Collisional-radiative modeling on optical emission spectroscopy for argon plasmas*

Optical emission spectroscopy (OES) which is comparatively simple, versatile, and non-intrusive, has been widely used in diagnostics to low-temperature plasmas such as capacitively-coupled plasma (CCP) and inductively-coupled plasma (ICP) for their numerous applications in analytical chemistry and microelectronic processing. The plasma parameters such as electron temperature and density can be determined by the OES combined with collisional-radiative modeling (CRM) for the population kinetics taking into account all possible collisional and radiative processes of atoms and ions in plasma. We have carried out OES and CRM for CCP and ICP systems and the spectroscopic results for Ar plasma depending on gas pressure, applied rf power, and electron temperature/density are presented and analyzed. The electron temperature and density determined by our OES and CRM have been compared with those by a Langmuir probe. The sensitivity of the CRM to the underlying atomic data, optical trapping, and electron energy distribution function is discussed in detail.