed comprising laminating an anodically treated aluminum surface against a thermoset plastic substrate, whereby the surface of the substrate after chemically removing the aluminum has an improved affinity for the adherence thereon of electrolessly deposited metal films.

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Bethlehem, CT, United States of America

Harold L Rhodenizer