The system 1, where in the pad is used in {HEAD ~ chemical mechanical polishing} of {TAIL ~ a semiconductor wafer} 
of
The system 1 , where in the pad is used in { HEAD ~ chemical mechanical polishing } of { TAIL ~ a semiconductor wafer }
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