Aluminum Etching in Carbon Tetrachloride Plasmas

Abstract

Etch rates of aluminum and native aluminum oxide films in carbon tetrachloride plasmas were investigated as functions of substrate temperature and electrode material in a parallel plate plasma etching system. Use of stainless steel electrodes resulted in the formation of a carbon‐chlorine polymer which precluded aluminum etching. Anodized aluminum electrodes minimized polymer formation and etching was achieved. Several inherent differences in the electrode materials were considered to account for this effect. Analysis of the effluent from the reactor suggested possible chemical reactions occurring in the carbon tetrachloride plasma, as well as a precursor to polymer formation.