After extensive experimentation, it has been found that {HEAD ~ different void growth rates} are provided with {TAIL ~ different Cu/cap interface materials} 
are provided with
After extensive experimentation , it has been found that { HEAD ~ different void growth rates } are provided with { TAIL ~ different Cu / cap interface materials }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL