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