Application of surface wave plasma technology for effective abatement of
environmentally harmful gases such as perfluorocompounds and chlorofluorocarbons is
investigated. Perfluorocompounds (PFCs) are gases that contribute to forced global
warming and have been favored for wafer etch and chamber clean applications in the
semiconductor industry. Chlorofluorocarbons (CFCs) are ozone depleting gases that
were used as refrigerants for commercial and domestic condensers and air conditioners,
but current reserves still pose threats to environmental sustainability. Increased average
global temperatures and further destruction of the ozone layer have prompted proposal
of international initiatives such as the Montreal Protocols and the Kyoto Agreement to
curtail emissions of such fugitive gases into the environment. These have increased the
need for effective abatement technologies to control such emissions and include surface
wave plasma abatement, the subject of this dissertation. Surface wave plasmas are
considered high frequency non-equilibrium traveling wave discharges in contrast to the
more frequently used standing wave discharges. The use of surface wave plasmas have
the advantages of a variety of discharge vessel shapes, reproducibility of application, numerous operating conditions and large plasma volumes which ultimately produce low,
molecular weight byproducts that are associated with high effective electron
temperatures but low heavy particle temperatures. For these reasons, surface wave
plasma abatement technology was developed for the destruction and removal of PFCs
and CFCs.
Results include final destruction and removal efficiencies (DREs) for
octafluorocyclobutane greater than 99.8%, dichlorodifluoromethane greater than
99.995% and trichlorofluoromethane greater than 99.999% using moderate applied
microwave powers of less than 2000 watts with the production of low molecular weight
byproducts, such as CO2, CO, HF and HCl, that prevent environmentally harmful
process emissions from entering the atmosphere. Characterizations of the initial and
final products were accomplished by the use of Fourier transform infrared spectroscopy
and quadrupole mass spectrometry to provide independent quantitative analyses of
plasma processes. In addition to these analytical methods, Global_Kin a kinetic model,
of plasma reactions were conducted and compared to all the experimental data
determined in order to facilitate understanding of the chemistry involved in the surface
wave plasma abatement applications studied. Basic plasma reaction mechanisms were
determined for the abatement of octafluorocyclobutane and dichlorodifluoromethane.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/4734 |
| Date | 25 April 2007 |
| Creators | Frantzen, Michelle E. Gunn |
| Contributors | Bevan, John W |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 780528 bytes, electronic, application/pdf, born digital |
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