Motorola Corporation

Yaroslaw A Magera

Vernon L Brown

Jovica Savic

Julia S Johnson

A method for metallizing selected areas of a two dielectric layered sequentially processed circuit board (100) involves exposing the resin A (204) by photo-definition. The resin A (204) contains 10% or less, by weight Cu.sub.2 O particles (300) mixed uniformly throughout the resin. The circuit board (100) is sprayed with a reduction solution to form catalytic islands (301) predominately of Cu.sup.0 or CuH. The circuit board (100) is then electrolessly plated to form conductors, pads or vias, where the resin A (204) has been exposed. The reduction solution includes a primary reducing agent, a secondary reducing agent and a capturing agent. The reduction solution preferably has a pH of 10 or greater. The primary reducing agent is preferably a borohydride. The secondary reducing agent is preferably an iodide and the capturing agent is a chelating agent preferably EDTA.

Method and reduction solution for metallizing a surface

A unique process metallizes a substrate surface using a reducing agent including a borohydride to reduce, in a starved reaction, metal oxide particles (300) substantially uniformly distributed and at a controlled concentration in a particle-filled resin (204) to produce catalytic island areas (301). The catalytic island areas (301) formed have a surface resistivity greater than 10.sup.6 ohms per square. These catalytic island areas (301) are then electrolessly metallized to a predetermined thickness, such that adjacent catalytic island areas (301) are interconnected and form metallic features, such as pads, vias (213), and conductors (210, 211 and 212). The starved reaction limits the reduction of metal oxide particles (300) to catalytic island areas (301) and prevents migration of reduced metal beyond each of the exposed surfaces of particle-filled resin (204) which are to be metallized.

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Arlington Heights, IL, United States of America

Yaroslaw A Magera