Role of sidewall scattering in feature profile evolution during Cl₂ and HBr plasma etching of silicon

A numerical simulation consisting of two-dimensional axisymmetric fluid plasma simulation is presented for the prediction of the fluxes and energies of particle impingement upon surfaces bounding the plasma. The plasma simulation is coupled to a feature profile evolution simulation for the accurate prediction of etch rate and shape. A reactor-and feature-scale model of crystalline silicon profiles are described. Isolated trench and line etching with Cl₂ and HBr plasmas were then compared to experimental results for the prediction of microtrench-free high aspect ratio trench etching in HBr contrasted with the occurrence of deep microtrenching in Cl₂ plasmas.