Principles of Extreme Mechanics (XM) in Design for Reliability (DfR) : With Special Emphasis on Recent Advances in Materials Characterization and Experimentation Techniques

This book addresses issues pertinent to mechanics and stress generation, especially in recent advanced cases of technology developments, spanning from micrometer interconnects in solar photovoltaics (PV), next-gen energy storage devices to multilayers of nano-scale composites enabling novel stretchable/flexible conductor technologies. In these cases, the mechanics of materials have been pushed to the extreme edges of human knowledge to enable cutting-edge, unprecedented functionalities and technological innovations. Synchrotron X-ray diffraction, in situ small-scale mechanical testing combined with physics-based computational modeling/simulation, has been widely used approaches to probe these mechanics of the materials at their extreme limits due to their recently discovered distinct advantages. The techniques discussed in this manuscript are highlights specially curated from the broad body of work recently reported in the literature, especially ones that the author had led the pursuits at the frontier himself. Extreme stress generation in these advanced material leads to often new failure modes, and hence, the reliability of the final product is directly affected. From the recent topics and various advanced case studies covered in this book, the reader gets an updated knowledge of how new mechanics can and has been applied in Design-for-Reliability (DfR) for some of the latest technological innovations known in our modern world. Further, this also helps in building better designs, which may avoid the pitfalls of the current practiced trends.-- Preface Preface 6 Contents 7 About the Author 11 1 Introduction 12 2 Extreme Mechanics in Advanced, Emerging Materials 16 2.1 Smaller is Stronger—Extending the Elasticity Limit of Nanoscale Crystalline Materials 17 2.1.1 Classical Flow-Stress Relationship: The Taylor Relation 18 2.1.2 The Nix and Gao Model of Strain Gradient Hardening 20 2.1.3 Dislocation-Starvation and Dislocation Nucleation-Controlled Hardening 23 2.2 Smaller is More Deformable—Controlling Defect Dynamics at the Nanoscales 28 2.2.1 Nanocale Metallic Multilayered Materials 28 2.2.2 Extreme Deformability as Revealed by Successive Micropillar Compression Experiments 30 2.2.3 Roles of Interfaces in Extreme Plasticity 33 2.3 Extreme Fracture Limits—Fracture at the Small Scales and Emerging 3D Architectures 38 2.3.1 Fracture at the Nanoscales 38 2.3.2 Fracture Interaction with the Interfaces in Nanolayers—Interfacial Sliding 52 2.3.3 Novel Fracture Mechanisms with Nature-Inspired 3D Architectures 60 References 69 3 Probing Mechanics at the Extremes 73 3.1 Synchrotron X-ray Microdiffraction (ΜSXRD) 74 3.1.1 Diffraction Physics and Beamline Instrumentation 75 3.1.2 Synchrotron White-Beam X-ray Microdiffraction 78 3.1.3 Local Plasticity Probing Using White-Beam ΜSXRD 89 3.1.4 Summary: Synchrotron X-ray Microdiffraction (μSXRD) 96 3.2 In-Situ Micromechanical and Fracture Testing 96 3.2.1 In-Situ Microfracture Testing 97 3.2.2 Micron-Scale Test Structure Fabrication and Sample Preparations 101 3.2.3 Small-Scale Nanomechanical Characterization Techniques 106 3.2.4 Summary: In-Situ Micromechanical and Fracture Testing 113 References 113 4 Recent Cases in Advanced Micro/Nanoelectronics, Microsystems and MEMS Devices and Technologies 119 4.1 Through-Silicon Vias (TSV) for Enabling 3D Integrated Circuits (IC) 120 4.1.1 Background and Overview 121 4.1.2 Experimental Methodologies—Probing Extreme Stress Generation 122 4.1.3 Extreme 3D Stress: Enabling Advanced Interconnects to Extend to the Third Dimension 123 4.2 Nanoplasticity in Low-Melting Temperature Metals 127 4.2.1 Background and Overview 128 4.2.2 Experimental Methodologies—Probing Extreme Plasticity and Strain-Rate Effects 129 4.2.3 New Insights on Plasticity of Low-Melting Temperature Metals at the Nanoscales 133 4.2.4 Extreme Plasticity: Enabling Advanced Nanoscale Packaging at Low Temperatures 138 4.3 Extended Linear Sensitivity Regime in Cu/Nb Nanolayers for Strain Sensing Applications 139 4.3.1 Background and Overview 140 4.3.2 Experimental Methodologies—Probing Mechano-Resistivity at the Nanoscales 144 4.3.3 Extreme Strain-Resistivity: Extending Linear Strain Sensitivity for Strain Monitoring 147 4.4 Stress-Induced Voiding in Advanced Submicron Interconnects 153 4.4.1 Background and Overview 153 4.4.2 Critical Temperature Shift for Stress-Induced Voiding in Advanced Cu Interconnects for 32 nm and Beyond 154 4.5 Summary 161 References 162 5 Latest Updates in Next-Generation Energy Technologies and Systems 170 5.1 Novel Silicon Nanowire Anode Technology for Next-Generation Lithium Ion Battery (LIB) 172 5.1.1 Background and Motivation—Novel Silicon Nanowire Anode 172 5.1.2 Experimental Methodology—Probing Stress in Extreme Expansion of Silicon Nanowires Anode 173 5.1.3 Enabling Novel Silicon Nanowire Anode for Next-Generation LIB 178 5.1.4 Summary 183 5.2 Enabling Thin Silicon Technologies for Next-Generation, Novel and Innovative Crystalline Silicon Photovoltaics Systems Design 184 5.2.1 Background and Motivation—Thin Silicon Solar Cell Technology 184 5.2.2 Experimental Methodology—Probing Stress of Thin Silicon While Already Encapsulated 187 5.2.3 Extreme Mechanics Characterization of Materials Enabling Thin Silicon Solar Cell Technology 189 5.2.4 Summary 193 5.3 Low-Stress Encapsulants?—Enabling PV with Extreme Reliability 193 5.3.1 Background and Motivation—Thinner But Stronger Silicon Solar PV 194 5.3.2 Experimental Methodology—Probing Strength of Thin Silicon PV Laminates 195 5.3.3 Low-Stress Encapsulant Enabling Extreme Fracture-Resistant Silicon PV Modules 197 5.3.4 Summary 202 References 203 6 Emerging Trends in Additively Manufactured Materials and Novel Flexible/Stretchable Conductor Technologies 209 6.1 Tunable Impact Resistance in Novel Composites with Helicoidal 3D Architecture Via Additive Manufacturing Methodologies 210 6.1.1 Background and Motivation—Helicoidally Aligned Fiber Composite Materials 211 6.1.2 Experimental Methodology—Electrospinning-Based Additive Manufacturing (Es-AM) and Advanced Materials Characterization Techniques 212 6.1.3 Additive Manufacturing Enabling Novel Materials with Helicoidal 3D Architecture 216 6.1.4 Additive Manufacturing Enabling Materials with Extreme and Tunable Impact Properties for Novel Lightweight Photovoltaics (PV) Technology 220 6.1.5 Additive Manufacturing Enabling Novel 3D Architected Anode Materials for Next-Generation Lithium Ion Battery (LIB) Technology 227 6.2 Enabling Stretchable Metallic Conductors Through Atomic Reconfigurations in FCC/BCC Nanolayers 231 6.2.1 Background and Motivation—Novel Metallic Stretchable Conductor Materials 232 6.2.2 Metallic FCC/BCC Nanolayered Materials System—Enabling Interfacial Sliding Through Atomic Reconfigurations 236 6.2.3 Novel Stretchable Metallic Conductors—Structural Versus Atomic Reconfigurations 239 6.2.4 Probing Atomic Reconfigurations Using In-Situ Synchrotron X-ray Nanodiffraction 240 6.2.5 Enabling Novel Stretchable Metallic Conductor Materials for Emerging Technologies 244 References 245 7 Conclusion 252 References 254