[1.12] future display 공정기술 - kocwcontents.kocw.net/kocw/document/2014/hanyang/...1st gen....
TRANSCRIPT
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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
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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
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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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