In one embodiment, the present invention relates to a method of forming a silicon oxynitride antireflection coating over a metal layer, involving the steps of providing a semiconductor substrate comprising the metal layer over at least part of the semiconductor substrate; depositing a silicon oxynitride layer over the metal layer having a thickness from about 100 Å to about 150 Å; and forming an oxide layer having a thickness from about 5 Å to about 50 Å over the silicon oxynitride layer to provide the silicon oxynitride antireflection coating. In another embodiment, the present invention relates to a method of reducing an apparent reflectivity of a metal layer having a first reflectivity in a semiconductor structure, involing forming a silicon oxynitride antireflection coating over the metal layer; wherein the silicon oxynitride antireflection coating formed over the metal layer has a second reflectivity and is formed by depositing silicon oxynitride on the metal layer by chemical vapor deposition and forming an oxide layer over the oxynitride, and the difference between the first reflectivity and the second reflectivity is at least about 60%.