Zersetzung von CCl4 im HF-Niederdruckplasma für plasmachemisches Ätzen von Aluminium

After a brief summary of decomposition processes occuring in a plasma etching reactor investigations of CCl₄-decomposition by gaschromatography and time resolved emission spectroscopy are described. The decomposition takes place in a plasma tube with external r.f. electrodes. The qualitative identification of decomposition products of CCl₄ shows few main products only quite in contrast to plasma decomposition of hydrocarbons. These are CCl₄, Cl₂, C₂Cl₄, C₂Cl₆ and glow polymers. The dependence of the product distribution on power density and flow rate gives some hints for a rapid decomposition mechanism. The time resolved emission spectroscopy bases on a two channel method using a reference signal of an Ar line to eliminate the changing plasma conditions during the decomposition process. The limits of application of this method are discussed. Investigations of CCl-, Cl₂- and Cl-intensity-time-functions also reveal the existence of a the rapid decomposition mechanism for which a dissociative electron attachment is supported giving rate constants in the expected order of magnitude.