An atmospheric-pressure plasma process for C₂F₆ removal

Perfluorocompounds (PFCs) are widely used in the semiconductor industry for plasma etching and chemical vapor deposition (CVD). They are relatively inert gases that intensely absorb infrared radiation and, therefore, aggravate the greenhouse effect. A bench-scale experimental system was designed and constructed to evaluate the effectiveness of C₂F₆ conversion by using dielectric barrier discharges (DBD) with atmospheric-pressure plasma processing. Experimental results indicated that the removal efficiency of C₂F₆ increased with applications of higher voltage and frequency. Combined plasma catalysis (CPC) is an innovative way for abatement of PFCs, and experimental results revealed that combining plasma generation with catalysts could effectively enhance C₂F₆ removal efficiency achieved with DBD. The major products of C₂F₆ with DBD processing include CO₂, COF₂, and CO, when O₂ was included in the discharge process. Experimental results indicated that as high as 94.5% of C₂F₆ were removed via CPC at applied voltage of 15 kV, frequency of 240 Hz in the gas stream of N₂:Ar:O₂:C₂F₆ = 50:40:10:0.03.