Total toxicity equivalents emissions of SF_6, CHF_3, and CCl_2F_2 decomposed in a RF plasma environment

摘要

Sulfur hexafluorine compound (SF_6), trifluoromethane (CHF_3) and diclorodifluoromethane (CCl_2F_2) are extensively used in the semiconductor industry. They are global warming gases. Most studies have addressed the effective decomposition of fluorine compounds, rather than the toxicity of decomposed by-products. Hence, the concepts of toxicity equivalents (TEQs) were applied in this work. The results indicated that HF and SiF_4 were the two greatest contributors of TEQ to the SF_6/H_2/Ar plasma system, while F_2 and SiF_4 were the two greatest contributors to the SF_6/O_2/Ar system. Additionally, SiF_4 and HF were the two greatest contributors of TEQ to both the CHF_3/H_2/Ar and CHF_3/O_2/Ar plasma systems. HF and HCl were the two greatest contributors of TEQ to the CCl_2F_2/H_2/Ar plasma system, and Cl_2 and COCl_2 were the two greatest contributors to the CCl_2F_2/O_2Ar system. HC1 and HF can be recovered using wet scrubbing, which reduces the toxicity of these emission gases. Consequently, the hydrogen-based plasma system was a better alternative for treating gases that contained SF_6, CHF_3 and CCl_2F_2 from the TEQs point of view.