providing a substrate defined with unit pixels;

forming a seed microlens on the substrate, wherein a top surface of the seed microlens comprises a height difference between a first region of the seed microlens corresponding to one of the unit pixels and a second region of the seed microlens corresponding to an area between adjacent unit pixels; and

forming a microlens by performing a blanket etching process on the seed microlens,

wherein forming the seed microlens comprises:

forming an inorganic layer on the substrate;

selectively forming an ion implantation region in a portion of the inorganic layer corresponding to the area between adjacent unit pixels, wherein the forming of the ion implantation region comprises:

forming a first photoresist pattern separated by a first gap exposing a first portion of the inorganic layer corresponding to a portion of the area between adjacent unit pixels,

forming a second photoresist pattern on the first photoresist pattern, the second photoresist pattern being separated by a second gap exposing at least the first gap of the first photoresist pattern, and

implanting ions into the inorganic layer using both the first and the second photoresist patterns as a mask; and

removing the ion implantation region to form a lens gap hole in the inorganic layer,

wherein the lens gap hole creates the height difference of the top surface of the seed microlens.