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

Pei & Worth 2 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing 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 C2F6, are made solely for use in semiconductor manufacturing Most PFC gas is not “consumed” in the etch and CVD processes

Pei & Worth 3 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing 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 4 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing PFC Lifetimes and GWPs GWP = Global Warming 100 year time horizon Source: IPCC

Pei & Worth 5 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Global Warming Potential (GWP) The following equation is used to calculate GWP: GWP t =   t 0 a i c i dt a c dt co 2 t 0 where: 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 6 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Million Metric Tons Of Carbon Equivalents (MMTCE) MMTCE = 12 x Kg x GWP GWP 100 = global warming potential at 100 yr. time horizon Kg = weight of PFC emitted

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

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

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

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

Pei & Worth 11 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing 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 12 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Chronology - PFC Technology Development (Cont’d) -Edwards develops and SEMATECH tests prototype burnbox -MIT successfully destroys destruction of PFCs in microwave reactor -Novellus and 3M develop C3F8 as C2F6 replacement 1996-Beta testing of PFC capture technologies Air Products/Radian at TI Air Liquide at TI BOC at IMEC

Pei & Worth 13 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing 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 -DuPont announces PFC replacement studies