Probing Crystal Plasticity at the Nanoscales (eBook)

Dr. Arief Suriadi Budiman received his Ph.D. in Materials Science and Engineering from Stanford University, CA. Before deciding to pursue his doctoral career, he first embarked on his technical career with Hewlett-Packard, Co in Singapore researching and developing microfabrication processes for HP’s latest generation of inkjet print head MEMS chip. During his doctoral candidacy at Stanford’s Department of Materials Science & Engineering under the supervision of Professor William D. Nix (MRS Von Hippel Award 2007), Dr. Budiman received several research awards (MRS Graduate Silver Award 2006, MRS Best Paper 2006) and contributed to several journal publications. Most recently Dr. Budiman has been awarded the prestigious Los Alamos National Laboratory (LANL) Director's Research Fellowship to conduct top strategic research for the energy and national security missions of the Los Alamos National Laboratory's. At the Center for Integrated Nanotechnologies (CINT) at Los Alamos, Dr. Budiman’s research program involves nanoscale multilayered composite materials for extreme environments with potential applications in advanced energy systems including for next generation nuclear power reactors.

Acknowledgments 6
Contents 8
1 Introduction 11
Abstract 11
1.1 Small Scale Plasticity 11
1.2 White-Beam X-ray Microdiffraction as Plasticity Probe 13
1.3 Electromigration in Metallic Interconnects 14
1.3.1 Electromigration Fundamentals 14
1.3.2 Electromigration Degradation Mechanisms in Cu Interconnects 16
1.4 Size Effects in Crystalline Materials 17
1.4.1 Classical Flow-Stress Relationship: The Taylor Relation 19
1.4.2 The Nix and Gao Model of Strain Gradient Plasticity 20
References 21
2 Synchrotron White-Beam X-ray Microdiffraction at the Advanced Light Source, Berkeley Lab 24
Abstract 24
2.1 Introduction 24
2.2 Beamline Components and Layout 25
2.3 Scanning White-Beam X-ray Microdiffraction 27
2.3.1 Experimental Procedure 27
2.3.2 Data Analysis Using XMAS 29
2.3.2.1 Laue Peak Searching and Indexation 30
2.3.2.2 Crystal Unit Cell Parameter Determination 34
2.3.2.3 Strain/Stress Tensor Calculation 35
2.4 Local Plasticity Probing Using Whitebeam mu XRD 37
2.4.1 Crystal Bending, Polygonization and Rotation 38
2.4.2 Quantitative Peak Study 40
References 43
3 Electromigration-Induced Plasticity in Cu Interconnects: The Length Scale Dependence 45
Abstract 45
3.1 Introduction 45
3.2 Background 46
3.3 Experimental 47
3.4 Results and Discussion 48
3.4.1 Microstructure of the Cu Interconnect Lines 48
3.4.2 Evolution of Cu Grains During Electromigration 50
3.4.3 Electromigration-Induced Plasticity: The Linewidth Effects 52
3.4.4 Electromigration-Induced Plasticity: The Directionality 54
3.4.5 Correlation Between In-Plane Texture and Occurrence of Plasticity 56
3.4.6 The Out-of-Plane Crystallographic Texture of the Cu Lines 58
3.5 Conclusions 59
References 60
4 Electromigration-Induced Plasticity in Cu Interconnects: The Texture Dependence 61
Abstract 61
4.1 Introduction 61
4.2 Background 62
4.2.1 Electromigration-Induced Plasticity in Metallic Interconnects 62
4.2.2 Microstructural Characterization of Cu Lines Manufactured by AMD 63
4.2.3 Influence of Dielectrics on Mechanical Stresses and Plastic Deformation 64
4.3 Experimental 66
4.4 Results and Discussions 67
4.4.1 EM-Induced Plasticity: Directionality and Extent 67
4.4.2 Influence of Dielectrics 70
4.4.3 Proposed Correlation: Texture Versus EM-Induced Plasticity 71
4.5 Conclusions 74
References 74
5 Industrial Implications of Electromigration-Induced Plasticity in Cu Interconnects: Plasticity-Amplified Diffusivity 76
Abstract 76
5.1 Introduction 76
5.2 Background 77
5.2.1 Dislocation Cores as Fast Diffusion Paths in Metallic Interconnects 77
5.2.2 Electromigration Reliability Assessment Methodology: Black's Law 79
5.3 Plasticity-Amplified Diffusion in Electromigration 80
5.3.1 Density of Core Dislocations ( rho core): Extent of Plasticity 81
5.3.2 Effect of Grain Boundary Diffusion: Effective Dcore 83
5.3.3 The Extra Dependency on J---The Plasticity Effect 89
5.4 Conclusions 91
References 92
6 Indentation Size Effects in Single Crystal Cu as Revealed by Synchrotron X-ray Microdiffraction 94
Abstract 94
6.1 Introduction 94
6.2 Background 95
6.3 Experimental 96
6.4 Results and Discussion 98
6.4.1 Mapping of Laue Peak Streaking on Individual Indents 98
6.4.2 Comparison of Laue Peak Streaking for Different Indentation Depths 100
6.4.3 Quantitative Analysis of Laue Peak Streaking-Based GND Density 101
6.4.4 Hardness Measurement and Revised Nix and Gao's GND Density 102
6.4.5 Strain Gradient Plasticity Analysis 103
6.5 Conclusions 106
References 106
7 Smaller is Stronger: Size Effects in Uniaxially Compressed Au Submicron Single Crystal Pillars 109
Abstract 109
7.1 Introduction 109
7.2 Background 110
7.3 Experimental 111
7.3.1 Thin Film of Au on Single Crystal Cr Substrate 111
7.3.2 Fabrication and Uniaxial Compression of Submicron Au Pillar 112
7.3.3 White-Beam X-ray Microdiffraction Experiment 113
7.4 Results and Discussion 114
7.4.1 Diffraction Intensity Mapping: Pillar Location Identification 114
7.4.2 Stress-Strain Behavior of Pillar Uniaxial Compression 116
7.4.3 Laue Diffraction Peak Shapes: Undeformed Versus Deformed 116
7.4.4 Limitation of the Technique: Quantitative Analysis of GND Density 118
7.4.5 Dislocation Starvation and Dislocation Nucleation-Controlled Plasticity 119
7.5 Conclusions 120
References 121
8 Conclusions 122
Abstract 122