Abatement of C2F6 in rf and microwave plasma reactors

Experimental results in a low temperature, low power density rf plasma reac tor show that C2F6 can be decomposed by plasma reaction with oxygen, but CF 4, an undesirable byproduct, is produced. Previously, it had been shown in a high temperature, high power density microwave reactor that C2F6 can be d ecomposed without CF4 formation. Calculations show that low temperature neu tral species kinetics favor the formation of CF4 over COF2, while the oppos ite is true at high temperature. Further, a high degree of feedstock dissoc iation such as that observed in high density plasma reactors is predicted t o lead to very little CF4 formation. Calculations show that adding hydrogen , water, or hydrocarbons to the C2F6+O-2 mixture should reduce the power ne cessary for abatement, and will reduce CF4 formation. Hydrogen is predicted to getter atomic fluorine to form thermodynamically stable HF, and thus pr event perfluorocompound reformation. (C) 2000 American Vacuum Society.