A process for etching a substrate and removing etch residue deposited on the surfaces in the etching chamber has two stages. In the first stage, an energized first process gas is provided in the chamber, and in the second stage, an energized second process gas is provided in the chamber. The energized first process gas comprises SF6 and Ar, the volumetric flow ratio of SF6 to other components of the first process gas being from about 5:1 to about 1:10. The energized second process gas comprises CF4 and Ar, the volumetric flow ratio of CF4 to other components of the second process gas being from about 1:0 to about 1:10.