Patent ID: 7250247

Claim:
An integrated circuit comprising: a reflective layer having a reflective upper surface defining a first interface; a first anti-reflective coating layer formed over the reflective layer, the first anti-reflective coating layer having a first index of refraction, a first absorption, a first thickness, and an upper surface defining a second interface; a second anti-reflective coating layer formed over said first anti-reflective coating layer, the second anti-reflective coating layer having a second index of refraction, a second absorption, a second thickness, and an upper surface defining a third interface, wherein the first, second, and third interface reflects radiation, and wherein the indices of refraction, absorptions, and thicknesses of the first and second anti-reflective coating layers are such that the amplitudes are approximately equal and the phase differences of the reflected radiation from said first, second, and third interfaces substantially mutually cancel when combined; a dielectric layer formed on said second anti-reflective coating layer; an opening formed in said dielectric layer to expose said second anti-reflective coating layer; and a metal layer formed over said dielectric layer and into said opening.