CF4 decomposition of flue gas from semiconductor process using inductively coupled plasma

Flue gases from semiconductor process, per-fluorinated compounds (PFCs) and hydrofluorinated compounds (HFCs) such as NF/sub 3/, CF/sub 4/, C/sub 2/F/sub 6/, CHF/sub 3/ and SF/sub 6/, are being regulated internationally because their gases cause green effect and have more than 5,000 times GWP (Global Warming Potential) in comparison of CO/sub 2/. PFCs are used as wafer etching and clean up of chemical vapor deposition (CVD) chambers. CF/sub 4/ is one of the most stable gases among PFCs and their decomposition is extremely difficult. CF/sub 4/ decomposition was investigated at low pressure (/spl sim/53.3 Pa) using inductive coupled plasma (ICP) reactor, which can be used to generate remote plasma in wafer etching process and chamber cleaning. When the total flow rate was below 0.26 SL/min, the complete CF/sub 4/ decomposition efficiency was achieved for a given power. However, when the total flow rate exceeded 0.26 SL/min, the CF/sub 4/ decomposition efficiencies decreased. The power of 1.2 kW was required in order to achieve more than 94% of the CF/sub 4/ removal efficiency when the total flow rate was 0.24 SL/min. The optimum amount of O/sub 2/ additive was about the same stoichiometric amount of CF/sub 4/. The Ar additive enhanced the decomposition of CF/sub 4/. On the other hand, the He additive was insignificant.