removing {HEAD ~ the dielectric layer} in the area of the opening of the mask to obtain {TAIL ~ the recess} 
to obtain
removing { HEAD ~ the dielectric layer } in the area of the opening of the mask to obtain { TAIL ~ the recess }
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL