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