Piloting R2R Atomic Layer Deposition: status and results with 500 mm wide web system

Dr. Mikko Söderlund, Pekka Soininen and Brad Aitchison - Beneq Philipp Maydannik and David Cameron - Lappeenranta University of Technology

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Key message

R2R ALD has taken giant steps from (.ppt) promise to reality!

”Proflex 2010 presentation – R2R ALD roadmap projection”

Introductions

Driver & motivation (Case Study – ultra barriers)

Atomic Layer Deposition (ALD)

R2R ALD system for 500 mm wide webs

Results

Technology outlook

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Outline

Beneq Role:

Area Sales Director, Western US

Education:

BA – Physics, Willamette University

MS – Materials Science and Engineering, UCLA

Career:

Thin Film Process Engineer for Hybrid Microwave Circuits (WJ)

Characterization Engineer for Electrochromic devices in Startup (Eyeonics)

Thin Film Process Engineer for Active Matrix Electroluminescent Displays (Planar)

ALD Process Engineer for High-k Dielectrics (ASM – Microchemistry / Planar)

ALD Process and Equipment Engineer for Optical Coating (MLD Technologies)

Director of Engineering for Carbon Nanotube based devices in Startup (Canatu)

Brad Aitchison

Beneq © 2013

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Equipment from lab to fab

Established: 2005, Finland.

Ownership: Privately owned, venture capital financed

People: 140 (Thin-film Equipment + Lumineq Displays)

Products: Industrial and research equipment for thin film coatings based on ALD (atomic layer deposition) and aerosol (nHALO®, nAERO®) technologies. TFEL displays.

Markets: Solar energy (photovoltaics), flexible and organic electronics, optical, flat glass (in-line and off-line), medical and lighting.

Identifying your opportunity

Application specific coating and material development services.

Beneq – Turning Innovations into Success.

Finding the solutions

Verifying the process and determi-ning industrial feasibility, including pilot production services.

Building the equipment

Off-the-shelf as well as cus-tomer-specific equipment, built to deliver and last.

10/30/13 Proflex 2013, Dresden, Germany

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ALD in 24/7 batch production

Facility located in Espoo, Finland

Industrial ALD operation since 1985, in 24/7 production

More than 3 Million TFEL displays produced sold worldwide

Automated batch ALD process with high uptime & high yield,

Typical batch area: 4 m2 (e.g. comparable to Gen5.5 substrate area)

Moisture barriers for OLED, OPV and flexible electronics

Rear surface passivation of c-Si solar cells

Buffer layer for CIGS solar cells

nSILVER® - Anti-tarnish coatings on silver

Glass strengthening

nOPTO - Optical coatings

nDECO - Decorative coatings

Anti-stiction coatings for MEMs

Beneq © 2012

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Applications of ALD

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Milestones in scaling

Large area

Roll-to-roll

Batch

Basis for large area ALD

-flow optimization

-precursor delivery

-precursor deactivation

-chemistry know-how

Large batch

> 10 m2/min > 0.5 m2/min

> 0.05 m2/min

Beneq © 2013

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Pulsed versus Spatial ALD

Convential Pulsed ALD

Precursors separated in time

Substrate is stationary

Separation by inert gas purge step

Purge step is typically the rate limiter

Spatial ALD

Precursors separated in space

Substrate is moving

No purge step -> fast process

P. Poodt et al., J. Vac. Sci. Technol. A 30(1), Jan/Feb 2012

Driven by need to reduce costs of ultra barrier films

Supports new manufacturing paradigms for OLED/PV

Merits of ALD-based approach:

Ultra-thin layer approach -> flexible barrier films

Low material costs -> low cost of ownership

Allows use of low-cost substrates

Roll-to-roll process is enabled by the spatial ALD concept

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Case study: R2R ALD Ultra barrier films

Beneq © 2013

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Spatial ALD Proof-of-concept results

Size: 120 x 300 mm (PET)

Process: Al2O3 (TMA + H2O) at 120 C

Speed: 12.5 m/min (linear speed)

Growth rate: 0.08 nm/cycle

Refractive index: 1.61-6.2 @ 633nm

Non-uniformity: < 4%

WVTR: ~10-3 g/(m2 day) @ 18 nm

Four ALD cycles/rotation

Polymer taped on drum

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Web Coating system 500

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Roll-to-roll ALD pilot system at ASTRaL (Advanced Surface Technology Research Laboratory), Mikkeli, Finland

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Key system features

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1. Vacuum R2R process

2. Web tensioned on drum

3. Proprietary ALD coating head

Principle

Caption: Principle of the spatial ALD coating head. The two precursors (TMA and water)

are separted by an inert gas buffer so that only the web is exposed to both of the two

precursors. Relative movement of the ALD coating head and the web produces film

growth only on the web. The gap between the web and the ALD coating head is in 0.5 –

1.0 mm range, a tolerance which allows easy scaling of the coating head width.

Film thickness uniformity target +/-5% reached

Good confidence for further scale-up with same coating head concept

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Al2O3 uniformity

Position (cm)

Thickness (nm)

2 52,8

10 54,1

20 53,4

30 52,1

40 54,2

48 54,0

Uniformity: +/- 2%

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Beneq © 2013

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Spatial ALD process sample

a) H2O zone, b) TMA zone

no wrap-around/undercoating

Sharp film end-profile

Possibility for area selective deposition

Applicable also to large area planar substrates

Film growth takes place only on the substrate

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Results (non-optimized process)

ms

20 nm Al2O3 on PEN, 100 C, TMA + H2O process

Process optimization to give consistent WVTR across residence time

”underdose” regime H2O ”overdose” regime

5*10-4 g/(m2 day)

WVTR ≤5*10-4 g/(m2 day) @ 0.25 m/min

R2R ALD productivity aspects

ALD precursors, Al2O3

Trimethylaluminum (TMA), low grade (< 1 $/g)

Titanium tetrachloride (TiCl4) costs even less

Water or alternative oxidizers

Material consumption

g/min level (for 500 mm web, 2 m/min)

Inert gas (N2) flows in 10s of SLM’s

Maintenance

In principle ”clean process”

Moving/wearable part maintenance

Maintenance of filter used for deactivating precursors

Cost of ownership

Estimated CoO < 1$/m2 for mass production

Allows use of lower cost substrates

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Excellent prospects to scaling to >1 meter widths, due to reasonable mechnical tolerances

0.5 mm gap across 500 mm web width

Second generation system(s) currently under construction

Collaboration with the Centre for Process Innovation (UK)

Facilitates rapid technology engagement with industry

Roadmap for R2R ALD

Scaling beyond 500 mm, line-integration

Further web speed improvement by PEALD

Pre-and post-processes to address particles

New Applications

Optical/index matching layers

Conductive films

Surface functionalization

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Technology outlook

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Thank you!

Beneq – Turning Innovations into Success.

Dr. Mikko Söderlund Technical Sales Director

mikko.soderlund@beneq.com