Abstract: A process for etching a substrate 25 in an etching chamber 105, and simultaneously removing etch residue deposited on the surfaces of the walls 110 and components of the etching chamber 105. In one version, a two-stage method of opening a nitride mask layer on the substrate includes a first stage of providing a highly chemically reactive process gas in the chamber 105 to etch the nitride layer 32 and/or an underlying oxide layer 34, and a second stage of providing a less chemically reactive process gas in the chamber to etch the nitride layer 32 and/or the oxide layer 34 at a slower rate than the first stage. The first and second stage process gases may each comprise a fluorine containing gas, with the fluorine ratio of the first gas higher than the fluorine ratio of the second gas.

Abstract: A process for etching a substrate 25 in an etching chamber 30, and simultaneously cleaning a thin, non-homogeneous, etch residue deposited on the surfaces of the walls 45 and components of the etching chamber 30. In the etching step, process gas comprising etchant gas is used to etch a substrate 25 in the etching chamber 30 thereby depositing etch residue inside the chamber 30. Cleaning gas is added to the process gas for a sufficient time and in a volumetric flow ratio that is sufficiently high, to react with and remove substantially all the etch residue deposited by the process gas. The present method advantageously cleans the etch residue in the chamber 30, during the etching process, and without use of separate cleaning, conditioning, and seasoning process steps.