Macdermid, Incorporated

Ppg Industries, Inc.

James A Johnson

Gary B Larson

Brian Jobson

Lance C Sturni

Composition and methods for providing a phosphate conversion coating on a metal surface, particularly a copper surface, characterized in that the phosphating composition includes at least one composition-soluble compound containing vanadium, niobium, tungsten or tantalum. The phosphate conversion coatings so produced are thicker, more durable and more uniform than those produced by known phosphating compositions. The compositions and processes are especially useful for providing a passivating/uniformizing coating layer on copper surfaces to which organic resin is thereafter deposited to serve as a resist in printed circuit fabrication sequences, particularly when the organic resin is an electrophoretically deposited organic resin. Also described is the microetching of copper surfaces with a phosphoric acid/peroxide microetchant preparatory to deposit thereon (or after a further provision of a phosphate conversion coating) of a photoresist which is then imagewise exposed and developed to provide a patterned resist.

Phosphating compositions and processes, particularly for use in

Copper surfaces upon which organic resins are electrophoretically deposited to serve as plating or etch resists in the course of manufacturing printed circuits, are preliminarily provided with a uniformizing/passivating coating layer, such as a layer of copper oxide or phosphate conversion coating, over which the organic resin is electrophoretically deposited, resulting in the organic resin being deposited with substantial uniformity in thickness and properties.

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Litchfield, CT, United States of America

James A Johnson