{TAIL ~ A solder alloy} making {HEAD ~ layer} for preventing dissolving and diffusion of tin into tin based lead free solder is thinly formed on a UBM layer 
{ TAIL ~ A solder alloy } making { HEAD ~ layer } for preventing dissolving and diffusion of tin into tin based lead free solder is thinly formed on a UBM layer
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH