(A) study on characteristics of $SF_6$/$O_2$ capacitive discharge with QMS and Langmuir probe사중극자 질량 분석기와 랑뮈어 탐침을 이용한 $SF_6$/$O_2$ 축전 결합 플라즈마의 특성에 관한 연구
The $SF_6$/$O_2$ CCP plasma is widely used in industry. To measure and control etching characteristic, relation between etching ions/radicals and plasma property are searched. QMS and Langmuir probe are used to measure $n_2, T_e,$ EEDF and positive ion ratio. The experiment is done under fixed pressure of 50 mTorr. Firstly the $SF_6$ mixing ratio in the total gas is changed. Secondly the current applied to the electrode is changed. The relation between $n_e, T_e$ and relative F positive ion density shows discrepancy between the two experiments. However EEDF graph reveals a common underlying relation in the two experiments. By observing electron densities of high energy tail, in-situ monitoring of etching profile is possible.