A numerical method for the efficient atomistic simulation of the plasma-etch of nano-patterned structures

In this work, we present a numerical model aimed to accurately and efficiently simulate the plasma dry-etching process in nano-patterned samples. The method is designed to reproduce the physical phenomena and control the parameters involved in the process. The modelling formulation is based on the Monte Carlo approach. This simulation technique is fundamental to efficiently compute the erosion kinetic at the atomic resolution. The atomic level simulation of the evolving profile is obtained linking (one to one) each virtual Monte Carlo event to each possible atomic phenomenon. The code has been designed to be coupled with a generic plasma status, characterized by the particle types (ions and neutrals), their flow rates and their energy/angle distributions. The simulation approach has been tested comparing numerical results and experimental analysis of etching processes for the case of Si etching in HBr/O-2 plasma. The results show the effectiveness of the implemented model which is able to predict the profile evolution and, consequently, to significantly support the process design.