Effect of planarity on the 3D integration in 3-D integrated CMOS image sensor

In this work, some of the tradeoffs that need to be considered in optimizing a back-illuminated (BSI) sensor were described. The manufacturing feasibility of a BSI CMOS image sensor was demonstrated and compared between the front-illuminated (FSI) and back-illuminated (BSI) versions of the sensor with the same fabrication process. 3D integration processes were evaluated to get stable performance of BSI CMOS image sensor.The broadband quantum efficiency (81% for BSI) improved 2.7 times over FSI sensitivity.