Plasma Diagnostics and Modeling of Inductive-Coupled SF6 Plasma Reactor

• Main Authors: Sih-Jyun Peng, 彭思君
• Other Authors: Ta-Chin Wei
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/52981811871752191590

碩士 === 中原大學 === 化學工程研究所 === 94 === Abstract In this study, the characteristics of inductively coupled SF6 plasma were investigated using mass spectrometry, optical emission spectroscopy and Langmuir probe. A combination of experimental diagnostics and computational modeling was utilized to understand the main reaction mechanism in an inductively coupled SF6 plasma reactor. The plasma diagnostics results show that the main dissociation mechanism in SF6 plasma is electron-impact dissociation of SF6 to form SF3 and SF2 radicals. The dominant positive ion is SF5+ at low RF power. As the input power is increased, SF3+ and SF2+ ions become the dominant ions. The fluorine atom concentration and the SF6 conversion increase with the input power. Langmuir probe results show that electron density, electron temperature and electro-negativity are variable in a wide range from 4.6×107 to 1.9×109cm-3, from 7.5 to 4.0eV and from 429 to 10, respectively. In addition, the electron energy distribution function (EEDF) is quite Maxwellian in SF6 plasma. A global model was developed to calculate the species density under various operating conditions. It was found that pure ICP model significantly overestimates the electron density, and the ICP-CCP composite model is able to capture most of the experimentally observed trends. Moreover, by comparing the amorphous Si etch rates with model predictions, the wall recombination coefficient of F-atoms on the plasma chamber is about 0.01 to 0.02.