4.6 A 1/2.3inch 20Mpixel 3-layer stacked CMOS Image Sensor with DRAM

Abstract

In recent years, the performance of cellphone cameras has improved, and is becoming comparable to that of SLR cameras. However, the big difference between cellphone cameras and SLR cameras is the distortion due to the rolling exposure of CMOS image sensors (CISs) because cellphone cameras cannot have a mechanical shutters [1]. In addition to this technical problem, the demands for high quality in dark situations and for movies are increasing. Frame-level signal processing can solve these problems, but previous generations of CIS could not achieve both high-speed readout and accessible I/F speed. This paper presents 3-layer-stacked back-illuminated CMOS Image Sensor (3L-BI-CIS) with mounted DRAM as the frame memory.