By Shou-Nan Li, Hui-Ya Shih, Jui-Hsiang Cheng, Jung-Nan Hsu, Kuang-Sheng Wang, Industrial Technology Research Institute, Hsinchu, Taiwan, and
Chun-Nan Lin, Winbond Electronics Corp., Hsinchu, Taiwan

The semiconductor industry has taken a leadership role in setting targets for reduced emissions of harmful perfluorocompounds (PFCs) into the earth’s atmosphere. Members of the World Semiconductor Council have voluntarily committed to lowering PFC emissions substantially by 2010. New measurements from advanced abatement systems and manufacturing tools now show the industry could be overstating PFC emissions when using existing Tier 2C Method default values to estimate the global warming potential (GWP) of fabs. A study shows these default values should be revised to accurately reflect improvements in abatement technology and the use of PFCs inside equipment.

Members of the World Semiconductor Council (WSC), including trade groups in the US, Europe, Japan, Korea, and Taiwan, have voluntarily committed to substantially reduce the emissions of perfluorocompounds due to their potential global warming effects. The “PFCs” term used by WSC members covers a range of gas compounds, including perfluoromethane (CF4), perfluoroethane (C2F6), perfluoropropane (C3F8), perfluorocyclobutane (C4F8), trifluoromethane (CHF3), nitrogen trifluoride (NF3) and sulfur hexafluoride (SF6). These PFCs are used for chamber cleaning of chemical vapor deposition (CVD) process tools and for dry etching of wafers. To estimate annual PFC emissions and then to monitor the progress of emission reduction, WSC members unanimously adopted the Tier 2C Method, which is published by the Intergovernmental Panel on Climate Change (IPCC). [1]