Ultra-high Barrier Plastic

Ultra-high Barrier Plastic
MSE5420 Flexible Electronics
Martin Yan, GE Global Research
Outline
• Introduction to plastic substrate and need for barrier
• Barrier technologies
• WVTR measurement technologies
• Summary
2/
September 30th, 2008
Evolution of Display Technology
Source: Displaybank’s presentation on 2007 Flexible
Display & Microelectronics Conference
3/
September 30th, 2008
OLED Technology
iRiver SPINN A/V Player
Sony XEL-1 11” OLED TV
Kodak EasyShare LS633 Camera
Cathode
n-layer
p-layer
DZ7086 OLED watch by
Diesel
Anode
Nokia Prism Mobile Phone
Light
4/
September 30th, 2008
Flexible OLED Display
Source: UDC presentation on 2007 Flexible Display &
Microelectronics Conference
5/
September 30th, 2008
Replace Glass with Plastic Substrate
NOW
FUTURE
“Roll-Up Displays”
Glass
Substrate
Plastic Film
Substrate
Plastic Advantages
• Rugged.
• Thinner.
• Lighter.
• Enable flexible display.
• Enable R2R processing.
6/
September 30th, 2008
Energy Consumption for Lighting: Year 2001
22% of the total electricity generated in the U.S. was used for lighting!
Total U.S. Primary Energy
Consumption for Lighting by Sector
Lighting Energy Consumption by Sector & Source
Source: U.S. Lighting Market Characterization Volume I:
Need to replace incandescent with more efficient light technology!
7/
September 30th, 2008
Organic Electronics (OE) Advanced Technology
Program at GE Global Research
Technologies:
• OLED Devices
• Low Cost Manufacturing
• High Barrier Substrate
V
V
Metal contact
Organic Active Layers
Transparent contact
Flexible substrate
“Ne
w
Roll spaper
-to-R
-L
oll F ike”
abri
cati
on
High barrier substrate enables R2R OLED manufacturing.
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September 30th, 2008
OLED Offers Novel Features
Mechanical Flexibility
Thin and Light
Transparent
Color Tunability
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September 30th, 2008
Flexible OLED Product Concepts
UDC’s Flexible Display Concept
Source: UDC’s presentation on 5th Flexible Display and
Microelectronics Conference
Polymer Vision’s Flexible Display Concept
Source: Polymer Vision’s presentation on 5th Flexible
Display and Microelectronics Conference
GE’s Flexible Lighting Concept
Source: Best Life Magazine – February 2006
10 /
September 30th, 2008
Opportunity for Plastic Substrate
Barrier Plastic Film
•Digital Paper
•Lighting
•Solar Cell (PV)
- OLED
- LCD
- E-paper
- Postage
- General lighting - Thin Film PV
- Back lighting
Major Players
•Flex.Display
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September 30th, 2008
Challenges for Flexible OLED Substrate
The Problem
OLED
Transparent electrode
Polymeric substrate
H2O O2
Commercial available
polymeric substrate
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September 30th, 2008
Substrate Requirement
- Key Properties
Moisture/Oxygen Permeability
Metal Cathode
Light Emitting Polymer
Hole Injector
Transparent Anode
Ultra High Barrier
Moisture
Transparent Conductor
Low Conductivity,
Low Transmission
Anode
H 2O
High Conductivity,
High Transmission
Anode
low 10-6 g/m2/day
O2
Oxygen
-3
2
< 10 cc/m /day
Ultra High Barrier
Thermo-mechanical stability
Low Temp.
Plastic
High Temp.
Polycarbonate
< 40 Ohm/ sq
> 90 %T
Optical Transmission
Metal Cathode
Light Emitting Polymer
High CTE Plastic
Shrinkage
< 20 ppm/hr @150°C
CTE Reduction / Stress Balance
CTE Reduction / Stress Balance
Hole
Injector
Transparent Anode
Ultra High Barrier
Bending
diameter <=1”
Adhesion
> 80 %T
Ultra High Barrier
≥ 4B
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September 30th, 2008
Barrier Substrate Development at GE Global
Research
Technology Development at GE
Plastic
Substrate
Film
Ultra-high
Barrier
Coating
Chemical
Resistant
Coating
Transparent
Conductor
Coating
Enable
Integrated Plastic OLED Substrate
Transparent electrode
Graded ultra high barrier
Chem resist layer
High heat polycarbonate
Chem resist layer
14 /
September 30th, 2008
Outline
• Introduction to plastic substrate and need for barrier
• Barrier technologies
• WVTR measurement technologies
• Summary
15 /
September 30th, 2008
Material Options for Transparent Hermetic Barrier
Log Thickness (meters)
Moisture Permeability
Ref. Traeger
OTR through Perfect SiO2 Barrier:
10nm ⇒ 10-24 cc/m2/day
Time to Reach 50% of Outside RH
10 nm continuous glass-like coatings would exceed the needs
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September 30th, 2008
Defect-Driven Moisture Permeation
Non-Fickian Diffusion
0
OTR @ 25 @ 100% O2
1000
~ 100 defects/mm2
Uncoated
Defect Imaging w/ Acetone
100
20x
10
~1mm
1
0.1
Detection limit
0.01
1
10
100
1000
SiNx Thickness (nm)
Barrier performance of single layer inorganic coating is defect limited
17 /
September 30th, 2008
Ultra-high Barrier: Single Layer Approach
–Uni. Of Colorado: Atomic Layer
Deposition of AlOx
–Dow Corning: Plasma
Enhanced Chemical Vapor
Deposition of SiOxCy
–Symmorphix: Sputtering of
AlSixOy
Source: Symmorphix’s presentation on 4th
Flexible Display and Microelectronics
Conference
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September 30th, 2008
Ultra-high Barrier: Multilayered Approach
Concept for Multilayer UHB
Defects
Organic coating
Hundreds of nm
Inorganic coating
Tens of µm
Source: VITEX’s presentation on 5th Flexible
Display and Microelectronics Conference
19 /
September 30th, 2008
Permeation Simulation: Multilayered Barrier
- 2 perfect barriers
- each barrier has 1 defect
- defects are offset/decoupled
Low
1
Fick’s Law:
Conduction
Limited
Regime
Continuity:
Diffusion
Equation:
Flux Ratio =
Flux2 Layer System
Flux Ratio
Assumptions:
Flux 1Barrier System
0.1
High
0.1
1
10
Distance/Offset
Distance
Offset
Work in this regime to
achieve Ultra-High Barrier
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September 30th, 2008
Ultra-high Barrier: Graded Approach
XPS Spectrum of Graded UHB
GE’s Graded Ultra High Barrier
Organic
zone
Inorganic
Cross-sectional TEM of Graded UHB
Continuous composition transition
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September 30th, 2008
Graded Ultra-high Barrier Plastic Film
Parallel plate PECVD
High T Lexan® film
Low temperature PECVD process is compatible with plastic substrates
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September 30th, 2008
Base Film Surface Quality is Critical
23 /
September 30th, 2008
Flexible OLED substrate
The Problem
OLED
Transparent electrode
Polymeric substrate
H2O O2
Commercial available
polymeric substrate
3,530 hrs at 23°C 40%RH
The Solution
OLED
Transparent electrode
Graded ultra high barrier
Chem resist layer
GE Barrier Substrate
High heat polycarbonate
H2O O2
Chem resist layer
12 mm
Proved that high barrier substrate is possible
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September 30th, 2008
GE’s Graded Barrier Plastic Performance
•
•
•
•
•
•
•
•
•
Moisture Barrier
Chemical Resistance
Electrical Conductivity
Optical Transparency
Mechanical Flexibility
Thermo-Mechanical Stability
Adhesion
Dimension stability
Average surface roughness
Key USDC Specifications*
10-6 g/m2/day
acid, solvent, alkali
≤40 Ω/Sq
>80%
bend around 1” radius
2000C for 1hour
≥4B
<20 ppm/hr at 150°C
<5 nm
GEGR Performance
low 10-5~mid 10-6 (at 23°C 50 % RH)
Pass
40.3 Ω/Sq
82 %
Pass.
Pass
4B
4 ppm/hr
0.6 nm
* Subset of complete USDC specification list
15 cm square flexible OLED
lighting Device on high
heat polycarbonate substrate
with graded UHB
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September 30th, 2008
Outline
• Introduction to plastic substrate and need for barrier
• Barrier technologies
• WVTR measurement technologies
• Summary
26 /
September 30th, 2008
WVTR measurement technologies
• Capacitive or Resistive (humidity sensor)
• Spectroscopy (mass spectroscopy, fluorescence quenching)
• Calcium degradation (optically or change in resistance)
• Radioactive (tritium)
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September 30th, 2008
Commercially Available Gas Permeation
Measurement
H2O or O2
H2O or O2
H2O or O2
Source: PERMATRAN-W® Model 3/33 Operator’s Manual
Fourier transform Infrared (FTIR)
Spectrometer
Detection limit for H2O: 5×10-3 g/m2/day
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September 30th, 2008
Calcium Corrosion Test: GE’s Setups
Ca test @ 23°C / 50%RH
Ca Test @ 60°C 90% RH
Initial
100% O.D.
525 hrs
90% O.D.
Glass
Epoxy
Ca
Barrier Coating
Polycarbonate
Detection limit for H2O: 1×10-5 g/m2/day
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September 30th, 2008
Tritium Test: GAT’s Setup
General Atomics Tritium Test
Source: RALF DUNKEL, ROKO BUJAS, ANDRE KLEIN, AND VOLKER HORNDT, PROCEEDINGS OF THE
IEEE, VOL. 93, NO. 8, AUGUST 2005, pg 1478-1482
Detection limit for H2O: 2×10-7 g/m2/day
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September 30th, 2008
OLED Device Test
Universal Display Corporation
OLED Shelf Lifetime Test @ 60°C 85% RH
Glass/Glass control
w/o desiccant
Device on GE
sample
Glass/Glass control
Device on GE
sample
w/ desiccant
Source: GE’s presentation on 4th Flexible Display and Microelectronics Conference
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September 30th, 2008