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Additive Plating on Chromium for Circuitizing Non-Epoxy Substrates

IP.com Disclosure Number: IPCOM000037151D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

McHatton, RC: AUTHOR

Abstract

Disclosed is a process for circuitizing non-epoxy substrates, such as alumina ceramics or polymer thin films, whereby copper is plated in an additive process onto a conductive layer of vacuum deposited chromium while simultaneously removing the chromium oxide layer and its application to the circuitization of substrates which show chromium selective adhesion, such as alumina ceramics, polyimide and fluorinated polymer films.

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Additive Plating on Chromium for Circuitizing Non-Epoxy Substrates

Disclosed is a process for circuitizing non-epoxy substrates, such as alumina ceramics or polymer thin films, whereby copper is plated in an additive process onto a conductive layer of vacuum deposited chromium while simultaneously removing the chromium oxide layer and its application to the circuitization of substrates which show chromium selective adhesion, such as alumina ceramics, polyimide and fluorinated polymer films.

Direct additive plating of copper onto such substrates suffers from the inherently weak adhesion of copper to these substrates. The ability to additively plate on chromium introduces a new route to circuitizing these substrates additively which takes advantage of the excellent adhesion of the underlying chromium layer.

Certain metal surfaces, such as chromium and tungsten, serve as poor electrodes due to electron transfer problems involving their passive oxide coatings. For this reason, direct acid copper plating on chromium requires such large overpotentials that hydrogen evolution dominates in the plating environment and the deposit produced has very little adhesion. These metals exhibit the interesting property that, when in contact with a dissimilar metal, such as copper, the open circuit potential of the bimetallic electrode becomes virtually identical to that of the other metal. This occurs because the electrode responds to that electrochemical reaction with the greatest...