Modeling of SiO₂ deposition in high density plasma reactors and comparisons of model predictions with experimental measurements

High-density-plasma deposition of SiO₂ is an important process in integrated circuit manufacturing. A list of gas-phase and surface reactions has been compiled for modeling plasma-enhanced chemical vapor deposition of SiO₂ from SiH₄, O₂, and Ar gas mixtures in high-density-plasma reactors. The gas-phase reactions include electron impact, neutral-neutral, ion-ion, and ion-neutral reactions. The surface reactions and deposition mechanism is based on insights gained from attenuated total reflection Fourier transform infrared spectroscopy experiments and includes radical adsorption onto the SiO₂ surface, ion-enhanced desorption from the surface layer, radical abstractions, as well as direct ion-energy-dependent sputtering of the oxide film. A well-mixed reactor model that consists of mass and energy conservation equations averaged across the reactor volume was used to model three different kinds of high-density plasma deposition chambers. Experimental measurements of total ion densities, relative radical densities, and net deposition rate, as functions of plasma operating conditions, have been compared to model predictions. The results show good quantitative agreement between model predictions and experimental measurements. The compiled reaction set and surface reaction network description was thus validated and can be employed in more sophisticated two- or three-dimensional plasma simulations.