The State-of-the-Art of Mainstream CMOS Image Sensors

Abstract

The steady growth of mobile phones sales (feature and smartphones) has been the primary driver for CMOS image sensor (CIS) unit shipment growth over the last 3-5 years. As CIS market revenue has grown, so have R&D spending and patent filings. This effort has resulted in advanced mobile camera systems containing phase detection pixel arrays for fast autofocus (AF), ~1 µm generation pixels with improved low-light sensitivity, advanced chip-stacking, featuring a back-illuminated CIS wafer joined with an image signal processor (ISP) wafer, and video recording up to 4K. Innovation for smartphone cameras will continue, although given the competition for these high-volume sockets, many IDMs and fabless companies are developing chips for emerging, higher margin imaging applications such as automotive, security, medical, etc. These emerging opportunities are driving technology transfers from mobile imaging to these growth areas.