The method 1, wherein the step of {HEAD ~ trimming} comprises performing {TAIL ~ an isotropic etch} 
The method 1 , wherein the step of { HEAD ~ trimming } comprises performing { TAIL ~ an isotropic etch }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL