- What are perfluorocompounds (PFCs) and why is EPA concerned?
- How do semiconductor manufacturers use PFCs?
- What is the goal of the PFC Reduction / Climate Partnership for the Semiconductor Industry?
- How do I know this partnership will work for my company?
- Can PFC emissions from semiconductor manufacturing be reduced?
1. What are perfluorocompounds (PFCs) and why is EPA concerned?
PFCs are highly potent greenhouse gases. With global warming potentials (GWPs) in the thousands, PFCs absorb infrared radiation (i.e., heat) and trap it in the atmosphere very effectively. PFCs are also generally very stable chemicals and therefore possess atmospheric lifetimes from 264 to 50,000 years. Consequently, these gases will accumulate in the atmosphere and their effect on the climate will be felt by many future generations. Please visit EPA’s Climate Change Web site for more information on the impacts of climate change.
2. How do semiconductor manufacturers use PFCs?
PFC gases are used for both etching intricate circuitry features on silicon wafers and for cleaning chemical vapor deposition (CVD) tool chambers. PFCs are energized and dissociated in plasmas to provide reactive fluorine atoms in the manufacturing tool chambers. In the case of plasma etching, the free fluorine atoms selectively react with and remove insulating and/or conductive materials from the exposed surface of a silicon wafer to create the intricate circuitry patterns found on modern semiconductors. In CVD tool chamber cleaning applications, the fluorine atoms react with and remove excess materials from the surface of the tool chambers themselves.
3. What is the goal of the PFC Reduction / Climate Partnership for the Semiconductor Industry?
The goal of the PFC Reduction/Climate Partnership is to reduce PFC emissions from U.S. and world semiconductor manufacturing by identifying and implementing the most cost-effective strategies and technologies. In April 1999, the U.S. partners and the World Semiconductor Council committed to reduce PFC emissions 10 percent below their 1995 baselines by 2010. Since PFC use in Korea and Taiwan was negligible in 1995, their baseline years are 1997 and the average of 1997 and 1999 respectively.
4. How do I know this partnership will work for my company?
The partnership is extremely flexible, and provides partners with broad latitude to pursue the goal of reducing PFC emissions. Partner companies are investigating and implementing a range of pollution prevention strategies and reporting their results at annual industry conferences such as Semicon West. Technical information sharing among otherwise highly competitive firms is one of the greatest benefits derived from EPA’s voluntary partnerships with industry.
5. Can PFC emissions from semiconductor manufacturing be reduced?
Yes, PFC emissions from semiconductor manufacturing can and are being reduced. EPA’s partners are implementing a variety of emission reduction strategies such as optimizing (i.e., fine tuning) their production processes to use and emit less PFC gas and switching to use alternative input gases, for example NF3, which are utilized more efficiently in the process thereby emitting much less PFC into the exhaust stream. The partners’ individual PFC emission reduction strategies vary greatly depending on the companies’ product and equipment mix as well as future business plans.