Abstract: A method for fabricating a backside illuminated image sensor is provided. An exemplary method can include providing a substrate having a front surface and a back surface; forming an alignment mark at the front surface of the substrate, wherein the alignment mark is detectable for alignment from the back surface; and processing the substrate from the back surface by performing registration from the back surface and using the alignment mark as a reference.

Abstract: A method for fabricating a back-side illuminated image sensor includes providing a semiconductor substrate having a front surface and back surface, providing a plurality of transistors, metal interconnects, and metal pads on front surface of the substrate, bonding a supporting layer to the front surface of the substrate, thinning-down the semiconductor substrate from the back surface, clearing-out a region of the semiconductor substrate from the back surface that covers a fine alignment mark by performing registration from the back surface and using a global alignment mark as a reference, and processing the back surface of the substrate by performing registration from the back surface and using the fine alignment mark as a reference.