Projecting PFC Emissions Using EPA’s PFC Emissions Vintage Model

1. Projecting PFC Emissions Using EPA’s PFC Emissions Vintage Model Presented at 9th Annual ISESH Conference June 9 – 13, 2002 San Diego, CA C. Shepherd Burton* Scott Bartos Consultant U. S. Environmental 2047 Huckleberry Rd. Protection Agency San Rafael, CA 1200 Pennsylvania Ave. Washington, DC

2. Outline • Introduction • Some considerations • PEVM: Formulation and structure • Results: 2010 Projections … • Key Uncertainties, limitations and caveats • Summary of findings

3. Introduction • Semiconductor manufacturing: At threshold of low to zero emissions future • Path to threshold well documented • Recognition of environmental risks of PFC emissions • Broad industry cooperation • International government-industry cooperation • Challenge ahead: Achieving aggressive WSC reduction goal by 2010 • What to do? • Our aim: Contribute to collective sense of what can be done using emissions modeling

4. Some Considerations • IPCC vs. PEVM: Bottoms-up and top-down methods • Are PFC emissions correlated with Si consumption? • Si demand: Historical and projected patterns • Trends in complexity and effect of copper on interconnects on emissions

5. IPCC estimation method Bottoms-up: Company inventories Q(MMTCE) = usage x (1 – UF) x (1 – DE) Tiered: Rigor varies Arguably impractical for projecting industry emissions Si - consumption method Top-down: Not now used <Q(MMTCE)> = Si x gas-process EF “Global” EF to be developed Partner reports and public information Arguably practical for projecting PFC emissions IPCC vs. PEVM: Bottoms-up and top-down methods

6. Partner Reported ‘99 MMTCE’s vs. MSI Si-Layers (2000 WFW SEMI)(Values not shown to preserve Partner confidentiality)

7. Correlating Partner PFC Emissions Totals (MMTCE) and MSI Silicon x Nominal Number of Layers

8. Historical and Projected Si Demand by Linewidth, 1988 - 2010

9. Process Complexity Trend

10. Reducing metal layers by switching from Al to Cu: How many?

11. Model Formulation, Structure and Operationalization • Formulation • Structure, sources of information and operationalization • Comparison of emissionsfactors

12. PEVM: Formulation and Structure • <PFC Emissions(y)> ≡ gas-process avg. PFC emissions in year, y • <PFC Emissions(y)> ≡ Ē(y) x S(y) • Definition of Ē(y), an emissions factor for uncontrolled emissions, MMTCE per unit area of Si consumed • <PFC Emissions(y)>, from Partner emission reports • S(y),from SEMI WFW database and VLSI Research, Inc. world Si consumption figures • Result: Estimate of Ē(y), does NOT account for complexity

13. PEVM Formulation and Structure: Accounting for “Complexity” • <PFC Emissions(y)> = Ē(y) S(y) = Σi λi(y) si(y)ē(y) λi(y) = nominal no. of layers for technology node i and year y (from ITRS); si(y) = Si consumed (from VLSI Res., Inc.) for node i ē(y) = avg. gas-process emissions per unit of area of Si consumed per average layer • ē(y) = Ē(y)/<λ(y)>; <λ(y)> = (1/ S(y)) Σiλi(y) si(y) • Result: Est. of gas-process average uncontrolled emission factor

14. PEVM Formulation and Structure:Integrating Concept and Mathematics • <PFC Emissions(y)>≡ Ē(y) x S(y) = Σiλi(y)si(y)ē(y) = Σi<PFC Emissions(y)>i • Result: Project uncontrolled gas-process average(BAU) emissions using <ē> = Avg(ē(y))and projected si(y) and λi(y)

15. Projecting Emissions Sources & Types of Information Method for Estimating PFC-Process Average Emission Factors Projecting Si Demand to 2010 Annual PFC Emissions Totals, ’95-’99 Partners U. S. share of world layer-weighted capacity, %, 1995 - 2000 U. S. Si demand by linewidth, in2 Si, 1988 - 2010 World Fab Watch databases: ownership, location, capacity, geometry, etc. ’95-’99 SEMI Partner PFC-Process average emission factors (MMTCE/in2 Si) 1995, ’96, ’97, ’98 & ‘99 U. S. PFC emissions by linewidth 1988 – 2010 MMTCE World CAGR for Si demand, 1988 - 2005 World Si demand (in2) by linewidth, 1988 - 2010 World Si Demand, wafer size, in2 , ‘83-’05 Partner per-average-layer emission factors (MMTCE/in2Si*layer) 1995, ’96, ’97, ’98, ‘99 Linewidth-specific emission factors (MMTCE/in2 Si), Avg. ’95-’99 World PFC emissions by linewidth 1988- 2005 MMTCE Adj. for full- process test wafers VLSI Research, Inc. World Si Demand, device type, ’83-’05 Analysis: Adoption/decay profiles for future technology nodes World Si Demand, linewidth, in2, ’83-’05 Compare calc. Partner avg. utilization with available world reports. Avg. number of layers/node Specs & outlook for industry ITRS Effect of Cu interconnect on number of wiring levels (layers) Test wafers full processed, Cu effect on layers, industry capacity utilization, etc. Industry Reports Schematic of EPA’s PFC Vintage Model (v.2.14) for Projecting US PFC Emissions from Semiconductor Manufacturing

16. Avg. PFC-Process Emission Factors:Formation of Ē(y) , ē(y) and <ē>

17. Some Results: Application of PEVM • Projected U. S. emissions: without and with Cu • Comparison of PEVM and IPCC-like Method

18. Projected PEVM PFC U. S. Emissions: With Cu, No Reduction Technology

19. Projected PEVM PFC U. S. Emissions: Without Cu, No Reduction Technology

20. Comparing PEVM and IPCC-like Method • IPCC-like Method: Extrap. DataQuest ’90 – ’96 survey figures • ~18 MMTCEs cf. 15 and 16 MMTCEs PEVM with and without Cu, respectively • CAGR: 20%, ’95 – ’10 period, IPCC-like • Partnership CAGR: 13%, ’95 – ’99 period

21. Key Assumptions, Uncertainties and Limitations • Emission factors: reflect process-gas average • Silicon projections: changes by wafer size and technology generation; metal layers across markets (MPUs, memory, logic, etc.) • Disaggregating avg. process-gas, node-specific emissions factors, <ē>λi(y): formation of process/gas-specific emission factors • Reduction cases: Selecting technology DEs and penetration rates for alternative control strategies • Estimating U. S. share of world emissions

22. Findings • Avg.emissions per unit of Si consumed per average layer appears a robust concept • BAU projections: PEVM PFC emissions estimates compare favorably with bottoms-up IPCC-like method • BAU 2010 projections with Cu: PEVM gives ~8 times corresponding 1995 emissions • PFC reduction technologies: On average >90% DE implemented at 200 mm and 300 mm fabs