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