The present invention is embodied in a method and apparatus for etching dielectric layers and inorganic ARC's without the need for removing the substrate being processed from the processing chamber and without the need for intervening processing steps such as chamber cleaning operations (in situ process). A layer and/or a multi-layer film deposited on a substrate, such as silicon, is located within a processing chamber. The substrate has a base, an underlying layer above the base, an overlying layer above the underlying layer, and a top dielectric anti-reflective coating (DARC) layer formed on the overlying layer. In the preferred method, first, the DARC layer and the overlying layer is etched by a first process gas. Next, the underlying layer is etched by a second process gas.