Comparison of different methods for simulating the effect of specular ion reflection on microtrenching during dry etching of polysilicon

For the simulation of etching processes, a key step is the calculation of the etch rates depending on the specific model and depending on the specific geometry of the feature. In this work, we demonstrate the calculation of etch rates using a Monte Carlo, a flux balancing, and an analytical approach. For a relatively simple model for etching of polysilicon in chlorine-based chemistry, the three approaches are compared and microtrenching is studied which results from the specular reflection of ions and depends on different parameters. The results for the different approaches are in good agreement for the cases studied.