Enhancement of Wafer Test/package Yields by Oxide-Capping of Microlens in CMOS Image Sensor

This paper reports the oxide-capping process of,microlens in CMOS image sensor and its effect on wafer test/package yields of the product. CMOS image sensors with 8 mum x 8 mum pixel size were fabricated by 0.5 mum CMOS logic process incorporated with color filter and microlens processes. After the formation of microlens, thin oxide film was deposited as a capping material, and finally pad windows were opened. From the analysis of the yield data, it is concluded that the oxide-capping of microlens guarantees the stable wafer test yield and also gives rise to noticeable increase of package yield of CMOS image sensors.