using a wet etch process for etching {TAIL ~ TiN}, etching {HEAD ~ said third layer} 
using a wet etch process for etching { TAIL ~ TiN } , etching { HEAD ~ said third layer }
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD