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 expose the first under-bump metallic layer. A plurality of solder bumps is implanted onto the second under-bump metallic layer. The exposed first under-bump metallic layer is removed so that only the first under-bump metallic layer underneath the second under-bump metallic layer remains.