BACK-SIDE ILLUMINATED IMAGE SENSOR

Image sensors and methods of manufacturing image sensors are provided herein. In an embodiment, a method of manufacturing an image sensor includes forming a structure having a front side and a back side. The structure includes a semiconductor layer extending between the front side and the back side of the structure, and a capacitive insulation wall extending through the semiconductor layer between the front side and the back side of the structure. The capacitive insulation wall includes first and second insulating walls separated by a region of a conductive or semiconductor material. The method further includes selectively etching, from the back side of the structure, portions of the semiconductor layer and the region of conductive or semiconductor material, while retaining adjacent portions of the first and second insulating walls.