Patent ID: 7883925

Claim:
A method comprising: forming a plurality of photodiodes and transistors with a constant interval in a semiconductor substrate; forming a first interlayer insulating layer over the semiconductor substrate; forming a plurality of metal lines over the first interlayer insulating layer electrically connected to a respective one of the photodiodes and a respective one of the transistors; forming a plurality of interlayer insulating layers including an upper interlayer insulating layer and a lower interlayer insulating layer whose refractive indexes are different from each other over the semiconductor substrate including the metal lines; forming a plurality of color filters over the plurality of interlayer insulating layers such that the color filters correspond to the photodiodes, respectively; forming a planarization layer over the semiconductor substrate including the color filters; and then forming a plurality of microlenses over the planarization layer such that the microlenses correspond to the color filters, respectively, wherein the plurality of interlayer insulating layers comprise an upper interlayer insulating layer having a smaller refractive index than that of a lower interlayer insulating layer.