September 15, 2014 – CMOS image sensors (CIS) have often been heralded as the first 3D devices in volume manufacturing. However this is not really the case. Shellcase MVP, the first generation of CIS that used through silicon vias (TSVs) to form interconnects was still a 2D device. (Remember, TSV is not always synonymous with 3D). Chip stacking only came about with the advent of backside illuminated (BSI) CIS, and involved reversing the order of the lens, circuitry, and photodiode from traditional front-side illumination so that the light coming through the lens first hits the photodiode and then the circuitry.
Read Full Article: Click Here or Image Below