DowLangmuir Surface Kinetics Model for the Fluorocarbon Plasma Etching of SiO2

In the etching of SiO2 in fluorocarbon plasmas, both etching and deposition occur simultaneously, and both processes need to be un-derstood. Based on the experimental results and models published earlier, Ding and Hershkowitz12 assumed that both etching and deposition are ion-induced, and the ion-enhanced chemical etch rate and the ion-enhanced chemical deposition rate are proportional to the energy flux multiplied by the surface coverage of the etching or deposition species. Thereby, they proposed a symmetric rate model ~a Langmuir-type surface chemistry model!, for etching and deposi-tion in fluorocarbon discharges. When there is no deposition, the rate model gives the plasma etch rate ER, as