Abstract: A process is disclosed which is beneficially employed in sensitizing plastic surfaces prior to etching which sensitization enhances the coverage and adhesiveness of the subsequent plate. The composition and process proposed use Limonene, solutions of Limonene and Emulsions of Limonene for the sensitizer.

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.