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© Fraunhofer FEP
page 1
ROLL-TO-ROLL MANUFACTURE OF OLED DEVICES
Stefan Mogck, Jacqueline Hauptmann, Claudia Keibler, Christian MayFraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP
OLED Stakeholder Meeting 2017, St Paul
© Fraunhofer FEP
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INTRODUCTION ROLL-TO-ROLL MANUFACTURING
Highest degree of automation level
Background and Mentality
© Fraunhofer FEP
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FRAUNHOFER FEP: FACTS AND FIGURES Fraunhofer FEP is one of 67 Fraunhofer within Fraunhofer Gesellschaft, Europe’s
largest application-oriented research organization Fraunhofer COMEDD merged within Fraunhofer FEP July 1st, 2014:
Fraunhofer Institute for Organic Electronics, Electron Beam, Plasma Technology (FEP)
Director: Prof. Dr. Volker Kirchhoff Figures 2016: employees 189, total budget 24.3 M€, industry returns 7.4 M€,
public funding 8.6 M€, investments 1.5 M€
Core competences:
ELECTRON BEAM TECHNOLOGY
SPUTTERING TECHNOLOGY
PLASMA-ACTIVATED HIGH-RATE DEPOSITION
HIGH-RATEPECVD
TECHNOLOGIESFOR ORGANICELECTRONICS
IC AND SYSTEMDESIGN
© Fraunhofer FEP
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PORTFOLIO OF THE DIVISION FLEXIBLE ORGANIC ELECTRONICS Customer specific R&D on novel device
concepts and manufacturing methods for Organic Electronics (mostly small molecule) mainly OLED lighting & signage, but also
OPV, OPD und OFET Flexible foil substrates (esp. Roll-to-Roll-
technology) for flexible applications (rigid substrates also possible)
Services along the full value chaine for (flexible) organic devices
Process development Test of new materials Prototype development Device integration (electrical, mechanical)
200 mm System: Glass substrates , metal and polymer web, flexible glass up to 200 x 200 mm²
R2R Line: Metal and polymer web, flexible glass up to 300 mm width
© Fraunhofer FEP
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BENEFIT OF ROLL-TO-ROLL OLED MANUFACTURING
Estimated cost reduction from 20% - 30% in comparison to sheet process
De-bonding process for ultra-thin glass, metal web and polymer films < 50 µm from a carrier glass might be challenging in S2S
Ultra-thin substrates < 50 µm can be a unique feature for R2R
Long OLED stripes only possible by R2R
Higher amount of devices, because of higher throughput
Manufacturing of >500 OLED devices in a size of 10 x 10 cm² per day already possible in FEP’s R&D line(web width 300 mm, web speed 0.2 m/min)
Limiting factor metal evaporation, because of the impact of heat on the web surface. Otherwise web speed up to > 1 m/minute possible.
Requirements on clean room conditions lower compared to S2S(substrate enveloped on the roll)
First focus: Design driven freeform ambient- and decorative OLED applications.
© Fraunhofer FEP
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GENERAL CHALLENGES FOR R2R MANUFACTURING
vacuum
evaporationorganic/metal
web tensionstretch/compression
surface water
water outgassing
heat impactdistance substrate – sourcematerial utilization
OLED substrate: polymer barrier filmultra-thin glass, metal
possible residual water in contact with unprotected OLED layers
“memory effects“electrostatic charging
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R2R inspection systemR2R printing and lamination unit (N2)
R2R vacuum coater
Substrate Inspection Structuring Substrate
inspectionVacuum coating Encapsulation OLED
characterisation
OVERVIEW PROCESS FLOW IN R2R R&D LINE
Typically 300 mm web width
vacuum based OLED deposition
Roll-to-Roll OLED fabrication process
Material evaluation from laboratory scale to R2R production, with significant yield statistic.
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R2R OLED LAYOUT
Substrate structuring by printing Any kind of customer specific active
OLED lighting areas are possible. Additional metallization printing for
interconnection will be available soon.
25 cm 10 cm
10 cm
Printing concept (up) and substrate after structuring (down)
Total layout length 300 x 628 mm.
© Fraunhofer FEP
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COMPARISON OF FLEXIBLE SUBSTRATES FOR OLED DEVICES
metal ultra-thin glass plastic
bendability o o √
permeation barrier √ √ o
roll-to-rollprocessabilty
√ (√) √
surface roughness o √ √
potential of low cost √ ??? ???
advantages good barrierthermal conductivity
good barriersurface quality transparency
transparencyhigh bendabilitytwistable
disadvantages top emissionadditional coatingwater in smoothing layer
brittledevice separation
barrier coatingthermal stabilityresidual waterpossible pinholes
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OLED DEMONSTRATION ON METAL FOIL (STATUS 2013)
Bendable lighting directly on the metal foil on large areas are possible.
Still a lot of developments of the planarization layer necessary. Top-emitting OLED is challenging for
white light illumination.
BMBF-R2FLEX
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OLED DEVICES ON STAINLESS STEEL FOIL
OLED on 50 µm stainless steel foil development in collaborationwith Nippon Steel Sumikin Materials.
© Fraunhofer FEP
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GLASS + ITO VERSUS PET + IMIOLED- Stack-simulation glass versus PET1-unit BE-OLED
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HIGHLY CONDUCTIVE POLYMER FILM FOR LARGE AREA LIGHTING
High conductivity embedded metallic wires result in a conductivity of 0.01 Ohmand in a transparency of about 90%. Electrode film and OLED embedded in a so called “Ravioli” approach.
OLED area 25 x 10 cm²
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Available Now
THE ROAD FROM S2S TO R2R
R2R vacuum coater: two process stations + pre-treatment
Special winding system for UTG handling
Substrate width: 330 mm
Substrate thickness: 50-100 µm
Coating temperature: 350 °C
Rollers touching substratebackside only
Minimized particle loadon substrate
Application examples
ITO for OLED, Invisible ITO for touch screens
IMI, AR
VON ARDENNE FOSA LabX 330 Glass – R2R vacuum coating of flexible glass
BMBF – KONFEKT
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R2R OLED ON THIN GLASS ENCAPSULATED WITH THIN GLASS (50 µM)
A successful demonstration of 25 x 10 cm² OLED devices without dark spot growth! Development of proper cutting technology!
Collaboration with
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FRAUNHOFER CEGLAFLEX PROJECT: FLEXIBLE OLED DEVICES ON ULTRA-THIN GLASS CERAMIC LAMINATES
Goal of the project: transparent ceramics for scratch protection
and OLED devices on ultra-thin glass laminates. laser cutting and polishing of transparent
ceramics and ultra-thin glass device compounds achieving high edge stabilities. develop of integrated switching OLED
devices
The Fraunhofer project is implementing the complete process chain at five Fraunhofer Institutes: ILT (coordination), IPT, IKTS, FEP, IMWS
Cutting process by direct ablation with ultrashort pulsed laser radiation.
polymer film
ultra-thin glass
device
laser beam separation
linear absorptionnon-linear absorption
transparent ceramic non-linear absorption
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Bendability: polymer vs. ultra thin glass
Polymer barrier substrates + IMI
no damage for bending with
R >8 mm
Lower bending radius possible with
neutral axis engineering and with
improved barrier technology
ultra thin glass (100 µm)
no damage for bending with
R >20 mm
Lower bending radius possible with
thinner glass thickness
(50 µm, 30 µm)
© Fraunhofer FEP
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WATER INGRESS INTO OLED‘S
1. Water permeation perpendicular through the barrier films
2. Side-ingression through adhesive layers (bulk material)
3. Water permeation through the interfaces
Substrate film
Adhesive
Substrate film
1 1
3
32
OLED
Barrier layer
Interface diffusion
Lat. bulk diffusion
Interface diffusion
≤ 1 µm25 µm250 nm
Dark spot formation aroundbarrier defects
Pixel shrinkage
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SIDE INGRESS VERSUS DIFFUSION THROUGH THE BARRIER ADHESIVE
Ca-test lamination of ZTO / Al2O3 coated glass with 5 mm edge sealing Side diffusion > 10-4 g/m²d (adhesive without water getter) Interfacial diffusion means strong dependency of the barrier film
coatings/materials
© Fraunhofer FEP
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PLASTIC BARRIER FILMS ARE SMOOTH BUT INCLUDING MOISTURE
Barrier film not dried before OLED process.
Barrier film dried for 10 min. at 100 °C under N2 condition before OLED process
Residual water affects the OLEDs during manufacturing
residual water on the surface, in the barrier and electrode films -> direct influence
residual water in the PET film -> indirect influence (backside in front of top side) typical water content ≈ 1000
ppm
R2R drying process for several substrates developed
proper storage/transport of rolls required
© Fraunhofer FEP
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LIFETIME MEASUREMENT FROM R2R OLEDS ON BARRIER FOILS
#7B dark spots: 0.18%#7B dark spots: 0.08% #20A dark spots: 0.02% #20A dark spots: 0.03%
Part 2: with out-gassing in vacuum (OLED 1 cm² and 10 cm²)Part 1: no out-gassing in vacuum
OLED devices after 1500h storage under ambient condition on WVTR 10-3 g/d*m² barrier film.
OLEDs from not out-gassed part show higher level of degradation (shadings) -> water residues cause a significant reduction of the OLED lifetime (1x1 cm²).
For “large” OLED areas at present it´s hard to get it dark spot free just a matter of price to guarantee very low pinhole levels in plastic barrier films?
© Fraunhofer FEP
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KNOWLEDGE MANAGEMENT FOR IMPROVEMENT PROCESS STABILITY
Shortcut Waferlabel V1000 J1000 CE1000 PE1000 CIEx1000 CIEy1000 [V] [mA/cm²] [cd/A] [lm/W]
4 A 3,89 2,3 43,2 35,0 0,464 0,530 4 B 3,84 2,3 44,2 36,3 0,453 0,541 7 A 3,72 2,3 43,5 36,9 0,454 0,540 7 B 3,77 2,3 42,9 35,9 0,444 0,549 11 A 3,61 2,2 45,9 40,1 0,450 0,543 11 B 3,58 2,2 45,7 40,2 0,440 0,553 15 A 3,59 4,5 21,5 18,7 0,450 0,543 15 B 3,57 2,1 47,9 42,3 0,441 0,552 17 A 3,55 2,2 46,5 41,3 0,450 0,543 17 B 3,52 2,1 47,0 42,0 0,441 0,552 21 A 3,49 2,1 46,8 42,1 0,447 0,546 21 B 3,47 2,7 36,8 33,1 0,445 0,548 22 A 3,51 2,2 45,8 41,0 0,449 0,545 22 B 3,49 2,1 47,2 42,5 0,450 0,544
OLED key values
process parameter, coil diameter control over time
Corresponding OLED key values on rigid glass fabricated in the cluster tool.
U[V]
CE[cd/A]
PE [lm/W]
CIEx CIEy
3.54 53.2 47.3 0.464 0.525
@ 1000 cd/m²
time
vacuum pressure
1-unit yellow
© Fraunhofer FEP
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AUTOCLAVE EXPERIMENTS OF ROLL-TO-ROLL OLED SAMPLES FOR AUTOMOTIVE APPLICATIONS
OLED on PET plastic barrier film. Temperature treatment at 125 °C for 90 minutes at 1 bar. Resin interlayer film: EVA Tiny degradation after autoclave process visible. Trend of higher leakage current!
before after
© Fraunhofer FEP
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SCOPE FOR R2R PILOT PRODUCTION
Complete and qualified supply chain
No matter with the OLED materials
Residual layer stress by TCO coatings on ultra-thin glass
Water vapor transmission rate for barrier films is an important value, but there exist more criteria to meet the requirements.
Good statistic analysis is needed for identification of killer defects.
Memory effect in coils: Standardization of winding and web tension.
Keep the OLED substrate development untouched for a while
Ultra-thin glass helped a lot for R2R process development
Changing of planarization and interlayer in barrier coatings have a huge impact on the winding process and process.
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 688093
Consortium & Capabilities
The pilot line includes all the steps required to create advanced flexible OLED product prototypes:• High performance moisture barrier and electrode films• Flexible OLED fabrication in sheet-to-sheet and roll-to-roll process• Flexible device encapsulation• Lamination, bonding and system-level hybrid integration of thin film flexible electronics
25
10/25/2017
2017 OLED DOE Stakeholder Meeting, October 10-11th, 2017, St. Paul, MN
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 688093
PI-SCALE
The PI-SCALE pilot line service fills that gap and helps to translate your ideas into products
26
TRL 1-4Research
Mainly Public
TRL 5-7Technology
DevelopmentPublic/Private Collaboration
TRL 8 & 9Commercializa
tionPrivate
10/25/2017
2017 OLED DOE Stakeholder Meeting, October 10-11th, 2017, St. Paul, MN
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 688093
R2R OLEDs Ideal for low price and quantity
10/25/2017 27
R2R evaporated OLED
• 300mm web-width, up to 100m campaign length
• Good performance OLED
• Customised OLED shapes and designs possible
• Large form factor OLEDs
Parameter PI-SCALE R2R evaporated OLEDsColor yellowLuminance efficacy 30 lm/WOperational lifetime > 500hShelf lifetime n.a.Operating current voltage @ luminan4-5V @1000 cd/m²Luminance 1000 cd/m²CIEx/y 0,490/0,504
Thicknessthin-glass + barrier: ≈300µmBarrier+ PET-ITO + Barrier: ≈420-500µmBarrier-ITO + barrier: ≈320µm
Shapeup to 600 mm length and 290 mm width all shaped are possible
Area design dependent
2017 OLED DOE Stakeholder Meeting, October 10-11th, 2017, St. Paul, MN
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 688093
R2R Flexible Barrier Film – current status
• Pinhole density = excellent measure for barrier properties• Standard R2R single SiNx barrier; iWVTR < 2.10-6 g/m2/day
– eWVTR ~ 2.10-7 g/m2/day; 0.13 pinholes/cm2
• Improved R2R single SiNx barrier– eWVTR~ 1.10-8 g/m2/day; 0.03 pinholes/cm2
2013
-14
2015
-16
2016
op
timiz
ed
OLED qualityR2R produced
Barrier
High quality level for barrier film manufacturing needed!
Pinhole results in black spots
2017 OLED DOE Stakeholder Meeting, October 10-11th, 2017, St. Paul, MN
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 688093
10/25/2017 29
R2R OLEDs Ideal for low price and quantity
2017 OLED DOE Stakeholder Meeting, October 10-11th, 2017, St. Paul, MN
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 688093
OLED Features Available from 2018
Active and passive matrix segmented OLEDs
Long strips >1m made by R2R
Transparent OLEDs
10/25/2017 302017 OLED DOE Stakeholder Meeting, October 10-11th, 2017, St. Paul, MN
© Fraunhofer FEP
page 31
Roll-to-roll OLED fabrication can be made feasible on metal-, plastic- and ultra-thin glass web for different kind of target applications Ultra-thin glass: great opportunity for high quality and dark spot free OLED
devices Metal foil: good heat management, but extra planarization layer needed Plastic barrier film: high bendability, but how to guarantee no pin holes?
Comparable power efficacy between R2R and lab-scale OLED possible Residual water as the most critical impact for reproducibility for R2R
manufacturing get the polymer film as thin as possible! Reliability improvements will be pushed within the EU PI-Scale project for S2S
and R2R Starting pilot production in Roll-to-Roll fabrication on ultra-thin glass with barrier
film as encapsulation coming soon feasible Remove residual moisture in coils needs to further minimized < 100 ppm Changes in the barrier film layer structure influences the winding behavior Module separation and patterning as currently hot development topics
SUMMARY
© Fraunhofer FEP
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ACKNOWLEDGEMENT
The research is funded within the framework for technology promotion by means of the European Fund for Regional Development (EFRE) as well as by means of the Free State of Saxony.
Parts of this work were supported by the German Federal Ministry of Education and Research within the projects R2Flex (FKZ 13N11058), R2D2 (FKZ: 13N12948) and this activities has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 688093 (PI-SCALE).
Special thanks to my colleagues, especially: Michael Stanel, André Philipp, Matthias Fahland, John Fahlteich, Nicolas Schiller, Manuela Junghähnel, Michael Törker, Jan Hesse