A combined solder alloy layer composed of a combination of intermetallic compounds, one of tin and {HEAD ~ the solder alloy} making {TAIL ~ layer}, and one of tin and the UBM layer, is formed by heating and melting 
making
A combined solder alloy layer composed of a combination of intermetallic compounds , one of tin and { HEAD ~ the solder alloy } making { TAIL ~ layer } , and one of tin and the UBM layer , is formed by heating and melting
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH