Patent ID: 7807493

Claim:
A method for fabricating a CMOS image sensor comprising steps of: providing a substrate having a sensor array region and a peripheral region defined thereon; forming at least a contact pad on the peripheral region; forming a dielectric layer covering the contact pad on the substrate; performing a first etching process to remove a portion of the dielectric layer in the peripheral region and to form a plurality of step heights; forming an optical shielding layer on the dielectric layer, wherein the step of forming the optical shielding layer further comprises: forming a cap layer on the dielectric layer; forming a photoresist layer on the cap layer; providing a photomask having an optical shielding layer pattern and performing an alignment step; performing exposure and development processes to pattern the photoresist layer; and forming the optical shielding layer on the dielectric layer with the patterned photoresist layer used as an etching mask, wherein the step heights are used to be alignment marks in the alignment step; forming a plurality of color filters on the dielectric layer of the sensor array region; forming a planarizing layer on the color filters and the optical shielding layer; forming a plurality of micro-lenses on the planarizing layer; and performing a second etching process to etch a portion of the dielectric layer and to expose the contact pad after forming the micro-lenses.