US Patent 7947526 Method of making backside illumination image sensor

An exemplary method for making a backside illumination image sensor includes the follow steps. A substrate having a top surface is firstly provided. Secondly, many recesses are formed in the top surface. Thirdly, a light pervious layer is applied on the top surface. The light pervious layer has a plurality of filling portions received in the recesses. Then, an epitaxial silicon layer is applied on the light pervious layer. Next, many light sensitive regions and circuits are formed on the epitaxial silicon layer. Finally, the substrate is etched to expose the filling portions of the light pervious layer, thereby forming the backside illumination image sensor with the filling portions functioning as micro-lenses.