Process for preparing the through hole walls of a printed wiring board for electroplating

Abstract

Abstract An improvement to the process for electroplating a conductive metal layer to the surface of a non-conductive material which comprises: (a) contacting said printed wiring board having said through holes with an alkaline dispersion of carbon black comprised of: (1) carbon black particles having an average particle diameter of less than about 3.0 microns in said dispersion; (2) an effective dispersing amount of a surfactant which is compatible with said carbon black; and (3) liquid dispersing medium, wherein the amount of carbon black is sufficient to coat substantially all of said non-conducting surfaces and is less than about 4% by weight of said liquid dispersion; (b) separating substantially all of said liquid dispersing medium from said carbon black particles, whereby said particles are deposited on said non-conductive surface in a substantially continuous layer; and (c) electroplating a substantially continuous conductive metal layer over the deposited carbon black layer and said non-conductive surface, thereby electrically connecting said metal layer of said printed wiring board; the improvement which comprises: contacting the non-conducting portions of said through holes immediately before step (a) with a pre-conditioning solution comprising an aqueous solution of an alkaline hydroxide wherein the alkaline hydroxide is present in a sufficient amount to wet said non-conductive portions of said through holes.

Inventors

• 👤 Frank Polakovic
• 👤 Anthony M. Piano

Bibliographic Details