Method of plasma etching organic antireflective coating

A semiconductor manufacturing process wherein an organic antireflective coating is etched with an O2-free sulfur containing gas which provides selectivity with respect to an underlying layer and/or minimizes the lateral etch rate of an overlying photoresist to maintain critical dimensions defmed by the photoresist. The etchant gas can include SO2 and a carrier gas such as Ar or He and optional additions of other gases such as HBr. The process is useful for etching 0.25 micron and smaller contact or via openings in forming structures such as damascene structures.