„large-area patterning by roller-based nanoimprint lithography · „large-area patterning by...

www.joanneum.at June 24th, 2015 - Chemnitz

„Large-area patterning by roller-based

nanoimprint lithography“

Ursula Palfinger, Dieter Nees, Stephan Ruttloff,

Markus Leitgeb, Maria Belegratis, Barbara Stadlober

JOANNEUM RESEARCH Forschungsgesellschaft

Institute MATERIALS, Weiz, Austria

2 Outline

Motivation – Small structures on large areas

Technology – Roll-to-roll Nanoimprinting (R2R NIL)

Processes

Machinery

Materials – Prerequisites for residual-free imprinting

Applications – Roller-based fabrication of highly resolved metal patterns by a combination of residual-free NIL and a subsequent lift-off for transparent conductive foils and product ID features

Summary

Outline

June 24th, 2015 - Chemnitz

Small structures on large areas 3

Motivation

Superhydro-

phobicity Lotus effect

Point-of-Care

Diagnostics

Structural

Colours Camouflage,

Attraction

Light

management

Low

friction Riblets

Flexible

electronics OFETs

Adhesion Gecko-effect

Architecture Antireflectivity

Others:

Transport

Traffic

Security

Packaging

Energy Harvesting

…

Where is highly resolved

patterning on large areas

interesting?


http://www.jenoptik.com/de-Entspiegelungen-ahmen-Optik-Mottenaugen-nach

Small structures on large areas 4

Motivation

Point-of-Care

Diagnostics

Structural

Colours Camouflage,

Attraction

Light

management

Low

friction Riblets

Flexible

electronics OFETs

Adhesion Gecko-effect

Architecture Antireflectivity

How can we

produce them? 1) micro and nano

2) 2D – 2.5D

3) large flexible areas

4) industrial process

Superhydro-

phobicity Lotus effect


http://www.jenoptik.com/de-Entspiegelungen-ahmen-Optik-Mottenaugen-nach

Nanoimprint lithography 5

Technology

Fast + accurate method for structure transfer

UV or thermal curing of resist

Very versatile (geometries, structure size)


Working stamp

Substrate, resist

Contact, imprint

Curing: T, UV

Release

1

2

3

4


Technology

Stamp Imprint

CD = 1.6 µm






Technology

Stamp Imprint

CD = 200 nm






Technology

Critical issues – Batch NIL (serial)

- Master (pattern quality, roughness)

- Control of adhesion between master and resist

- Resist viscosity (filling)

- Curing behavior (fast, low shrinkage)

- Fabrication volumes and process time

- Upscaling?


Working stamp

Substrate, resist

Contact, imprint

Curing: T, UV

Release

9

Technology

Roll-to-Roll Nanoimprint lithography


line pressure

Substrate

Photoresin

(liquid)

Photoresin

(structured

and cured)

Working stamp

Substrate, resist

Contact, imprint

Curing: T, UV

Release rubber-coated

counter roller

Shim

on

roller

Roll-to-Roll Nanoimprint lithography 10

Technology

Max. web width = 250 mm

Web speed = 0.5 – 30 m/min

Max. UV intensity = 200 W/cm

Line pressure UV-NIL = 18 kN

Line pressure HE = 100 kN


Resolution and throughput of printing technologies 11

Technology

Hig

h (

>1

) M

ediu

m

(0

,01

-1)

Low

(<

0,0

1)

High Resolution (< 10 µm) Medium Resolution

(10-50 µm) Low Resolution (> 50 µm)

Laser

ablation

R2R

photolitho

Inkjet

Rotary

screen Flexo

Gravure

Offset

Source: OE-A 2009, 3D-MM

Minimum feature size (µm)

Th

rou

gh

put (m

2/s

)

1 10 100 500

100

1

10-2

10-4

R2R – Nanoimprint lithography

R2R-vacuum

Flat

screen


12

Technology

Hig

h (

>1

) M

ediu

m

(0

,01

-1)

Low

(<

0,0

1)

High Resolution (< 10 µm) Medium Resolution

(10-50 µm) Low Resolution (> 50 µm)

Laser

ablation

R2R

photolitho

Inkjet

Rotary

screen Flexo

Gravure

Offset

Minimum feature size (µm)

Th

rou

gh

put (m

2/s

)

1 10 100 500

100

1

10-2

10-4

R2R – Nanoimprint lithography

R2R-vacuum

Flat

screen

Resolution and throughput of printing technologies

Source: OE-A 2009, 3D-MM


residue-free imprint

stuctured metal layer

metal

Application

13

Creation of highly resolved metal patterns in R2R environment


l : line width

s : space width

d : structure depth

ho: initial resist film thickness

Applications

14

Critical for residual-free imprint: PATTERN GEOMETRY


Structure depth and resist thickness

for open patterns

t : imprint time

η : resist viscosity

l : imprinted line width

p : imprint pressure

hr : residual resist film thickness

ho : initial resist layer thickness

For vanishing residual resist film thickness

the imprint time approaches infinity ...

“Stefan’s equation”: p

H. Schift, J. Vac. Sci. Technol. 2008

Applications

15

Critical for residual-free imprint: RESIST FLOW BEHAVIOR


Squeeze flow model

S = gSubstrate/Shim – (gSubstrate/Resin + gResinShim) < 0

gX/Y : interfacial energy S: spreading coefficient

SJ Choi, J. Colloid. Interface Sci. 2009

Applications

16

Critical for residual-free imprint: SURFACES VS. RESIST CHEMISTRY


Spontaneous dewetting and balance of interfacial forces

• low viscosity

• water soluble

• monofunctional Non-ionic surfactant

η = 10 mPas

Photoinitator

e.g.

e.g.

Monomer

Tuning of interfacial energies

20 mN/m < g < 45 mN/m

Applications

17

Critical for residual-free imprint: CHOICE OF RESIST

Auner, Palfinger et al, Organic Electronics, 2009+2010

Acrylate

UV-NIL resist for aqueous lift-off

polar rest group

UV-Resist

PET

Applications

18 Residual-free R2R imprint

Zoom

SEM: cross section


SEM: top view

UV resist

PET

Applications

19 Residual-free R2R imprint

Zoom

SEM: cross section


SEM: top view

1

2

water lift-off

metallization

Applications

20 Al lines, CD = 1.6 µm

3 nm Cr + 30 nm Al

Lift-off with H2O


21

web direction

Applications

21 Al patterns, CD = 1.6 µm

l/s = 1:4 web direction

Applications

22 Al patterns, CD = 400 nm

SEM

Applications

23

Application “nano”: Metal grids for transparent conductive foils


400 nm

SEM

Applications

24



400 nm

Source: PolyIC Source: Samsung PyzoFlex technology

Flexible displays, touch panels, sensor surfaces, shielding foils,…

SEM

Applications

25



200 nm

Roller-based nanoimprinting is a large area, high resolution patterning

process with very high potential.

Residue-layer free R2R UV-NIL is possible, when pattern geometries

and stamp and resin surface chemistry is optimized.

We developed an acrylate-based imprint resin for water-based lift-off

and used it for highly-resolved metal patterning on foil without the

need of etching.

Applications can be seen in electronics, optics, sensing, security

features…, shown examples: transparent conducting, packaging

Summary

26 Summary


Dieter Nees

Markus Leitgeb

Stephan Ruttloff

Maria Belegratis

Herbert Gold

Laco Kuna

Volker Schmidt

Barbara Stadlober

Acknowledgements

http://www.bmwfw.gv.at/

http://rp7.ffg.at/home

Lift-off in progress

Thank you for your interest!

http://www.bmwfw.gv.at/

http://rp7.ffg.at/home

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