ROLL-TO-ROLL MANUFACTURE OF OLED DEVICES · R2R vacuum . coater. Substrate Inspection. Structuring....

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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

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INTRODUCTION ROLL-TO-ROLL MANUFACTURING

Highest degree of automation level

Background and Mentality

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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

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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

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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.

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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.

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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.

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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)

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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

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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

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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

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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?

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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

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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

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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

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10/25/2017

2017 OLED DOE Stakeholder Meeting, October 10-11th, 2017, St. Paul, MN


PI-SCALE

The PI-SCALE pilot line service fills that gap and helps to translate your ideas into products

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TRL 1-4Research

Mainly Public

TRL 5-7Technology

DevelopmentPublic/Private Collaboration

TRL 8 & 9Commercializa

tionPrivate

10/25/2017



R2R OLEDs Ideal for low price and quantity

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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



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



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R2R OLEDs Ideal for low price and quantity



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

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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

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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

ROLL-TO-ROLL MANUFACTURE OF OLED DEVICES · R2R vacuum . coater. Substrate Inspection. Structuring....

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