Application of surface wave plasmas as an innovative technology for the destruction and removal of perfluorocompounds (PFC) emanating from semiconductor fabrication tools is demonstrated. The destruction of parts per thousand (ppt) concentrations of hexafluoroethane, C2F6, in oxygen and natural gas mixtures has been investigated as a function of microwave power in a low-pressure plasma reactor at 11.3 Torr. Effluent analysis included the determination of destruction and removal efficiencies (DRE) and product distributions by Fourier transform infrared spectroscopy and mass spectrometry. Destruction and removal efficiences of up to 99.6% for C2F6 were achieved using applied microwave powers from 500 to 2000 W, which corresponded to millisecond range residence times within the plasma. Product analysis indicated that hexafluoroethane conversion was limited to low molecular weight gases such as CO2, CO, COF2, H2O, and HF. CF4 was not produced as a plasma byproduct in any significant quantities. These investigations indicate that surface wave plasma destruction of perfluorocompounds at the point of use is a viable nonintrusive abatement technology for application to semiconductor manufacturing tools.

Projected exponential growth in semiconductor device manufacture over the next few years demands technology to reduce the corresponding increase in etchants such as perfluorocompounds (PFCs), CHF 3 , and SF 6 that would be emitted into the atmosphere. These compounds are a cause for concern because of their large global warming potentials relative to CO 2 and of their long lifetimes in the atmosphere, often tens of thousands of years. We demonstrate that a plasma-based technology can yield effective (up to 99.9%) destruction and removal efficiencies (DREs) for CF 4 and CHF 3 present in etch recipes widely used in the semiconductor industry. Specifically, we report application of surface wave plasmas at 2.45 GHz for this purpose. Post-plasma effluent analysis included the determination of DREs and product distributions, simultaneously by gas-phase FTIR and QMS. Application of microwave powers from 500 to 1950 W were investigated and DREs for CF 4 and CHF 3 reported. Final product analysis indicated that PFC conversion was limited to low molecular weight gases such as CO 2 , CO, COF 2 , H 2 O, and HF. These investigations demonstrate that surface wave plasma destruction of the referenced PFCs at the output of semiconductor etch tools is a viable nonintrusive point of use abatement technology.