Greg Raupp Chemical Engineering Program Arizona State University +1-480-727-8752 raupp@asu

1. ESH Challenges and Opportunities in Large Area High Tech Manufacturing:Displays, Thin Film Photovoltaics, Solid State Lighting, and Flexible Electronics Greg Raupp Chemical Engineering Program Arizona State University +1-480-727-8752 raupp@asu.edu

2. Principal Takeaways • ESH manufacturing challenges in the maturing flat panel display industry and the emerging thin film photovoltaic, solid state lighting and flexible electronics industries are strikingly similar to those encountered in microelectronics manufacturing • Philosophies, approaches and techniques successfully under development or adopted in the semiconductor industry can be leveraged to achieve success • Large area manufacturing industries produce products where 30-50% of the manufacturing cost is in the materials  substantial opportunity for green benefit for fab processes with higher materials utilization efficiency and/or reduction of steps

3. Representative FPD Industry Thinking(Source: www.cmo.tw) CMO's Green Operations … plan for 2011 has been specifically conceived to meet the following goals: • Implementation of 9 major initiatives in greening operations: Energy conservation, material conservation, recyclability, low toxicity, health-oriented, systems, water conservation, carbon emissions reduction, resource recycling • 90% reduction in PFC greenhouse gases and NF3 emissions • Increase in the waste resource recycling rate to 93% • Reduction in water and electricity use per unit area to 90% of current levels (2008)

4. Display Glass Manufacturing Generations Gen 10 = 2850 x 3050 mm (2010) (March 2006) Corning announced the commercial launch of Eagle XG, the first LCD glass substrate free of all heavy metals, including arsenic … is also free of antimony, barium, and halides … that can produce potentially harmful manufacturing by-products.

5. Display Technology Types • Light Emitting Displays • Light Transmitting Displays (light valves) • Light Reflecting Displays Emissive (OLED) Reflective (EPD) Transmissive with Backlight (LCD)

6. Pixels Source Line Gate Line TFT Capacitor Single Pixel with 3 sub-pixels RGB Active Matrix Displays SVGA Super Video Graphics Array Array of 800 x 600 pixels Dimensions Pixels: tens of microns Thin Film Transistors: several microns

7. PECVD n+ a-Si:H contact PECVD a-Si:H Channel PECVD a-SiNx:H gate dielectric a-Si:H TFT Fabrication PECVD a-SiNx:H IMDs Sputtered metallization Sputtered ITO Substrate Sputtered metal gate • Patterning by conventional photolithography • 3-5 masks for a-Si:H TFT arrays • 6-7 masks for poly-Si TFT arrays • Color Filter Arrays (CFAs) are also fabricated through conventional photolith processes

8. Large Area a-Si:H Production Systems • AKT PECVD Cluster Tool • a-Si / a-SiNx / n+ a-Si • GEN II 370 x 470 mm to GEN 8 2.2 x 2.5 m glass substrates • Total worldwide areal capacity increased 250% over last 3 years to 25 MSF • Applied SunFabTM Thin Film PV Production Line • mc-Si / a-Si PECVD • 5.7 m2 glass substrates • Planned turnkey plants will represent dramatic increase in worldwide areal capacity

9. NF3 Emissions a Growing Concern “This rise rate corresponds to about 620 metric tons of current NF3 emissions globally per year, or about 16% of the poorly-constrained global NF3 production estimate of 4,000 metric tons per year … a significantly higher percentage than has been estimated by industry (FPD, PV, Microelectronics), and thus strengthens the case for inventorying NF3 production and for regulating its emissions.” Measured and modeled atmospheric NF3 concentrations and trends from 1978 to 2008. Northern Hemisphere NF3 measurements are shown as filled circles, together with the spline curve Northern Hemisphere trend (solid line) fitted to these measurements. The modeled Southern Hemisphere trend and modeled global mean trend (dotted line) are shown as dashed and dotted lines, respectively. Southern Hemisphere measurements are plotted as filled squares. Click to enlarge. Source: Weiss et al., Geophys. Res Lett. (2008)

10. Emerging Technology: Flexible Displays Reflective Electrophoretic Displays Emissive Organic Light Emitting Displays • Low power • Vibrant full color • Full motion video • Ultra-low power • Sunlight readable • Near-video rates Click here to play EPD video clip Click here to play OLED video clip Source: Flexible Display Center at Arizona State University

11. Beyond Flexible Displays Macrotechnology does not compete / replace Si-based devices; instead complements in applications where Si CMOS is not well-suited (new markets) • Macrotechnology Unique Attributes: • Less is not Moore!  not driven by transistor down-scaling (performance), instead driven by unique integrated functionality and form factors • Bigger is Better!  large area (as well as small) applications • Be Flexible!  compact, ultra-thin, rugged, lightweight, implantable, wearable, conformable, and (potentially) transparent Sensors (ASU) Inflatable spacecraft and extra-terrestrial habitats Flexible Solar Cell Wearable Devices Flexible Digital Radiography Phased-array Antenna Building-integrated PV and SSL

12. Flexible Microelectronics and Display Manufacturing Pathways • Adapt existingplate-to-plate toolset infrastructure • Free-standing flexible substrates • Substrate fixturing / framing • Backside thinning: chemical etch or grind-polish • Substrate temporary bonding – debonding • Substrate coat - release • Layer transfer • AdoptRoll-to-Roll manufacturing infrastructure • Toolsets immaturewith significant issues – handling, layer alignment, resolution, reliability • Metrology strategy undefined • Take step-wise “R2R-compatible” approach focusing on critical issues

13. Coat – Laser ReleaseIBM Philips (EPLaR) PVI Layer TransferSeiko-Epson (SUFTLA) Sacrificial poly-Sion Carrier Spin-coated Polyimideon Carrier TFT Fabrication300 – 380 C TFT Fabrication130 – 180 C TFT Fabrication280 - 300 C Temporary Substrate bonded with Water-soluble Adhesive Laser Release: Ablation Triggered Debond:ThermalSolventLightMechanical Laser Release:Interfacial Melting Bond to Flex then release Options with Existing Manufacturing Infrastructure Bond - DebondFDC SEC LG-D ITRI PV Substrate bonded withTemporary Adhesiveto Carrier

14. Capability/Limitation Comparison

15. Temporary bonding with semiconductor-grade adhesive Compatible with Si-based TFTs Low total thickness variation (TTV) Defect (particle/bubble) free TFT and EO process flow and toolset compatible Automated de-bonding Triggered release (thermal, radiation, chemical, mechanical) Residue-free TFT array and substrate (and carrier) damage-free Temporary Bonding – Debonding:Manufacturing Challenges Complexity of component interactions requires system-level substrate/barrier/adhesive/carrier/toolset solution

16. SS on Si “Teacup” failure due to CTE mismatch between substrate and carrier Adhesive visco- elasticity also crucial Temporary Bonding Pitfalls HS-PEN on Si Blisters form at defect (bubble, particles) sitesExacerbated by adhesive out-gassing at temperature and in vacuum

17. Effect of Bow on TFT Array QualitySS Substrates 3.8-in. QVGA EPD Display Module Low (Pilot Line) defectivity <0.01% point defects 0-5 line defects TFT Drive Current Array Maps Original Materials and Process New Materials and Process

18. Evolutionary Approach toRoll-to-Roll Manufacturing

19. (Some) Critical Issues R2R incompatible processes (e.g., spin-on processes) Layer registration in photolithography Low defectivity handling including in-and-out-of vacuum Example Approaches Mist coating Imprint lithography with dry etch All printing process (fully additive, no vacuum) Towards Roll-to-Roll Manufacturing

20. Large Area Mist Coater High (> 90%) materials utilization efficiency High uniformity (< 3% non-uniformity across panel) Versatile: up to 4 materials; 0.5 to 15 mm films High uptime and throughput FDC Gen II System Scaled by EVG to Gen 3.5 for Plastic Logic

21. HP Self-Aligned Imprint Lithography (SAIL)Circumvents Alignment-Distortion Issue Mask removed Imprint mask thinned one level Bottom metal etched Exposed area etch down to expose gate contacts Then undercut to remove from under thinnest parts of mask Imprinted mask lowered one level to expose channel Top metal and n+ contact etched to create channel Stack etched down to the bottom metal Full TFT stack with imprinted polymer mask Imprint polymer Imprint polymer Imprint polymer Imprint polymer Imprint polymer Imprint polymer Imprint polymer Imprint polymer Imprint polymer S&D metal S&D metal Cr S&D metal Cr S&D metal Cr S&D metal Cr S&D metal Cr S&D metal Cr S&D metal Cr S&D metal Cr n+ uC Si contact n+ uC Si contact n+ uC Si contact n+ uC Si contact n+ uC Si contact n+ Si contact n+ uC Si contact n+ uC Si contact n+ uC Si contact a-Si:H channel a-Si semiconductor a-Si semiconductor a-Si semiconductor a-Si semiconductor a-Si semiconductor a-Si semiconductor a-Si semiconductor a-Si semiconductor SiNx dielectric SiNx dielectric SiNx dielectric SiNx dielectric SiNx dielectric SiNx dielectric SiNx dielectric SiNx dielectric SiNx dielectric Gate metal Al Gate metal Al Gate metal Al Gate metal Al Gate metal Al Gate metal Al Gate metal Gate metal Al Gate metal Al HP SAIL-fabricated AM-EPD on FDC thin film stack on HS-PEN Polymer substrate Polymer substrate Polymer substrate Polymer substrate Polymer substrate Polymer substrate Polymer substrate Polymer substrate Plastic substrate Imprint Lithography: Photomask-free Process SAIL TFT Etching Process 4 levels in 0.5 μm steps  Multiple mask levels Imprinted as single 3D structure O. Kwon, et al., IMID 2007, Daegu, ROK Compliments of Carl Taussig

22. Fully Additive Processing:Inkjet Printing Litrex 142 GEN II Printer Advantages • Low Temperature • Non-vacuum • Fewer process steps • High materials utilization Challenges • Alignment ( ±15 mm ) • Resolution (min. linewidth 30 mm) • Manufacturability (yield, throughput)

23. Materials Requirements for Fully Additive Printing Fabrication • High performance functional materials • Semiconductors • Dielectrics • Conductors • In form of solutions, dispersions, melts • Low temperature cureable • Adherent • Accurate linewidth and feature control A. Arias, et al., Flexible Displays and Microelectronics Conference 2007, Phoenix, AZ

24. Small Molecule OLED Vapor DepositionFull Color RBG with Shadow-masking Source: A. Chang, et al., Information Display 22(6), 20-22 (2006). Sequential deposition RGBW adds 4th step No pixelation for white SSL but more complicated stack Source: S. Krishnamurthy, OLEDs Asia (2006). Poor materials utilization efficiency Low throughput High COO

25. Alternative OLED Approaches to Enhance Materials Utilization Other Approaches: White smOLED with CF Vapor jetting Solution processing of polymer OLEDs – several printing approaches for pixelation Source: S. Krishnamurthy, OLEDs Asia (2006). High materials utilization efficiency On demand vaporization: rapid response and high throughput

26. Conclusions • ESH manufacturing challenges in the maturing flat panel display industry and the emerging thin film photovoltaic, solid state lighting and flexible electronics industries are strikingly similar to those encountered in microelectronics manufacturing • Philosophies, approaches and techniques successfully under development or adopted in the semiconductor industry can be leveraged to achieve success • Large area manufacturing industries produce products where 30-50% of the manufacturing cost is in the materials  substantial opportunity for green benefit for fab processes with higher materials utilization efficiency and/or reduction of steps • Emergence of flexible electronics technology and migration to R2R manufacturing provides unparalleled opportunity to design green / sustainable solutions

27. Acknowledgements • ASU gratefully acknowledges the substantial financial support of the U.S. Army through Cooperative Agreement W911NF-04-2-0005 • We also gratefully acknowledge the FDC’s Members for their technical and financial contributions to the Center

28. FDC Team

29. Thank You !