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