US Patent 7452822 Via plug formation in dual damascene process

A method for forming a dual damascene structure in a semiconductor device manufacturing process where via plugs which may include a thickness portion of a plug filling material overlying the process surface is formed by diffusing an acid into a plug filling material layer followed by reacting the acid with the plug filling material layer to form a soluble portion which is then removed using a solvent. A remaining portion of the plug filling material is cured and a BARC layer may be formed over the process surface prior to patterning trenches in an overlying resist layer and forming a dual damascene structure.