advanced sheet-to-sheet and roll -to-roll thin-film ... maneula...advanced sheet-to-sheet and roll...

© Fraunhofer FEP

page 1

M. Junghaehnel1, J. Westphalen1, F. Naumann2, G. Lorenz2, M. Fahland1, S. Mogck1

Advanced Sheet-to-Sheet and Roll-to-Roll thin-film processing on ultra-thin flexible glass for flexible electronic devices

1) Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP2) Fraunhofer Institute for Applied Microstructure of Materials and Systems IMWS

© Fraunhofer FEP

page 2Manuela Junghähnel, 2017FLEX, Ref.-Id.: 9.2

Progress in ultra-thin glass product development

Equipment S2S, R2R Processing Handling Cutting

Coatings Lighting Display Sensors Energy storage Automotive

Products

Glass manufacturer

Flexible Glassd > 1 mm

d ~ 1 … 0.2 mm

d < 0.2 mm

© Fraunhofer FEP


S2S technologies for PVD of ultra-thin flexible glass

In-line S2S vacuum coater for inorganic thin-films

Substrate size for UTG max. 600 x 600 mm² ~ Gen 3.5 format

PVD and PECVD processes

Post annealing: Heating up to 400°C or Flash Lamp Annealing (FLA)

“Stand alone” UTG handling or glass on carrier technology

© Fraunhofer FEP


S2S technologies for PVD of ultra-thin flexible glass Example “hot” ITO 150 nm ITO 100 µm Corning®

Willow® Glass Substrate size:

500 x 500 mm² Thermal annealing in

Vacuum @ 400°C after coating

ITO properties: Rsq. ~ 12 Ω TVIS ~ 87.3% ρ ~ 1.7·10-4 Ω·cm

Source: M. Junghähnel et al.; 59th SVC 2016

© 2016 Fraunhofer FEP

© Fraunhofer FEP


Challenges in processing of flexible glass

10 mm

ITO 1000 nmITO on

100 µm UTG

ITO on50 µm UTG ITO 750 nm

10 mm

Additional issues must be taken into consideration:

Selection of the substrate thickness

Pre-conditioning

Process parameters

Coating design

Post processing

Beside functional properties

Mechanical properties of the substrate-layer-compound

FhG internal project ZUG4Flex

© Fraunhofer FEP


Characterizations of flexible glass substrates

Types of flexible glass

100 µm thickness

3 different glass suppliers

Substrate states:

Substrates in initial state - uncoated

ITO coated – not annealed

After post annealing

Sputtering Processused target ITO 90/10

length 750 mmpprocess 0.3 Pa + 0.9 PaT RTpower 3 kW, DC-Mode coating rate 32 – 37 nm∙m/minO2 (Ar + O2) 0, 5, 10 %post treatment @ 350°C in vacuum/

FLA @ 6-23 J/cm², 2 ms

Strength testingsample size 10x10mm²

number of samples foreach glass

63

© Fraunhofer FEP


Mechanical Characterization of flexible glass Characterization of substrates – initial state Analysis to define the initial state before PVD-coating

Measurement of:

Surface hardness and Young’s modulus – nano-indentation

Surface topology - WLI

Fracture strength of the sample surface – both glass sides

Indentation Strength testingStress measurement

© Fraunhofer FEP


Mechanical Characterization of flexible glassSurface Hardness and Young’s modulus

Comparable to literature data No significant differences of the Young’s modulus between the front and back Small variation in the surface hardness between the samples (max ~5%)

© Fraunhofer FEP


Mechanical Characterization of flexible glassSurface topology (substrate curvature)

WLI measurement of the surface (reference for stress estimation):

ellipticparaboloidal behavior

hyperbolicparaboloidalbehavior

A significant deformation of all sample types can be measured-2

9.3

20.0

-7.0

23.2

65.4

12.1

Substrate A (blue)

Substrate A (red)

Substrate B (blue)

Substrate B (red)

Substrate C (blue)

Substrate C (red)

-20

0

20

40

60

Rad

ius

of c

urva

ture

[m]

sample size1x1cm²

© Fraunhofer FEP


Mechanical Characterization of flexible glassSurface Fracture Strength

The surface strength of all UTG-types is much higher than the edge strength Differences of the surface strength between the sample types of appr. 65% A theoretical max bending radius of 0.9-1.6 mm of the surface can be assumed.

*) theoretical bending radius of the surface strength neglectingedge flaws (@100 µm glass thickness)

r*theor.~ 0.9 mm

r*theor.~ 1.6 mm

Ball on Ring test:

Stress Calculation

© Fraunhofer FEP


0 0

2 2

4 4

0 0

5 5

10 10

0

500

1000

1500

2000

Com

pres

sive

Stre

ss [M

Pa]

O2/Ar+O2 concentration

Mechanical Characterization of flexible glassInfluence of ITO layer deposition Curvature measurement (WLI) and stress after ITO deposition

0.3 Pa 0.9 Pa

Surface at WP 0.3 PaFlow O2 = 0 sccm

Surface at WP 0.3 PaFlow O2 = 4 sccm

© Fraunhofer FEP


Mechanical Characterization of flexible glassInfluence of thermal annealing

Using nano-indentation, a strong reduction of the ITO-hardness and the Youngs modulus is measured. The resulting parameter are in a comparable range to the initial substrate.

Har

dnes

s[G

Pa]

Mod

ulus

[GPa

]

© Fraunhofer FEP


Mechanical Characterization of flexible glassInfluence of thermal annealing

*) theoretical bending radius of the surface strength neglecting edge flaws (@100 µm glass thickness)

Substrate type A

Estimated influence of the

post-annealing to the

fracture strength

A further reduction (~55%)

of the fracture strength

.

Cha

ract

eris

tic F

ract

ure

Stre

ss [M

Pa]

Weibull Modulus

© Fraunhofer FEP


The road from S2S to R2R – FOSA LabX 330 Glass

R2R vacuum coater Special winding system for UTG handling Substrate width: 330 mm Substrate thickness: 50-100 µm Coating temperature: 350 °C Rollers touching substrate

backside only

Application examples

ITO AR

BMBF – KONFEKT (FKZ 13N13818)

© Fraunhofer FEP


FOSA LabX 330 Glass – machine scheme


© Fraunhofer FEP


FOSA LabX 330 Glass – Example AR coating1st pass

Both stations „on“

Adjustment of the rate ratio to coat the first two layers in one run

No monitoring – film thickness to low

NbOx (Nb2O5) Si (SiO2)

In-linemonitoring)


© Fraunhofer FEP


FOSA LabX 330 Glass – Example AR coating2nd pass

Nb2O5 „on“; SiO2 „off“

Same power than during the 1st pass

Higher band speed

Monitoring „off“


In-linemonitoring)


© Fraunhofer FEP


FOSA LabX 330 Glass – Example AR coating3rd pass

Both stations „on““

Same rate ratio like 1st pass

lower band speed

Monitoring „on“


In-linemonitoring)


© Fraunhofer FEP


FOSA LabX 330 Glass – Example AR coating

400 500 600 700 8000

10

20

80

90

100

T R

Tran

smis

sion

/Ref

lect

ion

[%]

Wavelength [nm]

100 µm Schott glass

Single side coated


© Fraunhofer FEP


Summary

Mechanical Characterization of flexible glass allowing a deeper understanding of the interaction of PVD processes to the

mechanical properties, an identification of critical process parameters with respect to fragility of the

glass substrate, the optimization of critical process parameters to enhance fracture strength

properties, information of further handling conditions after PVD deposition

The road from S2S to R2R Next step in flexible glass processing is successfully done Integration in production lines Reduction of fabrication risks focus applications

© Fraunhofer FEP


Kindly acknowledgements:

Fraunhofer MEF-project ZUG4Flex

Corning Inc.

Schott AG

NEG Co., Ltd

VON ARDENNE GmbH

BMBF – KONFEKT(FKZ 13N13818)

Thank you very much for your attention!

CONTACT:[email protected] Flexible Glass Activities @ FEP

# Booth 1004

advanced sheet-to-sheet and roll -to-roll thin-film ... maneula...advanced sheet-to-sheet and roll...

Documents