Development of Chip-on-Wafer (CoW) stacked chip packaging for high-end CIS application

CIS is one of the important components in the coming big thing IoT since it has been popularly adopted in many applications. Smart phone is the most popular application seeing anywhere. The CIS cameras in a smart phone are usually defined as primary camera and secondary camera. The function of primary camera is mainly used to take photo and secondary camera is used either to take photo or for visual communication. The common package solution for the primary camera is wire bonding package module, and the secondary camera is chip scale package (CSP). For the primary camera, when the pixel size is getting smaller and resolution is getting higher, it leads a possibility of die partition of image sensor and signal processor. In this research, PTI developed an alternative packaging solution for high-end primary camera. Wafer support system, low aspect ratio TSV, and CoW die stacking are the key process developments enabling this technology. The reliability test passed pre-condition level 3 and temperature cycling test 1000 cycles to prove a robust package solution.