Simultaneous, multilayer plasma etching and deposition of fluorocarbon layers on silicon

Summary form only given. Plasma etching and deposition of the fluorocarbon layer on a silicon substrate are modeled by the simultaneous etching and deposition of a stack of fluorocarbon monolayers. The model covers three regimes: reactive sputtering, fluorocarbon suppression, fluorocarbon deposition. The innovative contribution is the simultaneous etching of the buried monolayers in contrast to models where the etching occurs only on the top exposed fluorocarbon monolayer. In addition explicit etch and deposition rates are given in terms of the ion energy. Langmuir kinetics apply in each of the monolayers to a depth where the energy of the bombarding ions exceeds or equals the threshold energy for breaking carbon-fluorine bonds. The ion energy controls many of the terms in the etch rate and deposition rate expressions. The fluorine etchant diffuses through the fluorocarbon layer to the silicon substrate where etching or deposition occurs depending on the ion energy. The deposition and etching of the fluorocarbon layer are ion assisted; the etching of the silicon is thermal and is assumed self-similar to the etching of the fluorocarbon layer based on experiments. Etch and deposition curves model CF/sup +/ ion beam deposition and etch on silicon and CHF/sub 3/ and C/sub 2/F/sub 6/ plasma etch and deposition on fluorocarbon covered silicon substrates.