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

TLDR

High‑density‑plasma deposition of SiO₂ is a critical step in integrated circuit manufacturing. The authors compiled a comprehensive gas‑phase and surface reaction set for plasma‑enhanced CVD of SiO₂ from SiH₄, O₂, and Ar, and employed a well‑mixed reactor model with mass and energy conservation to simulate three high‑density plasma chambers. Experimental measurements of ion and radical densities and deposition rates agreed quantitatively with the model, validating the reaction network and enabling its use in more advanced simulations.

Abstract

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.