Many processes utilized for the fabrication of integrated circuits involve the formation, by sputtering or deposition, of a material layer. A photoresist is spun on top of the material layer and subsequently patterned. The patterned photoresist serves as a mask through which the material layer may be etched using either dry or wet processes.
Anti-reflective coatings (ARC) are often positioned between the material layer and the photoresist. Anti-reflective coatings absorb the light which is used to expose the photoresist and prevent undesired reflections which might inadvertently expose portions of the photoresist which should not be exposed. Amorphous silicon is frequently employed as an anti-reflective coating over materials such as aluminum, spin-on glass, oxides, etc.