METHOD FOR FABRICATING BUMP STRUCTURE WITHOUT UBM UNDERCUT

摘要

A method for fabricating bump structure without UBM undercut uses an electroless Cu plating process to selectively form a Cu UBM layer on a Ti UBM layer within an opening of a photoresist layer. After stripping the photoresist layer, there is no need to perform a wet etching process on the Cu UBM layer, and thereby the UBM structure has a non-undercut profile.