CMOS IMAGE SENSOR WITH DUAL DAMASCENE GRID DESIGN HAVING ABSORPTION ENHANCEMENT STRUCTURE

摘要

The present invention relates to an image sensor integrated chip having a grid structure that reduces crosstalk between pixel regions of an image sensor chip. In some embodiments, the integrated chip has an image sensing element disposed within the substrate. An absorption strengthening structure is disposed along the back side of the substrate. A grid structure is placed on top of the absorption strengthening structure. The grid structure defines an opening disposed over the image sensing element and extends from above the absorption enhancement structure to a position within the absorption enhancement structure. By extending the grid structure into the absorption enhancement structure, the grid structure prevents radiation reflected from the non-planar surface of the absorption enhancement structure from moving to adjacent pixel regions, thereby preventing crosstalk between adjacent image sensing elements. Can be reduced.