Recent Advances in the Reliability of OTFTs

1. Recent Advances in the Reliability of OTFTs
Patrick Too, Herve Vandekerckhove, Guillaume Fichet, M. James Harding, Michael J. Banach
SPIE – 13th August 2012
San Diego

2. Outline
• Plastic Logic company introduction
• Reliability of OTFTs
• Challenges on the way from Lab to Fab
• Applications of Plastic Logic technology and
partnerships
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3. The Leader in Plastic Electronics
 Developed lightest, most durable display
technology available today
 Demonstrated scalability in the first and
largest production facility
 1-2 year lead over the competition for
flexible backplane technology
 A single display has 2.8M uniform and
reliable plastic transistors
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4. Company History
Display technology Development
10+ transistors 100+ transistors 1.2 M transistors Colour EPD 2.8 M transistors
Research, Process Development & Manufacturing
2000: Cambridge Technology 2008: Dresden Display Factory
Cambridge University Center translating research First plastic electronics factory in
Cavendish Laboratory into products the world
Research in organic electronics
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5. R&D and Production Set-Up
Technology
Transfer
Cambridge R&D
Prototype Line (14”)
Cambridge R&D Prototype Line
 Proof of concepts
 Highly configurable process
 New designs in < 1 month
 1” Chips to A4 displays
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6. Production Set-Up
Technology
Transfer
Dresden Factory (Gen 3.5)
Dresden Gen. 3.5 Factory
 Backplane Manufacturing
 Qualified volume process
 Production equipment
 Fully Automated Handling
 Process, Equipment, Integration
Engineers
 Thousands of backplane display
modules/week
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7. Electrophoretic Plastic Display
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8. Reliability of OTFTs
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9. Stress Test System Setup
Stress card module
• Fully Automated electrical test
system
• Flexibility in the electrical test and
stress test profiles
• Ability to test in different
environmental conditions
• Capability to test more than 1800
TFTs per day in Cambridge
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10. Stress Test Waveform
etc Gate
Source
1 Waveform
Large range of stress test waveforms available to mimic OLED and EPD displays driving
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11. OTFTs under video rate (60Hz) stress test
600C annealing 1200C annealing
 Video rate stressing was done at ambient controlled atmosphere
 Threshold voltage shift is observed under video rate stress test for low
annealing temperature (600C) of the OTFTs
 The OTFTs show an improvement in the threshold voltage stability after a
1200C annealing
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12. Effect of solvents on OTFT stability
O-Xylene (B.P=1370C) Mesitylene (B.P= 1650C)
Tetralin (B.P=2050C) Phenylcyclohexane (2380C)
All samples are annealed in air and stress tested at ambient controlled temperature
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13. Reliability testing
Name Test Purpose
Thermo cycling TST Mechanical robustness & CTE mismatch
High Temperature Storage HTS Storage of transport conditions
Advance Humidity Storage AHS Stability against Moisture ingress
Low Temperature Storage LTS Storage of transport conditions
Real World Usage RWU Display use in non accelerated mode
Advance Humidity Operation AHO Accelerated operation at high humidity
Low Temperature Operation LTO Accelerated operation at low temperature
Ambient Operation AO Accelerated operation at ambient conditions
Solar storage SOR Solar robustness
Altitude test ALT Pressure sensitivity
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14. Challenges on the way from Lab to Fab
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15. The Manufacturing Challenge
It is one thing to show a single display at a tradeshow…
...quite another to develop a high yield manufacturing process
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16. Process learning & Development
Printing process
2008
Thickness mean
2009
Thickness mean
Deposition process
2008
Thickness mean
2009
Thickness mean
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17. Progress in Plastic Logic display
2008 2009
Defects driven
High Quality Display
Equipment / Process driven
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18. Colour Flexible Displays: Now Available
Display size 1” - 10.7”
Backplane Grey Levels 4 – 16
Pixel pitch up to 225ppi
Contrast Ratio 12:1
Thickness thin as 130 µm
Weight down to 11g
Colour Available
NTSC 2-5%
 Paper-like finish
 Excellent readability
 Colour gamut high enough to
enable distinguishability
 Bistable enables long battery life
1280 x 960 Colour Display
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19. Colour Flexible Display
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20. Other Plastic Logic Technologies
Transmissive display Thin displays
Small displays
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21. Plastic Logic Technology in Action
1. 3.
2.
1. The world‘s first plastic organic
electronics factory
2. The most robust display on the market
3. Plastic Logic display at video rate
www.youtube.com/plasticlogic
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22. Partnerships
We are looking for further professional partners to enable future applications
and products
Partner areas
• Potential users of Plastic Logic display components
• Technology providers for sensors
• End users for flexible logics
• Materials and equipment suppliers to further progress the technology
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23. Plastic Logic Ltd
34, Cambridge Science Park
Cambridge, CB18DG
UK
Tel.: 01223706038
Email: patrick.too@plasticlogic.com
www.plasticlogic.com
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