The wafer/coating/carbon layer unit comprises {HEAD ~ a workpiece} useful in {TAIL ~ the practice} of the invention 
The wafer / coating / carbon layer unit comprises { HEAD ~ a workpiece } useful in { TAIL ~ the practice } of the invention
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH