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OLED Encapsulation

2019 U.S. DoE SOLID-STATE

LIGHTING R&D WORKSHOP January 29–31, 2019; Dallas, TX

Ofer Sneh

ofer@sundewtech.com

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OLED Encapsulation – Production

• Cellphone display Process of Record

• Polyimide/TFT/RGB-OLED

• 3 layers stack

• Inkjet printed polymer

• Edge sealed

• Adequate, small screen,

yield

• Vacuum/Atm/Vacuum

• Capital intensive

• Expensive (for SSL)

• 3 layers stack

• PECVD “polymer”

• Vacuum throughout

• Lower cost

• Not edge sealed

Emerging – All PECVD

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Atomic Layer Deposition (ALD)

• Pinhole/defect free

• 100% Conformal

• Enabler: MIL-SPEC RFICs in COTS packaging

100% Conformal in a void

Laminate barrier

Adhesion layer

Anti-corrosion

Ion milling debris

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ALD Encapsulation

• 0.2 m = MIL-SPEC performance

• 96 hours JEDEC JESD22-A110/A118 (HAST - 130C/85%RH)

• HAST, Highly Accelerated Stress Test - equivalent to 1,000 hours

@ 85/85

• In comparison, 0.8 m thick PECVD SiN failed HAST, miserably

• However, RFICs with 0.2 m PECVD SiN (wafer level) + ALD

coating (die in package COB level) easily passed HAST multiple

consecutive times!

FAIL

PASS

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Conclusion: ALD films repair/seal-off PECVD SiN’s defects

• 2 layers stack

• As thin as 0.22 m

• No polymer

• Vacuum throughout

• Lowest cost – Suitable for SSL

• Edge sealed

For OLED Encapsulation

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OLED TFE – Integration

OLED Stacks are: • Fragile

• Have relatively large CTE

• Are thermal budget sensitive

Therefore - preferably: • Avoid/reduce (integration related buildup of) strain

• Apply thinnest possible TFE (lowest added strain)

• Apply (PECVD SiN) TFE with compressive stress tuned to null

CTE related tensile stress (from lower CTE TFEs)

• Pre-set OLED stack at process temperature via anneal at process

temperature + slow cooling to RT

• Limit process temperature to 100 C or less

• Control cooling rate at ≤20 C/min in the range of 100-60 C

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OLED Display Manufacturing – Production

• Current cellphone display Process of Record

• GEN 5/6 Polyimide on glass “carrier”

• Polyimide/TFT/RGB-OLED/TFE Singulation

• UV assisted release of polyimide/TFT/OLED/TFE from carrier

• Lamination over heat-sink plate

• Attach to circular-polarizer and cover glass via transparent

encapsulation tape

OLED SSL Equivalent

• Glass or sealed-PET (aluminum-foil, Willow-glass) on glass

“carrier”

• Substrate/OLED/TFE Singulation

• UV assisted release of film/OLED/TFE from carrier, if relevant

• Lamination over heat-sink (if film was used)

• Attach to cover glass via transparent encapsulation tape

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OLED SSL Manufacturing – R2R

• Sealed “film” (Aluminum foil., etc), thermally pre-set + optically smooth

• Apply OLED stack (including TCO) via R2R tools

• Apply TFE via R2R tools

• Laminate a top flexible glass cover or sealed transparent film (PET) via

transparent encapsulation tape

• Singulate

ALD

modules

Collection

reel

Polymer

sheet

Deposition

roller

Atmosphere

vacuum

interface

Atmosphere

vacuum

interface

Source

reel

R2R ALD Tool • Retrofitted R2R

PECVD tool

• Single side coating

• No contact with

OLED during

process

• Collection with soft

PE foam liner

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Questions ?

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Sundew Technologies 3400 Industrial Lane, Unit 7

Broomfield, CO 80020, USA Phone: 303-466-2341

info@sundewtech.com

www.sundewtech.com

Thank you!