Modeling of inductively coupled plasma Ar/Cl2/N2 plasma discharge: Effect of N2 on the plasma properties

A global kinetic model of Cl2/Ar/N2 plasma discharge has been developed, which allows calculation of the densities and fluxes of all neutral and charged species considered in the reaction scheme, as well as the electron temperature, as a function of the operating conditions. In this work, the results from the global model are first compared to the calculations given by other models. Our simulation results are focused on the effect of nitrogen adding to the Cl2/Ar plasma mixture, which impacts both neutral and charged species transport phenomena. The N2 percentage is varied to the detriment of Cl2 by keeping the total flow rates of Cl2 and N2 constant. In order to better understand the impact of N2 addition to the Cl2/Ar gas mixture, the authors analyzed the output plasma parameters calculated from the model for different N2 flow rate percentages. Indeed, the simulation results show a decrease in electron density and an increase in electron temperature with increasing percentage of N2. Particular attention is paid to the analysis of electronegativity, Cl2 and N2 dissociation, and positive ion to neutral flux ratio evolution by varying percentage of N2. Such parameters have a direct effect on the etching anisotropy of the materials during the etching process.

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