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