An image sensor includes an active pixel photodiode, a black pixel photodiode, a metal grid structure, and a light shield. Each of the active pixel photodiode and the black pixel photodiode are disposed in a semiconductor material having a first side and a second side opposite the first side. The first side of the semiconductor material is disposed between the light shield and the black pixel photodiode. The metal grid structure includes a first multi-layer metal stack including a first metal and a second metal different from the first metal. The light shield includes a second multi-layer stack including the first metal and the second metal. A first thickness of the first multi-layer metal stack is less than a second thickness of the second multi-layer metal stack.