Outline

1. Overview of Flexible Electronics for LIFEJames C. Sturmand Sigurd WagnerDepartment of Electrical EngineeringDirector, Princeton Institute for the Science and Technology of Materials (PRISM)Princeton University, Princeton, NJ 08540 USAsturm: 609-258-5610, sturm@princeton.eduwagner: wagner@princeton.eduIf you really need to reach me, my administrative ass’t. is Ms. Sheila Gunning, sheila@princeton.edu, 609-258-1575

2. Outline • Conventional Microelectronics • Large Area and Flexible Microelectronics • Applications

3. Finished Silicon Wafer after fabrication • Each square (cm x cm about) is its own circuit, with millions (billions) of connected transistors. 100’s of chips on wafer, typically. • Also, miles and miles of wires (printed metal stripes) on them • The process of making them is known as “Very Large Scale Integrated” technology (VLSI) • Typical features sizes today = 0.1 micron = 100 nanometer = 10-5 cm

4. One chip • After it has been “diced” from the wafer. • Also known as a “die” • 0.5 – 2 cm on an edge, typically

5. Wire connection “pads” • Each metal leg of the package is connected to a mini-wire which is connected to the chip.

6. The chip is put into a black plastic/ceramic package for use in applications • Each metal leg of the package is connected to a mini-wire which is connected to the chip. • These are ususally soldered into green “printed circuit boards” (e.g. 6” x 6”) that you see in electronic products • Small, hard, and rigid,

7. Integrated Circuit Business Model • Make the transistors and wires on the chip smaller (nanotechnology) • chips are smaller and more chips fit on a wafer 3. The cost per chip is lower (or more on a chip for same cost): costs per function DROP over time (108 x in 35 years) • Increase sales through more applications enabled by low cost • The business problem: it is getting harder to make things smaller and still have the transistors work and be cheaper. So what do you do? (“End of Moore’s Law”)

8. Outline • Conventional Microelectronics • Large Area and Flexible Microelectronics • Applications

9. Samsung Flat panel TV Princeton Macroelectronics Group Apple Computer

10. Digital X-ray imager Princeton Macroelectronics Group Flat paneldetector High speednetwork Real time image processing in PC • Picture archiving and communications system (PACS) High performance display Richard Weisfield, dpiX

11. Solar electric module Princeton Macroelectronics Group Akihiro Takano, Fuji Electric Advanced Technology

12. switch, amplifier sensor actuator cell (pixel) Architecture of an electronic surface Princeton Macroelectronics Group “Front plane”: End function “Backplane”: Electronics a pixellated surface interconnects rigid, flexible, or deformable, or elastomeric substrate Steel foil, thin glass, rollable or stretchable plastic, ...

13. A liquid-crystal display Princeton Macroelectronics Group Frontplane

14. A brief history of large-area electronics • WasLCD readout (‘70s), laptop display (’80s), desktop monitor (90’s) • Isflat screen TV, X-ray imager, thin-film solar cell (’00s) • What will be next??? (’10s) • Much of large-area electronics was invented at the RCA Labs in Princeton: • Paul Weimer … thin-film transistor in the ’60s • George Heilmeier *62 … liquid-crystal display in the ‘60s • David Carlson and Chris Wronski … amorphous-silicon thin-film solar cell in the ‘70s

15. 3 degrees of shaping a “flexible” electronic surface Bend: Small deformation, elastic, one-time or repeated this case: steel foil substrate E Ink - Princeton Conformally shape: Large deformation, plastic, one-time Princeton this case: plastic foil substrate Stretch: Large deformation, elastic, repeated elastomeric substrate Princeton

16. Large area electronics is growing like microelectronics in the early ’90s The display industry is developing the tools and is reducing the cost for making large electronic surfaces Data courtesy of David Mentley, iSuppli; Ken Werner, Nutmeg Consultants; Barry Young, DisplaySearch

17. Industrial a-Si:H PE-CVD systems are huge Inline system for making solar cells on steel foil substrates Section of 300-ft. long roll-to-roll solar cell manufacturing line Energy Conversion Devices (USA)

18. 6 cm TFT on steel Silicon Thin Film Transistors on Flex Substrates Motorola E-ink display on backplane of a-Si TFT’s on steel foil Deformable plastic for 3-D shapes

19. Outline • Conventional Microelectronics • Large Area and Flexible Microelectronics • Applications: Think • Potential Large Area • Flex, Bend, Stretch, Deform • Backplane (electronics) + frontplane (function) • Arrays • Function: • sense light, temperature, strain, chemical properties, sound • control light, local heating (drug release?) • actuate: move, bend, squeeze • I will give 2 examples directed at medicine

20. A surround display Zenview A digital dashboard A Cyberhand Miltos Hatalis, Lehigh U. An e-Suit Givenchy Fall ‘99 Cyberhand Project

21. Rigid Microelectrode Arrays In Vivo(Thanks to B. Morrison, Columbia and S. Wagner, Princeton) Silicon Michigan Probe Fofonoff, IEEE Trans.Biome.Eng., 2004 Titanium Utah Array Micromachined silicon • Brain Computer Interface Kipke, IEEE Trans.Neural Sys.Rehab.Eng, 2003 Cyberkinetics Neurotechnology Systems Campbell, IEEE.Trans.Biomed.Eng., 1991

22. PDMS gold film Flexible vs. Stretchable MEAs Polyimide Keesara, Proc.MRS, 2006 • Electrodes on • Polyimide (5 GPa) • Flexible • Ultimate limit • 4% stretch • Bending • PDMS (1 MPa) • Stretchable • Ultimate limit • Max ~ 50% • Uniaxial • Maintains conduction Chambers, Proc.MRS, 2003

23. Nissl CA1 DG CA3 Traumatic Brain Injury Model • Complex organotypic brain slice culture • Apply deformations consistent with TBI • Study the tissue response Morrison, J.Neurosci. Meth., 2006

24. Application 2:(E-problem: file corrupted) • Front plane: “electret sensor” S. Bauer, U. Linz, Austria • Converts pressure to electricity • Array of pressure detectors – covering large area • Array of microphones over some array • Converts electricity into motion • Can make thin film “breathe” in and out, local control • Will send rest of file later

25. END

26. Moore’s Law • Not fundamental, just an observation • Has continued despite many predictions of demise • Billions of T’s on a single chip!!!!! (in DRAM memory, one bit requires one transistor)

27. How do they get all that stuff on the chip: It’s a Small World!! Feature Sizes on Integrated Circuits (millionths of meters, thousandths of millimeters) (billionths of meters, millionths of millimeters) 2006: gate length ~ 30 nm in advanced production Gate length is key number: often the smallest size of the width of a layer on a chip Where Nanotechnology came from!