Preferably, {HEAD ~ the edge portion} defining {TAIL ~ the via opening} is greater in diameter compared to a via bottom portion by about 10 percent to about 30 percent 
defining
Preferably , { HEAD ~ the edge portion } defining { TAIL ~ the via opening } is greater in diameter compared to a via bottom portion by about 10 percent to about 30 percent
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH