OXIDATIVE DECOMPOSITION OF POLYMETHYLMETHACRYLATE (PMMA) IN PLASMA-ETCHING

Investigations on the plasma chemical oxidation process of polymethylm ethacrylate have been performed in a parallel-plate RF discharge. Oxyg en radicals are shown to be the chemical species that is essential for oxidative etching. ion bombardment of the polymer surface is characte rized as the energetically dominant activation mechanism. Based on a m acroscopic point of view taking only the stable reactants into account and an exact quantitative balance of all initial substances and react ion products, it is demonstrated that elementary rules of chemistry, s uch as stoichiometric substance conversion and a modified mass action law, are also valid in plasma chemical processes. By means of these fu ndamental laws, the composition of stable gases in the reactor and the effectiveness of the process are explained.