Advances in Measurements of Electron Temperature and Density in Low-pressure Plasmas Using Optical Emission Spectroscopy and Data Science Techniques

This presentation reports measurement method of electron temperature and density resolved spatially by optical emission spectroscopy of low-pressure inductively-coupled argon plasma, and of low-pressure plasma for plasma etching using argon as the parent gas. In order to interpret the spectral intensity of observed lines, a collisional-radiative model must be employed. Recently, there has been progress in the method of searching for input values of electron temperature and density that can reproduce the measured level density as accurately as possible by directly applying the CR model. It was necessary to investigate the parameter dependence of each level density over a wide range of electron temperature and density, but the application of the trust region method made it possible to perform simple measurements. Recent advances in tomographic spatially resolved measurement techniques are also presented.