A CFD MODEL FOR THE PECVD OF SILICON-NITRIDE

This work describes the methodology used to develop a computational fl uid dynamic (CFD) model for the plasma-enhanced chemical vapor deposit ion (PECVD) of silicon nitride (SiN(x)) for an N2-SiH4-NH3 process. Th e model has been developed for the Applied Materials Precison 5000 sin gle-wafer reactor, and has the reaction chamber geometry, thermal char acteristics, and reactant delivery system incorporated into it. A one- dimensional simulator was used to investigate the initial reaction mec hanisms. An experimental design was carried out using physically-based transformations in order to provide model calibration data. The react ion 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 ava ilable computational fluid dynamics program. A simplified plasma model ing technique has been developed which permits the incorporation of el ectron-initiated reactions generated by the radio-frequency (RF) plasm a. 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.