The vertical via lines may be realized by etching {TAIL ~ holes} vertically into {HEAD ~ the substrate} such that they partially overlap and contact the metal lines 
The vertical via lines may be realized by etching { TAIL ~ holes } vertically into { HEAD ~ the substrate } such that they partially overlap and contact the metal lines
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH