Development and Reliability study of 3D WLCSP for automotive CMOS image sensor using TSV technology

With the rise of intelligent driving market, automotive CMOS image sensor is more and more widely used. Compared with cameras in mobile phones, automotive CMOS image sensor need to pass critical reliability test, namely, AEC-Q100. In this paper, a novel and highly reliable wafer level packaging technology using through via technology (TSV) was developed for automotive CMOS image senor. Several new key process such as wafer level bonding, backside grinding, via etching, low temperature PECVD, spray coating passivation layer, RDL formation and ball drop were investigated. Reliability of the developed WLCSP based on AEC-Q100 was characterized by Temperature Humidity Bias Test (THB), Temperature Humidity Test (THS), Temperature Cycling Test (TC), High Temperature Storage Life Test (HTS) and Low Temperature Storage Life Test (LTS). No failure was found after the reliability rest. Good package reliability results demonstrate that WLCSP technology can meet the requirements of low cost and high reliability for automotive CMOS image sensors.