Modeling and Simulation for Microelectronic Packaging Assembly

Sheng Liu is a ChangJiang Professor of Mechanical Engineering at Huazhong University of Science and Technology. He holds a dual appointment at Wuhan National Laboratory for Optoelectronics, and has served as tenured faculty at Wayne State University. He has over 14 years experience in LED/MEMS/IC packaging and extensive experience in consulting with many leading multi-national and Chinese companies. Liu was awarded the White House/NSF Presidential Faculty Fellowship in 1995, ASME Young Engineer Award in 1996, and China NSFC Overseas Young Scientist in 1999. He is currently one of the 11 National Committee Members in LED under Ministry of Science and Technology. He obtained a Ph.D. from Stanford in 1992, and got MS and BS in flight vehicle design, Nanjing University of Aeronautics and Astronautics, and he had three years industrial experience in China and USA. He has filed more than 70 patents in China and the USA, and has published more than 300 technical articles. Yong Liu is a global team leader of electrical, thermal-mechanical modeling and analysis at Fairchild Semiconductor Corp in South Portland, Maine. His main interest areas are IC packaging, modeling and simulation, reliability and material characterization. He has previously served as Professor at Zhejiang University of Technology, and has worked as an opto package engineer at Nortel Networks in Boston. Liu has co-authored over 100 papers in journals and conferences, has filed over 40 US patents in the area of IC packaging and power device, and has won numerous awards and fellowships in academia and industry: the Fairchild President Award, Fairchild Key Technologist, Fairchild New Product Innovation Award, the Alexander von Humboldt European Fellowship for study at Braunschweig University of Technology and University of Cambridge. Liu holds a PhD from Nanjing University of Science and Technology.

Foreword by C. P. Wong xiii Foreword by Zhigang Suo xv

Preface xvii

Acknowledgments xix

About the Authors xxi

Part I Mechanics and Modeling 1

1 Constitutive Models and Finite Element Method 3

1.1 Constitutive Models for Typical Materials 3

1.1.1 Linear Elasticity 3

1.1.2 Elastic-Visco-Plasticity 5

1.2 Finite Element Method 9

1.2.1 Basic Finite Element Equations 9

1.2.2 Nonlinear Solution Methods 12

1.2.3 Advanced Modeling Techniques in Finite Element Analysis 14

1.2.4 Finite Element Applications in Semiconductor Packaging Modeling 17

1.3 Chapter Summary 18

References 19

2 Material and Structural Testing for Small Samples 21

2.1 Material Testing for Solder Joints 21

2.1.1 Specimens 21

2.1.2 A Thermo-Mechanical Fatigue Tester 23

2.1.3 Tensile Test 24

2.1.4 Creep Test 26

2.1.5 Fatigue Test 31

2.2 Scale Effect of Packaging Materials 32

2.2.1 Specimens 33

2.2.2 Experimental Results and Discussions 34

2.2.3 Thin Film Scale Dependence for Polymer Thin Films 39

2.3 Two-Ball Joint Specimen Fatigue Testing 41

2.4 Chapter Summary 41

References 43

3 Constitutive and User-Supplied Subroutines for Solders Considering Damage Evolution 45

3.1 Constitutive Model for Tin-Lead Solder Joint 45

3.1.1 Model Formulation 45

3.1.2 Determination of Material Constants 47

3.1.3 Model Prediction 49

3.2 Visco-Elastic-Plastic Properties and Constitutive Modeling of Underfills 50

3.2.1 Constitutive Modeling of Underfills 50

3.2.2 Identification of Material Constants 55

3.2.3 Model Verification and Prediction 55

3.3 A Damage Coupling Framework of Unified Viscoplasticity for the Fatigue of Solder Alloys 56

3.3.1 Damage Coupling Thermodynamic Framework 56

3.3.2 Large Deformation Formulation 62

3.3.3 Identification of the Material Parameters 63

3.3.4 Creep Damage 66

3.4 User-Supplied Subroutines for Solders Considering Damage Evolution 67

3.4.1 Return-Mapping Algorithm and FEA Implementation 67

3.4.2 Advanced Features of the Implementation 69

3.4.3 Applications of the Methodology 71

3.5 Chapter Summary 76

References 76

4 Accelerated Fatigue Life Assessment Approaches for Solders in Packages 79

4.1 Life Prediction Methodology 79

4.1.1 Strain-Based Approach 80

4.1.2 Energy-Based Approach 82

4.1.3 Fracture Mechanics-Based Approach 82

4.2 Accelerated Testing Methodology 82

4.2.1 Failure Modes via Accelerated Testing Bounds 83

4.2.2 Isothermal Fatigue via Thermal Fatigue 83

4.3 Constitutive Modeling Methodology 83

4.3.1 Separated Modeling via Unified Modeling 83

4.3.2 Viscoplasticity with Damage Evolution 84

4.4 Solder Joint Reliability via FEA 84

4.4.1 Life Prediction of Ford Joint Specimen 84

4.4.2 Accelerated Testing: Insights from Life Prediction 87

4.4.3 Fatigue Life Prediction of a PQFP Package 91

4.5 Life Prediction of Flip-Chip Packages 93

4.5.1 Fatigue Life Prediction with and without Underfill 93

4.5.2 Life Prediction of Flip-Chips without Underfill via Unified and Separated Constitutive Modeling 95

4.5.3 Life Prediction of Flip-Chips under Accelerated Testing 96

4.6 Chapter Summary 99

References 99

5 Multi-Physics and Multi-Scale Modeling 103

5.1 Multi-Physics Modeling 103

5.1.1 Direct-Coupled Analysis 103

5.1.2 Sequential Coupling 104

5.2 Multi-Scale Modeling 106

5.3 Chapter Summary 107

References 108

6 Modeling Validation Tools 109

6.1 Structural Mechanics Analysis 109

6.2 Requirements of Experimental Methods for Structural Mechanics Analysis 111

6.3 Whole Field Optical Techniques 112

6.4 Thermal Strains Measurements Using Moire Interferometry 113

6.4.1 Thermal Strains in a Plastic Ball Grid Array (PBGA) Interconnection 113

6.4.2 Real-Time Thermal Deformation Measurements Using Moire Interferometry 116

6.5 In-Situ Measurements on Micro-Machined Sensors 116

6.5.1 Micro-Machined Membrane Structure in a Chemical Sensor 116

6.5.2 In-Situ Measurement Using Twyman–Green Interferometry 118

6.5.3 Membrane Deformations due to Power Cycles 118

6.6 Real-Time Measurements Using Speckle Interferometry 119

6.7 Image Processing and Computer Aided Optical Techniques 120

6.7.1 Image Processing for Fringe Analysis 120

6.7.2 Phase Shifting Technique for Increasing Displacement Resolution 120

6.8 Real-Time Thermal-Mechanical Loading Tools 123

6.8.1 Micro-Mechanical Testing 123

6.8.2 Environmental Chamber 124

6.9 Warpage Measurement Using PM-SM System 124

6.9.1 Shadow Moire and Project Moire Setup 125

6.9.2 Warpage Measurement of a BGA, Two Crowded PCBs 127

6.10 Chapter Summary 131

References 131

7 Application of Fracture Mechanics 135

7.1 Fundamental of Fracture Mechanics 135

7.1.1 Energy Release Rate 136

7.1.2 J Integral 138

7.1.3 Interfacial Crack 139

7.2 Bulk Material Cracks in Electronic Packages 141

7.2.1 Background 141

7.2.2 Crack Propagation in Ceramic/Adhesive/Glass System 142

7.2.3 Results 146

7.3 Interfacial Fracture Toughness 148

7.3.1 Background 148

7.3.2 Interfacial Fracture Toughness of Flip-Chip Package between Passivated Silicon Chip and Underfill 150

7.4 Three-Dimensional Energy Release Rate Calculation 159

7.4.1 Fracture Analysis 160

7.4.2 Results and Comparison 160

7.5 Chapter Summary 165

References 165

8 Concurrent Engineering for Microelectronics 169

8.1 Design Optimization 169

8.2 New Developments and Trends in Integrated Design Tools 179

8.3 Chapter Summary 183

References 183

Part II Modeling in Microelectronic Packaging and Assembly 185

9 Typical IC Packaging and Assembly Processes 187

9.1 Wafer Process and Thinning 188

9.1.1 Wafer Process Stress Models 188

9.1.2 Thin Film Deposition 189

9.1.3 Backside Grind for Thinning 191

9.2 Die Pick Up 193

9.3 Die Attach 198

9.3.1 Material Constitutive Relations 200

9.3.2 Modeling and Numerical Strategies 201

9.3.3 FEA Simulation Result of Flip-Chip Attach 204

9.4 Wire Bonding 206

9.4.1 Assumption, Material Properties and Method of Analysis 207

9.4.2 Wire Bonding Process with Different Parameters 208

9.4.3 Impact of Ultrasonic Amplitude 210

9.4.4 Impact of Ultrasonic Frequency 212

9.4.5 Impact of Friction Coefficients between Bond Pad and FAB 214

9.4.6 Impact of Different Bond Pad Thickness 217

9.4.7 Impact of Different Bond Pad Structures 217

9.4.8 Modeling Results and Discussion for Cooling Substrate Temperature after Wire Bonding 221

9.5 Molding 223

9.5.1 Molding Flow Simulation 223

9.5.2 Curing Stress Model 230

9.5.3 Molding Ejection and Clamping Simulation 236

9.6 Leadframe Forming/Singulation 241

9.6.1 Euler Forward versus Backward Solution Method 242

9.6.2 Punch Process Setup 242

9.6.3 Punch Simulation by ANSYS Implicit 244

9.6.4 Punch Simulation by LS-DYNA 246

9.6.5 Experimental Data 248

9.7 Chapter Summary 252

References 252

10 Opto Packaging and Assembly 255

10.1 Silicon Substrate Based Opto Package Assembly 255

10.1.1 State of the Technology 255

10.1.2 Monte Carlo Simulation of Bonding/Soldering Process 256

10.1.3 Effect of Matching Fluid 256

10.1.4 Effect of the Encapsulation 258

10.2 Welding of a Pump Laser Module 258

10.2.1 Module Description 258

10.2.2 Module Packaging Process Flow 258

10.2.3 Radiation Heat Transfer Modeling for Hermetic Sealing Process 259

10.2.4 Two-Dimensional FEA Modeling for Hermetic Sealing 260

10.2.5 Cavity Radiation Analyses Results and Discussions 262

10.3 Chapter Summary 264

References 264

11 MEMS and MEMS Package Assembly 267

11.1 A Pressure Sensor Packaging (Deformation and Stress) 267

11.1.1 Piezoresistance in Silicon 268

11.1.2 Finite Element Modeling and Geometry 270

11.1.3 Material Properties 270

11.1.4 Results and Discussion 271

11.2 Mounting of Pressure Sensor 273

11.2.1 Mounting Process 273

11.2.2 Modeling 274

11.2.3 Results 276

11.2.4 Experiments and Discussions 277

11.3 Thermo-Fluid Based Accelerometer Packaging 279

11.3.1 Device Structure and Operation Principle 279

11.3.2 Linearity Analysis 280

11.3.3 Design Consideration 284

11.3.4 Fabrication 285

11.3.5 Experiment 285

11.4 Plastic Packaging for a Capacitance Based Accelerometer 288

11.4.1 Micro-Machined Accelerometer 289

11.4.2 Wafer-Level Packaging 290

11.4.3 Packaging of Capped Accelerometer 296

11.5 Tire Pressure Monitoring System (TPMS) Antenna 303

11.5.1 Test of TPMS System with Wheel Antenna 304

11.5.2 3D Electromagnetic Modeling of Wheel Antenna 306

11.5.3 Stress Modeling of Installed TPMS 307

11.6 Thermo-Fluid Based Gyroscope Packaging 310

11.6.1 Operating Principle and Design 312

11.6.2 Analysis of Angular Acceleration Coupling 313

11.6.3 Numerical Simulation and Analysis 314

11.7 Microjets for Radar and LED Cooling 316

11.7.1 Microjet Array Cooling System 319

11.7.2 Preliminary Experiments 320

11.7.3 Simulation and Model Verification 322

11.7.4 Comparison and Optimization of Three Microjet Devices 324

11.8 Air Flow Sensor 327

11.8.1 Operation Principle 329

11.8.2 Simulation of Flow Conditions 331

11.8.3 Simulation of Temperature Field on the Sensor Chip Surface 333

11.9 Direct Numerical Simulation of Particle Separation by Direct Current Dielectrophoresis 335

11.9.1 Mathematical Model and Implementation 335

11.9.2 Results and Discussion 339

11.10 Modeling of Micro-Machine for Use in Gastrointestinal Endoscopy 341

11.10.1 Methods 343

11.10.2 Results and Discussion 348

11.11 Chapter Summary 353

References 354

12 System in Package (SIP) Assembly 361

12.1 Assembly Process of Side by Side Placed SIP 361

12.1.1 Multiple Die Attach Process 361

12.1.2 Cooling Stress and Warpage Simulation after Molding 365

12.1.3 Stress Simulation in Trim Process 366

12.2 Impact of the Nonlinear Materials Behaviors on the Flip-Chip Packaging Assembly Reliability 369

12.2.1 Finite Element Modeling and Effect of Material Models 371

12.2.2 Experiment 374

12.2.3 Results and Discussions 375

12.3 Stacked Die Flip-Chip Assembly Layout and the Material Selection 381

12.3.1 Finite Element Model for the Stack Die FSBGA 383

12.3.2 Assembly Layout Investigation 385

12.3.3 Material Selection 389

12.4 Chapter Summary 393

References 393

Part III Modeling in Microelectronic Package Reliability and Test 395

13 Wafer Probing Test 397

13.1 Probe Test Model 397

13.2 Parameter Probe Test Modeling Results and Discussions 400

13.2.1 Impact of Probe Tip Geometry Shapes 401

13.2.2 Impact of Contact Friction 403

13.2.3 Impact of Probe Tip Scrub 403

13.3 Comparison Modeling: Probe Test versus Wire Bonding 406

13.4 Design of Experiment (DOE) Study and Correlation of Probing Experiment and FEA Modeling 409

13.5 Chapter Summary 411

References 412

14 Power and Thermal Cycling, Solder Joint Fatigue Life 413

14.1 Die Attach Process and Material Relations 413

14.2 Power Cycling Modeling and Discussion 413

14.3 Thermal Cycling Modeling and Discussion 420

14.4 Methodology of Solder Joint Fatigue Life Prediction 426

14.5 Fatigue Life Prediction of a Stack Die Flip-Chip on Silicon (FSBGA) 427

14.6 Effect of Cleaned and Non-Cleaned Situations on the Reliability of Flip-Chip Packages 434

14.6.1 Finite Element Models for the Clean and Non-Clean Cases 435

14.6.2 Model Evaluation 435

14.6.3 Reliability Study for the Solder Joints 437

14.7 Chapter Summary 438

References 439

15 Passivation Crack Avoidance 441

15.1 Ratcheting-Induced Stable Cracking: A Synopsis 441

15.2 Ratcheting in Metal Films 445

15.3 Cracking in Passivation Films 447

15.4 Design Modifications 452

15.5 Chapter Summary 452

References 452

16 Drop Test 453

16.1 Controlled Pulse Drop Test 453

16.1.1 Simulation Methods 454

16.1.2 Simulation Results 457

16.1.3 Parametric Study 458

16.2 Free Drop 460

16.2.1 Simulated Drop Test Procedure 460

16.2.2 Modeling Results and Discussion 461

16.3 Portable Electronic Devices Drop Test and Simulation 467

16.3.1 Test Set-Up 467

16.3.2 Modeling and Simulation 468

16.3.3 Results 470

16.4 Chapter Summary 470

References 471

17 Electromigration 473

17.1 Basic Migration Formulation and Algorithm 473

17.2 Electromigration Examples from IC Device and Package 477

17.2.1 A Sweat Structure 477

17.2.2 A Flip-Chip CSP with Solder Bumps 480

17.3 Chapter Summary 496

References 497

18 Popcorning in Plastic Packages 499

18.1 Statement of Problem 499

18.2 Analysis 501

18.3 Results and Comparisons 503

18.3.1 Behavior of a Delaminated Package due to Pulsed Heating-Verification 503

18.3.2 Convergence of the Total Strain Energy Release Rate 504

18.3.3 Effect of Delamination Size and Various Processes for a Thick Package 505

18.3.4 Effect of Moisture Expansion Coefficient 514

18.4 Chapter Summary 515

References 516

Part IV Modern Modeling and Simulation Methodologies: Application to Nano Packaging 519

19 Classical Molecular Dynamics 521

19.1 General Description of Molecular Dynamics Method 521

19.2 Mechanism of Carbon Nanotube Welding onto the Metal 522

19.2.1 Computational Methodology 522

19.2.2 Results and Discussion 523

19.3 Applications of Car–Parrinello Molecular Dynamics 530

19.3.1 Car–Parrinello Simulation of Initial Growth Stage of Gallium Nitride on Carbon Nanotube 530

19.3.2 Effects of Mechanical Deformation on Outer Surface Reactivity of Carbon Nanotubes 534

19.3.3 Adsorption Configuration of Magnesium on Wurtzite Gallium Nitride Surface Using First-Principles Calculations 539

19.4 Nano-Welding by RF Heating 544

19.5 Chapter Summary 548

References 548

Index 553