內(nèi)容參考文稿tft-lcd introduction

1、TFT-LCD IntroductionPi-Fu ChenEMAIL: .twOutlineTFT-LCD IntroductionFPD ClassificationTFT-LCD MarketingTFT-LCD StructureTFT-LCD OperationTFT-LCD ManufacturingTFT Array ProcessLC Cell ProcessLCM ProcessDisplay PerformanceBrightnessContrast RatioViewing AngelFlat Panel Display ClassificationFPDsPDPsLED

2、sLCDsPassiveActiveMIMTFTa-Si:TFTLTPS TFTHTPS TFTTN、STN.etc.LCOSMarket of TFT-LCD非晶矽(Amorphous Si TFT)低溫複晶矽(LTPS TFT)高溫複晶矽(HTPS TFT)市場比例92%4%4%應用產(chǎn)品NB 62%LCD-Monitor 13%Camcorder 4%Car Navigator 3%Game 2% Other 16%NB 43%Camcorder 32%DSC 25%Projector 50%Camcorder 46%Projector TV 4%Toshiba 搭配LTPS-TFT面板手

3、機 A3013T(資料來源:東芝網(wǎng)頁)資料來源: Fuji Chimera 2000/PIDATFT-LCD StructureVertical Structure of TFT PanelTFT-LCD StructureTFT ArrayColor FilterTFT-LCD StructureAV Equipment: Delta configuration-full colorOffice Equipment: Stripe configuration-sharp contrastTFT-LCD StructurePrism lens sheetDiffuserLight Guide

4、PlateCCFLReflection PlateLC cellLamp CoverBack Light ModuleTFT-LCD OperationDisplay on/offLow Power ConsumptionHigh Resolution ApplicationHigh resolution (200ppi) and more readability10.4 inch UXGA has 4 times content than VGA (a-Si TFT : 500K and LTPS-TFT: 2M pixels)Limitation of a-Si TFTDisplay re

5、solution is limited to 130ppi by TAB-IC pitchLTPS-TFT covers the whole range of displayHuman eye limitedDegrees of IntegrationMore degree of driver integration and less connectionAnalog and digital driving methodOutlineFeatures of LTPS-TFT LCDLTPS-TFT TechnologyAdvanced LTPS-TFT Technology World-Wid

6、e LTPS-TFTs Technology Roadmap SummaryLTPS-TFT Technology Process Flow IntroductionKey Process Technology -Crystallization -Ion Doping -Activation -Hydrogenation -OthersDevice ArchitectureElectrical Characteristics LTPS-TFT Structure ClassifyNormal Top GateStaggered Top Gate(a) Top Gate Structure(b)

7、 Top Gate Structure(c) Bottom Gate StructureNormal Bottom Gate(1) Toshiba(2) CMOS Based LTPS Tech.(1) LG(2) P-type Based LTPS Tech.(1) Sanyo, Sony(2) CMOS Based LTPS Tech.General Top-Gate CMOS Process (Through Oxide Doping)Buffer Layer & a-SiCrystallization Poly-SiLaser BeamIsland Etching & Gate Ins

8、ulator & Gate MetalN+/p+ doping & ActivationInterlayer & M2Passivation & ITOglassBuffer layera-SiGate insulatorGate interlayer M2 passivation ITONon-Through Oxide Doping ProcessBuffer Layer & a-SiCrystallization Poly-SiLaser BeamIsland Etching & n+doping & ActivationGate insulator & Gate Metal &p+ d

9、oping & ActivationInterlayer & M2Passivation & ITOglassBuffer layera-SiGate insulatorGate interlayer M2 passivation ITOGeneral Bottom-Gate ProcessGate insulator & Gate Electrodea-Si &Crystallization Laser BeamIsland Etching &n+/p+ doping & ActivationInterlayerM2Passivation & ITOglassGate insulatorGa

10、tePoly-Si Bottom-Gate /Top-Gate ComparisonTop-Gate Process FlowKey Process Technology -CrystallizationGeneral 3 crystallization method -SPC (Solid Phase Crystallization) -ELA (Excimer Laser Anneal) -RTA (Rapid Thermal Anneal) Excimer Laser CrystallizationGeneral ELA method - Overlapped Scanning over

11、lap scan help to improve the uniformity and mobility - Single Shot (Sopra) better uniformityExcimer Laser CrystallizationLaser Energy Density EffectLaser Shot Number EffectLaser Beam Profile EffectPrecursor Thickness EffectBuffer Layer Thickness EffectLaser Ambient EffectLaser duration timeLaser Cry

12、stallization Process FactorEnergy Density & Grain SizeRegion I : - partial melting - grain size as energy densityRegion II : - almost full melting - grain size is suddenly increasingRegion III : - full melting - the poly-Si is back into a-Si Super Lateral Growth ModelEnergy Density & Grain SizeEnerg

13、y Density & TFT PerformanceConditionLaser Overlap: 95% ambient: AirBy Seiko Epson lab J.A.P 99Shot Number & Grain SizeGrain Size e larger as number of shot increaseGrain Size e larger as energy density increase (the same shot number) From:SID 01Grain Size & Mobilityn-TFT mobility e larger as Grain S

14、ize increase p-TFT mobility is not change as Grain Size 0.3m. (different mechanism) From:SID 99Grain Size & Subthreshold Swingn-TFT subthreshold swing e smaller as Grain Size increase By Fujitsu lab IEDM 99Advance Crystallization TechnologyLateral Growth Technology -Phase Shift Mask Method -Sequenti

15、al Lateral Solidification -Pre-Patterned a-Si -Twin-Grain TFTTwo-Step Anneal (TSA) -SPC+ELA -MILC+ELA -ELA+Solid State LaserCW Laser CrystallizationSequential Lateral SolidificationBy NEC SID01 Phase-Shift MaskBy NEC SID01 Interference effect of laser light forming phase different spatial distributi

16、on Light intensity difference at sample surfaceContinuous Grain SiliconGlassSiOxa-SiMetal Catalyst: NiSiOxa-SiSiOx MaskGlassNi Catalyzed Poly-Si film as precursor World first CPU on glass substrateFrom: SEL Web PageFrom SID 99ELC+Solid State LaserFrom: Hitachi SID02Ion Doping ProcessPurpose 1. Sourc

17、e/Drain Doping (High Dosage) 2. Channel Doping (Low Dosage)Method 1. Through Oxide (Higher Energy) Doping 2. Non-through Oxide (Low Energy) DopingType 1. Ion Shower 2. ImplanterIon Doping ProcessVth vs B dosageFrom: SID 99Ion Shower/ Implanter comparisonFrom: ASID 98Activation Type 1. Laser Anneal 2

18、. Furnace Anneal 3. RTA (Rapid Thermal Anneal)Activation Type ComparisonFrom ASID 98Device ArchitectureGate StructureTop-Gate : High mobility Bottom-Gate : a-Si compatibleDrain StructureLDD or Offset : leakage current and reliabilitySelf-align : alignment error freeBasic Circuit CMOS: low power and

19、wide design marginN-MOS or P-MOS : simple processElectrical CharacteristicsLeakage CurrentHot Carrier EffectKink EffectSelf-Heating EffectElectrostatic Discharge EffectOthersLeakage Current on LTPSLeakage in PolysiliconThermionic emission Thermionic field emissionPure tunnelingHigh Leakage CurrentTr

20、apsHigh electrical fieldLeakage Current on LTPSReduce traps in active layer -Thinner active layer -Crystallization improvementReduced lateral field -TFT structure Engineering (LDD , Offset , Multi-Gate.)Offset or LDD lengthDual-Gate StructureHot Carrier Effect on LTPSTFT-LCD Driving in high voltage(

21、pixel)Hot carrier effect : CHC , DAHCDegradation by trapping(defect) in interface , oxide and grain boundaryKink Effect on LTPSAvalanche induced effect and floating body effectAvalanche induced effect -Trap charging enhance local electrical field -Trap existence enhance the impact ionizationShort ch

22、annel effect Self-Heating on LTPSLow thermal conductivity of glass (SiO2:1.3 , Si: 168Wm-1K-1)Joules Heat (Q=IdVd )Degradation of device characteristicSelf-heating enhance leakage currentElectrostatic Discharge EffectSubstrate transfer, TFT and LCM process, operation.Degradation with applied ESD pro

23、pertyFirst ESD stress is most seriousESD protection (Circuit, Shorting Ring.)OutlineTFT-LCD IntroductionFeatures of LTPS-TFT LCDLTPS-TFT TechnologyAdvanced LTPS-TFT Technology World-Wide LTPS-TFTs Technology Roadmap SummaryMemory in PixelPixel with SRAM or DRAMPower consumption in standby mode is cu

24、t by 50%, and overall standby time for cellular phone is raised by 23%Integrated Color FilterHigh Resolution and High ApertureLess alignment errorDesign rule on TFT and CFYield improvementAM-OLED or AM-LCD ?Excellent image quality-high brightness and Full colorNo need light sourceWide viewing angle

25、and fast response timeThinness LTPS on Plastic SubstrateLow temperature manufacture (Ultra low)Could be made by Roll-to RollAdopt Laser and SputteringGlass & Plastic (weight, durable,flexible.)OLED, E-INK,EPD.)OutlineTFT-LCD IntroductionFeatures of LTPS-TFT LCDLTPS-TFT TechnologyAdvanced LTPS-TFT Te

26、chnology World-Wide LTPS-TFTs Technology Roadmap SummaryWorld Wide LTPSJapan Toshiba 、Sanyo、Sony-Toyota、Matsushita、NEC、Hitachi、Sharp、Fujitsu、Mitsubishi、Seiko Epson.Korea LG-Philips、SamsungTaiwan Toppoly、AU、Prime View、ERSO/ITRI.LTPS on ToshibaNumber one in LTPS field (55% 2000)First 12.1 inch XGA LTP

27、S-TFT (1997)Combine with Matsushita (AFPD 2001)High-Accuracy DAC and AmplifierPixel with SRAMIntegrate Color FilterLTPS on ToshibaAMLEP on ToshibaThe largest AMPLED panel (2002)World First 260000-Color AMLEP DisplayInk-printing technologyFlexible Display on ToshibaExtremely thin glass substrate (les

28、s than 0.4mm)TFTs attach to a flexible sheetManufacture at normal temperature Bent to form a curve (radius of curvature as high as 20 cm)LTPS on SonyLTPS and HTPSCollaborating with Sanyo (1995)Combine with Toyota (ST in 1997)Double LDD and reflective structure in pixelPDA, DSC, AMOLEDAMOLED on SONYT

29、AC (Top emission adaptive current drive) AMOLEDJoint development with UDCFlex Display on SONYManufacture at normal temperatureNo significant damage to TFTIntegrated Color FilterProtection MaterialWet etching take time LTPS on SANYOCollaborating with SONY (1995)First 2.5 inch LTPS on AMOLED (1996)Bot

30、tom gate and Top-Gate technologySmall size (28 inch) and reflective displayPixel with SRAMAMLCD and AMOLEDAMOLED on SANYOFirst AMOLED panel (1999)Joint development with KodakShadow Mask technology to form RGB pixelLTPS on SHARPContinuous Grain Silicon Technology Joint development with Semiconductor

31、Energy LaboratoryAnode oxidation method in TFT processHigh mobility (300cm2/Vs)First complete approach for system on panel AMOLED on SHARPAMOLED technology developed with Pioneer and SELLTPS on Seiko EpsonElder of LCD field (1971)More than 10 years experience in developing LTPSELA and 8-mask technol

32、ogyLTPS,HTPS, AMOLED, MIMAMLEP on Seiko EpsonFirst monochrome AMLEP(1998)Joint development with CDTInkjet methodArea ratio and time ratio gray scale method Plastic LTPS on Seiko EpsonSUFTAL= Surface Free Technology by Laser Ablation/AnnealManufacture at normal temperatureHydrogen atoms in sacrificia

33、l a-Si layer evaporate when it is heated rapidly by laser irradiationComplex and more process stepMay damage TFT device LTPS on NECTop Gate and 8 mask processCross license with LG.PHILIPSBM as storage capacitance(staked Cst)Joint development AMOLED with Samsung(SNMD)AMLCD and LCLVLTPS on FujitsuInte

34、grated black matrixCs form by ITO/BM (High aperture ratio)High mobility (600cm2/Vs)44 bit SRAM and 270MHz shift registerCW-Laser Lateral CrystallizationAMLCD, HTPS, LCLV, PDPLTPS on SamsungTop-Gate and ELA technologyIntrinsic Storage CapacitorHalf-gate and sub-gate structureLTPS LCD, AMOLED, PDP, CN

35、T-FETAMOLED/LEP on SamsungJoint development with NECKodak signs OLED licensingLTPS on LG-PHILIPSCombine with Philips (1999)5 mask process and BBC (buried bus line) structureOnly P-Type doping simplifying processLow cost (reduce 30%)LTPS on MitsubishiTop-Gate and ELA technologyPixel built-in DRAMAMLC

36、D, LCLVLTPS and AMOLED on HitachiSELAX (selectively enlarge laser crystallization)High mobility (670 cm2/Vs)Driver IC, AMLCD, AMOLEDLTPS in TaiwanToppoly: 1.5, 2.2, 3.5, 7 and 14.1 inch LTPS technology transfer from Sanyo Tottori AU: 3.8 inchPrime viewERSO/ITRI: 12.4, 4.1, 3 inchOutlineTFT-LCD Intro

37、ductionFeatures of LTPS-TFT LCDLTPS-TFT TechnologyAdvanced LTPS-TFT Technology World-Wide LTPS-TFTs Technology Roadmap SummarySystem on Panel IssueTFT performance variation variation in number, size, and location of grain boundary in polysilicon channelHigh power consumption of TFT circuitry high th

38、reshold voltage limits TFT driving currentLow manufacturing yield more complex process High degree of integration Development of LTPSChallenge to large size displayDemonstration of fully integrated displayWay to grain boundary less (free) in channelContinuous grain silicon Generation of LTPS technology1st