[1.12] Future Display 공정기술

- Flexible Display 공정

- Printed Electronics & Printed Display

2

Trend in Advanced Displays

Flexible Displays Flexible Displays

Bendable Foldable Wearable Stretchable

Thin n Light Unbreakable

Conformable Comfortable

Galaxy Round

Flexible OLED Products today, but it’s just starting

Restrictions to make true Flexible Smartphone

- Cover Glass

- Touch Panel on Glass

- Limited Bending Battery Package

Display itself has Radius of Curvature 400, 750 mm

Galaxy Note Edge

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4 4

New Concept Mobile Electronics

Mechanical flexibility Transparent

Nokia

Samsung

Wexler

Flexible E-book

5 5

Tomorrow’s True Flexible OLED for Any Shape

Bendable Wearable

Rollable Any shape

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Core Technologies for Flexible Displays Core Technologies for Flexible Displays

Bendable Rollable Foldable Stretchable

R r=8mm r=5mm r=1mm

Degrees of Flexibility

Bendability is function of radius of Curvature and thickness

r=<1mm

Core Components for Flexible Displays

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Flexible Substrate

Flex TFT

Flex Touch Screen

Flex Circuit

Flex Encapsulation

Flex Cover Glass

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Plastic Window

(Cover Glass)

Plastic Touch Screen

• Hard coating on PET film • Thin Polarizer • Flexible adhesive

• Single layer Metal mesh, Silver Nano wire on PET film

Flexible Display

Flexible Window

Flexible Touch Screen

+

+

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Trend in Advanced Displays

Printable Display Printable Display

• Inkjet Printed OLED-TV

OLED TV With advanced Inkjet Printing method • inkjet printer : Kateeva, Seiko Epson

• EL ink : Epson/Merck, Sumitomo

Low Cost approach to Printing RGB

Printed Display

Solution based TFT (AMLCD, AMOLED, Flexible display 적용목적) Solution based TFT (AMLCD, AMOLED, Flexible display 적용목적)

진공 장비 사용에 의한 고가의 장비 저 비용 solution process 진공 장비 사용에 의한 고가의 장비 저 비용 solution process 1

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미래형 디스플레이에 대한 기술적 요구 증대 미래형 디스플레이에 대한 기술적 요구 증대

포토 및 식각 등의 복잡한 공정 coating/etching or Printing 포토 및 식각 등의 복잡한 공정 coating/etching or Printing

3 대면적 적용을 위한 큰 위험 부담 대면적에도 쉽게 적용 가능 대면적 적용을 위한 큰 위험 부담 대면적에도 쉽게 적용 가능

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□ Target 공정 흐름도

• Plastic Handling 공정 : Laser 탈착형

• Laser 탈착 공정

- ELA 장비 적용

- Excimer : 308nm

- Energy : 410mJ/cm2

- 폭 370mm, 20mm/s

□ Laser 탈착 공정 확보

• 불투명 PI 적용 TFT 공정 개발 (300x400)

- 공정 온도 : 220 ℃ 이하

- Mis-align : glass 수준 확보

□ Plastic 신소재 개발

• 투과형 Display 재료 : 투명 PI 및 FRP

• 반사형 Display 재료 : 불투명 PI

1. 기판 Pre-compaction

Glass Carrier

2. PI계 접착제 Coating Coated PI계 접착제 (< 100nm)

Glass Carrier

3. Lamination & Curing

Glass Carrier

4. TFT & C/F Process (220℃ 공정 가능)

Laser Scan

Glass Carrier

5. Laser 탈착 공정 Plastic backplane : 후속 공정

Carrier Recycling

Batch type Plastic Process

1st

Gen.

2nd

Gen.

3rd

Gen.

Supply Roll Take-Up

Roll

Supply Roll Take-Up Roll

Thin Film Deposition & Laser Processing

Photolithography

Wet Chemical Etching & Cleaning

Cooling

Drum Laser

Panels

(Backplanes)

Vacuum Stage

Nano Imprint Ink Jet

μContact

Print

Supply Roll

Mold

Source: CAMM

Photo

lithography

Supply Roll

Low Pressure

Thin Film

Deposition

Vacuum Stage

Panels

(Backplanes)

Wet Chemical

Etching & Cleaning

Low Pressure

Dry Etch

Roll-to-Roll Process (미래기술)

Organic Thin Film Transistor

Bottom Gate / Bottom Contact Structure

pixel electrode

Passivation Organic Semiconductor

bank

substrate

gate

gate dielectric

S/D

Solution Organic TFT instead of vacuum a-Si process

Organic Semiconductors

Oxides Oxides

• precursor type • oxide nano-particles

• high mobility • relatively good stability • new technology • weak physical backgnd. compared to Si devices

Silicon Silicon

• precursor type - cyclo-penta-silane (CPS)

• Si nano-particles • high elec. performance • well-known material • p+, n+ doped material

• material oxidation • process (maybe laser)

Kovio

Nanogram

m = 80 (poly) m = 2 (nc)

Organics Organics

• small molecules • polymers • low-temp. process • mechanically stable • stability, but improving

• low performance

diF TES ADT

PQT

Ph-PXX

Sony m = 0.4

Printable Semiconductor Materials

Hosono et al.

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【 TFT Array 특성 】

-40 -20 0 20 40

1E-13

1E-12

1E-11

1E-10

1E-9

1E-8

1E-7

after inkjet

Id

Vg

0.000

0.005

0.010

0.015

0.020

0.025

0.030

m

μ= 0.012 cm2/Vs

□ Array TFT 특성 (100 TFT)

Ion = 1.42 x 10-7

(@-20V)

On/off ratio > 5X105

Vth = 3V

SS = 2.3 V/dec

Period = 100ms, Duty cycle = 50%

TFT life time >1300 hr @qVGA

□ Bias Stress Test by AC Pulse for 50min

Inkjet OTFT Process

• IMPRINT 기술 高難度 형상 구현 ( 포토공정 대응 불가 )

임프린팅/UV경화 Etching / Resist Stripping 잔류막 제거

Substrate

Metal

O2 Plasma

Substrate

Metal

Substrate

Metal

Mold

Substrate

Photo Resist

Metal

Mold

Wire Grid Polarizer (주기: 100~150nm)

다단형 Resist 패턴 고반사 반투과형 Device

微細 선폭 공정 單純화 (Slit 노광 대체)

3次元 형상 구현

IMPRINT

Nano Imprinting Process

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Flexible Process SMD Flexible AMOLED

Flexible OLED

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Core Technologies for Printable Displays Core Technologies for Printable Displays

R

Inkjet Printed OLED-TV

Inkjet Printed Flexible OLED Encapsulation (Organic Layer; UV curable acrylate)

- EL Thickness Uniformity Control < 0.6% for ‘Mura’ free - Improve Life time of Printed EL ~ 60%

5~7 layers of

Organic/Inorganic

Active OLED

Inorganic Layers

Substrate

Inorganic Layers

Substrate

Inkjet Printed Organic Layers

Organic Layer

Coating Active OLED

Printed Organic/1~2 Inorganic layer