New GWP Values – Affect on the 2010 PFC Emissions Goals
Van Gompel, Joe; Cottle, Steve
(Exhaust Gas Management)
The World Semiconductor Council has set a goal for the semiconductor idustry to reduce fluorocarbon (FC) emissions by 10% based on kg carbon based 1995 emissions. The original strategies devised by fabs were based on global warming potentials (GWPs) for individual FCs that were released by the IPCC in their Second Assessment Report in 1996. Some of the GWP factors have changed dramatically in the Third Assessment Report in 2001, most notably CHF3 (23% increase), CF4 (30% increase), and NF3 (115% increase). The Fourth Assessment Report (November 2007) will have more changes. The semiconductor industry has seen a dramatic shift to NF3 in chamber cleaning steps from C2F6. Even though it is a potent global warming gas in itself, NF3 is also very well utilized in the process chamber and realizes a net decrease in global warming emissions over C2F6. However, the higher GWP values of CHF3 and CF4 put added emphasis on the impact of etch processes on the global warming emissions of a fab. This presentation will present some scenarios and examine the effect of the different GWPs on simulated fab emissions.