Data and modeling of negative ion transport in gases of interest for production of integrated circuits and nanotechnologies

Abstract

We review techniques to prepare, evaluate and apply sets of cross section and transport data for negative ions that are required for the modeling of collisional non-equilibrium plasmas used for processing of microelectronic circuits. We collect and discuss the transport coefficients and cross section sets.We have compiled data for negative ions in CF4 and CF4-related negative ions in rare gases. In addition, we consider data for F− and CF3− in rare gases. Furthermore, we analyze the cross sections of halogen negative ions in rare gases and other molecules. This is followed by the data for SF6 related ions in SF6 and in rare gases. The cross section for scattering of O− in O2 has been derived from the transport data and used to make calculations of the transport properties. Finally we give a brief discussion of the availability of the data for H− ions in H2. We have derived cross sections in several cases but the basic aim is to show the basic features of transport coefficients. In particular we discuss the need to represent properly some details such as the non-conservative nature of transport coefficients and the anisotropy of diffusion. Application of approximate theories and representations of cross sections are also discussed.