Abstract: A method of fabricating an image sensor on a semiconductor substrate including a sensor array region is introduced. First, an R/G/B color filter array (CFA) is formed on portions of the semiconductor substrate corresponding to the sensor array region. Then, a spacer layer is formed on the R/G/B CFA, and a plurality of U-lens is formed on the spacer layer corresponding to the R/G/B CFA. Afterwards, a buffer layer is coated to fill a space between the U-lens, and a low-temperature passivation layer is deposited on the buffer layer and the U-lens at a temperature of about 300° C. or less to prevent the R/G/B CFA from damage.