A method for etching a dielectric layer over a substrate and disposed below a mask is provided. The substrate is placed in a plasma processing chamber. An etchant gas comprising O2 and a sulfur component gas comprising at least one of H2S and a compound containing at least one carbon sulfur bond is provided into the plasma chamber. A plasma is formed from the etchant gas. Features are etched into the etch layer through the photoresist mask with the plasma from the etchant gas.