Computer simulation of WSi{sub}x CVD VLSI processing - effect of abnormal inlet gas flows

摘要

We made two- and three-dimensional computer simulations of tungsten silicide (Wsi{sub}x) CVD from tungsten hexafluoride and silane (WF{sub}6/SiH{sub}4) source gases in a cold-wall single-wafer reactor with the gas introduced through a showerhead using a computational fluid dynamics (CFD) model. We investigated the effect of the following inlet parameters on the radial deposition rate and composition profile: inlet flow through a 2-mm-wide annular slit in the showerhead where the flow velocity through this inlet was different from average flow velocity through the showerhead; variable showerhead-to-substrate distance; presence of partially clogged radial gas inlet; and discrete gas inlet hole. We used simulations of the effect of varying each of these parameters to determine the effect of abnormal operating conditions on the film deposition rate and composition profiles. These results demonstrate how CFD simulations can be used to simulate the effect of operating conditions on CVD reactor performance.