Abatement of C2F6 in rf and microwave plasma reactors

Experimental results in a low temperature, low power density rf plasma reactor show that C2F6 can be decomposed by plasma reaction with oxygen, but CF4, an undesirable byproduct, is produced. Previously, it had been shown in a high temperature, high power density microwave reactor that C2F6 can be decomposed without CF4 formation. Calculations show that low temperature neutral species kinetics favor the formation of CF4 over COF2, while the opposite is true at high temperature. Further, a high degree of feedstock dissociation such as that observed in high density plasma reactors is predicted to lead to very little CF4 formation. Calculations show that adding hydrogen, water, or hydrocarbons to the C2F6+O2 mixture should reduce the power necessary for abatement, and will reduce CF4 formation. Hydrogen is predicted to getter atomic fluorine to form thermodynamically stable HF, and thus prevent perfluorocompound reformation.