1. A method of etching an organic antireflective coating with selectivity to an overlying and/or underlying layer, comprising: supporting a semiconductor substrate in a plasma etch reactor, the substrate including an organic antireflective coating over an underlying layer; energizing an O 2 -free etch gas into a plasma state and etching openings in the organic antireflective coating, the etch gas comprising a sulfur-containing gas and a carrier gas.