Spatially Resolved Electronic Temperatures, Species Concentrations and Electron Energy Distributions in Inductively-Coupled Chlorine Plasmas, Measured by Trace-Rare Gases Optical Emission Spectroscopy

Determining the spatial dependence of charged and neutral species concentrations and energies in inductively coupled plasmas (ICP) is important for understanding basic plasma chemistry and physics, as well as for optimizing the placement of the wafer with respect to the ICP source to maximize properties such as etching rate uniformity, while minimizing charging-induced damage and feature profile anomalies. We have determined the line-integrated electron temperature and Cl-atom number density as a function of the distance from the wafer in a chlorine ICP, using trace rare gases optical emission spectroscopy (TRG-OES).