We developed 3D stacked 16 million pixel CMOS image sensor to achieve ideal image sensor and Global shutter performance, using 4 million micro bump inter-connections at a 7.6-um pitch with wafer bonding technology. We then evaluated its reliability. This 3D stacked technology was proven to have no negative effect on CIS characteristics and to provide a high density and narrow pitched in-pixel connection with high reliability, no defects, and no deterioration over a 1000-cycle heat cycle test and after a 1000-hour high temperature and high humidity test. This CIS sensor has a set of readout circuits in each substrate, which enable us to detect any connection failure among 4 million micro bumps between substrates individually. These results show that this 3D technology has enough reliability for application to products like multi band imaging.