US Patent 10134790 Image sensor and fabrication method therefor

A method of fabricating an image sensor includes depositing a first dielectric layer over a substrate, removing a portion of the first dielectric layer from the substrate to form a trench, depositing a conductive layer over the first dielectric layer and in the trench, forming a protective layer lining a top surface of the conductive layer and sidewalls and a bottom surface of the groove in the conductive layer, and removing a portion of the conductive layer to form a grid structure. A groove corresponding to the trench is formed in the conductive layer.