플라즈마 공정을 위한 2차원 플라즈마 진단 및 플라즈마 특성 분석 연구

Abstract

In this paper, a real time measurement method for two-dimensional (2D) spatial distribution of plasma is developed based on the floating harmonic method, and studies on plasma discharge characteristics are performed by using the measurement method. The details of our measurement method, such as the principle of diagnostic method, measurement circuit, and data plotting algorithm, are described, and experimental results under various discharge conditions (input power, gas pressure, gas mixing ratio, etc) are given. The dramatic changes in the plasma uniformity are observed with changing the external variables, and these are explained by diffusion effect, electro-negativity, and E-H heating mode transition. In addition, the Boltzmann relation, which is a fundamental characteristic of plasmas, is investigated in argon and oxygen plasmas by changing the gas pressure and gas mixture ratio. Especially in oxygen discharge, the Boltzmann relation is broken at relatively low pressures, and this can be explained by the difference of the collisional loss process. The Boltzmann relation for escaping electrons is also investigated. This can be verified by generalized Boltzmann relation which describes the non-local electron kinetics.