Effect of RF discharge structure on silicon etching in CF4/O2

The effect of RF discharge structure on silicon etching process in CF₄/O₂ mixture was studied. The calculations were carried out based on an advanced mathematical model of plasma-chemical reactor with taking into account a peculiarities of RF discharge plasma. The model includes the equations of multi-component physical-chemical hydrodynamics describing convective-diffusion transfer and production of all mixture components. The special fixed distributions of electron density as well as results of RF discharge numerical simulation in hydrodynamic approximation were examined. The numerical evaluations of electron density influence on the main characteristics of silicon etching shown that the etching uniformity index substantially depends on the electron density variation in the radial direction. This fact is naturally neglected in the 1D-calculations of RF discharge.