Water: A Key Process Fluid and an Environmental Bottleneck in Semiconductor Manufacturing

1. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Water: A Key Process Fluid and an Environmental Bottleneck in Semiconductor Manufacturing Farhang Shadman University of Arizona  1999 Arizona Board of Regents for The University of Arizona

2. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Water Usage In Semiconductor Plants Goal: Significant reduction in water use for the next three years: 2-3 fold reduction in UPW usage per in2 of Si for the 300 mm wafers. Shadman 148

3. WATER AND ENERGY TECHNOLOGY REQUIREMENTS 1997 2000 2003 2006 2009 2012 250 nm 180 nm 130 nm 100 nm 70 nm 50 nm Decrease net feed water use 30 10 6 5 2 2 Gal/in2 Decrease UPW use 22 10 7 6 5 5 Gal/in2 Lower water X 90%X 80%X 70%X 60%X 50%X purification cost Decrease energy consumption 9 8 7 5 5 4 KWh/in2 300MM energy 4 4 4 3 consumption KWh/in2 Solutions Solutions No Known Exist Being Pursued Solutions

4. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Strategies to Achieve the UPW Goals • Replace wet processes: • The environmental gain is not obvious or guaranteed • Reduce water usage: • Emphasis on FEOL and rinse processes for FEOL and post-CMP • Reuse and recycle

5. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Drivers for Water Conservation Strategies Improve process and products performance Lower cost Insure sustainability in operation and growth • The three drivers are interdependent • The three drivers are not contradictory • Insuring sustainable growth is the primary environmental justification

6. UPW Plant Rinse Operation Feed Water Cooling / Gas Scrubbing NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Recycle and Reuse Which one is preferred What are the determining factors?

7. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Rinse Operations UPW Plant Determining Factors: • Purity at the POU • Purification cost • System & installation cost • Real risk • Perceived risk Reuse Cooling/Scrubbing Recycle Guidelines: • Match the flow rates for supply and demand (water balance) • Match the water quality for supply and demand (optimization) Rinse Operations UPW Plant Cooling/Scrubbing

8. Feed Polishing Loop (400 gpm) UV Secondary Treatment Primary Treatment IEx Point-Of-Use Polishing Reverse Osmosis UV/Ion Exchange 20,000 20,000 20,000 (700 gpm) S (130 gpm) (100 gpm) Recycle Treatment 10,000 (200 gpm) (40 gpm) NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Effect of Recycle on POU Purity Humic Acid @ 3 ppm 270 gpm with recycle 430 gpm without recycle (160 gpm) Recycle/Feed Ratio (R/F) Point of Use TOC Conc. (ppb) 0 4.1 0.30 3.6 0.60 2.1

9. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Rinse and Reuse Inter-dependence Q C Rinse A (QA) Rinse Operations UPW Plant Q * C Rinse B (QB) Area A = Area B Time

10. Rinse and Recycle Inter-dependence 1000 1000 Rinse Present operation: UPW Plant (150) (50) 200 200 UPW Plant Rinse Option 1: Reduce the rinse flow (50) (550) 500 500 P (100) (10) Option 2: Keep the rinse flow; add moderate recycle 500 500 1000 UPW Plant Rinse S (30) (50) (160) NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing

11. Rinse and Recycle Inter-dependence 1000 1000 Present operation: Rinse UPW Plant (150) (50) Option 3: Keep the rinse flow; add aggressive recycle 950 950 P (~108) (~8) 50 50 1000 UPW Plant Rinse S (10) (50) (150) NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing

12. Rinse and Recycle Inter-dependence 1000 1000 Rinse UPW Plant (150) (50) Present operation: Option 4: Decrease the rinse flow, combine with recycle 450 450 P (~205) (10) 50 50 500 500 UPW Plant Rinse S (300) (214) (14) (50) NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing

13. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing

14. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Adverse Effects of Concentrating the Recycled or Reused Wastewater Stream • Lowering TOC removal efficiency • Lowering ion exchange utilization factor • Being out of range for some of the purification unit processes • Triggering fouling mechanism • Biofouling and biofilm • Corrosion

15. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing UPW Strategic Research Needs for 2003 and Beyond 1. Low water, high performance FEOL and post-CMP rinse 2. Low energy, robust purification processes 3. Advance waste segregation and collection 4. Simulator-based metrology and control 5. Matched supply and demand purity 6. Advanced design tools to facilitate low-cost, low risk, high performance preparation and distribution of UPW 7. Special UPW sub-system for CMP 8. On-line rapid-response multi-component sensors for 3,4,5,7

16. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Issues and Technology Gaps Related to Water and Wastewater Purification • Low-energy and low-chemical new purification processes • Multi-component interactions of process-generated impurities • Robust purification methods with tolerance to system upsets and transience • Improved removal of recalcitrant compounds, particularly organic impurities

17. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing

18. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Trends and Technology Gaps for Water Usage 2009 70 nm / 450 mm Year Technology 1997 250 nm / 200 mm 1999, 2001 180 nm / 300 mm 150 nm / 300 mm 2003 130 nm / 300 mm 2006 100 nm / 300 mm 2012 50 nm / 450 mm 30 Strategic Solutions Research Gaps Tactical Solutions 20 Net Feed ( gal / in2 ) 10 10 Recycle New Purification Metrology AdvancedControl UPW Use ( gal / in2 ) Recycle Conservation Metrology Recycle Conservation 20 Shadman p173

19. IWW IWW Primary Treatment NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing UPW System with Recycle Options Sensor/ Sensor/ FAB Divertor Divertor Recycle SRW Process Monitoring/ Storage Tools Purification Tank UPW Return Municipal UPW Supply Feed 1 st RO UPW Feed Primary Reject Reject Polishing Reject Storage Tank Storage Tank Tank Pre- Polishing Treatment Treatment 2 nd RO UF Reject Reject Reject

20. Structure of the UPW Recycle Simulator Input Output User- Friendly Level - Impurity concentration (time and location) - Water balance Flow Sheet Specifications Parameter Database Linkage Level Dynamic Link Water Balance Model (Flow Balance Equations) Treatment Modules Rinse Module Main Code Level AC RO IEx UV Main Program: Simultaneous PDE’s for Species Balance Loop Solver NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing

21. Feed Polishing Loop Humic Acid @ 3 ppm 270 gpm with recycle 430 gpm without recycle (400 gpm) UV Secondary Treatment Primary Treatment IEx Point-Of-Use Polishing Reverse Osmosis UV/Ion Exchange 20,000 20,000 20,000 (700 gpm) S (130 gpm) (100 gpm) Recycle Treatment 10,000 (160 gpm) (200 gpm) (40 gpm) Calcium Sulfate NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Effect of Recycle on POU Impurity Concentration

22. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Importance of Multi-Component Interactions • A critical technology gap in approaching risk-free recycling. • Potentials for chemical interactions caused by process- generated reactive compounds; formation of problematic impurities. • Change in the efficiencies of purification processes. • Re-entrainment of impurities due to multi-component effect. • Effect on metrology and control.

23. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Key Questions • What are the important impurities? • Which impurities are trouble makers in UPW systems with recycle? • How can we remove these harmful impurities? • How should we collect the waste water: mixed or segregated; diluted or concentrated? • What are the treatment options? • Given the above information, how do we design a recycle system, optimize it, or control its operation? Issues: effectiveness, cost and reliability.

24. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Organic Impurities Problems: • Proven detrimental effect on yield • Wide variety of impurities with different properties • Conversions and reactions • Recalcitrant impurities Removal Method: • Separation by membranes and filters • Adsorption • Degasification • Chemical reactions (oxidation, decomposition)

25. UPW System Mixing Tee 3-Way Valve Cup Filter Stainless Steel Filters Adsorption Media Column Wall Metering Pump Impurity Source TOC Analyzer Ion Chromatograph Sample Ports UPW Stream Impurity Stream Metering Valve Bypass Line To Drain NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Experimental Setup for Adsorption Studies (Ion Exchange and Activated Carbon Application)

26. Dynamics of Multicomponent Impurity Removal by Adsorption NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing U Z Dispersion Convection Activated carbon particle S = unoccupied site Si = solid phase impurity Ci = fluid phase impurity Competitive adsorption

27. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Secondary Contamination due to Desorption of IPA from Activated Carbon 900 Start 100 ml/min of Start 100 ml/min of UPW thru column 10 ppm HCl thru column 800 700 600 15" column 500 TOC (ppb) Secondary Contamination 400 9" column 300 200 6" column 100 UPW 0 0 50 100 150 200 250 300 350 400 450 Time (min)

28. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Impurity Release due to Multicomponent Interactions (Adsorption on Activated Carbon) Component A Multicomponent Inlet Concentration for Component A 700 ppb Component A Single Component Fluid Phase Concentration (ppb) Component B Multicomponent Net impurity release from the column Both components A and B Component A only Time (min)

29. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Desorption of IPA from Activated Carbon Model Deviation due to Fluid Retention in Pores 6” Test column 9” Test Column 12” Test Column 15” Test Column Model Fit Fluid Phase Concentration (ppb) Time (min)

30. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Adsorption of IPA on Activated Carbon Start 150 ml/min of 150 ppb IPA thru column Fluid Phase Concentration (ppb) 6” Test column 9” Test Column 12” Test Column 15” Test Column Model Fit Time (min)

31. Bench-Scale UPW Testbed NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Bypass Water Softener AC Prefilter RO Tank Ion Exchange Ion Exchange RO #1 RO #2 Primary Treatment Pre-Treatment Recycle Tank Feed To Drain 10 gal Tank 100 Gal Tank Recycle Loop Polish Loop Degassifier Ultra Filter Ion Exchange Ion Exchange 185 nm UV Pump

32. HP Recycle System with IPA 3000 gal. Bypass Bypass Carbon Bed Cation Exchange Anion Exchange 254 nm UV RO Storage Tank Return NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Spent Rinse Water Data Model Concentration (ppb) Time (min)

33. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Trends and Technology Gap for Energy Usage Strategic Solutions Research Gap Tactical Solutions

34. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Two Configurations Under Development Catalytic sites UV Flow-through configuration (oxidation and filtration) Organics Water Support Membrane Water Organics Tangential configuration (oxidation and degasification)

35. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Catalytic Membrane Experimental Setup Water Tank UV Source Quartz Window UV TOC Analyzer Water Capillary Multi-port Valve Vacuum Chamber NDIR CO/CO2 Reactive Membrane MS GC Membrane Support Gas Out Gas In Purge gas Catalytic Packing

36. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Effect of Adsorption on Photocatalytic TOC Removal (Response to 30 ppb IPA in the feed) 30 Non-catalytic 25 20 Adsorption 15 IPA Concentration (ppb) Reaction 10 5 Photocatalytic 0 0 10 20 30 40 Time (min)

37. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Catalytic Oxidation of IPAInitial IPA Concentration: 2.2 ppm