US Patent 7932171 Dual metal stud bumping for flip chip applications

A method for forming a stud bumped semiconductor die is disclosed. The method includes forming a ball at the tip of a coated wire passing through a hole in a capillary, where the coated wire has a core and an oxidation-resistant coating. The formed ball is pressed to the conductive region on the semiconductor die. The coated wire is cut, thereby leaving a conductive stud bump on the conductive region, where the conductive stud bump includes an inner conductive portion and an outer oxidation-resistant layer.