A wet etching process is performed to remove {TAIL ~ the first un etched portion} of {HEAD ~ the substrate} after the mask removing process, thereby forming the piezoelectric resonator element 
A wet etching process is performed to remove { TAIL ~ the first un etched portion } of { HEAD ~ the substrate } after the mask removing process , thereby forming the piezoelectric resonator element
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH