Abstract

The state-of-the-art in CMOS image sensors (CIS) is rapidly evolving with significant advancements in technology. Key focus areas include the establishment of backside, stacked imagers, global shutter, and improved dynamic range. There is a notable industry trend towards reducing pixel pitch and increasing array resolution, transitioning into the sub-0.6 um generation. This paper provides insights into the signal path necessary for high-quality images, starting with Phase Detection Autofocus (PDAF) pixels and Color Filter Arrays (CFA), and covering technology aspects such as aperture grid and trench technologies for effective isolation, and critical pixel transistors like the transfer FET and the Source Follower. It highlights the importance of off-chip analog signal transfer using Direct Bond Interface (DBI) and Through Silicon Vias (TSV) to the underlying Image Signal Processor (ISP) where digitization and signal processing take place.