High-Efficiency PFC Abatement System Utilizing Plasma Decomposition and Ca(OH) $_{2}$ /CaO Immobilization

In order to minimize contributions to global warming, it is important to develop a perfluorocompound (PFC) abatement system that can remove PFCs effectively with low electric power. We have developed a new PFC abatement system consisting mainly of a 2-MHz ICP plasma source and two Ca(OH)₂/CaO columns operated under a decompression pressure. Reactive fluorinated compounds including SiF₄ are immobilized in the Ca(OH)₂/CaO columns without a water scrubber. Stable compounds such as CF₄ are excited by the 2-MHz ICP plasma. When the emissions from an Si oxidation film etching process chamber were treated by this abatement system, F₂ equivalent removal efficiency was 99.6%, which was about one order of magnitude larger than that of a conventional abatement system. But the CO₂ equivalent removal efficiency was calculated to be 91.4% because over 95% of CO₂ equivalent emissions were caused by the plasma source power consumption of 2.4 kWh. It means that minimization of the plasma source power consumption, depending on PFC emissions, is a very effective method of minimizing contributions to global warming in a manner similar to improving the PFC removal efficiency.