Modeling Etching Plasmas: Needs and Challenges in Atomic and Molecular Data

This paper reviews works of the team to characterize and model chlorine high-density plasmas. The model allows in particular determining the pressure-dependence of the concentration of neutral and charged species. Comparison of this model to experimental measurements achieved in high-density surface-wave-produced plasmas shows an excellent agreement for the neutral atomic and molecular species. As far as charged species are concerned, the model reproduces well experiments for atomic chlorine ions and electrons, but some discrepancy occurs for molecular positive ions and negative ions at low pressure. The cause of this discrepancy remains to be clarified but might result from an underestimation of the creation rates of Cl2+ and Cl-. The model seems promising for predicting the ion density in a recently installed ICP reactor.