Flexible Electronic Packaging and Encapsulation Technology

Preface xv 1 Overview of Flexible Electronic Encapsulating Technology 1 Zhenguo Liu and Yongji Chen 1.1 Flexible Electronics Overview 1 1.2 Development of Flexible Electronic Encapsulating Technology 5 1.2.1 Flip Chip Process 11 1.2.2 Progress of CIF-Based Flexible Electronic Encapsulating Technology 13 1.3 Encapsulating Technology of Several Important Flexible Electronic Devices 14 1.3.1 Organic Light-Emitting Diode 14 1.3.2 Flexible Solar Cell Encapsulating 21 1.3.3 Flexible Amorphous Silicon Solar Cells 21 1.3.4 Flexible Perovskite Solar Cells 23 1.4 Flexible Electronic Encapsulating Materials 26 1.4.1 Selection Principle of Flexible Electronic Encapsulating Materials 26 1.4.2 Desirable Properties of Flexible Electronic Encapsulating Materials 27 1.5 Overview of the Development of Flexible Electronic Packaging at Home and Abroad 28 References 29 2 Basic Concepts Related to Flexible Electronic Packaging 33 Peng-an Zong and Mengran Chen 2.1 Composition of Flexible Electronic Packaging 33 2.1.1 Flexible Substrate 34 2.1.2 Electronic Components 35 2.1.3 Crosslinked Conductive Materials 36 2.1.4 Adhesive Layer 36 2.1.5 Coating Layer 37 2.2 Flexible Electronic Packaging Structure 37 2.2.1 Curved Structures of Hard Thin Films 38 2.2.2 Island-Bridge Structure 39 2.2.3 Pre-strained Super-Soft Interconnect Structure 40 2.2.4 Open Grid Structure 40 2.3 Encapsulation Principle 41 2.3.1 Basic Principle of Penetration 41 2.3.2 Permeation Mechanism of Water Vapor and Gas 43 2.3.3 Barrier Performance Measurement 47 2.3.4 Thin-Film Barrier Technology for Organic Devices 49 2.3.4.1 Single-Layer Film Package 50 2.3.4.2 Multilayer Film Packaging 53 2.3.5 Film Encapsulation Mechanics 58 2.4 Packaging Technology 62 2.4.1 Local Multilayer Packaging 62 2.4.2 Multilayer Barrier Film Packaging 62 2.4.3 Online Thin-Film Encapsulation 63 2.4.4 Atomic Layer Deposition (ALD) Encapsulation 63 2.4.5 Inkjet Packaging 64 2.4.6 Flexible Glass Packaging 65 2.5 Packaging Stability 65 2.6 Encapsulated Products 67 2.7 Chapter Summary 69 References 69 3 Flexible Substrates 77 Yanhui Chen, Xian Zhang, and Zhiqiang Wu 3.1 Concept and Connotation of Flexible Substrates 77 3.2 Development History of Flexible Substrates 78 3.3 Flexible Substrate Materials 82 3.3.1 Polydimethylsiloxane 82 3.3.2 Polyvinyl Alcohol 82 3.3.3 Polycarbonate 84 3.3.4 Polyester 85 3.3.5 Polyimide 88 3.3.6 Polyurethane 89 3.3.7 Parylene 91 3.3.8 Liquid Crystal Polymer 92 3.3.9 Hydrogel 93 3.4 Molding Technology of Flexible Substrate 94 3.4.1 Coating Technology 94 3.4.1.1 Dip Coating Method 94 3.4.1.2 Air Knife Coating Method 95 3.4.1.3 Scraper Coating Method 96 3.4.1.4 Rotary Coating Method 96 3.4.2 Melt Extrusion Molding 96 3.4.3 Melt Extrusion Blow Molding 96 3.4.4 Solution Tape Casting 98 3.4.5 Bidirectional Drawing Molding 98 3.4.6 Chemical Vapor Deposition 99 3.5 Performance Evaluation of Flexible Substrates 101 3.5.1 Mechanical Flexibility 101 3.5.2 Ductility 102 3.5.3 Adhesive Property 103 3.5.4 Barrier Property 103 3.5.5 Electrical Property 105 3.5.6 Chemical Stability 105 3.5.7 Dimensional Stability 105 3.5.8 Surface Smoothness and Thickness Uniformity 106 3.5.9 Optical Clarity (Transmittance) 106 3.5.10 Biocompatibility 107 3.5.11 Bioabsorbability 107 3.6 Application of Flexible Substrates 108 3.6.1 Flexible Display Substrates 108 3.6.2 Flexible Electrode Substrates 109 3.6.3 Flexible Sensing Substrates 110 3.7 Development Trend of Flexible Substrates 111 3.7.1 Intelligent and Functional Flexible Substrates 111 3.7.2 Green Degradable Flexible Substrates 112 3.7.3 Optimization of Interface Compatibility of Flexible Substrates 113 References 114 4 Test Methods 123 Junjie Yuan 4.1 Sealing Test 123 4.1.1 Direct Diffusion Method 124 4.1.1.1 Weight Cup Test 124 4.1.1.2 Differential Pressure Method 124 4.1.1.3 Balancing Method 124 4.1.1.4 Tunable Diode Laser Absorption Spectrometry 125 4.1.1.5 Isotope Labeling Mass Spectrometry 126 4.1.2 Indirect Optical Method 128 4.1.3 Indirect Electrical Method 129 4.1.3.1 Calcium Electrical Test 129 4.1.3.2 Dielectric Measurement Method 132 4.1.4 Indirect Electrochemical Method 133 4.1.4.1 Electrochemical Impedance Spectroscopy (EIS) 134 4.1.4.2 Leakage Current Monitoring Method (LCM) 134 4.1.4.3 Linear Scanning Voltammetry (LSV) 135 4.1.5 Indirect Electromechanical Method 136 4.2 Bending Test 136 4.2.1 Static Bending and Dynamic Bending 137 4.2.2 Three-Point Bending and Four-Point Bending 138 4.2.3 Push Bending and Roll Bending 140 4.2.3.1 Push Bending 140 4.2.3.2 Rolling Bend 141 4.3 Mechanical Performance Testing 143 4.4 Stability Testing 147 References 149 5 Flexible Electronic Encapsulation 157 Tao Yu 5.1 Inorganic Encapsulating Material 158 5.1.1 Metal Encapsulating Material 158 5.1.1.1 Copper, Aluminum 158 5.1.1.2 Favorable Alloys 160 5.1.1.3 Copper–Tungsten Alloy (Cu–W) 160 5.1.2 Ceramic Encapsulating Material 161 5.1.2.1 Al 2 O 3 Ceramic Encapsulation Material 161 5.1.2.2 AlN Ceramic Encapsulation Materials 161 5.1.2.3 BeO Ceramic Encapsulation Material 161 5.1.2.4 BN Ceramic Encapsulation Materials 161 5.1.3 New Trend in Inorganic Encapsulating Materials Combined with Flexible Electronic Technology 162 5.2 Organic Encapsulating Material 164 5.2.1 Polymer Encapsulating Material 164 5.2.1.1 Epoxy Resins 165 5.2.1.2 Polyimide Resins 165 5.2.1.3 Organic Silicon 166 5.2.1.4 Bismaleimide 167 5.2.1.5 Bismaleimide Triazine Resin 168 5.2.2 Development Trend of Organic Encapsulating Materials in Flexible Electronic Devices 169 5.3 Organic–Inorganic Hybrid Encapsulating Material 170 5.3.1 Application of Organic–Inorganic Hybrid Materials in Flexible Electronics 170 5.3.1.1 Strain and Pressure Sensors 171 5.3.1.2 Temperature Sensor 172 5.3.1.3 Humidity Sensor 173 5.3.1.4 Optical Sensors 173 5.3.1.5 Other Types of Sensing Devices 174 5.3.2 Development Trends of Organic–Inorganic Hybrid Materials 174 References 175 6 Development of Flexible Electronics Packaging Technology 179 Qiushi Rao 6.1 Flexible Electronics Packaging 179 6.1.1 Single-Layer Thin-Film Packaging 179 6.1.2 Multi-Layer Thin-Film Packaging 180 6.1.2.1 Barix Multilayer Thin-Film Packaging 180 6.1.2.2 Other Multilayer Thin-Film Packaging 182 6.2 Thin-Film Packaging Technology 183 6.2.1 PECVD Atomic Layer Deposition Packaging Technology 183 6.2.1.1 Introduction to PECVD Technology 183 6.2.1.2 Development of PECVD Technology 184 6.2.2 ALD Atomic Layer Deposition Packaging Technology 185 6.2.2.1 Introduction to ALD Technology 185 6.2.2.2 Development of ALD Technology 186 6.2.3 Inkjet Packaging Technology 189 6.2.3.1 Introduction to Inkjet Encapsulation Technology 189 6.2.3.2 Continuous Inkjet Printing 189 6.2.3.3 Drop-on-Demand Inkjet Printing 190 6.2.3.4 Development of Inkjet Printing Technology 191 References 192 7 Application of Flexible Electronics Packaging 195 Yuezhou Zhang 7.1 Industry Chain Analysis of Flexible Electronics Packaging 195 7.1.1 Upstream, Midstream, and Downstream of the Flexible Electronics Industry Chain 195 7.1.2 Overview of the Development of Flexible Packaging Materials 196 7.2 Packaging Applications of Flexible OLED Devices 197 7.2.1 Stability Issues of Flexible OLED Devices 198 7.2.2 Flexible OLED Packaging Technology 201 7.2.2.1 Lack of Breakthrough in Encapsulating Technology 202 7.2.2.2 Low Yield Rate 203 7.3 Packaging Applications for Flexible Solar Cells 208 7.3.1 Inorganic Flexible Solar Cells 209 7.3.2 Organic Flexible Solar Cells 211 7.3.3 Dye-Sensitized Solar Cells 213 7.3.3.1 Structure of Dye-Sensitized Solar Cells 213 7.3.3.2 Light Anode 215 7.3.3.3 Counter Electrode 216 7.4 Packaging Applications for Flexible Electronic Devices 217 7.4.1 Basic Structure of Flexible Electronic Devices 217 7.4.2 Application of Flexible Electronic Devices 218 7.4.2.1 Optoelectronics 219 7.4.2.2 Robot 220 7.4.2.3 Biomedical 221 7.4.2.4 Energy Equipment 223 7.5 Packaging Applications for Flexible Electronics Sensors 226 7.5.1 Common Materials of Flexible Sensors 228 7.5.1.1 Flexible Substrate 228 7.5.1.2 Metal Materials 228 7.5.1.3 Inorganic Semiconductor Materials 229 7.5.1.4 Organic Materials 229 7.5.1.5 Carbon Materials 230 7.5.2 Flexible Gas Sensors 230 7.5.3 Flexible Pressure Sensors 230 7.5.4 Flexible Humidity Sensor 232 7.5.5 Normal Sensors Compare with Flexible Sensors 232 References 233 8 Testing Standards 239 Junjie Yuan 8.1 Terminology and Alphabetic Symbols 240 8.1.1 Scope 240 8.1.2 Terms and Definitions 240 8.1.2.1 Terminology Classification 240 8.1.2.2 General Terms 240 8.1.2.3 Physical Characteristics Related Terms 240 8.1.2.4 Terms Related to Construction Elements 241 8.1.2.5 Symbols Related to Performances and Specifications 241 8.1.2.6 Terms Related to the Production Process 242 8.1.3 Alphabetic Symbols (Quantity Symbols/Unit Symbols) 242 8.1.3.1 Classification 242 8.1.3.2 Symbols 242 8.2 Mechanical Test Method (Deformation Test) 242 8.2.1 Cyclic Bending Test 243 8.2.1.1 Purpose 243 8.2.1.2 Testing Device 243 8.2.1.3 Test Procedure 245 8.2.1.4 Test Conditions and Reports 245 8.2.2 Static Bending Test 246 8.2.2.1 Purpose 246 8.2.2.2 Testing Device 246 8.2.2.3 Test Steps 247 8.2.2.4 Test Conditions and Reports 247 8.2.3 Combined Bending Test 247 8.2.3.1 Purpose 248 8.2.3.2 Testing Device 248 8.2.3.3 Test Procedure 248 8.2.3.4 Test Conditions and Reports 249 8.2.4 Rolling Test 250 8.2.4.1 Purpose 250 8.2.4.2 Testing Device 250 8.2.4.3 Test Procedure 250 8.2.4.4 Test Conditions and Reports 251 8.2.5 Static Rolling Test 251 8.2.5.1 Purpose 251 8.2.5.2 Testing Device 251 8.2.5.3 Test Procedure 252 8.2.5.4 Test Conditions and Reports 252 8.2.6 Torsion Test 253 8.2.6.1 Purpose 253 8.2.6.2 Testing Device 253 8.2.6.3 Test Procedure 253 8.2.6.4 Test Conditions and Reporting 254 8.2.7 Tensile Test 255 8.2.7.1 Purpose 255 8.2.7.2 Testing Device 255 8.2.7.3 Test Procedure 255 8.2.7.4 Test Conditions and Reports 256 8.3 Environmental Test Methods 256 8.3.1 Storage at High Temperature 257 8.3.1.1 Purpose 257 8.3.1.2 Test Conditions 257 8.3.2 Storage at Low Temperature 257 8.3.2.1 Purpose 257 8.3.2.2 Test Conditions 257 8.3.3 Temperature Change and Storage 257 8.3.3.1 Purpose 257 8.3.3.2 Rapid Temperature Change 258 8.3.3.3 Specified Rate of Temperature Change 258 8.3.4 Humidity and Heat, Steady State, and Storage 258 8.3.4.1 Purpose 258 8.3.4.2 Test Conditions 258 8.3.5 Moist Heat, Circulation, and Storage 259 8.3.5.1 Purpose 259 8.3.5.2 Test Conditions 259 8.3.6 High-Temperature Operation 260 8.3.6.1 Purpose 260 8.3.6.2 Test Conditions 260 8.3.7 Low-Temperature Operation 260 8.3.7.1 Purpose 260 8.3.7.2 Test Conditions 260 8.3.8 Humidity and Heat, Steady State, Operation 261 8.3.8.1 Purpose 261 8.3.8.2 Test Conditions 261 8.4 Mechanical Test Methods (Impact and Hardness Tests) 261 8.4.1 Scope 261 8.4.2 Sample Preparation 261 8.4.3 Ball Drop Test 262 8.4.3.1 Purpose 262 8.4.3.2 Testing Device 262 8.4.3.3 Test Procedure 263 8.4.4 Impact Test 263 8.4.4.1 Purpose 263 8.4.4.2 Test Equipment for Impact Testing 263 8.4.4.3 Test Process 264 8.4.5 Pendulum Side Impact Test 265 8.4.5.1 Purpose 265 8.4.5.2 Testing Device 265 8.4.5.3 Test Steps 266 8.4.6 Stylus Scratch Test 266 8.4.6.1 Purpose 266 8.4.6.2 Testing Device 266 8.4.6.3 Test Steps 267 8.4.7 Steel Wool Wear Test 267 8.4.7.1 Purpose 267 8.4.7.2 Testing Device 268 8.4.7.3 Test Procedure 268 References 268 9 Analysis of Flexible Electronic Packaging Enterprise 271 Zhenrong Wei 9.1 Flexible Electronic Packaging Enterprise 271 9.1.1 Samsung SDI-Korea 271 9.1.1.1 Product Appearance 271 9.1.1.2 Business History 271 9.1.1.3 Product Features 272 9.1.1.4 Product Specifications 272 9.1.2 LG Chem-Korea 274 9.1.2.1 Basic Materials and Chemicals 274 9.1.2.2 Information Technology and Electronic Materials 274 9.1.2.3 Energy Solutions 275 9.1.3 3M-United States 279 9.1.4 UDC-United States 284 9.1.5 Amcor-United States 286 9.1.6 Vitriflex-United States 289 9.1.7 TBF-Singapore 291 9.1.8 Fraunhofer ISC-Germany 295 9.1.9 Sigma Technologies-The United States 298 9.1.9.1 Monolayer Barrier Films 298 9.1.9.2 Multilayer Barrier Films 298 9.1.10 Toppan Printing-Japan 300 9.1.10.1 Information Network 300 9.1.10.2 Living Environment 301 9.1.10.3 Electronics 301 9.1.11 BASF(Rolic)-Germany 305 9.1.12 Vitex(Samsung)-The United States 308 9.1.13 General Electrics-The United States 316 9.1.14 Mitsui Chem-Japan 318 9.1.15 Mitsubishi Chem-Japan 320 9.1.16 Fujifilm-Japan 321 9.1.17 Konica Minolta-Japan 324 9.1.18 KDX-China 325 9.1.19 Wanshun-China 327 9.1.20 Lucky-China 329 9.2 Analysis of Flexible Electronic Packaging Enterprises 331 References 334 10 Flexible Electronics Packaging Development Trends 337 Mingqiang Liu 10.1 Flexible Electronics Packaging Trends Overview 337 10.2 Introduction of Three Packaging Technologies for Flexible Electronic Devices 341 10.2.1 Application of Electronic Packaging Technology in the OLED Field 341 10.2.2 Advances in Packaging Research for Flexible Bioelectronic Implants 345 10.2.3 Advances in Packaging Research of Flexible Chalcogenide and Organic Photovoltaics 348 10.3 Flexible Electronics Packaging Development Trend Summary 351 References 351 Index 353