1

CONTACT CLEANING FOR

BARRIER COATINGS

Sheila Hamilton

Teknek Ltd

22

OUTLINE

• Current market Drivers

• What is Contact Cleaning

• How does contact cleaning work

• Science of adhesion

• Surface roughness analysis

• Adhesion measurements

• Contact Cleaning in a vacuum

• Conclusions

33

MARKET DRIVERS

• Requirement for increased lifetimes in

OLEDs and OPV

• Increasing use of Organic functional

coatings which are moisture sensitive

• Thinner coatings

• Thinner films

• Static generative materials

44

HOW IT WORKS

55

CLEANING FUNDAMENTALS

• Adhesive force between the elastomer

roller and the particle must be greater than

the force between the particle and the

substrate

• The adhesive force between the particle

and the adhesive must be greater than

that between the elastomer roller and the

particle

66

MACRO ADHESION

RUBBER COPPER STEEL Cu/KAPTON POLYESTER POLYCARBONATE

(Gloss) (Matt)

SOFT 1.17 3.26 0.51 2.55 2.37

PANEL 1.49 3.32 0.81 2.63 1.07

FILM 0.63 0.81 0.34 1.68 1.4

F3 0.11 0.11 0.11 0.05 0.12

NANO 0.08 0.04 0.07 0.75 0.34

77

INTERFACIAL FORCES

88

EXAMPLES OF ADHESION

FORCES

99

CONTACT AREA

Contact area is impacted by

• Roller surface roughness

• Pressure

• Shore hardness

• Particle morphology

1010

SURFACE ROUGHNESS

Scan Size

Sample name

1 2 3

Soft

2.169 11.143 38.582

Panel

7.355 13.493 23.467

Nanoclean

3.616 1.400 6.292

Film

7.453 16.861 18.54

F3

31.009 49.085 98.334

1111

SURFACE ROUGHNESS

1212

SURFACE OF PANEL

ELASTOMER

1313

SURFACE OF NANOCLEEN

ELASTOMER

1414

ADHESION FORCES

Type of Probe

Sample name

Silica Gold-coated silica Polystyrene

Soft

752.08±147.06 951.87±69.48 1027.79±109.82

Panel

848.11±112.98 823.55±160.72 847.12±214.75

Nanoclean

803.08±443.79 285.14±161.34 1073.17±629.94

Film

866.80±144.75 1152.12±125.74 1177.89±81.77

F3

1076.98±420.92 746.64±329.49 813.09±393.31

1515

ADHESION FORCES

• Panel and Nanocleen

1616

SUMMARY

• Hydrophobicity of materials is important for

adhesion

• Adhesion on the macro scale does not

relate to the micro scale

• Surface roughness on a micro scale

causes variations in the adhesion forces

1717

CLEANING IN A VACUUM

• Does the Cleaning system detrimentally

affect the performance of the vacuum

system ?

• Does exposure to high vacuum alter the

performance of the cleaning system?

The use of Teknek equipment in Vacuum

Chambers

Test Results undertaken as part of the Clean 4

Yield Program

Testing carried out by Holst Centre

19

Introduction

In the R2R vacuum tool web cleaning can be very

important for removal of particles from the surface of the

polymer film reel before deposition. This cleaning could be

done with cleaning rollers from Teknek.

Cleaning Roller tested;

1.Nanocleen

And two kind of adhesive sheets/rollers are tested:

1.Adhesive Blue roller

2.Adhesive ECO roller (Oxy-degradable product)

20

The quality of the elastomer rollers and adhesive sheets

are tested before and after vacuum exposure.

Tests that are done:

• Weight loss before and after vacuum exposure of the

rollers and adhesive sheets.

• Particle pickup test before and after vacuum exposure of

the rollers and adhesive sheet.

• Outgassing test of the tacky rollers and adhesive

sheets/rollers

Residual gas analysis (RGA), short and long time

testing.

Testing

21

Weight loss rollers before

and after vacuum

Vacuum test at 1e-7mbar (Scud vacuum system 032), total time in vacuum 66hrs (1 weekend).

4 small rollers are put in vacuum system, weight measurement before and after.

Weight measurement: analytical balance (readability 0,0001gr)

typ

e r

oll

er

nr

we

igh

t b

efo

re

we

igh

t af

ter

vacu

um

we

igh

t

dif

fere

nce

[gr

]

we

igh

t lo

ss [

%]

nanoclean 1 16,98 16,91 0,07 0,41%

nanoclean 2 17,16 17,1 0,06 0,35%

ultraclean 3 17,44 17,37 0,07 0,40%

ultraclean 4 17,55 17,49 0,06 0,34%

0,38%

average weight loss 0,4%,no differencebetween rollers

22

Particle pickup test before and after

vacuumTungsten particles are put in oven tray (60degree) and after getting out of oven the rollers are rolled into the metal powder (6 times)

After tungsten particle pickup the roller is rolled over a 6"adhesive sheet. The weight of the sheet is measured before and after on a balance with readability 0.1gr

Width roller: 25mm. Rollers are stored in high vacuum system, adhesive sheets in a low and high vacuum system.

Ro

lle

r

roll

er

vacu

um

con

dit

ion

adh

esi

ve s

he

et

con

dit

ion

we

igh

t b

efo

re

we

igh

t af

ter

par

ticl

e p

icku

p

we

igh

t

dif

fere

nce

[gr

]

nanocleen ambient ambient 4,3 4,6 0,3

1 weekend in vac (0.1 mbar) 4,3 4,5 0,2

18 hrs in high vac (1e-6 mbar) 4,3 4,5 0,2

1 weekend in vac (1e-6mbar) ambient 4,3 4,5 0,2

1 weekend in vac (1e-6mbar) ambient 4,2 4,5 0,3

ultracleen ambient ambient 4,3 4,5 0,2

1 weekend in vac (0.1 mbar) 4,3 4,5 0,2

18hrs in high vac (1e-6mbar) 4,3 4,5 0,2

1 weekend in vac (1e-6mbar) ambient 4,4 4,6 0,2

1 weekend in vac (1e-6mbar) ambient 4,3 4,5 0,2

Repeatability test (after cleaning roller repeat particle pickup measurement).

ultraclean ambient ambient 4,3 4,5 0,2

4,3 4,5 0.2

nanoclean ambient ambient 4,3 4,6 0,3

4,3 4,5 0,2

No difference in particle pickup for rollers and/or adhesive sheets in vacuum or ambient conditions !!

23

Outgassing test rollers

(RGA analysis)

nanocleen roller

A common surface contaminant is

silicone oil or polydimethylsiloxane,

which has been found to result in a

group of ion fragments serving as

fingerprints (for example, positive

secondary ions at m/z 28, 73, 147,

207, 221 and 281, which are

assigned to Si+, SiC3H9+,

Si2C5H15O+,Si3C5H15O3

+,Si3C7H21O2+

and Si4C7H21O4+, respectively).

- CONFIDENTIAL -

no PDMS

24

24 hrs. Outgassing test Teknek

adhesive rolls (ECO and Blue) – RGA analysis

Remark:

• No PDMS (peak 73) signal visible for both adhesive rolls !!

• Both adhesive rolls contain quite a lot of water, specially the blue adhesive

roll. After 24hrs the ECO contains no more water. Teknek blue after 6hrs

pumping contains much water.

.

25

Conclusions

• Weight loss before and after high vacuum storage of the nanocleen Teknek roller is about 0.4%.

• The nanocleen rollers and adhesive rollers (Teknek Blue and ECO) show no peaks in the RGA

analysis, so there is no outgassing from this roller in vacuum. Measured weight loss is probably due

to moisture/water outgassing.

• The particle pickup rate for the rollers and adhesive foil is not influenced by storing under high

vacuum (1e-6mbar during a weekend) !!

• The nanocleen rollers in combination with the adhesive blue or ECO rollers are the best option for

our R2R tool. Specially because there is no outgassing in vacuum and particle pickup rate is not

influenced by vacuum. An additional advantage of the nanocleen roller is that this elastomer is

static dissipative .

26CCR Barrier Technologies

Workshop 2012

26

AREAS OF APPLICATION

• After stripping of protective film to remove

possibility of static induced recontamination

• Immediately prior to sputtering to remove any

particles deposited from the walls of the

chamber

• Before rewind to stop particles imprinting on the

layer below or fracturing the film

• Cleaning the protective film at rewind prior to

application to stop damage to the coating

27CCR Barrier Technologies

Workshop 2012

27

CONCLUSIONS

• Weight loss before and after high vacuum storage of the

Nanocleen rollers is about 0.4%. Measured weight loss

is probably due to moisture/water outgassing.

• The Nanocleen rollers show no peaks in the RGA

analysis, so there is no outgassing from this roller in

vacuum.

• The particle pickup rate for the rollers and adhesive is

not influenced by storing under high vacuum

• There are several areas within a vacuum system where

Contact Cleaning could be implemented to reduce

defects caused by particle contamination

28

IntroductionIn the R2R vacuum tool cleaning is very important for

removal of particles from the machine. This cleaning can

be done with:

•Industrial vacuum cleaner with HEPA filter

Very suited for removal of large SiN flakes around the

microwave tubes and other locations

•Tissues with IPA

Very suited for cleaning drums

•Tacky roller (Teknek)

Very suited for cleaning walls/shields of all the chambers

- CONFIDENTIAL -

< 28

29

Cleaning results

- CONFIDENTIAL -

< 29

Shieldings PC1

Shieldings PC1

Backside foil LL1-

PC1 1 PC1 walls LL1 bottom

Bottom PC1Bottom PC1

1 Backside foil dirty

because of removal slit

30

Conclusion

Review Meeting TP2 -

CONFIDENTIAL -

< 30

With the Teknek contamination audit kit the

Rollcoat machine is cleaned on several

locations. And it can be a very useful

extension for cleaning the tool. Lots of small

dirt (mostly SiN dust) can be removed from

walls/bottoms/doors/shieldings etc.

The best cleaning is done with a rough

vacuum clean and after this a fine clean with

the Teknek roll.

31

Acknowledgements

• University of Sheffield Polymer Centre

• The Holst Centre, Eindhoven

• Clean4Yield European Programme