US Patent 7736938 Methods for fabricating CMOS image sensor

A method for fabricating a CMOS image sensor for preventing corrosion of a metal pad. The method for fabricating the CMOS image sensor can include sequentially forming a dielectric film, a metal pad having an opening, and a first passivation film on a semiconductor substrate having a scribe lane and a pixel region defined therein, forming a color filter layer on the first passivation film at the pixel region, forming an overcoat layer on the entire surface of the semiconductor substrate, including the metal pad, to reduce the step difference between the scribe lane and the pixel region, forming a micro lens on the overcoat layer at the pixel region, forming a photo resist to expose the overcoat layer at the scribe lane, performing an etching process on the entire surface of the semiconductor substrate to etch the overcoat layer at the scribe lane, and removing the photo resist by a cleaning process.