a method for manufacturing an image sensor according to an embodiment includes performing a plasma surface treatment on an oxide film microlens to mitigate high surface morphology . the image sensor can include a passivation layer on a substrate having a pad region and a pixel region and a color filter layer on the passivation layer . a first low temperature oxide can be formed over the substrate including the color filter layer ; and an oxide film microlens can be formed on the first low temperature oxide layer . a portion of the first low temperature oxide layer can provide a seed microlens upon which a second low temperature oxide layer is formed to form the oxide film microlenses . the plasma surface treatment can then be applied with respect to the oxide film microlenses .