The substrate is etched using reactive ion etching, creating {HEAD ~ a coil shaped trench} in {TAIL ~ the substrate} 
in
The substrate is etched using reactive ion etching , creating { HEAD ~ a coil shaped trench } in { TAIL ~ the substrate }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL