The method includes forming a first dry etching mask in a first masking region of a first surface of the substrate in a first mask forming process and performing {TAIL ~ a first dry etching process} to remove a portion of the substrate in {HEAD ~ areas} between the first dry etching mask after the first mask forming process 
The method includes forming a first dry etching mask in a first masking region of a first surface of the substrate in a first mask forming process and performing { TAIL ~ a first dry etching process } to remove a portion of the substrate in { HEAD ~ areas } between the first dry etching mask after the first mask forming process
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