on roll-to-roll manufacturing

inspectorwormsElectronics - Devices

Nov 27, 2013 (4 years and 1 month ago)

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Printed
Electronics with emphasis
on roll
-
to
-
roll manufacturing


Saurabh Suryavanshi

(08d07037)

EE 728 Seminar


Prof: B. M. Arora

EE 728, 15th April

1

Print + Electronics


Patent


“Printed Wire”, in 1903 by
Albert Hanson in England.


Produce
conductive metal patterns on
dielectric substrate. Metal foil was
first cut or stamped out into
conductor patterns. The copper or
brass traces were then adhesively
bonded to paraffined
paper.


Thomas Edison has also worked on
the problem and produced “Additive
Solutions”


selectively applying glue (polymer
adhesive) and dusting the wet

ink”
with conductive graphite or bronze
powder

Patent Figure

Edison’s idea of depositing/printing

conductor

EE 728, 15th April

2

Introduction


New
types of multidisciplinary cooperation will
emerge to drive renewal
of industry
with printed
electronics
.


Device manufactured at once; changes in
manufacturing value chain.


Technology in early phase, difficult to get
companies to co
-
operate for printed electronics.


End User does not care about printing processes
as long as product price and functionality remains
same.

EE 728, 15th April

3

Introduction
-
2

AIM:
Use present printing technology to create electrically functional
devices.


Substrate


paper, glass,
c
eramic, silicon



Printing technology
-
screen
printing, flexography, gravure, offset,
lithography and inkjet.



Printed Components
-

e.g. electrodes comprising
printed metal
particle ink, carbon ink or conductive polymers or diodes and
transistors
comprising, printed
organic semiconductor and
dielectric
layer



Inks

-
solution
-
based material
, including organic semiconductors,
metallic conductors, nanoparticles,
nanotubes etc
.

EE 728, 15th April

4

Why Printed?

Benefits

Trade

offs

Simple Fabrication

Reduced Performance

Cost
-
Effective

-
Frequency

Roll
-
to
-
roll manufacturing

-
Mobility

Short production

runs

Temperature

restrictions

Low

temperature processing

Additive Process


Environment friendly

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5

Future is Present!

Plastic Logic : e
-
paper

Philips:

Thinnest active matrix

display

Thinnest watch (3mm) : Citizen

Low cost RFID

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6

Ink

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7

Metallic ink:

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8

Metal Nano particles


typical idea

-
Nanoparticles
can be stabilized in ink solutions by organic ligand

shells, which can be removed after printing
.


-
Nanoparticles
can be further cured or sintered to highly conductive

films at low temperatures
. Increase temperature increases
conductivity.

EE 728, 15th April

9

Ink

Application of inks:

-
Solvent Based

-
Water Based

-
UV
-

Curable

Major constraints : Viscosity




Surface Tension




Density




Evaporation rate




Particle size etc.

EE 728, 15th April

10

Data Sheet For ink (Supplier : Novacentrix)

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11

Thermal Budget vs. Resistance

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12

Characterization

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13

Characterization
-

Conductors


Resistivity


-
Longer length

-
constant width and cross section

-
Sensitive measurement

Errors:

-
Positive error due to large current density : Make length larger than width





-
Contact and lead resistance , especially when resistivity of sample is small
-

Use four


probe measurement

Print efficiency:
Very essential in case of printed

conductors. Ratio of theoretical to observed.


Gravure
-

deep cuts. Flexographic


raised platform.

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14

Mass production, R2R techniques

EE 728, 15th April

15

Flexographic Printing

Printing plate:
Prints in rotary fashion using a relief image pattern

Impression
cylinder:
helps transfer the ink from the printing plate and the

image on to the printing substrate


Anilox roll:
transfers ink to the printing plate; ink transfer can be
controlled


Just like Rubber stamp!

EE 728, 15th April

16

Gravure Printing


-
Ink
transferred from ink reservoir to
rotogravure and Image
is engraved

-

Doctor blade removes extra ink

-

Surface of substrate must be smooth
for successful printing

-
Reverse
of flexographic printing in terms of wetting ink on printing plate
. Extra
ink is removed first before printing is done.

EE 728, 15th April

17

Sheet Fed
printing methods

EE 728, 15th April

18

Offset Lithography

-
Printing
plate has hydrophophobic and hydrophilic
areas. Very different Idea from
previous methods

-

hydrophobic
ink is transferred to the hydrophobic areas on the printing plate.

-
Printing
image is on surface of anilox
roller cylinder
.

-

Offset plate: transfers ink the image on to the substrate with the help of

impression cylinder

-

Wetting printing plate is very complex

EE 728, 15th April

19

Ink Jet Printing

Like Scanning Electrode

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20

Step
-
by
-
step production

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21

Technology
Comparision

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22

OLED flow

-
Ideal processing flow for R2R manufacturing

-
Combination of above methods

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23

Optimization of parameters


The
challenges and limitations of the current state of art lies in the vast amount
of
parameters
that need to be
optimized
and developed.


Compatibility
of all processes used
in production
is a
real issue
.

Ex: Trade off of Viscosity. For printing high viscosity is required, but for having good
characteristics high viscosity is necessary.


The
following parameters have to be
optimized
and
developed:

-

Line width, gap width

-

Substrate
distortion

-

Registration

-

Throughput

-

Layer
thickness and uniformity
,

-

Layer
Edge
quality

-

Drying time

-

Curing time

-

Solvent
compatibility, viscosity and
wetting

-

Materials
performance

EE 728, 15th April

24

Applications


RFID


Sensors


Displays


LEDs


Batteries


Bio
-
compatible electronics


EE 728, 15th April

25

Ring Oscillator

Ref
-

Vaidyanathan
, J.
Granstrom
, S. Liu, A.
Sydorenko
, T.
Zillger
, G. Schmidt, K.
Preissler
, E.
Reichmanis
, P.
Eckerle
, F.
Richter, T. Fischer, U. Hahn,
“Ring
oscillator fabricated completely by
means of
mass
-
printing
technologies”
,
Organic Electronics, Volume 8, Issue 5, October 2007.

An oFET
top gate architecture was chosen
primarily because
the first deposition
step of source and
drain contacts
requires the highest resolution and can
be
accomplished
most easily on a plain and
defined substrate
like a smooth polyester
foil (PET)
rather than
on a printed multilayer surface with
significant roughness
.

Offset printing : patterning of source and drain. The layout of source and drain

largely determines the performance of device

EE 728, 15th April

26

Fabrication

-
Offset Printing results in very
inhomogeneous layers

with average thickness
of 600nm with local layer thickness of 50nm to 3 um.

-
Dielectric of few micrometer needs to be used for insulation between gate
and source/drain structure.

-
As
the active semiconducting
layer
used
a THF
-
formulation
of commercially
available poly(9,9
-
dioctyl
-
fluorene
-
co
-
bithiophene
)
(F8T2)
of American
Dye
Source, which exhibits field
effect motilities
of up to 102 cm2/V s after high
temperature Alignment
. Integration of such high temperature process
alignment with printing techniques is not possible. Therefor the mobility is
at least for an order less than high temperature alignment on glass
substrate.

-
Gravure
printing is known to
handle low
viscosity inks
and deposit high
-
quality layers.

For good surface we require the solution with high viscosity.

Dual gate oxide deposits. High k dielectric which is deposition first and high
dielectric.

-
Gate electrode by silver ink of Precicion

EE 728, 15th April

27

Circuitry of the seven
-
stage ring oscillator and
photographic image of a fully
-
printed circuit.

-
Shows feasibility of R2R printing as all process involved where carried at 1m/s

-
Frequency is dependent on length, with better optimization (in terms of resolution) we
can achieve higher operating frequency

-
It is highly desirable to enhance conductivity , uniformity.

EE 728, 15th April

28

Printed Electronics on paper


Challenges


Roughness




-

Absorption of ink


Paper choice: NopaCoatStratos

-
minor
roughness (Ra ~ 300 nm)


-
low
absorption capacity (~ 3
g/m^2)


The homogeneity of different layers and the substrate


are of great importance for printed electronics.


Ink splitting causes Peaks in structure.

Gravure printed S/D
structures, printing ink


PANI
-
T, channel length
approx.50μm

T
he
humidity contained in the paper
and absorbed
from the air can cause short circuits in
the
small channels
between source and drain. This is even intensified
by the
hygroscopic
properties of PEDOT:PSS.

Gravure and Offset printed PEDOT:PSS S/D structures. Gravure has smaller peaks.

EE 728, 15th April

29

Substrate Waviness.

Larger resistance when deposited on substrate due to larger absorption of doping

Ref: Printed
electronics on
paper, H. Kempa

et. al.,

Proceedings of OEC
-
07

EE 728, 15th April

30

Conclusion
-

challenges


Materials

-
Very few substrates available

-
Lack of printable solutions (
functional ink
)
though lot of Nano
-
materials and Nano
-
particles available


Mass
-
manufacturing


mostly handmade
prototypes available

-

The problem with getting high yield in mass
manufacturing

EE 728, 15th April

31

Additional Requirement.

EE 728, 15th April

32

Thank you!

EE 728, 15th April

33