{TAIL ~ A first dielectric layer} is formed overlying the substrate and has a dielectric island surrounded by {HEAD ~ a ring shaped trench} 
{ TAIL ~ A first dielectric layer } is formed overlying the substrate and has a dielectric island surrounded by { HEAD ~ a ring shaped trench }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD