A hole may be formed in {HEAD ~ the trench} and contact {TAIL ~ a section} of the metal layer 
A hole may be formed in { HEAD ~ the trench } and contact { TAIL ~ a section } of the metal layer
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH