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