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