A 3D stacked CMOS image sensor with 16Mpixel global-shutter mode using 4 million interconnections

Abstract

We have developed a 16Mpixel 3D stacked global-shutter CMOS image sensor with pixel level interconnections using 4 million micro bumps. The four photodiodes in the unit pixel circuit on the top substrate share one micro-bump interconnection in 7.6μm pitch. Each signal of the photodiodes is transferred to the corresponding storage node on the bottom substrate via the interconnection to achieve a global shutter function. The ratio of the parasitic light sensitivity of an in-pixel storage node and the light sensitivity of a photodiode is -180dB with 3.8μm pixel size.