The precursor reacts to form the desired material, and {TAIL ~ at least some} of the desired material forms {HEAD ~ a film} on the substrate 
The precursor reacts to form the desired material , and { TAIL ~ at least some } of the desired material forms { HEAD ~ a film } on the substrate
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH