{HEAD ~ A bonding surface} of first semiconductor substrate 11 , and a bonding surface of second semiconductor substrate 12 are mirror finished to provide a surface roughness of {TAIL ~ below 500 Å} each 
{ HEAD ~ A bonding surface } of first semiconductor substrate 11 , and a bonding surface of second semiconductor substrate 12 are mirror finished to provide a surface roughness of { TAIL ~ below 500 Å } each
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH