Therefore, the following materials, including, but not limited to, polyimide (PI), benzocyclobutane (BCB), silicon, or other polymers can all be used toform second stress buffer layer 32.Photo-resistor 26 is again used to define the locations of under bump metallurgy (UBM) 34, and an etching technique is applied on second stress buffer layer 32 to expose the second conductive material 30 used as w