Flexible Electronic Packaging and Encapsulation Technology

Hong Meng, PhD, is Professor in the School of Advanced Materials at Peking University Shenzhen Graduate School, China. He has been working in the field of organic electronics for more than 30 years, including working at the Instute of Materials Science and Engineering (IMRE) in Singapore, Lucent Technologies Bell Labs, and DuPont Experimental Station. Wei Huang, PhD, is Professor at Frontiers Science Center for Flexible Electronics, Institute of Flexible Electronics, Northwestern Polytechnical University, China. He is Academician of Chinese Academy of Sciences, Russian Academy of Sciences, International Member of the National Academy of Engineering of USA, Academy of Engineering and Technology, Asian Pacific Academy of Materials, and Pakistan Academy of Sciences. He is an eminent scientist in the area of organic optoelectronics and flexible electronics.

• Preface xv1 Overview of Flexible Electronic Encapsulating Technology 1Zhenguo Liu and Yongji Chen1.1 Flexible Electronics Overview 11.2 Development of Flexible Electronic Encapsulating Technology 51.2.1 Flip Chip Process 111.2.2 Progress of CIF-Based Flexible Electronic Encapsulating Technology 131.3 Encapsulating Technology of Several Important Flexible Electronic Devices 141.3.1 Organic Light-Emitting Diode 141.3.2 Flexible Solar Cell Encapsulating 211.3.3 Flexible Amorphous Silicon Solar Cells 211.3.4 Flexible Perovskite Solar Cells 231.4 Flexible Electronic Encapsulating Materials 261.4.1 Selection Principle of Flexible Electronic Encapsulating Materials 261.4.2 Desirable Properties of Flexible Electronic Encapsulating Materials 271.5 Overview of the Development of Flexible Electronic Packaging at Home and Abroad 28References 292 Basic Concepts Related to Flexible Electronic Packaging 33Peng-an Zong and Mengran Chen2.1 Composition of Flexible Electronic Packaging 332.1.1 Flexible Substrate 342.1.2 Electronic Components 352.1.3 Crosslinked Conductive Materials 362.1.4 Adhesive Layer 362.1.5 Coating Layer 372.2 Flexible Electronic Packaging Structure 372.2.1 Curved Structures of Hard Thin Films 382.2.2 Island-Bridge Structure 392.2.3 Pre-strained Super-Soft Interconnect Structure 402.2.4 Open Grid Structure 402.3 Encapsulation Principle 412.3.1 Basic Principle of Penetration 412.3.2 Permeation Mechanism of Water Vapor and Gas 432.3.3 Barrier Performance Measurement 472.3.4 Thin-Film Barrier Technology for Organic Devices 492.3.4.1 Single-Layer Film Package 502.3.4.2 Multilayer Film Packaging 532.3.5 Film Encapsulation Mechanics 582.4 Packaging Technology 622.4.1 Local Multilayer Packaging 622.4.2 Multilayer Barrier Film Packaging 622.4.3 Online Thin-Film Encapsulation 632.4.4 Atomic Layer Deposition (ALD) Encapsulation 632.4.5 Inkjet Packaging 642.4.6 Flexible Glass Packaging 652.5 Packaging Stability 652.6 Encapsulated Products 672.7 Chapter Summary 69References 693 Flexible Substrates 77Yanhui Chen, Xian Zhang, and Zhiqiang Wu3.1 Concept and Connotation of Flexible Substrates 773.2 Development History of Flexible Substrates 783.3 Flexible Substrate Materials 823.3.1 Polydimethylsiloxane 823.3.2 Polyvinyl Alcohol 823.3.3 Polycarbonate 843.3.4 Polyester 853.3.5 Polyimide 883.3.6 Polyurethane 893.3.7 Parylene 913.3.8 Liquid Crystal Polymer 923.3.9 Hydrogel 933.4 Molding Technology of Flexible Substrate 943.4.1 Coating Technology 943.4.1.1 Dip Coating Method 943.4.1.2 Air Knife Coating Method 953.4.1.3 Scraper Coating Method 963.4.1.4 Rotary Coating Method 963.4.2 Melt Extrusion Molding 963.4.3 Melt Extrusion Blow Molding 963.4.4 Solution Tape Casting 983.4.5 Bidirectional Drawing Molding 983.4.6 Chemical Vapor Deposition 993.5 Performance Evaluation of Flexible Substrates 1013.5.1 Mechanical Flexibility 1013.5.2 Ductility 1023.5.3 Adhesive Property 1033.5.4 Barrier Property 1033.5.5 Electrical Property 1053.5.6 Chemical Stability 1053.5.7 Dimensional Stability 1053.5.8 Surface Smoothness and Thickness Uniformity 1063.5.9 Optical Clarity (Transmittance) 1063.5.10 Biocompatibility 1073.5.11 Bioabsorbability 1073.6 Application of Flexible Substrates 1083.6.1 Flexible Display Substrates 1083.6.2 Flexible Electrode Substrates 1093.6.3 Flexible Sensing Substrates 1103.7 Development Trend of Flexible Substrates 1113.7.1 Intelligent and Functional Flexible Substrates 1113.7.2 Green Degradable Flexible Substrates 1123.7.3 Optimization of Interface Compatibility of Flexible Substrates 113References 1144 Test Methods 123Junjie Yuan4.1 Sealing Test 1234.1.1 Direct Diffusion Method 1244.1.1.1 Weight Cup Test 1244.1.1.2 Differential Pressure Method 1244.1.1.3 Balancing Method 1244.1.1.4 Tunable Diode Laser Absorption Spectrometry 1254.1.1.5 Isotope Labeling Mass Spectrometry 1264.1.2 Indirect Optical Method 1284.1.3 Indirect Electrical Method 1294.1.3.1 Calcium Electrical Test 1294.1.3.2 Dielectric Measurement Method 1324.1.4 Indirect Electrochemical Method 1334.1.4.1 Electrochemical Impedance Spectroscopy (EIS) 1344.1.4.2 Leakage Current Monitoring Method (LCM) 1344.1.4.3 Linear Scanning Voltammetry (LSV) 1354.1.5 Indirect Electromechanical Method 1364.2 Bending Test 1364.2.1 Static Bending and Dynamic Bending 1374.2.2 Three-Point Bending and Four-Point Bending 1384.2.3 Push Bending and Roll Bending 1404.2.3.1 Push Bending 1404.2.3.2 Rolling Bend 1414.3 Mechanical Performance Testing 1434.4 Stability Testing 147References 1495 Flexible Electronic Encapsulation 157Tao Yu5.1 Inorganic Encapsulating Material 1585.1.1 Metal Encapsulating Material 1585.1.1.1 Copper, Aluminum 1585.1.1.2 Favorable Alloys 1605.1.1.3 Copper–Tungsten Alloy (Cu–W) 1605.1.2 Ceramic Encapsulating Material 1615.1.2.1 Al 2 O 3 Ceramic Encapsulation Material 1615.1.2.2 AlN Ceramic Encapsulation Materials 1615.1.2.3 BeO Ceramic Encapsulation Material 1615.1.2.4 BN Ceramic Encapsulation Materials 1615.1.3 New Trend in Inorganic Encapsulating Materials Combined with Flexible Electronic Technology 1625.2 Organic Encapsulating Material 1645.2.1 Polymer Encapsulating Material 1645.2.1.1 Epoxy Resins 1655.2.1.2 Polyimide Resins 1655.2.1.3 Organic Silicon 1665.2.1.4 Bismaleimide 1675.2.1.5 Bismaleimide Triazine Resin 1685.2.2 Development Trend of Organic Encapsulating Materials in Flexible Electronic Devices 1695.3 Organic–Inorganic Hybrid Encapsulating Material 1705.3.1 Application of Organic–Inorganic Hybrid Materials in Flexible Electronics 1705.3.1.1 Strain and Pressure Sensors 1715.3.1.2 Temperature Sensor 1725.3.1.3 Humidity Sensor 1735.3.1.4 Optical Sensors 1735.3.1.5 Other Types of Sensing Devices 1745.3.2 Development Trends of Organic–Inorganic Hybrid Materials 174References 1756 Development of Flexible Electronics Packaging Technology 179Qiushi Rao6.1 Flexible Electronics Packaging 1796.1.1 Single-Layer Thin-Film Packaging 1796.1.2 Multi-Layer Thin-Film Packaging 1806.1.2.1 Barix Multilayer Thin-Film Packaging 1806.1.2.2 Other Multilayer Thin-Film Packaging 1826.2 Thin-Film Packaging Technology 1836.2.1 PECVD Atomic Layer Deposition Packaging Technology 1836.2.1.1 Introduction to PECVD Technology 1836.2.1.2 Development of PECVD Technology 1846.2.2 ALD Atomic Layer Deposition Packaging Technology 1856.2.2.1 Introduction to ALD Technology 1856.2.2.2 Development of ALD Technology 1866.2.3 Inkjet Packaging Technology 1896.2.3.1 Introduction to Inkjet Encapsulation Technology 1896.2.3.2 Continuous Inkjet Printing 1896.2.3.3 Drop-on-Demand Inkjet Printing 1906.2.3.4 Development of Inkjet Printing Technology 191References 1927 Application of Flexible Electronics Packaging 195Yuezhou Zhang7.1 Industry Chain Analysis of Flexible Electronics Packaging 1957.1.1 Upstream, Midstream, and Downstream of the Flexible Electronics Industry Chain 1957.1.2 Overview of the Development of Flexible Packaging Materials 1967.2 Packaging Applications of Flexible OLED Devices 1977.2.1 Stability Issues of Flexible OLED Devices 1987.2.2 Flexible OLED Packaging Technology 2017.2.2.1 Lack of Breakthrough in Encapsulating Technology 2027.2.2.2 Low Yield Rate 2037.3 Packaging Applications for Flexible Solar Cells 2087.3.1 Inorganic Flexible Solar Cells 2097.3.2 Organic Flexible Solar Cells 2117.3.3 Dye-Sensitized Solar Cells 2137.3.3.1 Structure of Dye-Sensitized Solar Cells 2137.3.3.2 Light Anode 2157.3.3.3 Counter Electrode 2167.4 Packaging Applications for Flexible Electronic Devices 2177.4.1 Basic Structure of Flexible Electronic Devices 2177.4.2 Application of Flexible Electronic Devices 2187.4.2.1 Optoelectronics 2197.4.2.2 Robot 2207.4.2.3 Biomedical 2217.4.2.4 Energy Equipment 2237.5 Packaging Applications for Flexible Electronics Sensors 2267.5.1 Common Materials of Flexible Sensors 2287.5.1.1 Flexible Substrate 2287.5.1.2 Metal Materials 2287.5.1.3 Inorganic Semiconductor Materials 2297.5.1.4 Organic Materials 2297.5.1.5 Carbon Materials 2307.5.2 Flexible Gas Sensors 2307.5.3 Flexible Pressure Sensors 2307.5.4 Flexible Humidity Sensor 2327.5.5 Normal Sensors Compare with Flexible Sensors 232References 2338 Testing Standards 239Junjie Yuan8.1 Terminology and Alphabetic Symbols 2408.1.1 Scope 2408.1.2 Terms and Definitions 2408.1.2.1 Terminology Classification 2408.1.2.2 General Terms 2408.1.2.3 Physical Characteristics Related Terms 2408.1.2.4 Terms Related to Construction Elements 2418.1.2.5 Symbols Related to Performances and Specifications 2418.1.2.6 Terms Related to the Production Process 2428.1.3 Alphabetic Symbols (Quantity Symbols/Unit Symbols) 2428.1.3.1 Classification 2428.1.3.2 Symbols 2428.2 Mechanical Test Method (Deformation Test) 2428.2.1 Cyclic Bending Test 2438.2.1.1 Purpose 2438.2.1.2 Testing Device 2438.2.1.3 Test Procedure 2458.2.1.4 Test Conditions and Reports 2458.2.2 Static Bending Test 2468.2.2.1 Purpose 2468.2.2.2 Testing Device 2468.2.2.3 Test Steps 2478.2.2.4 Test Conditions and Reports 2478.2.3 Combined Bending Test 2478.2.3.1 Purpose 2488.2.3.2 Testing Device 2488.2.3.3 Test Procedure 2488.2.3.4 Test Conditions and Reports 2498.2.4 Rolling Test 2508.2.4.1 Purpose 2508.2.4.2 Testing Device 2508.2.4.3 Test Procedure 2508.2.4.4 Test Conditions and Reports 2518.2.5 Static Rolling Test 2518.2.5.1 Purpose 2518.2.5.2 Testing Device 2518.2.5.3 Test Procedure 2528.2.5.4 Test Conditions and Reports 2528.2.6 Torsion Test 2538.2.6.1 Purpose 2538.2.6.2 Testing Device 2538.2.6.3 Test Procedure 2538.2.6.4 Test Conditions and Reporting 2548.2.7 Tensile Test 2558.2.7.1 Purpose 2558.2.7.2 Testing Device 2558.2.7.3 Test Procedure 2558.2.7.4 Test Conditions and Reports 2568.3 Environmental Test Methods 2568.3.1 Storage at High Temperature 2578.3.1.1 Purpose 2578.3.1.2 Test Conditions 2578.3.2 Storage at Low Temperature 2578.3.2.1 Purpose 2578.3.2.2 Test Conditions 2578.3.3 Temperature Change and Storage 2578.3.3.1 Purpose 2578.3.3.2 Rapid Temperature Change 2588.3.3.3 Specified Rate of Temperature Change 2588.3.4 Humidity and Heat, Steady State, and Storage 2588.3.4.1 Purpose 2588.3.4.2 Test Conditions 2588.3.5 Moist Heat, Circulation, and Storage 2598.3.5.1 Purpose 2598.3.5.2 Test Conditions 2598.3.6 High-Temperature Operation 2608.3.6.1 Purpose 2608.3.6.2 Test Conditions 2608.3.7 Low-Temperature Operation 2608.3.7.1 Purpose 2608.3.7.2 Test Conditions 2608.3.8 Humidity and Heat, Steady State, Operation 2618.3.8.1 Purpose 2618.3.8.2 Test Conditions 2618.4 Mechanical Test Methods (Impact and Hardness Tests) 2618.4.1 Scope 2618.4.2 Sample Preparation 2618.4.3 Ball Drop Test 2628.4.3.1 Purpose 2628.4.3.2 Testing Device 2628.4.3.3 Test Procedure 2638.4.4 Impact Test 2638.4.4.1 Purpose 2638.4.4.2 Test Equipment for Impact Testing 2638.4.4.3 Test Process 2648.4.5 Pendulum Side Impact Test 2658.4.5.1 Purpose 2658.4.5.2 Testing Device 2658.4.5.3 Test Steps 2668.4.6 Stylus Scratch Test 2668.4.6.1 Purpose 2668.4.6.2 Testing Device 2668.4.6.3 Test Steps 2678.4.7 Steel Wool Wear Test 2678.4.7.1 Purpose 2678.4.7.2 Testing Device 2688.4.7.3 Test Procedure 268References 2689 Analysis of Flexible Electronic Packaging Enterprise 271Zhenrong Wei9.1 Flexible Electronic Packaging Enterprise 2719.1.1 Samsung SDI-Korea 2719.1.1.1 Product Appearance 2719.1.1.2 Business History 2719.1.1.3 Product Features 2729.1.1.4 Product Specifications 2729.1.2 LG Chem-Korea 2749.1.2.1 Basic Materials and Chemicals 2749.1.2.2 Information Technology and Electronic Materials 2749.1.2.3 Energy Solutions 2759.1.3 3M-United States 2799.1.4 UDC-United States 2849.1.5 Amcor-United States 2869.1.6 Vitriflex-United States 2899.1.7 TBF-Singapore 2919.1.8 Fraunhofer ISC-Germany 2959.1.9 Sigma Technologies-The United States 2989.1.9.1 Monolayer Barrier Films 2989.1.9.2 Multilayer Barrier Films 2989.1.10 Toppan Printing-Japan 3009.1.10.1 Information Network 3009.1.10.2 Living Environment 3019.1.10.3 Electronics 3019.1.11 BASF(Rolic)-Germany 3059.1.12 Vitex(Samsung)-The United States 3089.1.13 General Electrics-The United States 3169.1.14 Mitsui Chem-Japan 3189.1.15 Mitsubishi Chem-Japan 3209.1.16 Fujifilm-Japan 3219.1.17 Konica Minolta-Japan 3249.1.18 KDX-China 3259.1.19 Wanshun-China 3279.1.20 Lucky-China 3299.2 Analysis of Flexible Electronic Packaging Enterprises 331References 33410 Flexible Electronics Packaging Development Trends 337Mingqiang Liu10.1 Flexible Electronics Packaging Trends Overview 33710.2 Introduction of Three Packaging Technologies for Flexible Electronic Devices 34110.2.1 Application of Electronic Packaging Technology in the OLED Field 34110.2.2 Advances in Packaging Research for Flexible Bioelectronic Implants 34510.2.3 Advances in Packaging Research of Flexible Chalcogenide and Organic Photovoltaics 34810.3 Flexible Electronics Packaging Development Trend Summary 351References 351Index 353