Plasma-assisted etching of aluminum in CCl4−Cl2 mixtures

The etching of aluminum has been studied in a diode reactor fed with CCl₄–Cl₂ mixtures. The overall reaction has been found to be influenced by the contemporaneous deposition of low-volatile etch products and/or a chlorocarbon polymer film originating from the polymerization of CCl_x species. A simple approach is described which allows the chemical contribution to the etch process to be distinguished from the physical one of through-film diffusion. The etching of a clean Al surface is shown to be controlled by chlorine chemisorption at low temperature.Work partially supported by Progetto Finalinalizzato Materiali per l'Elettronica a Stato Solido del CNR and by the Italian Ministry of Education (MPI).