TFT介绍

Wet etching vs. dry etching (RIE)
Photoresist Etched layer Glass substrate
Tapered etching with resist erosion
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Photo Process
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Photo Process
Layer to be patterned glass Resist Photoresist coating
High throughput Large, expensive quartz masks
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Typical Design rules a-Si TFT LCD
XY stage
Bottom left Bottom right viewing viewing area area section section
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Mirror Projection Aligner (CANON)
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Glass Substrate Sizes
2400
Gen. 7
Gen 7 - ‘05 Gen 6 - ‘04
2200
Gen. 6
1800 mm
1870 mm
2000
Substrate dimension Y (mm)
1800
Gen. 5
10
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Thin Film Deposition - PECVD
s ces r Pro mbe a Ch
Pro Ch cess am be r
Process Chamber Transfer robot
Lo un ad/ loa d
Heating Chamber
Exposure through mask
Photoresist developing
Etching of layer Patterned layer Photoresist stripping
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Material a-Si Si3N4 SiO2 n+ a-Si
Function Semiconductor Gate insulator, passivation Gate insulator, passivation Contact layer at source and drain
TFT
Data line (source line)
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Glass Substrates
Low sodium content glass specially developed for AMLCDs: Corning 1737 Corning Eagle Asahi NEG
Substrate holder
Ar+ plasma
Target holder
Glass
Target
Used for ITO (Indium Tin Oxide transparent conductor) and for metals (Al, Mo, Ti, Cr, etc.)
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Gen5 substrate (LG Philips LCD)
First Gen5 factory Photo shows 15 displays with 15 in. diagonal size
ad/ Lo ad lo un
Transfer robot Cassette station
Cluster tool for Plasma Enhanced Chemical Vapor Deposition AKT 50k for Gen8 2200x2600 mm
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1500 mm 2200 mm 1300 mm 1100 mm
ቤተ መጻሕፍቲ ባይዱ
1600
1400
1200 1000
Gen 5 - ‘02 Gen 4 - ‘00 Gen 3.5 - ‘98 Gen 3 - ‘95 Gen 2 - ‘93 Gen 1 - ‘90
800
600
Six 26 in. displays
Six 37 in. displays
Mask 3
Top right viewing area section
Mask 4
Bottom right viewing area section
Masks Projection lens Substrate
Top left viewing area section
Top right viewing area section
Isotropic wet etching Photoresist Etched layer Glass substrate
Anisotropic dry etching Photoresist Etched layer Glass substrate
Photoresist Photoresist Etched layer Glass substrate
13
Photo Process – Resist Coating
Resist dispenser Extrusion head Rotating glass Glass
Photoresist
Spin coating
Slit (extrusion) coating
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Flat Panel Stepper (NIKON)
Hg light source
edge
Mask 1
Bottom left viewing area section edge
Mask 2
Top left viewing area section
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Glass Cleaning
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Example Glass Cleaning Equipment
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Thin Film Deposition - Sputtering
RF power 13.56 MHz ~ 1 mTorr
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Etching processes
O2 containing etching gas Photoresist Etched layer Glass substrate
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Construction of a TFT LCD
Polarizers
Anisotropic Conductive Adhesive Driver chip Peripheral seal Polarizers LC Films
Tianma Presentation A3
Manufacturing of TFT LCDs
1
Schedule
Time Thursday July 6 Friday July 7 Monday July 10 Tuesday July 11 Wednesday July 12 Thursday July 13 Friday July 14 Entry level Operation TFT LCD Manufacturing AMLCDs Operation TFT LCD –cont. Performance Improvements Special Applications Alternative FPDs Advanced level Operation TFT LCD Manufacturing AMLCDs Array designs and Driving methods Performance Improvements Special Applications Alternative FPDs
R
R B G Glass
G
B
Color plate TFT plate
Liquid Crystal Storage capacitor
Backlight Flex PCB
Glass
Select line (gate line) Pixel electrode
Color filter
ITO common electrode
Six 46 in. displays
400
200
Tianma – Gen 4.5 – 730 x 920 mm
1200 1400 1600 1800 2000 2200
0 0 200 400 600 800 1000
> 100 small LCDs per substrate
Substrate dimension X (mm)
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Thin Film Deposition - PECVD
RF power ~ 100 mW/cm2)
PLASMA ~1 Torr T=300 ºC substrate
Feed gas SiH4, H2 SiH4, N2, NH3 SiH4, N20 SiH4, PH3, H2
Process TFT array Black matrix of CF array CF array CF to TFT array
Resolution 4 µm 4 µm ~ 8 µm N/A
Registration/Overlay 1 µm 1 µm 2 µm <3 µm
LTPS manufacturing sometimes has tighter design rules – requires more advanced photolithography
Standard a-Si TFT array process
Five photolithography steps (5 masks) 3 sputtering steps (gate metal, source/drain metal, ITO) 2 PECVD steps (SiN/a-Si/n+ and passivation SiN)
Thickness: 1.1 mm > 0.7 mm > 0.5 mm Grinding to 0.2 or 0.3 mm sometimes done after LC assembly to reduce weight and module thickness
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