Abstract: Disclosed herein are compositions for use in a process for preparing the surfaces of through-holes in printed circuit boards (especially multilayer printed circuit boards) preparatory to a treatment of the through-holes with an alkaline permanganate solution, the composition being in the form of a substantially homogeneous, substantially clear mixture comprised of a substantially water-immiscible organic material which acts upon the insulating substrate of the circuit board, water, an alkakli metal compound and a surfactant component. The composition is useful as a pretreatment prior to the use of an alkaline permanganate solution in a desmearing and/or etch-back process, a combined desmearing-conditioning process, or a conditioning process following a separate desmearing process.

Abstract: Disclosed herein is a process for preparing the surfaces of through-holes in printed circuit boards (especially multilayer printed circuit boards) for subsequent metallization, in which the through-hole surfaces are treated with a substantially water-immiscible organic liquid which acts upon the insulating substrate of the board, and preferably in the form of a substantially homogeneous, clear mixture comprised of the water-immiscible organic liquid, water, an alkali metal compound and a surfactant component, followed by treatment of the through-hole surfaces with an alkaline permanganate solution. The process can be used as a desmearing and/or etch-back process, a combined desmearing-conditioning process, or a conditioning process following a separate desmearing process.

Abstract: An electrolytic oxidation process for producing alkali metal permanganate from alkali metal manganate, and particularly for effecting such production to regenerate a permanganate working bath, such as used in desmearing, etch-back or cleaning processes in the manufacture of printed circuits, which has reached a level of decreased working efficiency, wherein an aqueous alkaline soluiton of manganate in alkali metal hydroxide is electrolytically oxidized using a non-sacrificial anode and a cathode compised of an alkali-resistant electrode immersed in a concentrated aqueous solution of sodium hydroxide in a container porous to ions.

Abstract: A process is described for the electrolytic oxidation of manganese dioxide to an alkali metal permanganate by carrying out the electrolysis in dilute alkali metal hydroxide solution using a non-sacrificial anode and a cathode comprising an alkali-resistant electrode immersed in concentrated alkali metal hydroxide solution in a porous container. The process is particularly adapted to the regeneration of alkali metal permanganate from manganese dioxide which has been precipitated during use of a permanganate bath as an etchant in the fabrication of printed circuit boards and like purposes.