A method of forming bumps on the active surface of a silicon wafer. A first under-bump metallic layer is formed over the active surface of the wafer. A second under-bump metallic layer is formed over the first under-bump metallic layer. A portion of the second under-bump metallic layer is removed to...http://www.google.com/patents/US6989326?utm_source=gb-gplus-sharePatent US6989326 - Bump manufacturing method
