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