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