Structures for grounding metal shields in backside illumination image sensor chips

摘要

A device includes a semiconductor substrate having a front side and a backside. A photo-sensitive device is disposed on the front side of the semiconductor substrate. A dielectric layer is disposed on the backside of the semiconductor substrate, wherein the dielectric layer is over a back surface of the semiconductor substrate. A metal shield is over the dielectric layer and overlapping the photo-sensitive device. A metal plug penetrates through the dielectric layer, wherein the metal plug electrically couples the metal shield to the semiconductor substrate.