Aqueous quaternary ammonium hydroxide as a screening mask cleaner

This invention relates to cleaning of objects that relate to semiconductor printing, such as, for example, screening masks. This invention is basically directed to removing, for example, an organic polymer-metal composite paste from screening masks used in printing conductive metal pattern onto ceramic green sheet in the fabrication of semiconductor packaging substrates. More particularly, this invention is concerned with automated in-line cleaning of paste screening masks with aqueous alkaline solution of a quaternary ammonium hydroxide as an environmentally friendly alternative to non-aqueous organic solvents based cleaning in screening operations for the production multilayer ceramic (MLC) substrates. This invention relates to the cleaning of objects that relate to semiconductor printing, such as, for example, screening masks. This invention is basically directed to removing, for example, an organic polymer-metal composite paste from screening masks used in printing conductive metal patterns onto ceramic green sheets in the fabrication of semiconductor packaging substrates. More particularly, this invention is concerned with the automated in-line cleaning of paste screening masks with an aqueous alkaline solution of a quaternary ammonium hydroxide as a more environmentally friendly alternative to non-aqueous organic solvents-based cleaning in screening operations for the production multilayer ceramic (MLC) substrates.