Abstract: The present invention is directed to an improved method for treating an oxidized surface of a copper film for bonding to a resinous layer such as in the formation of a single-sided, double-sided, or multi-layered circuit board and to a layered product produced by the method. In particular, the method of the present invention comprises the steps of: contacting the oxidized surface of a copper film, having cupric oxide whiskers protruding therefrom, with an acidic reducing solution having a pH of 1 to 6.5 and having an effective amount of a water soluble thiosulfate reducing agent dissolved therein to provide a reduced copper surface; and rinsing the reduced copper surface with an acidic solution to produce a rinsed and reduced copper surface having reduced whiskers protruding therefrom, said reduced whiskers each being a mix of cuprous oxide and metallic copper. Preferably, the reduced surface is treated with a passivating agent to minimize any reoxidation prior to laminate formation.

Abstract: A composition and process for preparing a non-conductive substrate for electroplating. The composition comprises 0.1 to 20% by weight carbon (e.g. graphite or carbon black) having a mean particle size within the range of 0.05 to 50 microns; optionally, 0.01 to 10% by weight of a water soluble or dispersible binding agent for binding to the carbon particles; optionally, an effective amount of an anionic dispersing agent for dispersing the bound carbon particles; optionally, an amount of a surfactant that is effective for wetting the through hole; a pH within the range of 4-14; and an aqueous dispersing medium. Improved methods of applying the composition to a through hole, a printed wiring board having a through hole treated with the composition, and a method of fixing a carbon coating deposited on a through hole using an acid solution are also disclosed.

Abstract: The present invention is directed to an improved composition and process for preparing a non-conductive substrate for electroplating. The composition comprises 0.1 to 20% by weight graphite having a mean particle size within the range of 0.05 to 50 microns; 0.01 to 10% by weight of a water soluble or dispersible binding agent for binding to the graphite particles; an effective amount of an anionic dispersing agent for dispersing the bound graphite particles; a pH within the range of 4-14; and an aqueous dispersing medium. Optionally, the composition may contain an amount of a surfactant that is effective for wetting the through hole. The resulting graphite dispersion is capable of uniformly coating the through holes in either a double-sided or multi-layer circuit board prior to electroplating. Through holes that were treated with the disclosed graphite dispersion prior to electroplating were free of visible voids after electroplating.