Design of a Plasma Abatement System for Perfluoronated Compounds

The plasma abatement system co-developed by Rf Environmental, Inc. and Texas A & M University has been effective at destroying the global warming gases CF4 and C4F8. The destruction of greenhouse gases, specifically perfluorocompounds, hydrofluorocompounds, chlorofluorocompounds (PFCs, HFCs, CFCs) and SF6, is paramount to significantly affecting atmospheric pollution. The premise of this study was to examine the design of the plasma abatement system for Global Warming Gases (GWGs) and its abatement potential for these gases.

The first goal was to reduce the cost of ownership by examining the cooling system. The cost of an air cooling design was $1400/yr. The intent was to reduce the amount of air used or use a different medium that would produce the same amount of heat transfer. A liquid cooling system design had a cost of only $150/yr. A C4F8 abatement experiment was run on the liquid cooling design. The abatement process resulted in a destruction removal efficiency (DRE) of C4F8 of 97.5 percent. A lower operational cost unit was developed, but the operational performance was less than previous investigations.

The second goal was to simulate the semiconductor radio frequency etching process and abate the output gases of the C4F8 and SiO2 reaction. The outcomes of this experiment included a microwave simulation of the radio frequency etching reaction and an abatement that resulted in a 99.98 plus/minus .05 percent DRE for C4F8 with no formation of any other CFC gases.

The third goal was to simulate the etching process and abate the output gas, CF4 using H2O vapor as the additive gas. The outcomes of this experiment included a microwave simulation of the radio frequency etching reaction and an abatement that resulted in a 99.96 plus/minus .05 percent DRE for CF4 with no formation of any other CFC gases.

A low cost of ownership and effective abatement levels will make this system viable for commercial use. The latest data shows the amount of PFC emissions from the semiconductor industry was 3.6 Tg CO2 Eq. The use of this or a similar abatement technology will have a significant impact on reducing environmental pollution.