A CFD model for the PECVD of silicon nitride

This work describes the methodology used to develop a computational fluid dynamic (CFD) model for the plasma-enhanced chemical vapor deposition (PECVD) of silicon nitride (SiN_x) for an N ₂SiH₄-NH₃ process. The model has been developed for the Applied Materials Precision 5000 single-wafer reactor, and has the reaction chamber geometry, thermal characteristics, and reactant delivery system incorporated into it. A one-dimensional simulator was used to investigate the initial reaction mechanisms. An experimental design was carried out using physically-based transformations in order to provide model calibration data. The reaction rates were then optimized using the experimental data and the one-dimensional simulator in conjunction with a nonlinear optimizer. A two-dimensional model has been developed using FLUENT, a commercially available computational fluid dynamics program. A simplified plasma modeling technique has been developed which permits the incorporation of electron-initiated reactions generated by the radio-frequency (RF) plasma. This model provides the capability to predict the film composition and deposition rates across the substrate surface. A comparison to the nominal point experimental data has been performed and is reported as well