Cleaning Techniques for OLED and OPV of Delft Summer...R2R compatible cleaning techniques Technique...
Transcript of Cleaning Techniques for OLED and OPV of Delft Summer...R2R compatible cleaning techniques Technique...
Cleaning Techniques for
OLED and OPV
Adding Value by Reducing
Defects
TU Delft Summer School 13/5/2019
Outline
• Introduction
• Clean4Yield
• Cleaning Technologies
• The Theory of Small Particle Adhesion
• Empirical Evaluation
• The Cleaning Outcomes
• New Applications
• Summary3/5/2019 TU Delft Summer School 2
INTRODUCTION - TEKNEK
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Who are we?
• Company formed 1984
• Acquired by ITW (Illinois Tool Works) in July 2011.
- $18billion sales
• Inventors & world leaders in the manufacture & design of roller
contact cleaning systems
• Global footprint
• Distribution world-wide
• Over 20,000 machines manufactured and delivered to diverse range
of industries
• Produces its own cleaning rollers & adhesives
– 10,000 cleaning rollers per year
– Design and Produce in UK, adhesive centres in UK, USA & UK
– Use around 1.2 million sq. metres of adhesive product per year
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Primary Converting
Secondary Converting
FPD and BLU Assembly
Cleaning Applications
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CLEAN4YIELD PROJECT
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Clean4Yield
• Clean4Yield is a collaborative EU funded project which is tackling
one of the most pressing issues in organic electronics – ensuring
high enough yields for cost-effective manufacturing.
• Objectives
• The objective of the Clean4Yield research project is the
development and demonstration of a holistic concept for the
detection/inspection, cleaning, prevention, and repair of defects and
contaminations in nano-scale layers applied in OLED and OPV as
well as high end moisture barrier films, which are deposited on
flexible substrates by R2R (roll-to-roll) coating and printing
techniques. This will lead to increased yield, better performance,
longer operational device lifetimes and reduced production costs.
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Clean4Yield WP3 Objectives
• Removal of particles down to 100nm
• No damage to substrate or underlying layers
• No unwanted change in surface energy
• No cross contamination
• In atmospheric coating and vacuum deposition
• Substrates of PET and PEN foils, glass and
coated substrates
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CLEANING TECHNOLOGIES
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Technology Drivers
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• Films are getting thinner – easier to damage by
particles in the wind of the roll
• Coatings are getting thinner – even nanoscale
particles can cause pinholes
• The functional requirements on coatings are
becoming more demanding
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Issues
• Particles of contamination on substrates cause
defects in processes used in Flat Panel Display
manufacturing and Organic and Flexible
Electronics
• Defects cause significant yield loss
• Removal of particles is essential for high
functionality and reliability
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R2R compatible cleaning techniquesTechnique
Particle removal efficiency indication / %Remark
0.1 - 1 1 - 10 10 - 40 > 40 µm
Contact cleaning
Rotary wet wipe ? > 90 > 90 > 90 risk of damage of soft layers and cross
contamination
Rotary brush + vacuum 0 0 > 50 > 90 risk of damage of soft layers and cross
contamination
Tacky rollers
metal particles
organic particles
50 - 90
?
> 90
< 50
> 90
50 - 90
> 90
> 90
depending strongly on substrate and
particle material and humidity
Non contact – traditional
Air knife 0 0 < 50 > 50 no small particles
Air + ultrasound 0 0 > 50 > 90 no small particles
High velocity + vacuum 0 < 10 < 50 > 90 no small particles
Non contact – new
narrow gap (liquid or gas) ? ? ? ?new technology
only for rigid substrates so far
high velocity nano spray > 50 > 90 > 90 > 90 only DI water needed, no damage
CO2 snow ? > 50 > 90 > 90high gas consumption, cooling down of
substrates
Plasma
Plasma
(only organic particles)> 10 < 10 < 10 < 10
only organic thin film contaminants and
small particles
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100 75 50 30 25 10 5 1 0.5 0.2
Air Knife
Brush & Vac
High Velocity Vacuum
Ultrasonic
Contact Clean Machine
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Particle Size, Microns
Efficiency of Cleaning Methods
Comparison of cleaning efficiency's
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Contact Cleaning Technology
The Teknek Cleaning Core
PPT 7 / 21
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THE THEORY
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Basic Theory
• Adhesion force applied by elastomer to particle
must be greater than the force holding the
particle onto the substrate
• Force exerted on the particle by the adhesive
must be greater than the adhesion force of the
elastomer
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Cleaning Scenario
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Adhesion Forces
• Adhesion describes how a particle and a surface
are held together
• A number of different forces will act together to
produce the adhesion force combination
• Two bodies in contact, an attractive force occurs
that requires a mechanical load to separate
them
• Strength of adhesion is determined by how
strong the interactions are
Adhesion forces
• At least 15 types of adhesion force, including 38
variables
• Analysis done on the force equations and
variables
• Two key variables identified, namely particle size
and contact area
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Conceptual Model
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Contact Area
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EMPIRICAL EVALUATION
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Initial Research
• Focus on measuring adhesion forces
• Using AFM
• Particle size 10micron
• Particle types – Silica, gold and
polystyrene latex
• Substrates – Elastomers and standard
films
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Shore Hardness vs PPU
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Elastomer properties
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Substrate Adhesion
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Particle measurement
‘PMC’ tool - a method using adhesive cards from forensic technologies
(developed with TNO-D) used to measure surface contamination (> 2mu)
levels
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Cleaning Efficiency
0
100
200
300
400
500
600
700
800
0 1 2 3 4
Par
ticl
es/c
m2
Number of cleaning strokes
Particle removal with manual Nanocleen roller from PET foil
Copper 3-10 micron Copper 3-10 micron
PSL 10 micron PSL 10 micron
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Other Collaborations
• The Holst Institute
• The Fraunhofer Institute
• Technical University Dresden
• Technical University Delft
• Korean Institute of Machinery and Materials3/5/2019 TU Delft Summer School 29
CONTACT CLEANING
OUTCOMES
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Silicone Free Cleaning Engine
• Silicone free cleaning rollers
• Silicone free adhesive
• Silicone free confirmed by – FTIR,
– Edx (Energy-dispersive X-ray spectroscopy)
– RGA (residual gas analysis)
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Nanocleen RGA
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Static Dissipating Elastomer
• Nanocleen
– Static dissipating NO conductive particles – clever
polymers not cheap additives
– Dyne Neutral, contact angle (Measurements on PET)
• Uncleaned contact angle 71.57, SD +/- 1.49
• Cleaned with Nanocleen 71.80, SD +/- I.46
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Static Trials - Japan
Traditional
Rollers
Static
1000 volts
Nanocleen™
Static
100 volts
Static Bars – switched OFF
Traditional
Rollers
Static
100 volts
Nanocleen™
Static
10 volts
Static Bars – switched ON
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