A semiconductor image sensor includes a metal layer formed on a semiconductor substrate. An oxide layer is disposed over the semiconductor substrate to cover the metal layer. A SOG is disposed on the oxide layer, a color filter is disposed on the SOG and a silicon-oxy-nitride layer is disposed thereon. By using the high transmittance of the SOG and the silicon-oxy-nitride layer, the blue light transmittance by the semiconductor image sensor is therefore enhanced.