The second interconnect structure is formed with {HEAD ~ a second interfacial structure} different from {TAIL ~ the first interfacial structure} of the first interconnect structure 
The second interconnect structure is formed with { HEAD ~ a second interfacial structure } different from { TAIL ~ the first interfacial structure } of the first interconnect structure
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH