General Electric Company

Rca Inc.

David Sarnoff Research Center, Inc.

Simon M Boardman

Ashok Narayan Prabhu

Kenneth Warren Hang

Edward J Conlon

Valerie A Pendrick

In the manufacture of printed circuit boards, a first photoresist post is patterned on the substrate where via holes are to be made. A dielectric layer is put down, a second photoresist layer patterned so as to have openings over and in alignment with the photoresist posts, and the dielectric removed from the via holes. Barrier layers to reduce interaction between layers of copper, dielectric and photoresist during filling of the via holes with a conductor via fill ink are also described.

Manufacture of printed circuit boards

An improved copper via-fill ink for forming post-ups in a thick dielectric layer separating two patterned layers of copper conductor in a multilayer circuit assembly is provided. The via-fill ink comprises copper powder, a suitable organic vehicle and a glass frit consisting of a devitrifying glass and a vitreous glass. The devitrifying glass is a zinc-magnesium-barium-aluminum-zirconium-phosphosilicate glass and the vitreous glass is a barium-calcium-borosilicate glass.

Thick film copper via-fill inks

An improved ink composition suitable for the formation of thick film resistor inks which can be terminated directly to copper foil conductors. The subject compositions comprise an epoxy resin, conductive carbon particles, a suitable solvent and particulate alumina, wherein the alumina is present in an amount at least equal to the resin content on a weight basis.

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Holland, PA, United States of America

Simon M Boardman