The second macro is formed with a metal wiring layer on the first level electrically connected to a metal wiring layer on the second layer with a same process flow of the first macro, and additionally includes forming a capping layer over the metal wiring layer on the second layer which has {TAIL ~ a second electromigration resistance} different from {HEAD ~ the first electromigration resistance} 
The second macro is formed with a metal wiring layer on the first level electrically connected to a metal wiring layer on the second layer with a same process flow of the first macro , and additionally includes forming a capping layer over the metal wiring layer on the second layer which has { TAIL ~ a second electromigration resistance } different from { HEAD ~ the first electromigration resistance }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD