A barrier layer is formed that extends over the core region and {HEAD ~ a pre metal dielectric film} is formed that extends over {TAIL ~ the barrier layer} 
extends over
A barrier layer is formed that extends over the core region and { HEAD ~ a pre metal dielectric film } is formed that extends over { TAIL ~ the barrier layer }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL