A first conductive layer is formed in {HEAD ~ the ring} shaped trench of {TAIL ~ the first dielectric layer} 
A first conductive layer is formed in { HEAD ~ the ring } shaped trench of { TAIL ~ the first dielectric layer }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL