Patent ID: 7510899

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 first dielectric layer covering the contact pad on the substrate; performing a first etching process to remove a portion of the first dielectric for exposing the contact pad and forming a step height; forming an optical shielding layer on the first dielectric layer of the peripheral region; forming a plurality of color filters on the first dielectric layer of the sensor array region; forming a planarizing layer on the color filters and the optical shielding layer; and forming a plurality of micro-lenses on the planarizing layer; wherein the step of forming the optical shielding layer further comprises: forming a cap layer on the first 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 first dielectric layer with the patterned photoresist layer used as an etching mask, wherein the step of forming the optical shielding layer further comprising a step of forming a second dielectric layer covering the first dielectric layer and the step height before forming the optical shielding layer, wherein the step height is used to be an alignment mark in the alignment step; and performing a second etching process to etch a portion of the second dielectric layer and to expose the contact pad after forming the micro-lenses.