NanoMas_FlexTech
- 1. Conductive Nanoparticle Inks for Flexible and Printed Electronics Zhihao Yang, Ph.D. & CTO NanoMas Technologies, Inc. 1093 Clark Street Endicott, N E di tt New York 13760 Y k Phone: 607-755-4121 Fax: 866-367-1128 Website: www.nanomastech.com 3rd Annual Flexible Electronics Symposium 3rd Annual Flexible Electronics Symposium August 17‐18, 2010, Binghamton, New York
- 2. Printed Electronics: Fabricating Electronic Devices with Printing • Low equipment cost • Continuous roll to roll processing • Additive deposition and p p patterning g
- 3. Application Market (by IDTechEX projection)
- 4. Conductive Inks for Printed Electronics Highly conductive and high resolution patterns fabricated using low cost and roll-to-roll processes (such as inkjet and low-cost roll to roll gravure printing) are one of the most critical technology components in making printed electronics and displays What are the requirements: High performance: high conductivity (close to pure metal) Low temperature processing: plastic compatible Printability: solution processed with “high” resolution patterning High throughput: R2R and fast curing Mechanically robust: adhesion to substrates, tolerance to mechanical deformation Low cost
- 5. Nanoparticle Inks for Printed Electronics • Nanoparticles can be stabilized in ink solutions by organic ligand shells, which can be removed after printing. • N Nanoparticles can b f th cured or sintered t hi hl conductive fil ti l be further d i t d to highly d ti films at low temperatures. 70-90°C 70 90°C 100-150°C 100 150°C Deposited Ag nanoparticles Conductive Ag film on PET cured from printed nanoparticle inks 150°C 200 nm
- 6. NanoMas Proprietary Technology: Producing High Quality Nanoparticles with Large-Scale and Low-Cost Processes g NanoMas silver nanoparticles with 5 6 nm ith 5-6 in size (SEM) 50L pilot production reactor at NanoMas NanoMas Ag nanoparticle powders and inks
- 7. NanoMas Conductive Nanoparticle Inks Technology gy • Patented unique nanoparticle synthesis technology, widely q p y gy y compatible with the low cost production processes in the chemical industry • Low cost and fully scalable to large scale mass production • Ultra-small nanoparticle size (2 to 10 nm) with specially designed surface chemistry allows low annealing temperature, short process time, and high conductivity • Variety of surface chemistry for different solvent dispersion and applications • Low resistivity (as low as ~2.4 μΩ-cm, 1.5x of pure Ag) • Low process temperature (as low as ~70°C) compatible with most p ast c substrates plastic subst ates • Also curable by laser or UV light at room temperature
- 8. Fully Scalable Process y • NanoMas patented process built around traditional wet chemistry manufacturing – Lowest cost method of nanoparticle production – Superior quality and reproducibility p q y p y 2000L HV Production 8
- 9. NanoMas Metal Nanoparticles (Ag, Au, Pd, Pt) Silver (~5 nm) Gold ( 3-4 nm) Platinum ( ~2 nm) Palladium ( ~3 nm)
- 10. Thermal Curing Profile of NanoMas Silver & Gold Nanoparticles 40 NanoMas NanoSilver Ink (~5 nm) NanoMas NanoGold Ink (3-4 nm) 30 m) Resistiv (μΩ-cm 20 vity 10 Bulk Silver Resistivity 0 80 100 120 140 160 180 200 Annealing Temperature (C)
- 11. In-Situ Resistance Measurements The measurements show the evolution of the electrical resistance of Ag‐NP films over more than 5 decades upon sintering. The final resistance is relatively invariant, whereas kinetics vary dramatically. Three characteristic times, the onset, the peak rate, and the terminal times, have been identified. Arrhenius analysis reveals an activation energy of ca. 600 meV.
- 12. Morphology of Sintered Silver NP Films 5s 10 s 20 s 30 s 60 s 300 s Ag-NP thin films sintered at 120oC
- 13. Control Film Morphology by Formulation and Processing g Film processed with normal NanoSilver ink formulation Film processed with a special NanoSilver ink formulation
- 14. Mechanical Performance of NanoSilver Films Stretching apparatus Printed Ag-NP films before & after stretching ~ 6 inch 6 inch 3 inch II Regime Regime IV III I Regio n II Resistance increases with elongation Still conducting with >200% elongation PET substrate fails first
- 15. NanoSilver Ink for Inkjet Printing Dimatix DMP2800 used for development df d l 15
- 16. Inkjet Printing Advantages Ink Jet Printing g g Challenges g • Inexpensive system • Depositing thick materials • Proven high volume • Inks require nanoparticles production tool and for stability (free of technology aggregations) • Digital flexible can make Digital, flexible, • Depositing on three- changes on the fly dimensional objects • 50-100 micron line resolution with 10 pl heads
- 17. NanoMas Inkjet Inks Properties Value % Loading 10‐50% Viscosity Vi it 5‐ 16 cps 5 16 Surface tension 27‐35 dynes/cm Trace height up to 400nm/per pass Curing Temperature <180⁰C Conductivity 5 µΩ‐cm • Customizable to meet customer needs 17
- 18. Inkjet Printing using NanoMas Inks Line width ~200 μm ~100 μm Jetting from 10pL head at 5KHz NanoSilver ink printed on glass & cured at 150⁰C 18
- 19. NanoSilver Ink for Pneumatic Aerosol Jet Printing Optomec Aerosol Jet Printer used for Development 19
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- 21. 3D Multi‐Chip Stack Packaging • 3D multi-chip stack packaging enables portable devices with more functions that consumers are looking for (such as smart phones). • Printed vertical interconnects to replace wire bonding ertical ire • Lower cost, higher yield, better device performance and reliability… 21
- 22. Aerosol Jet Printing Advantages Aerosol Jet Printing Challenges (ink): • Capable of depositing traces on • Loss of solvent from ink during 3-dimensional packages aerosol formation • High deposition rates g p • Agglomeration of p gg particles • High throughput tools currently during aerosol formation being developed • Depositing thick materials • Does not require <100nm particles in ink • Very high resolution can be achieved (<10 micron)
- 23. Example of Target Material Specification for Optomec Ink Physical Property Target Spec. Formulated Ink Particle Size <100nm 5nm Solids Loading 50wt% (or greater required), >66% >70wt% preferred Resistivity <5x10‐8 ohm.m < 5x10‐8 ohm.m Sintered trace Sintered trace Several microns thick Several microns thick Demonstrated several microns thick Demonstrated several microns thick traces Agglomerates Very few required, none preferred None observed Sedimentation No cake formation in 1‐2 hours None observed required, no cake formation preferred Multiple No preferential sedimentation Single component Components Pot Life Pot Life > 12 hr shift > 12 hr shift >8 hour operation with no measurable >8 hour operation with no measurable change in total dispersed solids level Shelf Life 6 months required, Projected to be > 6months 12 months preferred (under testing) Viscosity 1 30cP 1‐30cP 5 6cP 5‐6cP Solvent Systems High boiling point/low evaporation BP 240 C , 0.07mmHg @ 20C rate (e.g. BP 193C, 0.06mmHg @ 20C) 23
- 24. Characterization of Printing Sintered Trace Height: 3.8µm Width 40 µm 24
- 25. Cross-Section of Printed Trace High conductive (~5 uohm‐cm), high resolution (<30 um line width), high aspect ratio width), high aspect ratio (20‐30 um height) printing can be achieved 25
- 26. NanoSilver Ink for High Throughput Commercial Gravure Printing 26
- 27. High Throughput Gravure Printing of RFID Antenna g • Demonstrated low cost production of RFID antenna using a commercial gravure printing press • 25-50 m/s roll-to-roll printing p g
- 28. Applications in Fabricating Printed Electronic Devices with NanoMas Nanoparticle Inks 28
- 29. Solar Cell Metallization Advantages of using NanoMas special solar inks and pastes: • Low temperature processing (<250˚C) compatible with most thin-film and organic solar cell technologies g g • High resolution printing enables better efficiency • Excellent electric contact and mechanical adhesion with silicon, glass ITO, etc. 29
- 30. Fine Line Solar Cell Metallization Printed with Aerosol Jet 30
- 31. All-Printed Hydrogen Sensors on Plastics • Sensing hydrogen as low as 200 ppm • Response time less than 1s Response time less than 1s • Low cost for large area sensing 31
- 32. Printed Organic TFTs (a) Ag OSC Ag (b) Silicon dioxide gate dielectric Single crystal silicon gate (a) (b) Optical microscopy of fabricated bottom- gate-bottom-contact polythiophene IV I-V characterization of OTFT based on OTFTs with (a) evaporated Au and (b) polythiophene as the organic SC and printed printed Ag as the electrode materials, Ag electrodes. (on/off ratio ~ 103 and carrier respectively. mobility ~ 0.02 cm2 V-1 S-1) 32
- 33. Printed Silver Contacts on Single Walled Carbon Nanotube FET Vsd SEM on SWNT‐FET Source S SWCNTs Drain D i SiO2 P‐Si Vgate SWNT FET SWNT‐FET 33
- 34. Summary • NanoMas has developed a low cost process for producing A A P and Pd nanoparticles d i Ag, Au, Pt d i l • The particles are some of the smallest and most stable commercially available, while allowing low temperature sintering compatible with most flexible substrates for printed electronics • The nanoparticles can be formulated into inks suited to p a number of printing techniques including gravure, ink- jet, Aerosol-Jet printing. • The printed traces can be sintered at low temperatures p p to produce low resistivity, adherent, mechanically robust conductive patterns suitable for use in the printed electronics applications. 34
- 35. Acknowledgements NanoMas Technologies, Inc. Dr. David van Heerden Dr. Hichang Yoon Dr. Yu Du Dr. Jalal Salami D J l lS l i Binghamton University Prof. Prof Howard Wang Liwei Huang Dr. Yayong Liu (SiPix now) Nano Material LINX‐CONSULTING Investors, LLC C