An image sensor include an interlayer dielectric layer formed over a semiconductor substrate; a color filter array formed over the interlayer dielectric layer; a planarization layer formed over the color filter; and a microlens array having a continuous, gapless shape formed over the planarization layer and spatially corresponding to the color filter array. The microlens array is composed of a first dielectric layer and a second dielectric layer formed over the first dielectric layer.