Use of the ultraviolet absorption spectrum of CF 2 to determine the spatially resolved absolute CF 2 density, rotational temperature, and vibrational distribution in a plasma etching reactor

Abstract

The CF 2 densities in a plasma etch reactor used for industrial wafer processing were determined using broadband ultraviolet absorption spectroscopy. The absorption cross sections of CF 2 at selected wavelengths, used for calculating the number densities from the experimental spectra were determined using Franck Condon factors. The number densities of CF 2 were also determined in different regions of the plasma, including the center of the plasma and outside the plasma volume. The CF 2 rotational temperatures and vibrational energy distributions were also estimated.