{TAIL ~ A first polishing step} is performed to remove a portion of the silicon oxide layer until a thickness of {HEAD ~ the remaining portion} of the oxide layer reaches a predetermined thickness 
{ TAIL ~ A first polishing step } is performed to remove a portion of the silicon oxide layer until a thickness of { HEAD ~ the remaining portion } of the oxide layer reaches a predetermined thickness
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH