Three-dimensional simulation of profile evolution in plasma etching of polysilicon

A 3-D Monte Carlo simulator was used to model the profile evolution of silicon during plasma etching. The profile simulation is based on the kinetics model developed from beam studies. The profile evolution of patterned samples etched in an inductively coupled plasma etcher was simulated. The mechanisms of microtrenching and sidewall bowing forming were discussed. Nondirectional ions were primarily responsible for the sidewall bowing; while ions reflected form bowed feature sidewalls were primarily responsible for the microtrenching. The profile evolutions under different processing conditions were simulated, including different neutral-to-ion ration, different energy and different ion angular distribution.