Global Warming Science Status and Statistics Phyllis Pei

Global Warming Science: Status and Statistics Phyllis Pei Walter Worth Sematech 1999 Arizona Board of Regents for The University of Arizona Pei & Worth NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing 1

Perfluorocompounds (NF 3, SF 6, C 2 F 6, CF 4, CHF 3) • Have long atmospheric lifetimes • Stable, non-toxic • Strong infrared absorbers • Continuing emissions will likely accumulate with unknown consequences • Some, such as C 2 F 6, are made solely for use in semiconductor manufacturing • Most PFC gas is not “consumed” in the etch and CVD processes Pei & Worth NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing 2

Key Greenhouse Gases Affected by Human Activity ATMOSPHERIC CONCENTRATION NOTE: H 2 O has largest greenhouse effect, but is not affected by human sources and sinks Pei & Worth NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing 3

PFC Lifetimes and GWPs GWP = Global Warming Potential @ 100 year time horizon Source: IPCC NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Pei & Worth 4

Global Warming Potential (GWP) The following equation is used to calculate GWP: t �a i c i dt 0 GWPt= where: t �a co 2 cco 2 dt 0 a 1 = the instantaneous radiative forcing resulting from a unit increase in the atmospheric concentration of trace gas, i c 1 = concentration of trace gas, i, remaining in the atmosphere at time, t, after release of unit mass at t=0 t = number of years over which the calculation is performed Pei & Worth NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing 5

Million Metric Tons Of Carbon Equivalents (MMTCE) MMTCE = 12 x Kg x GWP 100 44 109 GWP 100 = global warming potential at 100 yr. time horizon Kg = weight of PFC emitted Pei & Worth NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing 6

Global Warming Calculations Wavelength & Molecular Size & Lifetime [ Rad. Forcing & Conc. & Time ] { [GWPt] & Mass } { Million Metric Tons Carbon Equivalent } Pei & Worth NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing 7

U. S. Greenhouse Gas Emissions Each source, although small, contributes to the whole Pei & Worth NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing 8

PFC Emissions/Use Chart Data Source: EPA & Dataquest Tons/year Pei & Worth NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing 9

1993 PFC Purchases (U. S. Semiconductor Industry) 1993 Purchases of PFCs (metric tons) Pei & Worth NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing 10

Chronology - PFC Technology Development 1994 - Tested first commercial PFC thermal destruction device (Delatech’s CDO) - Alzeta develops and installs first inwardly-fired burner at SEMATECH - MIT starts screening PFC alternative chemicals 1995 - Alzeta licenses burner technology to Edwards IBM demonstrates 50% C 2 F 6 reduction by process optimization Pei & Worth NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing 11

Chronology - PFC Technology Development (Cont’d) - Edwards develops and SEMATECH tests prototype burnbox - MIT successfully destroys destruction of PFCs in microwave reactor - Novellus and 3 M develop C 3 F 8 as C 2 F 6 replacement 1996 - Beta testing of PFC capture technologies • Air Products/Radian at TI • Air Liquide at TI • BOC at IMEC Pei & Worth NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing 12

Chronology - PFC Technology Development (Cont’d) - Schumacher unveils potential PFC alternative (TFAA) - C 3 F 8 is being evaluated in fabs at TI and AMD as drop -in replacement for C 2 F 6 - Edwards improves burnbox to destroy CF 4, tested at Motorola - Du. Pont announces PFC replacement studies Pei & Worth NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing 13