A backside illuminated image sensor includes a substrate layer having a frontside and a backside. An array of photosensitive pixels is disposed within the substrate layer and is sensitive to light incident through the backside of the substrate layer. A metal grid is disposed over the backside of the substrate layer. The metal grid surrounds each of the photosensitive pixels and defines optical apertures for receiving the light into the photosensitive pixels through the backside. The metal grid includes intersecting wires each having a triangular cross-section. A material layer surrounds the metal grid.