High-Performance Decomposition and Fixation of Dry Etching Exhaust Perfluoro-Compound Gases and Study of Their Mechanism

Abstract

We report on the high-performance decomposition and fixation of perfluoro compounds (PFCs) exhausted from dry etching processes and their reaction mechanism with the fixation material prepared from Ca(OH)2 and Al(OH)3 mixture. Using gas chromatography–mass spectrometry (GC–MS), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and other analysis methods, it was found that PFCs were successfully decomposed and fixated by the reaction only with calcium compounds, resulting in calcium fluoride (CaF2). Aluminum compounds existing very close to calcium compounds work as a catalyst so that the reaction progresses at much lower temperatures, in the range of 650 to 750 °C, compared with the direct decomposition by combustion. The reaction mechanism is discussed on the basis of the proposed microscopic reaction model. These results are useful for the development of more efficient abatement systems for the greenhouse gases in the exhaust of dry etching processes.