The Flat Panel Display Paradigm: Successful Implementation of Microelectronic Processes on Gigantic Wafers

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1 The Flat Panel Display Paradigm: Successful Implementation of Microelectronic Processes on Gigantic Wafers Dr. Zvi Yaniv Applied Nanotech, Inc Longhorn Blvd., Suite 107 Austin, TX Phone x103 Fax

2 Flat Panel Displays (FPD) 2007 Active Matrix Liquid Crystal (AMLCD) FPD Plasma (PDP) Active Matrix Organic Light Emitting Diodes (AMOLED) Field Emission (FED)

3 Samsung PDP Ken Werner (Nutmeg Consultants)

4 Sharp AMLCD Ken Werner (Nutmeg Consultants)

5 LG Philips LTPS AMOLED 20.1 Ken Werner (Nutmeg Consultants)

6 Predictions Once FPDs have achieved comparable size and performance to CRTs, FALLING PRICE PREMIUM FPD UNIT PRICE CRT? YEAR American Electronics Association (1990)

7 Predictions, their intrinsic advantages will result in penetration constrained only by their relative price premium versus CRTs...AND INCREASING SCREEN SIZE... CRT MAXIMUM SCREEN SIZE (INCHES) FPD YEAR American Electronics Association (1990)

8 Solids, Liquids and Gases - It s all About Order O R D E R I N G No Long-Range Order Less Than 3-D Long Range Order 3-D Long Range Order Glasses Isotropic Liquids Gases Mesomorphic Glasses Plastic Crystals Crystalline Solids Liquid Crystals (Mesomorphic Fluids) Definite Shape And Volume Definite Volume Only Complete Mobility MOBILITY

9 Liquid Crystal?! Flat Panel Display Technology, Solid State Technology, 1994

10 Twisted Nematic (TN) Structure The molecules along the upper plate point in direction a and those along the lower pate in direction b, thus forcing the liquid crystals into an overall twisted state.

11 Why LC Active Matrix Displays are Necessary? Need of Time-Multiplexed Matrix Addressing For passive displays (such as LCDs) time multiplexing has inherent limitations

12 Principals of Operation of a TFT AMLCD t p scanning pulse length liquid crystal resistivity Ω-cm storage time 20 msec polarity of the applied voltage must be inverted periodically: reversing the data voltage polarity in each frame reversing the data voltage polarity on alternative rows

13 Energy Band Diagram of Crystalline and Amorphous Silicon ENERGY 1.1 ev ENERGY 1.75 ev DENSITY OF STATES DENSITY OF STATES

14 Plasma Vapor Deposition RF OR DC POWER ~.1 WATT/CM 2 PRESSURE ~ 1 TORR GAS EXHAUST PLASMA GAS FEED SUBSTRATE HEATER TEMP ~ 250 C MATERIAL α - Si (INTRINSIC) α -Si (p-type) α -Si (n-type) SiO 2 Si 3 N 4 FEED GAS SiH 4, SiF 4, H 2 (+ B 2 H 6 ) (+ PH 3 ) SiH 4 +N 2 O SiH 4 + NH 3

15 Cross-Section of TFT Pixel Array with Storage Capacitor

16 Projected Limitations of α-si TFT AMLCD s Based on Predicted Technological Improvements 10 8 Resolution (mm 1 ) Lithography Transistor Performance Gate Delay Diagonal (in)

17 AMLCD Process Flow Active Plate Passive Plate Cell Display Completed Display Functional In-Process Test Optical Pattern In-Process Inspection Panel Inspection Repair

18 Pixel Layout Example (α-si TFT)

19 Example of Clean Room Layout YELLOW ROOM Exp Coater / Developer Exp Coater / Developer Exp Coater / Developer Exp Coater / Developer Exp Coater / Developer Exp Coater / Developer WET ROOM Wet Etching Stations Resist Removal Stations Cleaning Stations CVD CVD Sputtering Dry Etcher Dry Etcher CVD CVD Sputtering Dry Etcher CVD Sputtering Sputtering Dry Etcher

20 Cluster Tool Configuration Process Chamber Process Chamber Process Chamber Heating Chamber LD/UL LD/UL Transportation Robot Transportation Robot Cassette Station

21 Block Diagram of TFT-LCD Module

22 LSI Driver Connection to TCP (tape-carrier package) by ACF

23 From GEN 1 to GEN 7

24 Display Size & Pixel Density for Large Screen Screen Size x x x x x1024 XGA.8M pixels SXGA 1.5 M UXGA 1.9 M D-TV 1M/2M WUXGA 2.3M 1M 2M Pixel Contents 4M 5M

25 Yield Depend on Screen Size and Pixel Contents

26 First Generation 7 α-si

27 Display Cost TFT Plate Lighting Color Filter Plate Drive

28 Comparison of Various Silicon Films

29 Major Crystallization Methods

30 Industry Transition to Polysilicon High Electrical Performance (Mobility) Material Single Crystal Silicon x-si Wafers Polysilicon* p-si Microcrystalline Silicon m-si Thin Films Applications Integrated Circuits (Semiconductors) Pixels + Integrated Circuits Low Amorphous Silicon a-si Pixels Only * Crystallization converts a-si or m-si to p-si

31 Wide Viewing Technologies

32 The Old Dream of Hang on the Wall TV is Here Today Courtesy of Information Display Magazine

33 The Old Dream of Hang on the Wall TV is Here Today Courtesy of Information Display Magazine

34 What is Plasma Shigeo Mikoshiba, SID Seminars

35 Where Does the Light Come From? Shigeo Mikoshiba, SID Seminars

36 Cross Section of Fundamental Color PDP Structure

37 Sandblasting Method

38 Barrier Ribs Made with the Sandblasting Method Rib Pitch: 130 µm

39 Negative Features of PDPs Low luminance (400 cd/m 2 ) Low contrast ratio (20:1 in bright room) Low luminous efficiency (1.4 lm/w) High drive voltage

40 OLED Displays

41 OLEDs Need an Active Matrix Shown is a simplified cross-sectional view of a full-color solutionprocessed OLED device structure.

42 Ink Jet Processing?

43 LTPS vs. α-si as Materials for AMOLED TFTs LTPS TFT α-si TFT Mobility (cm 2 /V-sec) Type of TFT TFT Uniformity Number of Process Steps Cost (array only) Cost (modile) Equipment Investment Yield Overall Cost Current Stability OLED Degradation PMOS and NMOS Worse 9 or 10 masks High Low (Built-in Driver) High Low Lower for small panel sizes High Much less sensitive NMOS Better 4 or 5 masks Low High (External Driver) Low High Lower for large panel size Low Much more sensitive

44 The Competing Powers for Large Area FPDs

45 LCD vs Plasma vs OLEDs

46 Target for ultra-high definition and wide screen display F. Sato and M. Seki, IDW 01, p.1153

47 Cross-section of FED in operation Light Anode Glass Phosphor Black Matrix Electrons Grid Conducting Feedlines Insulating Grid Spacer Layer Cathode Glass

48 SCE Display Schematic cross section of the construction in the SCE display.

49 PdO fabrication process Schematic diagram of the PdO fabrication process by using ink jet printing.

50 SED demo

51 Glass vs Silicon Information Display Magazine, 11/05

52 1995 Lithography Requirements Minimum Feature Size: 2µm - 5µm Linewidth Control: +10% Layer-to-Layer Overlay: +0.5µm - +1µm Throughput: >10 x 10 6 mm 2 per hour Typical Products: TVs, Computer Terminals, CAD Workstations, Auto Dashboards, Image sensors & Scanners, Print Heads MRS Technology Inc.

53 Coating Technology Spin Coating Roller Coating Spray Coating Slot Coating

54 Lithography Systems Contact / Proximity Aligners Mirror Projection Aligners Step-and-Repeat Aligners

55 Schematic of a Scanning Projection Aligner & Schematic of a Stitching Aligner Flat Panel Display Technology, Solid State Technology, 1994

56 Stepping Aligners Available Systems are Adapted IC Steppers Advantages Multiple Suppliers Resolution, Overlay: Sub-Micron Available High Defect Limited Yield Use Standard IC Masks Available from Multiple Suppliers High Throughput for Small Displays Problems Limitations of Projection Optics Constrain Display Size No Migration Path to Large Displays MRS Technology Inc.

57 The Stitching Aligner The Job: Make a display of any arbitrary size by stitching together multiple subfields. Analogous to making a brick wall out of individual bricks. Problem #1: Doing it The mortar joints between the bricks must be invisible! Many kinds of bricks are used! Problem #2: Doing it Fast! Many exposures, mask changes needed to pattern a single display layer Slow = Expensive = Prototype Displays Fast = Inexpensive = Production Displays Problem #3: Doing it Easily Multiple subfield stitching jobs are complex Need to know what you get is what you want MRS Technology Inc.

58 Cross Pollinations from FPDs to MCMs to Large Si Wafers Areas of Emphasis FPD MCM 400mm Critical Segments Large area process Large area process Large area process Equipment Mechanical interface Material handling Contamination control CIM Mechanical interface Material handling Contamination control CIM Mechanical interface Material handling Contamination control CIM Materials Substrate specs Process materials Substrate specs Process materials Substrate specs Process materials Critical Elements / Technologies Manufacturing equip Material handling Test / inspection Materials Manufacturing equip Assembly equipment Test equipment Materials Manufacturing equip Assembly equipment Test equipment Materials Major Applications / Commercial Computer screens Video telephones HDTV Avionics Information display Smaller computers Hand-held devices Global positioning Image processing Array processors CPU Memory DSP ASIC s Defense Command & control Avionics Rugged displays Smart weapons Encryption Radar Same as above

59 Organic Electronics for Flat-Panel Displays Passive Matrix and Active Matrix OLED Displays OTFT Active Matrix Displays on Plastic Organic Light-Emitting Diodes Organic Thin-Film Transistors OTFT LCDs on Plastic Organic light-emitting (OLEDs) and organic thin-film transistors (OTFTs) are complementary technologies displays. Either technology can stand alone, but they complement one another when used together.

60 Electronic Ink An electrical field is applied across a microcapsule to control the motion of contrasting particles and achieve white, black and gray optical states.

61 Organic AMOLED Recently, active matrix displays on ultra-thin foil have been fabricated using solutionprocessed organic TFTs based on a bottom-gate device architecture. The illustration shows cross sections of such a TFT and of a vertical interconnect (via).

62 Flexible Displays?... What for? A flexible AMOLED could enable a multipurpose communications device, such as this pen communicator concept from UDC.

63 Flexible Displays

Latest News A Bridgestone employee displays Quick Response Liquid Display (QR- LPD) featuring its nanotechnology already in use for making tires at the company s laboratory in Tokyo 27 December

64 Latest News A Bridgestone employee displays Quick Response Liquid Display (QR- LPD) featuring its nanotechnology already in use for making tires at the company s laboratory in Tokyo 27 December The Japanese government plans to set itself national goals in 10 critical technology fields to strengthen the country s global competitiveness, a report said. (AFP / File / Yoshikazu Tsuno)

65 Why Plastic Substrates May Be Needed Glass is a Wonderful Technology Unbelievable advances over the last few decades Large established infrastructure Massive impact on our daily lives Continuing performance improvements but Very capital intensive Volatile supply & demand Complex packaging / interconnections Lengthy turnaround / cycle times

66 Conventional Electronics Manufacturing vs. Printing

67 Plastic Electronics Will Enter a Range of Markets $2Bn Industry Revenues $10Bn Industry Revenues P E R F O R M A N C E Flexible Backplanes OLED TV (light, thin, robust ) LCD TV (light, thin, robust, conformal Performance Logic (standard RFID) e-film for X-ray sensors Basic Logic (disposable electronics e-paper (portable e-readers, signage) TIME

Flexible Electronics Production Deployment on FPD Standards: Plastic Displays & Integrated Circuits. Stanislav Loboda R&D engineer

Flexible Electronics Production Deployment on FPD Standards: Plastic Displays & Integrated Circuits Stanislav Loboda R&D engineer The world-first small-volume contract manufacturing for plastic TFT-arrays