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