According to the aspect of the invention, it is preferable that the wet etching be performed to {HEAD ~ a front surface} of {TAIL ~ the substrate} provided with the dry etching mask in the wet etching process 
According to the aspect of the invention , it is preferable that the wet etching be performed to { HEAD ~ a front surface } of { TAIL ~ the substrate } provided with the dry etching mask in the wet etching process
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH