Optical Emission Spectroscopy Measurement of Processing Plasmas

Abstract

The present paper reviews fundamentals of optical emission spectroscopy (OES) of plasmas and, in particular, its applications to processing plasmas. Collisional radiative model is described to understand the excitation kinetics and population distributions of excited states in order to examine the electron temperature and density. It is shown that corona equilibrium is often adopted as justifiable assumption of excitation kinetics for general processing plasmas. Two OES methods to understand molecular gas discharge plasmas are also reviewed. One of them is to determine vibrational or rotational temperatures of molecular gas discharge plasmas by OES measurement. The other is the actinometry measurement method to examine neutral radical density.