an etched portion formed by selectively etching said {HEAD ~ insulation film} and said {TAIL ~ first semiconductor substrate} of said composite substrate to reach at least said second semiconductor substrate 
an etched portion formed by selectively etching said { HEAD ~ insulation film } and said { TAIL ~ first semiconductor substrate } of said composite substrate to reach at least said second semiconductor substrate
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH