On the effect of additional CF$_2$ scattering data on a CF$_4$/O$_2$ plasma etch simulation

An analysis of the effect of adding a number of new CF$_2$ processes to a CF$_4$ and a CF$_4$/O$_2$ plasma chemistry model is presented. A CF$_4$ and a CF$_4$/O$_2$ capacitively coupled plasma (CCP) etch process is simulated using a zero-dimensional global plasma model. The reaction data is then extended using a new set of electron impact reaction rates for CF$_2$. Namely, \begin{eqnarray*} e + \mathrm{CF}_2 & \rightarrow & e + \mathrm{CF}_2^*(^3B_1), \\ e + \mathrm{CF}_2 & \rightarrow & e + \mathrm{CF} + \mathrm{F}, \\ e + \mathrm{CF}_2^*(^3B_1) & \rightarrow & e + \mathrm{CF}_2, \\ e + \mathrm{CF}_2^*(^3B_1) & \rightarrow & e + \mathrm{CF} + \mathrm{F}, \end{eqnarray*} the addition of which leads to a significant change in the concentration of CF$_2$. These electron-impact reaction rates are derived from cross-section calculations using Quantemol-N[1]. Measured etch-rates from an equivalent CCP tool are used to validate the model. [1] J. Tennyson et al, J. Phys.: Conf. Ser., 86, 012001 (2007)