roll-to-roll technology for transparent high barrier … technology for transparent high barrier ......
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Roll-to-roll Technology for Transparent High Barrier Films
Presented at the AIMCAL Fall Technical Conference,October 19 - 22, 2008, Myrtle Beach, SC, USA
Nicolas Schiller, John Fahlteich, Matthias Fahland, Waldemar SchönbergerFraunhofer FEP, Germany
InstitutElektronenstrahl- undPlasmatechnik
aFraunhofer
FEP
page 2
Outline
Motivation and Approach
Magnetron PECVD process
Layer properties
Summary and Conclusion
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
page 3
Outline
Motivation and Approach
Magnetron PECVD process
Layer properties
Summary and Conclusion
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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"Be flexible:" Flexible displays, signage, lightning, and solar cells
offer unique application and cost saving potentials.
Source: PolymerVision
Source: Konarka
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Flexible substrates
Potential benefits for designers and users
• thin,
• low weight
• new design concepts
• Ultra low cost applications
Potential benefits for producers
• Roll-to-roll production scheme
However, Encapsulation is needed to protect the device from water vapor and oxygen
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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water vapor oxygen
Electronic devicepermeation barrier
flexible solar cell
flexible OLED
today:• Ultra-High-Barrier olny
with glass• not flexible
future:• thin film encapsulation for
ultra-high-barrier• low cost• flexible
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Direct Encapsulation vs. Barrier Foil
Direct Encapsulation Barrier Foil
• All encapsulation processes must be compatible
• Substrate exposed to (plasma) process• All in vacuum roll-to-roll encapsulation
possible
• Free choice for processes (combine vacuumand non-vacuum processes)
• OLED and barrier development independent• Additional process: lamination
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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14.10.2008
Requirements and coating technologies for transparent barriers
10010110-110-210-310-410-510-6
Water Vapour Transmission [g / m² day]
Food Packaging
Solar Modules
Organic Electronic Devices
Polymers (intrinsic)
Evaporation
Sputtering
Combination Processes
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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barrier layer
Substrate(polymer film, OLED, solar cell…)
defect in barrier layer
Models suggest that barrier performance is controlled by defects in the barrier layer. (The layer itself is supposed to be impermeable.)
All concepts to improve barrier performance are focused to hinder the growth of defects.
Challenge of thin film encapsulation
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Concept: dense single layer
Virtually defect free or low defect single barrier layer
• Atomic Layer Deposition – thin layer by layer deposition[1]
• Ion-beam assisted sputter deposition[2]
[2] R. Dunkel: High Performance low cost single layer barrier coatingson plastic, General Atomics Produktpräsentation
[1] P. F. Carcia et al.: APPLIED PHYSICS LETTERS 89, 031915 (2006)
sputtered Al2O3
GA - Super Sapphire
[2]
barrier layer
Substrate
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Concepts: graded single layer
Graded (organic/inorganic/organic) layer
Substrate(polymer film, OLED, solar cell…)
[1] A. G. Erlat et al.: Ultra-High Barrier Coatings for Flexible OrganicElectronics, SVC – 48th Technical Conference Proceedings, p. 116 (2005)
inorganicorganic
[1]
• Variation of film composition by changing process gas
• Batch-process not applicable for roll-to-roll encapsulation
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interlayerbarrier layer
Substrate(polymer film, OLED, solar cell…)
barrier layer
Multi-layer barrier
defect in barrier layer
• defect decoupling: tortuous path for moisture and oxygen diffusion
• increased lag time of diffusion
• decoupling of mechanical stress
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Example: multi-layer barrier with ORMOCER®s
ORMOCER®
barrier layer ("PVD-layer")
Substrate(polymer film, OLED, solar cell…)
barrier layer ("PVD-layer")
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Outline
Motivation and Approach
Magnetron PECVD process
Layer properties
Summary
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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All-in-vacuum approach: interlayer by Magnetron PECVD
interlayer: PECVD-layerbarrier layer ("PVD-layer")
Substrate(polymer film, OLED, solar cell…)
barrier layer ("PVD-layer")
"PVD-layer": Layer deposited by Physical Vapor Deposition (e.g.sputtering)
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Why PECVD / PVD multilayer structure?
Main Goal: Development of an all-in-vacuum encapsulation technology for flexible
electronic devices
• Cost reduction with roll-to-roll encapsulation
• Magnetron-based PECVD and PVD run in one machine at the same time
• suitable for production of barrier films as well as direct encapsulation
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Reactive Magnetron Sputtering
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Magnetron PECVD
SiSi
O
CH3
pressure range: ca. 0,5 ... 5 Pa
High potential for large area/wide web processing
coating rate > 400 nm•m/min
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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multilayer stack for barriers
Combination of Sputtering with Magnetron based PECVD
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Outline
Motivation and Approach
Magnetron PECVD process
Layer properties
Summary and Conclusion
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Layer composition (HMDSO)
Process parameters:2.3 W/cm², HMDSO+O2= 80 sccm
measured using XPS
low amount of target material (Ti) incorporated into the layers
composition adjustable from silicon oxide like to polymer like layers
reference (sputtered SiO2)
0 6 13 19 25 31 38 44 50 560
10
20
30
40
50
60
Ti
Si
C
Con
cent
ratio
n [a
t. %
]
HMDSO/(HMDSO + O2) [%]
O
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Mechanical Properties
• substrate: PET75 µm
• hardness measured for HMDSO:O2 = 1:10 using Nano-indentation
• lower hardness compared to sputtered layers
• low internal stress
6 13 19 25 31 38 44 500
1
2
3
4
5
9
10
SiCxOy - PECVD
sputtered SiO2
sputtered SiNx
hard
ness
[G
Pa]
HMDSO/(HMDSO + O2) [%]
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Permeation Barrier Properties of SiOxCy
0 50 100 150 200 250 300 350 4000,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
4,0
4,5
5,0
WV
TR [
g/(m
²d)]
film thickness [nm]
ratio HMDSO:O2 7:73 20:60 40:40
substrate: 125 µm PET
polymer like layers reflect barrier properties of substrate
SiOx-like layers:WVTR > 0.2 g/(m2d)
increase of barrier performance at high thickness
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Single layer optical coating (SiOxCy on PET)
• TEOS-based process
• Low internal stress
0 500 1000 1500 2000 2500
0
20
40
60
80
100
Tran
smis
sion
[%]
Wavelength [nm]
80 nm 240 nm uncoated PET
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Magnetron PECVD in optical multilayer stacks
PET substrate
SiO Cx y
TiO2
appr. 640 nm
300 400 500 600 700 800
0
20
40
60
80
100
Tran
smis
sion
[%]
Wavelength [nm]
SiOxCy + reactively sputtered TiO2
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Pilot sputter roll coater coFlex® 600flexible substrates (polymer webs, thin metal foils)
600 mm deposition width
web speed 0,1...100 m/min
6 coating stations (dual magnetrons)
Pulsed Magnetron Sputtering
Magnetron PECVD
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Pilot roll coater novoFlex® 600flexible substrates (polymer webs, thin metal foils)
600 mm deposition width
web speed 0,1...600 m/min
double side coating
5 coating stations
combination of evaporation, sputtering and PECVD
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Scaling up to pilot-scale
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
reactivesputtering
Magnetron-PECVD
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Deposition Rates
• deposition rate increases with monomer flow
• higher rates at higher power: 400 nm*m/min possible at 20 kW (7 W/cm²) with HMDSO and HMDSN
HMDSN 10 kW
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Long term process stability
plasma impedance increases within first 30 min
dynamic deposition rate stabilizes within 15 min
rate drift within 6 hours± 5%
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Multilayer barriers - Sputtering + Magnetron-PECVD
PEN
ZnSnOx – 75 nm
SiOx - PECVD - 60 nm (7:73)
ZnSnOx – 75 nm
PEN
ZnSnOx – 75 nm
SiOx - PECVD - 60 nm (7:73)
PEN
ZnSnOx – 75 nm
WVTR = 0,045 g/(m²d)
WVTR = 0,045 g/(m²d)
WVTR = 0,007 g/(m²d)
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
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Outline
Motivation and Approach
Magnetron PECVD process
Layer properties
Summary
Roll-to-roll Technology for Transparent High Barrier FilmsPresented at the AIMCAL Fall Technical Conference 2008
page 33
Summary
InstitutElektronenstrahl- undPlasmatechnik
aFraunhofer
FEP
A novel concept for the all-in-vacuum, roll-to-roll deposition of multilayer barrier stacks has been developed. The basis of the concept is the in-line combination of magnetron sputtering and a magnetron PECVD-process.
The magnetron PECVD process offers several benefitslow working pressure of 0.5 Pa up to few Pa, thus allowing the in-line combination with sputtering processwide range of properties for SiOxCy layers high potential for large area processing by using dual magnetrons as power sourcehigh coating rates (> 400 nm•m/min)
Our basic concept allows an all-in-vacuum roll-to-roll deposition of multilayer barrier stacks. The process has been installed in a pilot-scale multi-chamber pilot roll-to-roll coater.