Typically, the first group of semiconductor wafers have impurities therein which are to be removed and {HEAD ~ the second group} of semiconductor wafers are to receive {TAIL ~ the impurities} 
are to receive
Typically , the first group of semiconductor wafers have impurities therein which are to be removed and { HEAD ~ the second group } of semiconductor wafers are to receive { TAIL ~ the impurities }
OTH OTH 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 REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL