The rarefied flow of gas mixture in a low pressure etching reactor is simulated by means of the Direct Simulation Monte Carlo(DSMC) method. The SiO2 etching process is modeled as a single step surface reaction SiO2 + CF4 ---> SiF4 + CO2. By using an extension of the method created by Ikegawa and Kobayashi the gas composition at downstream boundary is calculated automatically. The obtained flow and mean residence time of each gas species are demonstrated in this paper.

Key Words : Rarefied flow, Direct Simulation Monte Carlo method, Plasma etching