of the same anti-reflective coating for the back illuminated image sensor and method for manufacturing

The present invention relates to an image sensor with improved quantum efficiency. There is provided a back illuminated (BSI) image sensor, comprising a substrate having a front side and a back side, and a light-sensitive area on the front side of the substrate, and an antireflection layer on the backside of the substrate. The antireflective layer has a refractive index greater than or equal to about 2.2 and an extinction coefficient less than or equal to about 0.05, measured at a wavelength less than 700 nm.