The Simulation Of A Low Pressure Argon RF Glow Discharge Using A Self-consistent Particle Model

A self-consistent particle model has been developed for the simulation of low pressure rf glow discharges which are commonly used for etching thin films during the manufacture of integrated circuits. Particle modeling and Monte Carlo simulation techniques have been merged to create a model that accurately simulates these highly non-equilibrium collisional discharges. Particle modeling methods are used to move the large swarms of electrons and ions under the influence of a self-consistently calculated electric field. Monte Carlo techniques are used to include random electron and ion collisions with neutral background gas molecules in the model. Electric field and charged particle density profiles determined from simulations of an argon rf glow discharge are consistent with results obtained from continuum models. Spatially and temporally calculated argon excitation rates are compared to experimentally measured data. The model correctly predicts both the times and positions of the peaks in the argon excitation rate in the discharge. The average ion energy is found to vary greatly between the bulk of the discharge and the sheaths, contrary to the assumption that the ion energy is uniform, as assumed in some continuum models. For large rf voltages, ion impact ionization is found to occur within the plasma sheaths. As with secondary electron emissions, this process can lead to the generation of very high energy electrons due to the large electric fields present at the time of their creation.