Solder ball reflow soldering methods are used to connect {HEAD ~ the electronic device} to {TAIL ~ the secondary substrate} and to connect the secondary substrate to the primary substrate 
Solder ball reflow soldering methods are used to connect { HEAD ~ the electronic device } to { TAIL ~ the secondary substrate } and to connect the secondary substrate to the primary substrate
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH