Next, {TAIL ~ a layer} of BPSG is deposited and reflowed in {HEAD ~ a steam atmosphere} to produce an approximately planar surface 
Next , { TAIL ~ a layer } of BPSG is deposited and reflowed in { HEAD ~ a steam atmosphere } to produce an approximately planar surface
OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH