Volume I
List of Contributors ........................................ xxvii
Preface ...................................................... xxxi
Materials Physics
Chapter 1
Polymer Materials Characterization, Modeling and
Application
L.J. Ernst, K.M.B. Jansen, D.G. Yang, C. van't Hof,
H.J.L. Bres and G.Q. Zhang ................................... 3
1.1. Introduction .............................................. 3
1.2. Polymers in Microelectronics .............................. 4
1.3. Basics of Visco-Elastic Modeling .......................... 6
1.3.1. Preliminary: State Dependent Viscoelasticity ...... 6
1.3.2. Incremental Relationship ......................... 10
1.3.3. Linear State Dependent Viscoelasticity ........... 13
1.3.4. Isotropic Material Behavior ...................... 14
1.3.5. Interrelations between Property Functions ........ 15
1.3.6. Elastic Approximations ........................... 17
1.4. Linear Visco-Elastic Modeling (Fully Cured Polymers) ..... 18
1.4.1. Introduction ..................................... 18
1.4.2. Static Testing of Relaxation Moduli .............. 18
1.4.3. Time-Temperature Superposition Principle ......... 23
1.4.4. Static Testing of Creep Compliances .............. 24
1.4.5. Dynamic Testing .................................. 27
1.5. Modeling of Curing Polymers .............................. 34
1.5.1. "Partly State Dependent" Modeling
(Curing Polymers) ................................ 35
1.5.2. "Fully State Dependent" Modeling
(Curing Polymers) ................................ 49
1.6. Parameterized Polymer Modeling (PPM) ..................... 53
1.6.1. PPM Hypotheses ................................... 54
1.6.2. Experimental Characterizations ................... 55
1.6.3. PPM Modeling in Virtual Prototyping .............. 62
Acknowledgments ................................................ 62
References ..................................................... 62
Chapter 2
Thermo-Optic Effects in Polymer Bragg Gratings
Avram Bar-Cohen, Bongtae Han and Kyoung Joon Kim ............ 65
2.1. Introduction ............................................. 65
2.2. Fundamentals of Bragg Gratings ........................... 67
2.2.1. Physical Descriptions ............................ 67
2.2.2. Basic Optical Principles ......................... 68
2.3. Thermo-Optical Modeling of Polymer Fiber Bragg Grating ... 70
2.3.1. Heat Generation by Intrinsic Absorption .......... 70
2.3.2. Analytical Thermal Model of PFBG ................. 78
2.3.3. FEA Thermal Model of PFBG ........................ 80
2.3.4. Thermo-Optical Model of PFBG ..................... 80
2.4. Thermo-Optical Behavior of PMMA-Based PFBG ............... 84
2.4.1. Description of a PMMA-Based PFBG and
Light Sources .................................... 85
2.4.2. Power Variation Along the PFBG ................... 86
2.4.3. Thermo-Optical Behavior of the PFBG-LED
Illumination ..................................... 87
2.4.4. Thermo-Optical Behavior of the PFBG-SM LD
Illumination ..................................... 92
2.4.5. Thermo-Optical Behavior of the PFBG Associated
with Other Light Sources ........................ 101
2.5. Concluding Remarks ...................................... 102
References .................................................... 102
Appendix 2.A: Solution Procedure to Obtain the Optical
Power Along the PFBG ............................ 104
Appendix 2.B: Solution Procedure to Determine the
Temperature Profile Along the PFBG .............. 106
2.В.1. Solution Procedure of the Temperature
Profile Along the PFBG with the LED ........... 106
2.B.2. Solution Procedure of the Temperature
Profile Along the PFBG with the SM LD ......... 106
Chapter 3
Photorefractive Materials and Devices for Passive Components
in WDM Systems
Claire Gu, Yisi Liu, Yuan Xu, J.J. Pan, Fengqing Zhou,
Liang Dong and Henry He .................................... 111
3.1. Introduction ............................................ 111
3.2. Tunable Flat-Topped Filter .............................. 114
3.2.1. Principle of Operation .......................... 114
3.2.2. Device Simulation ............................... 116
3.2.3. Design for Implementation ....................... 117
3.3. Wavelength Selective 2 x 2 Switch ....................... 117
3.3.1. Principle of Operation .......................... 118
3.3.2. Experimental Demonstration ...................... 119
3.3.3. Theoretical Analysis ............................ 121
3.3.4. Optimized Switch Design ......................... 123
3.3.5. Discussion ...................................... 125
3.4. High Performance Dispersion Compensators ................ 126
3.4.1. Multi-Channel Dispersion-Slope Compensator ...... 126
3.4.2. High Precision FBG Fabrication Method and
Dispersion Management Filters ................... 129
3.5. Conclusions ............................................. 133
References .................................................... 133
Chapter 4
Thin Films for Microelectronics and Photonics: Physics,
Mechanics, Characterization, and Reliability
David T. Read and Alex A. Volinsky ......................... 135
4.1. Terminology and Scope ................................... 135
4.1.1. Thin Films ...................................... 135
4.1.2. Motivation ...................................... 136
4.1.3. Chapter Outline ................................. 136
4.2. Thin Film Structures and Materials ...................... 137
4.2.1. Substrates ...................................... 137
4.2.2. Epitaxial Films ................................. 137
4.2.3. Dielectric Films ................................ 140
4.2.4. Metal Films ..................................... 141
4.2.5. Organic and Polymer Films ....................... 142
4.2.6. MEMS Structures ................................. 142
4.2.7. Intermediate Layers: Adhesion, Barrier,
Buffer, and Seed Layers ......................... 142
4.3. Manufacturability/Reliability Challenges ................ 143
4.3.1. Film Deposition and Stress ...................... 144
4.3.2. Grain Structure and Texture ..................... 147
4.3.3. Impurities ...................................... 151
4.3.4. Dislocations .................................... 152
4.3.5. Electromigration and Voiding .................... 153
4.3.6. Structural Considerations ....................... 155
4.3.7. Need for Mechanical Characterization ............ 155
4.3.8. Properties of Interest .......................... 156
4.4. Methods for mechanical characterization of thin films ... 157
4.4.1. Microtensile Testing ............................ 157
4.4.2. Instrumented Indentation ........................ 159
4.4.3. Other Techniques ................................ 164
4.4.4. Adhesion Tests .................................. 165
4.5. Materials and Properties ................................ 172
4.5.1. Grain Size and Structure Size Effects ........... 172
4.6. Properties of Specific Materials ........................ 173
4.7. Future Research ......................................... 175
4.7.1. Techniques ...................................... 175
4.7.2. Properties ...................................... 175
4.7.3. Length Scale .................................... 175
References .................................................... 176
Chapter 5
Carbon Nanotube Based Interconnect Technology: Opportunities
and Challenges
Alan M. Cassell and Jun Li ................................. 181
5.1. Introduction: Physical Characteristics of Carbon
Nanotubes ............................................... 181
5.1.1. Structural ...................................... 181
5.1.2. Electrical ...................................... 182
5.1.3. Mechanical ...................................... 185
5.1.4. Thermal ......................................... 186
5.2. CNT Fabrication Technologies ............................ 186
5.2.1. Chemical Vapor Deposition of Carbon Nanotubes ... 187
5.2.2. Process Integration and Development ............. 189
5.3. Carbon Nanotubes as Interconnects ....................... 191
5.3.1. Limitations of the Current Technology ........... 191
5.3.2. Architecture, Geometry and Performance
Potential Using Carbon Nanotubes ................ 191
5.4. Design, Manufacture and Reliability ..................... 194
5.4.1. Microstructural Attributes and Effects on
Electrical Characteristics ...................... 194
5.4.2. Interfacial Contact Materials ................... 196
5.4.3. End-contacted Metal-CNT Junction ................ 198
5.4.4. Thermal Stress Characteristics .................. 198
5.4.5. Reliability Test ................................ 199
5.5. Summary ................................................. 200
References .................................................... 200
Chapter 6
Virtual Thermo-Mechanical Prototyping of Microelectronics
and Microsystems
A. Wymyslowski, G.Q. Zhang, W.D. van Driel and
L.J. Ernst ................................................. 205
6.1. Introduction ............................................ 205
6.2. Physical Aspects for Numerical Simulations .............. 206
6.2.1. Numerical Modeling .............................. 208
6.2.2. Material Properties and Models .................. 211
6.2.3. Thermo-Mechanical Related Failures .............. 215
6.2.4. Designing for Reliability ....................... 219
6.3. Mathematical Aspects of Optimization .................... 225
6.3.1. Design of Experiments ........................... 226
6.3.2. Response Surface Modeling ....................... 236
6.3.3. Advanced Approach to Virtual Prototyping ........ 242
6.3.4. Designing for Quality ........................... 249
6.4. Application Case ........................................ 252
6.4.1. Problem Description ............................. 252
6.4.2. Numerical Approach to QFN Package Design ........ 253
6.5. Conclusion and Challenges ............................... 259
6.6. List of Acronyms ........................................ 264
Acknowledgments ............................................... 264
References .................................................... 264
Chapter 7
Fiber Optics Structural Mechanics and Nano-Technology Based
New Generation of Fiber Coatings: Review and Extension
E. Suhir ................................................... 269
7.1. Introduction ............................................ 269
7.2. Fiber Optics Structural Mechanics ....................... 270
7.2.1. Review .......................................... 270
7.3. New Nano-Particle Material (NPM) for Micro- and
Opto-Electronic Applications ............................ 273
7.3.1. New Nano-Particle Material (NPM) ................ 273
7.3.2. NPM-Based Optical Silica Fibers ................. 274
7.4. Conclusions ............................................. 277
Acknowledgment ................................................ 277
References .................................................... 277
Chapter 8
Area Array Technology for High Reliability Applications
Reza Ghaffarian ............................................ 283
8.1. Introduction ............................................ 283
8.2. Area Array Packages (AAPs) .............................. 284
8.2.1. Advantages of Area Array Packages ............... 285
8.2.2. Disadvantages of Area Arrays .................... 285
8.2.3. Area Array Types ................................ 286
8.3. Chip Scale Packages (CSPs) .............................. 286
8.4. Plastic Packages ........................................ 288
8.4.1. Background ...................................... 288
8.4.2. Plastic Area Array Packages ..................... 288
8.4.3. Plastic Package Assembly Reliability ............ 289
8.4.4. Reliability Data for BGA, Flip Chip BGA,
and CSP ......................................... 291
8.5. Ceramic Packages ........................................ 293
8.5.1. Background ...................................... 293
8.5.2. Ceramic Package Assembly Reliability ............ 294
8.5.3. Literature Survey on CBGA/CCGA Assembly
Reliability ..................................... 295
8.5.4. CBGA Thermal Cycle Test ......................... 297
8.5.5. Comparison of 560 I/O PBGA and CCGA assembly
reliability ..................................... 302
8.5.6. Designed Experiment for Assembly ................ 305
8.6. Summary ................................................. 309
8.7. List of Acronyms and Symbols ............................ 310
Acknowledgments ............................................... 311
References .................................................... 311
Chapter 9
Metallurgical Factors Behind the Reliability of High-Density
Lead-Free Interconnections
Toni T. Mattila, Tomi T. Laurila and Jorma K. Kivilahti .... 313
9.1. Introduction ............................................ 313
9.2. Approaches and Methods .................................. 315
9.2.1. The Four Steps of The Iterative Approach ........ 315
9.2.2. The Role of Different Simulation Tools in
Reliability Engineering ......................... 321
9.3. Interconnection Microstructures and Their Evolution ..... 324
9.3.1. Solidification .................................. 324
9.3.2. Solidification Structure and the Effect of
Contact Metalization Dissolution ................ 325
9.3.3. Interfacial Reactions Products .................. 330
9.3.4. Deformation Structures (Due to Slip and
Twinning) ....................................... 333
9.3.5. Recovery, Recrystallization and Grain Growth .... 335
9.4. Two Case Studies on Reliability Testing ................. 335
9.4.1. Case 1: Reliability of Lead-Free CSPs in
Thermal cycling ................................. 337
9.4.2. Case 2: Reliability of Lead-Free CSPs in Drop
Testing ......................................... 341
9.5. Summary ................................................. 347
Acknowledgments ............................................... 348
References .................................................... 348
Chapter 10
Metallurgy, Processing and Reliability of Lead-Free Solder
Joint Interconnections
Jin Liang, Nader Dariavach, and Dongkai Shangguan .......... 351
10.1. Introduction ............................................ 351
10.2. Physical Metallurgy of Lead-Free Solder Alloys .......... 352
10.2.1. Tin-Lead Solders ................................ 352
10.2.2. Lead-Free Solder Alloys ......................... 353
10.2.3. Interfacial Reaction: Wetting and Spreading ..... 357
10.2.4. Interfacial Intermetallic Formation and Growth
at Liquid-Solid Interfaces ...................... 363
10.3. Lead-Free Soldering Processes and Compatibility ......... 377
10.3.1. Lead-Free Soldering Materials ................... 378
10.3.2. PCB Substrates and Metalization Finishes ........ 380
10.3.3. Lead-Free Soldering Processes ................... 381
10.3.4. Components for Lead-Free Soldering .............. 384
10.3.5. Design, Equipment and Cost Considerations ....... 387
10.4. Reliability of Pb-Free Solder Interconnects 388
10.4.1. Reliability and Failure Distribution of
Pb-Free Solder Joints ........................... 388
10.4.2. Effects of Loading and Thermal Conditions on
Reliability of Solder Interconnection ........... 389
10.4.3. Reliability of Pb-Free Solder Joints in
Comparison to Sn-Pb Eutectic Solder Joints ...... 395
10.5. Guidelines for Pb-free Soldering and Improvement in
Reliability ............................................. 406
References .................................................... 406
Chapter 11
Fatigue Life Assessment for Lead-Free Solder Joints
Masaki Shiratori and Qiang Yu .............................. 411
11.1. Introduction ............................................ 411
11.2. The Intermetallic Compound Formed at the Interface of
the Solder Joints and the Cu-pad ........................ 412
11.3. Mechanical Fatigue Testing Equipment and Load
Condition in the Lead Free Solder ....................... 413
11.4. Results of Mechanical Fatigue Test ...................... 414
11.5. Critical Fatigue Stress Limit for the Intermetallic
Compound Layer .......................................... 417
11.6. Influence of the Plating Material on the Fatigue Life
of Sn-Zn (Sn-9Zn and Sn-8Zn-3Bi) Solder Joints .......... 424
11.7. Conclusion .............................................. 426
References .................................................... 426
Chapter 12
Lead-Free Solder Materials: Design For Reliability
John H.L. Pang ............................................. 429
12.1. Introduction ............................................ 429
12.2. Mechanics of Solder Materials ........................... 430
12.2.1. Fatigue Behavior of Solder Materials ............ 431
12.3. Design For Reliability (DFR) ............................ 433
12.4. Constitutive Models For Lead Free Solders ............... 435
12.4.1. Tensile Test Results ............................ 435
12.4.2. Creep Test Results .............................. 440
12.5. Low Cycle Fatigue Models ................................ 443
12.6. FEA Modeling and Simulation ............................. 448
12.7. Reliability Test and Analysis ........................... 454
12.8. Conclusions ............................................. 456
Acknowledgments ............................................... 456
References .................................................... 456
Chapter 13
Application of Moire Interferometry to Strain Analysis of
PCB Deformations at Low Temperatures
Arkady Voloshin ............................................ 459
13.1. Introduction ............................................ 459
13.2. Optical Method and Recording of Fringe Patterns ......... 460
13.2.1. Fractional Fringe Approach ...................... 461
13.2.2. Grating Frequency Increase ...................... 461
13.2.3. Creation of a High-Frequency Master Grating ..... 462
13.2.4. Combination of the High Grating Frequency and
Fractional Fringe Approach ...................... 463
13.3. Data Processing ......................................... 463
13.4. Test Boards and Specimen Grating ........................ 463
13.5. Elevated Temperature Test ............................... 465
13.6. Low Temperature Test .................................... 468
13.7. Conclusions ............................................. 470
Acknowledgment ................................................ 472
References .................................................... 473
Chapter 14
Characterization of Stresses and Strains in Microelectronics
and Photonics Devices Using Photomechanics Methods
Bongtae Han ................................................ 475
14.1. Introduction ............................................ 475
14.2. Stress/Strain analysis .................................. 476
14.2.1. Moire Interferometry ............................ 476
14.2.2. Extension: Microscopic Moire Interferometry ..... 477
14.2.3. Specimen Gratings ............................... 479
14.2.4. Strain Analysis ................................. 480
14.2.5. Thermal Deformation Measured at Room
Temperature ..................................... 481
14.2.6. Deformation as a Function of Temperature ........ 485
14.2.7. Hygroscopic Deformation ......................... 494
14.2.8. Micromechanics .................................. 501
14.3. Warpage Analysis ........................................ 505
14.3.1. Twyman/Green Interferometry ..................... 505
14.3.2. Shadow Moire .................................... 509
14.3.3. Far Infrared Fizeau Interferometry .............. 514
Acknowledgment ................................................ 520
References .................................................... 520
Chapter 15
Analysis of Reliability of 1С Packages Using the Fracture
Mechanics Approach
Andrew A.O. Tay ............................................ 523
15.1. Introduction ............................................ 523
15.2. Heat Transfer and Moisture Diffusion in 1С Packages ..... 525
15.3. Fundamentals of Interfacial Fracture Mechanics .......... 527
15.4. Criterion for Crack Propagation ......................... 529
15.5. Interface Fracture Toughness ............................ 529
15.6. Total Stress Intensity Factor ........................... 530
15.7. Calculation of SERR and Mode Mixity ..................... 531
15.7.1. Crack Surface Displacement Extrapolation
Method .......................................... 531
15.7.2. Modified J-integral Method ...................... 532
15.7.3. Modified Virtual Crack Closure Method ........... 533
15.7.4. Variable Order Boundary Element Method .......... 536
15.7.5. Interaction Integral Method ..................... 536
15.8. Experimental Verification ............................... 538
15.9. Case Studies ............................................ 542
15.9.1. Delamination Along Pad-Encapsulant Interface .... 542
15.9.2. Delamination Along Die-Attach/Pad Interface ..... 544
15.9.3. Analysis Using Variable Order Boundary
Element Method .................................. 546
15.10.Discussion of the Various Numerical Methods for
Calculating G and ψ ..................................... 549
15.11.Conclusion .............................................. 551
References .................................................... 551
Chapter 16
Dynamic Response of Micro- and Opto-Electronic Systems to
Shocks and Vibrations: Review and Extension
E. Suhir ................................................... 555
16.1. Introduction ............................................ 555
16.2. Review .................................................. 556
16.3. Extension: Quality of Shock Protection with a Flexible
Wire Elements ........................................... 557
16.4. Analysis ................................................ 558
16.4.1. Pre-Buckling Mode: Small Displacements .......... 558
16.4.2. Post-Buckling Mode: Large Displacements ......... 564
16.5. Conclusions ............................................. 567
References .................................................... 568
Chapter 17
Dynamic Physical Reliability in Application to Photonic
Materials
Dov Ingman, Tatiana Mirer and Ephraim Suhir ................ 571
17.1. Introduction: Dynamic Reliability Approach to the
Evolution of Silica Fiber Performance ................... 571
17.1.1. Dynamic Physical Model of Damage Accumulation ... 572
17.1.2. Impact of the Three-Dimensional Mechanical-
Temperature-Humidity Load on the Optical Fiber
Reliability ..................................... 575
17.1.3. Effect of Bimodality and Its Explanation Based
on the Suggested Model .......................... 576
17.2. Reliability Improvement through NPM-Based Fiber
Structures .............................................. 585
17.2.1. Environmental Protection by NPM-Based Coating
and Overall Self-Curing Effect of NPM Layers ... 585
17.2.2. Improvement in the Reliability Characteristics
by Employing NPM Structures in Optical
Fibers .......................................... 587
17.3. Conclusions ............................................. 593
References .................................................... 593
Chapter 18
High-Speed Tensile Testing of Optical Fibers—New
Understanding for Reliability Prediction
Sergey Semjonov and G. Scott Glaesemann .................... 595
18.1. Introduction ............................................ 595
18.2. Theory .................................................. 596
18.2.1. Single-Region Power-Law Model ................... 596
18.2.2. Two-Region Power-Law Model ...................... 598
18.2.3. Universal Static and Dynamic Fatigue Curves ..... 599
18.3. Experimental ............................................ 602
18.3.1. Sample Preparation .............................. 602
18.3.2. Dynamic Fatigue Tests ........................... 604
18.3.3. Static Fatigue Tests ............................ 605
18.4. Results and Discussion .................................. 606
18.4.1. High-Speed Testing .............................. 606
18.4.2. Static Fatigue .................................. 610
18.4.3. Influence of Multiregion Model on Lifetime
Prediction ...................................... 613
18.5. Conclusion .............................................. 613
References .................................................... 614
Appendix 18.A: High Speed Axial Strength Testing:
Measurement Limits ............................................ 616
Appendix 18.B: Incorporating Static Fatigue Results into
Dynamic Fatigue Curves ........................................ 620
18.B.1. Static Fatigue Test ............................. 620
18.B.2. Dynamic Fatigue Test ............................ 621
18.B.3. Discussion ...................................... 622
Chapter 19
The Effect of Temperature on the Microstructure Nonlinear
Dynamics Behavior
Xiaoling He ................................................ 627
19.1. Introduction ............................................ 627
19.2. Theoretical Development ................................. 630
19.2.1. Background on Nonlinear Dynamics and Nonlinear
Thermo-Elasticity Theories ...................... 630
19.2.2. Nonlinear Thermo-Elasticity Development for
an Isotropic Laminate Subject to Thermal
and Mechanical and Load ......................... 631
19.3. Thin Laminate Deflection Response Subject to Thermal
Effect and Mechanical Load .............................. 633
19.3.1. Steady State Temperature Effect ................. 633
19.3.2. Transient Thermal Field Effect .................. 638
19.4. Stress Field in Nonlinear Dynamics Response ............. 653
19.4.1. Stress Field Formulation ........................ 653
19.4.2. Stress Distribution ............................. 654
19.4.3. Failure Analysis ................................ 654
19.5. Discussions ............................................. 660
19.6. Summary ................................................. 661
Nomenclature .................................................. 662
Acknowledgment ................................................ 663
References .................................................... 663
Chapter 20
Effect of Material's Nonlinearity on the Mechanical Response
of some Piezoelectric and Photonic Systems
Victor Birman and Ephraim Suhir ............................ 667
20.1. Introduction ............................................ 667
20.2. Effect of Physical Nonlinearity on Vibrations of
Piezoelectric Rods Driven by Alternating Electric
Field ................................................... 668
20.2.1. Physically Nonlinear Constitutive
Relationships for an Orthotropic Cylindrical
Piezoelectric Rod Subject to an Electric Field
in the Axial Direction .......................... 670
20.2.2. Analysis of Uncoupled Axial Vibrations .......... 673
20.2.3. Solution for Coupled Axial-Radial Axisymmetric
Vibrations by the Generalized Galerkin
Procedure ....................................... 677
20.2.4. Numerical Results and Discussion ................ 678
20.3. The Effect of the Nonlinear Stress-Strain Relationship
on the Response of Optical Fibers ....................... 683
20.3.1. Stability of Optical Fibers ..................... 684
20.3.2. Stresses and Strains in a Lightwave Coupler
Subjected to Tension ............................ 686
20.3.3. Free Vibrations ................................. 690
20.3.4. Bending of an Optical Fiber ..................... 692
20.4. Conclusions ............................................. 695
Acknowledgment ................................................ 696
References .................................................... 697
Index ......................................................... 701
Volume II
List of Contributors ........................................ xxvii
Preface ...................................................... xxxi
Physical Design
Chapter 1
Analytical Thermal Stress Modeling in Physical Design for
Reliability of Micro- and Opto-Electronic Systems: Role,
Attributes, Challenges, Results
E. Suhir ..................................................... 3
1.1. Thermal Loading and Thermal Stress Failures ............... 3
1.2. Thermal Stress Modeling ................................... 4
1.3. Bi-Metal Thermostats and other Bi-Material Assemblies ..... 5
1.4. Finite-Element Analysis ................................... 5
1.5. Die-Substrate and other Bi-Material Assemblies ............ 6
1.6. Solder Joints ............................................. 8
1.7. Design Recommendations .................................... 9
1.8. "Global" and "Local" Mismatch and Assemblies Bonded at
the Ends ................................................. 10
1.9. Assemblies with Low Modulus Adhesive Layer at the Ends ... 11
1.10. Thermally Matched Assemblies ............................. 11
1.11. Thin Films ............................................... 12
1.12. Polymeric Materials And Plastic Packages ................. 13
1.13. Thermal Stress Induced Bowing and Bow-Free Assemblies .... 14
1.14. Probabilistic Approach ................................... 15
1.15. Optical Fibers and other Photonic Structures ............. 15
1.16. Conclusion ............................................... 16
References ..................................................... 17
Chapter 2
Probabilistic Physical Design of Fiber-Optic Structures
Satish Radhakrishnan, Ganesh Subbarayan and Luu Nguyen ...... 23
2.1. Introduction ............................................. 23
2.1.1. Demonstration Vehicle ............................. 24
2.2. Optical Model ............................................ 25
2.2.1. Mode Field Diameter .............................. 26
2.2.2. Refraction and Reflection Losses ................. 27
2.2.3. Calculations for Coupling Losses ................. 27
2.2.4. Coupling Efficiency .............................. 28
2.3. Interactions in System and Identification of Critical
Variables ................................................ 30
2.3.1. Function Variable Incidence Matrix ............... 30
2.3.2. Function Variable Incidence Matrix to Graph
Conversion ....................................... 31
2.3.3. Graph Partitioning Techniques .................... 34
2.3.4. System Decomposition using Simulated Annealing ... 34
2.4. Deterministic Design Procedures .......................... 37
2.4.1. Optimal and Robust Design ........................ 40
2.4.2. A Brief Review of Multi-Objective Optimization ... 42
2.4.3. Implementation ................................... 43
2.4.4. Results .......................................... 43
2.5. Stochastic Analysis ...................................... 44
2.5.1. The First and Second Order Second Moment
Methods ........................................... 44
2.6. Probabilistic Design for Maximum Reliability ............. 46
2.6.1. Results ........................................... 49
2.7. Stochastic Characterization of Epoxy Behavior ............ 51
2.7.1. Viscoelastic Models .............................. 52
2.7.2. Modeling the Creep Test .......................... 53
2.7.3. Dynamic Mechanical Analysis ...................... 54
2.7.4. Experimental Results ............................. 55
2.8. Analytical Model to Determine VCSEL Displacement ......... 57
2.8.1. Results ........................................... 63
2.9. Summary .................................................. 67
References ..................................................... 67
Chapter 3
The Wirebonded Interconnect: A Mainstay for Electronics
Harry K. Charles, jr. ....................................... 71
3.1. Introduction ............................................. 71
3.1.1. Integrated Circuit Revolution .................... 71
3.1.2. Interconnection Types ............................ 72
3.1.3. Wirebond Importance .............................. 80
3.2. Wirebonding Basics ....................................... 81
3.2.1. Thermocompression Bonding ........................ 81
3.2.2. Ultrasonic Bonding ............................... 83
3.2.3. Thermosonic Bonding .............................. 85
3.2.4. Wirebond Reliability ............................. 87
3.2.5. Wirebond Testing ................................. 89
3.2.6. Bonding Automation and Optimization .............. 93
3.3. Materials ................................................ 95
3.3.1. Bonding Wire ..................................... 95
3.3.2. Bond Pad Metallurgy ............................. 100
3.3.3. Gold Plating .................................... 102
3.3.4. Pad Cleaning .................................... 104
3.4. Advanced Bonding Methods ................................ 105
3.4.1. Fine Pitch Bonding .............................. 105
3.4.2. Soft Substrates ................................. 108
3.4.3. Machine Improvements ............................ 110
3.4.4. Higher Frequency Wirebonding .................... 110
3.4.5. Stud Bumping .................................... 115
3.5. Summary ................................................. 116
Acknowledgments ............................................... 116
References .................................................... 116
Chapter 4
Metallurgical Interconnections for Extreme High and Low
Temperature Environments
George G. Harman ........................................... 121
4.1. Introduction ............................................ 121
4.2. High Temperature Interconnections Requirements .......... 122
4.2.1. Wire Bonding .................................... 122
4.2.2. The Use of Flip Chips in HTE .................... 127
4.2.3. General Overview of Metallurgical Interfaces
for Both HTE and LTE ............................ 129
4.3. Low Temperature Environment Interconnection
Requirements ............................................ 129
4.4. Corrosion and Other Problems in Both HTE, and LTE ....... 130
4.5. The Potential Use of High Temperature Polymers in HTE ... 131
4.6. Conclusions ............................................. 132
Acknowledgments ............................................... 132
References .................................................... 132
Chapter 5
Design, Process, and Reliability of Wafer Level Packaging
Zhuqing Zhang and C.P. Wong ................................ 135
5.1. Introduction ............................................ 135
5.2. WLCSP ................................................... 137
5.2.1. Thin Film Redistribution ........................ 137
5.2.2. Encapsulated Package ............................ 139
5.2.3. Compliant Interconnect .......................... 139
5.3. Wafer Level Underfill ................................... 141
5.3.1. Challenges of Wafer Level Underfill ............. 142
5.3.2. Examples of Wafer Level Underfill Process ....... 143
5.4. Comparison of Flip-Chip and WLCSP ....................... 145
5.5. Wafer Level Test and Burn-In ............................ 145
5.6. Summary ................................................. 149
References .................................................... 149
Chapter 6
Passive Alignment of Optical Fibers in V-grooves with
Low Viscosity Epoxy Flow
S.W. Ricky Lee and C.C. Lo ................................. 151
6.1. Introduction ............................................ 151
6.2. Design and Fabrication of Silicon Optical Bench with
V-grooves ............................................... 152
6.3. Issues of Conventional Passive Alignment Methods ........ 158
6.3.1. V-grooves with Cover Plate ...................... 158
6.3.2. Edge Dispensing of Epoxy ........................ 161
6.4. Modified Passive Alignment Method ....................... 162
6.4.1. Working Principle ............................... 162
6.4.2. Alignment Mechanism ............................. 163
6.4.3. Design of Experiment ............................ 164
6.4.4. Experimental Procedures ......................... 164
6.4.5. Experimental Results ............................ 165
6.5. Effects of Epoxy Viscosity and Dispensing Volume ........ 168
6.6. Application to Fiber Array Passive Alignment ............ 170
6.7. Conclusions and Discussion .............................. 172
References .................................................... 172
Reliability and Packaging
Chapter 7
Fundamentals of Reliability and Stress Testing
H. Anthony Chan ............................................ 177
7.1. More Performance at Lower Cost in Shorter
Time-to-market .......................................... 178
7.1.1. Rapid Technological Developments ................ 178
7.1.2. Integration of More Products into Human Life .... 178
7.1.3. Diverse Environmental Stresses .................. 178
7.1.4. Competitive Market .............................. 179
7.1.5. Short Product Cycles ............................ 179
7.1.6. The Bottom Line ................................. 179
7.2. Measure of Reliability .................................. 180
7.2.1. Failure Rate .................................... 180
7.2.2. Systems with Multiple Independent Failure
Modes ........................................... 181
7.2.3. Failure Rate Distribution ....................... 182
7.3. Failure Mechanisms in Electronics and Packaging ......... 184
7.3.1. Failure Mechanisms at Chip Level Include ........ 184
7.3.2. Failure Mechanisms at Bonding Include ........... 184
7.3.3. Failure Mechanisms in Device Packages Include ... 185
7.3.4. Failure Mechanisms in Epoxy Compounds Include ... 185
7.3.5. Failure Mechanisms at Shelf Level Include ....... 185
7.3.6. Failure Mechanisms in Material Handling
Include ......................................... 185
7.3.7. Failure Mechanisms in Fiber Optics Include ...... 185
7.3.8. Failure Mechanisms in Flat Panel Displays
Include ......................................... 186
7.4. Reliability Programs and Strategies ..................... 186
7.5. Product Weaknesses and Stress Testing ................... 187
7.5.1. Why do Products Fail? ........................... 187
7.5.2. Stress Testing Principle ........................ 189
7.6. Stress Testing Formulation .............................. 191
7.6.1. Threshold and Cumulative Stress Failures ........ 191
7.6.2. Stress Stimuli and Flaws ........................ 192
7.6.3. Modes of Stress Testing ......................... 193
7.6.4. Lifetime Failure Fraction ....................... 194
7.6.5. Robustness Against Maximum Service Life
Stress .......................................... 195
7.6.6. Stress-Strength Contour ......................... 197
7.6.7. Common Issues ................................... 198
7.7. Further Reading ......................................... 201
Chapter 8
How to Make a Device into a Product: Accelerated Life
Testing (ALT), Its Role, Attributes, Challenges, Pitfalls,
and Interaction with Qualification Tests
E. Suhir ................................................... 203
8.1. Introduction ............................................ 203
8.2. Some Major Definitions .................................. 204
8.3. Engineering Reliability ................................. 204
8.4. Field Failures .......................................... 205
8.5. Reliability is a Complex Property ....................... 206
8.6. Three Major Classes of Engineering Products and Market
Demands ................................................. 206
8.7. Reliability, Cost and Time-to-Market .................... 208
8.8. Reliability Costs Money ................................. 208
8.9. Reliability Should Be Taken Care of on a Permanent
Basis ................................................... 209
8.10. Ways to Prevent and Accommodate Failures ................ 210
8.11. Redundancy .............................................. 211
8.12. Maintenance and Warranty ................................ 211
8.13. Test Types .............................................. 212
8.14. Accelerated Tests ....................................... 212
8.15. Accelerated Test Levels ................................. 213
8.16. Qualification Standards ................................. 213
8.17. Accelerated Life Tests (ALTs) ........................... 214
8.18. Accelerated Test Conditions ............................. 215
8.19. Acceleration Factor ..................................... 216
8.20. Accelerated Stress Categories ........................... 217
8.21. Accelerated Life Tests (ALTs) and Highly Accelerated
Life Tests (HALTs) ...................................... 218
8.22. Failure Mechanisms and Accelerated Stresses ............. 219
8.23. ALTs: Pitfalls and Challenges ........................... 219
8.24. Burn-ins ................................................ 220
8.25. Wear-Out Failures ....................................... 221
8.26. Non-Destructive Evaluations (NDE's) ..................... 222
8.27. Predictive Modeling ..................................... 222
8.28. Some Accelerated Life Test (ALT) Models ................. 223
8.28.1. Power Law ....................................... 224
8.28.2. Boltzmann-Arrhenius Equation .................... 224
8.28.3. Coffin-Manson Equation (Inverse Power Law) ...... 225
8.28.4. Paris-Erdogan Equation .......................... 226
8.28.5. Bueche-Zhurkov Equation ......................... 227
8.28.6. Eyring Equation ................................. 227
8.28.7. Peck and Black Equations ........................ 227
8.28.8. Fatigue Damage Model (Miner's Rule) ............. 228
8.28.9. Creep Rate Equations ............................ 228
8.28.10.Weakest Link Models ............................. 228
8.28.11.Stress-Strength Models .......................... 229
8.29. Probability of Failure .................................. 229
8.30. Conclusions ............................................. 230
References .................................................... 230
Chapter 9
Micro-Deformation Analysis and Reliability Estimation of
MicroComponents by Means of NanoDAC Technique
Bernd Michel and Jüirgen Keller ............................ 233
9.1. Introduction ............................................ 233
9.2. Basics of Digital Image Correlation ..................... 234
9.2.1. Cross Correlation Algorithms on Gray Scale
Images .......................................... 234
9.2.2. Subpixel Analysis for Enhanced Resolution ....... 236
9.2.3. Results of Digital Image Correlation ............ 238
9.3. Displacement and Strain Measurements on SFM Images ...... 239
9.3.1. Digital Image Correlation under SPM
Conditions ...................................... 239
9.3.2. Technical Requirements for the Application
of the Correlation Technique .................... 241
9.4. Deformation Analysis on Thermally and Mechanically
Loaded Objects under the SFM ............................ 241
9.4.1. Reliability Aspects of Sensors and Micro
Electro-Mechanical Systems (MEMS) ............... 241
9.4.2. Thermally Loaded Gas Sensor under SFM ........... 242
9.4.3. Crack Detection and Evaluation by SFM ........... 243
9.5. Conclusion and Outlook .................................. 250
References .................................................... 250
Chapter 10
Interconnect Reliability Considerations in Portable
Consumer Electronic Products
Sridhar Canumalla and Puligandla Viswanadham ............... 253
10.1. Introduction ............................................ 253
10.2. Reliability—Thermal, Mechanical and Electrochemical ..... 255
10.2.1. Accelerated Life Testing ........................ 255
10.2.2. Thermal Environment ............................. 257
10.2.3. Mechanical Environment .......................... 257
10.2.4. Electrochemical Environment ..................... 264
10.2.5. Tin Whiskers .................................... 267
10.3. Reliability Comparisons in Literature ................... 267
10.3.1. Thermomechanical Reliability .................... 268
10.3.2. Mechanical Reliability .......................... 270
10.4. Influence of Material Properties on Reliability ......... 271
10.4.1. Printed Wiring Board ............................ 271
10.4.2. Package ......................................... 272
10.4.3. Surface Finish .................................. 272
10.5. Failure Mechanisms ...................................... 273
10.5.1. Thermal Environment ............................. 273
10.5.2. Mechanical Environment .......................... 276
10.5.3. Electrochemical Environment ..................... 286
10.6. Reliability test Practices .............................. 291
10.7. Summary ................................................. 294
Acknowledgments ............................................... 295
References .................................................... 295
Chapter 11
MEMS Packaging and Reliability
Y.C. Lee ................................................... 299
11.1. Introduction ............................................ 299
11.2. Flip-Chip Assembly for Hybrid Integration ............... 304
11.3. Soldered Assembly for Three-Dimensional MEMS ............ 309
11.4. Flexible Circuit Boards for MEMS ........................ 313
11.5. Atomic Layer Deposition for Reliable MEMS ............... 316
11.6. Conclusions ............................................. 320
Acknowledgments ............................................... 320
References .................................................... 320
Chapter 12
Advances in Optoelectronic Methodology for MOEMS Testing
Ryszard J. Pryputniewicz ................................... 323
12.1. Introduction ............................................ 323
12.2. MOEMS Samples ........................................... 324
12.3. Analysis ................................................ 328
12.4. Optoelectronic Methodology .............................. 330
12.5. Representative Applications ............................. 334
12.6. Conclusions and Recommendations ......................... 338
Acknowledgments ............................................... 339
References .................................................... 339
Chapter 13
Durability of Optical Nanostructures: Laser Diode Structures
and Packages, A Case Study
Ajay P. Malshe and Jay Narayan ............................. 341
13.1. High Efficiency Quantum Confined (Nanostructured)
III-Nitride Based Light Emitting Diodes And Lasers ...... 342
13.1.1. Introduction .................................... 342
13.2. Investigation of Reliability Issues in High Power
Laser Diode Bar Packages ................................ 348
13.2.1. Introduction .................................... 348
13.2.2. Preparation of Packaged Samples for
Reliability Testing ............................. 349
13.2.3. Finding and Model of Reliability Results ........ 350
13.3. Conclusions ............................................. 357
Acknowledgments ............................................... 358
References .................................................... 358
Chapter 14
Review of the Technology and Reliability Issues Arising as
Optical Interconnects Migrate onto the Circuit Board
P. Misselbrook, D. Gwyer, C. Bailey, D. Gwyer,
C. Bailey, P.P. Conway and K. Williams ..................... 361
14.1. Background to Optical Interconnects ..................... 362
14.2. Transmission Equipment for Optical Interconnects ........ 362
14.3. Very Short Reach Optical Interconnects .................. 365
14.4. Free Space USR Optical Interconnects .................... 366
14.5. Guided Wave USR Interconnects ........................... 367
14.6. Component Assembly of OECB's ............................ 370
14.7. Computational Modeling of Optical Interconnects ......... 373
14.8. Conclusions ............................................. 380
Acknowledgments ............................................... 380
References .................................................... 381
Chapter 15
Adhesives for Micro- and Opto-Electronics Application:
Chemistry, Reliability and Mechanics
D.W. Dahringer ............................................. 383
15.1. Introduction 383
15.1.1. Use of Adhesives in Micro and Opto-Electronic
Assemblies ...................................... 383
15.1.2. Specific Applications ........................... 384
15.2. Adhesive Characteristics ................................ 385
15.2.1. General Properties of Adhesives ................. 385
15.2.2. Adhesive Chemistry .............................. 390
15.3. Design Objective ........................................ 393
15.3.1. Adhesive Joint Design ........................... 393
15.3.2. Manufacturing Issues ............................ 397
15.4. Failure Mechanism ....................................... 401
15.4.1. General ......................................... 401
15.4.2. Adhesive Changes ................................ 401
15.4.3. Interfacial Changes ............................. 401
15.4.4. Interfacial Stress .............................. 401
15.4.5. External Stress ................................. 402
References .................................................... 402
Chapter 16
Multi-Stage Peel Tests and Evaluation of Interfacial
Adhesion Strength for Micro- and Opto-Electronic Materials
Masaki Omiya, Kikuo Kishimoto and Wei Yang ................. 403
16.1. Introduction ............................................ 403
16.2. Multi-Stage Peel Test (MPT) ............................. 407
16.2.1. Testing Setup ................................... 407
16.2.2. Multi-Stage Peel Test ........................... 408
16.2.3. Energy Variation in Steady State Peeling ........ 409
16.3. Interfacial Adhesion Strength of Copper Thin Film ....... 413
16.3.1. Preparation of Specimen ......................... 413
16.3.2. Measurement of Adhesion Strength by the MPT ..... 414
16.3.3. Discussions ..................................... 415
16.4. UV-Irradiation Effect on Ceramic/Polymer Interfacial
Strength ................................................ 419
16.4.1. Preparation of PET/ITO Specimen ................. 419
16.4.2. Measurement of Interfacial Strength by MPT ...... 422
16.4.3. Surface Crack Formation on ITO Layer under
Tensile Loading ................................. 424
16.5. Concluding Remarks ...................................... 426
Acknowledgment ................................................ 427
References .................................................... 427
Chapter 17
The Effect of Moisture on the Adhesion and Fracture of
Interfaces in Microelectronic Packaging
Timothy P. Ferguson and Jianmin Qu ........................ 431
17.1. Introduction ............................................ 432
17.2. Moisture Transport Behavior ............................. 433
17.2.1. Background ...................................... 433
17.2.2. Diffusion Theory ................................ 434
17.2.3. Underfill Moisture Absorption Characteristics ... 435
17.2.4. Moisture Absorption Modeling .................... 438
17.3. Elastic Modulus Variation Due to Moisture Absorption .... 442
17.3.1. Background ...................................... 442
17.3.2. Effect of Moisture Preconditioning .............. 444
17.3.3. Elastic Modulus Recovery from Moisture Uptake ... 447
17.4. Effect of Moisture on Interfacial Adhesion .............. 449
17.4.1. Background ...................................... 449
17.4.2. Interfacial Fracture Testing .................... 451
17.4.3. Effect of Moisture Preconditioning on
Adhesion ........................................ 452
17.4.4. Interfacial Fracture Toughness Recovery from
Moisture Uptake ................................. 461
17.4.5. Interfacial Fracture Toughness Moisture
Degradation Model ............................... 462
References .................................................... 469
Chapter 18
Highly Compliant Bonding Material for Micro- and
Opto-Electronic Applications
E. Suhir and D. Ingman ..................................... 473
18.1. Introduction ............................................ 473
18.2. Effect of the Interfacial Compliance on the
interfacial Shearing Stress ............................. 474
18.3. Internal Compressive Forces ............................. 476
18.4. Advanced Nano-Particle Material (NPM) ................... 476
18.5. Highly-Compliant Nano-Systems ........................... 478
18.6. Conclusions ............................................. 479
References .................................................... 480
Appendix 18.A: Bimaterial Assembly Subjected to an
External Shearing Load and Change in Temperature:
Expected Stress Relief due to the Elevated Interfacial
Compliance .................................................... 480
Appendix 18.B: Cantilever Wire ("Beam") Subjected at its
Free End to a Lateral (Bending) and an Axial (Compressive)
Force ......................................................... 483
Appendix 18.C: Compressive Forces in the NPM-Based Compound
Structure ..................................................... 485
Chapter 19
Adhesive Bonding of Passive Optical Components
Anne-Claire Pliska and Christian Bosshard .................. 487
19.1. Introduction ............................................ 487
19.2. Optical Devices and Assemblies .......................... 489
19.2.1. Optical Components .............................. 489
19.2.2. Opto-electronics Assemblies: Specific
Requirements .................................... 489
19.3. Adhesive Bonding in Optical Assemblies .................. 503
19.3.1. Origin of Adhesion .............................. 503
19.3.2. Adhesive Selection and Dispensing ............... 508
19.3.3. Dispensing Technologies ......................... 515
19.4. Some Applications ....................................... 518
19.4.1. Laser to Fiber Assembly ......................... 518
19.4.2. Planar Lightwave Circuit (PLC) Pigtailing ....... 520
19.5. Summary and Recommendations ............................. 522
Acknowledgments ............................................... 523
References .................................................... 523
Chapter 20
Electrically Conductive Adhesives: A Research Status Review
James E. Morris and Johan Liu .............................. 527
20.1. Introduction 527
20.1.1. Technology Drivers .............................. 527
20.1.2. Isotropic Conductive Adhesives (IСAs) ........... 529
20.1.3. Anisotropic Conductive Adhesives (ACAs) ......... 529
20.1.4. Non-Conductive Adhesive (NCA) ................... 529
20.2. Structure ............................................... 529
20.2.1. ICA ............................................. 529
20.2.2. АСА ............................................. 532
20.2.3. Modeling ........................................ 534
20.3. Materials and Processing ................................ 534
20.3.1. Polymers ........................................ 534
20.3.2. ICA Filler ...................................... 536
20.3.3. АСА Processing .................................. 536
20.4. Electrical Properties ................................... 538
20.4.1. ICA ............................................. 538
20.4.2. Electrical Measurements ......................... 544
20.4.3. АСА ............................................. 544
20.5. Mechanical Properties ................................... 546
20.5.1. ICA ............................................. 546
20.5.2. АСА ............................................. 547
20.6. Thermal Properties ...................................... 553
20.6.1. Thermal Characteristics ......................... 553
20.6.2. Maximum Current Carrying Capacity ............... 553
20.7. Reliability ............................................. 554
20.7.1. ICA ............................................. 554
20.7.2. АСА ............................................. 557
20.7.3. General Comments ................................ 565
20.8. Environmental Impact .................................... 565
20.9. Further Study ........................................... 565
References .................................................... 565
Chapter 21
Electrically Conductive Adhesives
Johann Nicotics and Martin Mündlein ........................ 571
21.1. Introduction and Historical Background .................. 571
21.2. Contact Formation ....................................... 574
21.2.1. Percolation and Critical Filler Content ......... 574
21.2.2. ICA Contact Model ............................... 575
21.2.3. Results ......................................... 578
21.3. Aging Behavior and Quality Assessment ................... 595
21.3.1. Introduction .................................... 595
21.3.2. Material Selection and Experimental
Parameters ...................................... 595
21.3.3. Curing Parameters and Definition of Curing
Time ............................................ 597
21.3.4. Testing Conditions, Typical Results, and
Conclusions ..................................... 598
21.4. About Typical Applications .............................. 602
21.4.1. ICA for Attachment of Power Devices ............. 602
21.4.2. ICA for Interconnecting Parts with Dissimilar
Thermal Expansion Coefficient ................... 604
21.4.3. ICA for Cost-Effective Assembling of Multichip
Modules ......................................... 606
21.5. Summary ................................................. 607
Notations and Definitions ..................................... 607
References .................................................... 608
Chapter 22
Recent Advances of Conductive Adhesives: A Lead-Free
Alternative in Electronic Packaging
Grace Y. Li and C.P. Wong .................................. 611
22.1. Introduction ............................................ 611
22.2. Isotropic Conductive Adhesives (IСAs) ................... 613
22.2.1. Improvement of Electrical Conductivity of
ICAs ............................................ 614
22.2.2. Stabilization of Contact Resistance on
Non-Noble Metal Finishes ........................ 615
22.2.3. Silver Migration Control of ICA ................. 618
22.2.4. Improvement of Reliability in Thermal Shock
Environment ..................................... 618
22.2.5. Improvement of Impact Performance of ICA ........ 619
22.3. Anisotropic Conductive Adhesives (ACAs)/Anisotropic
Conductive Film (ACF) ................................... 619
22.3.1. Materials ....................................... 620
22.3.2. Application of АСА/ACF in Flip Chip ............. 621
22.3.3. Improvement of Electrical Properties of ACAs .... 621
22.3.4. Thermal Conductivity of АСА ..................... 623
22.4. Future Advances of ECAs ................................. 623
22.4.1. Electrical Characteristics ...................... 623
22.4.2. High Frequency Compatibility .................... 623
22.4.3. Reliability ..................................... 623
22.4.4. ECAs with Nano-filler for Wafer Level
Application ..................................... 625
References .................................................... 625
Chapter 23
Die Attach Quality Testing by Structure Function Evaluation
Márta Rencz, Vladimir Székely and Bernard Courtois ......... 629
Nomenclature .................................................. 629
Greek symbols ................................................. 629
Subscripts .................................................... 630
23.1. Introduction ............................................ 630
23.2. Theoretical Background .................................. 630
23.3. Detecting Voids in the Die Attach of Single Die
Packages ................................................ 634
23.4. Simulation Experiments for Locating the Die Attach
Failure on Stacked Die Packages ......................... 636
23.4.1. Simulation Tests Considering Stacked Dies of
the Same Size ................................... 637
23.4.2. Simulation Experiments on a Pyramidal
Structure ....................................... 639
23.5. Verification of the Methodology by Measurements ......... 642
23.5.1. Comparisot! of the Transient Behavior of
Stacked Die Packages Containing Test Dies,
Prior Subjected to Accelerated Moisture and
Temperature Testing ............................. 642
23.5.2. Comparison of the Transient Behavior of
Stacked Die Packages Containing Real
Functional Dies, Subjected Prior to
Accelerated Moisture and Temperature Testing .... 644
23.6. Conclusions ............................................. 649
Acknowledgments ............................................... 649
References .................................................... 650
Chapter 24
Mechanical Behavior of Flip Chip Packages under Thermal
Loading
Enboa Wu, Shoulung Chen, C.Z. Tsai and Nicholas Kao ........ 651
24.1. Introduction ............................................ 651
24.2. Flip Chip Packages ...................................... 652
24.3. Measurement Methods ..................................... 654
24.3.1. Phase Shifted Shadow Moire Method ............... 654
24.3.2. Electronic Speckle Pattern Interferometry
(ESPI) Method ................................... 655
24.4. Substrate CTE Measurement ............................... 656
24.5. Behavior of Flip Chip Packages under Thermal Loading .... 661
24.5.1. Warpage at Room Temperature ..................... 661
24.5.2. Warpage at Elevated Temperatures ................ 662
24.5.3. Effect of Underfill on Warpage .................. 666
24.6. Finite Element Analysis of Flip Chip Packages under
Thermal Loading ......................................... 668
24.7. Parametric Study of Warpage for Flip Chip Packages ...... 669
24.7.1. Change of the Chip Thickness .................... 670
24.7.2. Change of the Substrate Thickness ............... 670
24.7.3. Change of the Young's Modulus of the
Underfill ....................................... 671
24.7.4. Change of the CTE of the Underfill .............. 672
24.7.5. Effect of the Geometry of the Underfill
Fillet .......................................... 672
24.8. Summary ................................................. 674
References .................................................... 674
Chapter 25
Stress Analysis for Processed Silicon Wafers and Packaged
Microdevices
Li Li, Yifan Guo and Dawei Zheng ........................... 677
25.1. Intrinsic Stress Due to Semiconductor Wafer
Processing .............................................. 677
25.1.1. Testing Device Structure ........................ 678
25.1.2. Membrane Deformations ........................... 679
25.1.3. Intrinsic Stress ................................ 681
25.1.4. Intrinsic Stress in Processed Wafer: Summary .... 683
25.2. Die Stress Result from Flip-chip Assembly ............... 685
25.2.1. Consistent Composite Plate Model ................ 685
25.2.2. Free Thermal Deformation ........................ 687
25.2.3. Bimaterial Plate (BMP) Case ..................... 688
25.2.4. Validation of the Bimaterial Model .............. 691
25.2.5. Flip-Chip Package Design ........................ 695
25.2.6. Die Stress in Flip Chip Assembly: Summary ....... 697
25.3. Thermal Stress Due to Temperature Cycling ............... 698
25.3.1. Finite Element Analysis ......................... 698
25.3.2. Constitutive Equation for Solder ................ 699
25.3.3. Time-Dependent Thermal Stresses of Solder
Joint ........................................... 700
25.3.4. Solder Joint Reliability Estimation ............. 701
25.3.5. Thermal Stress Due to Temperature Cycling:
Summary ......................................... 703
25.4. Residual Stress in Polymer-based Low Dielectric
Constant (low-k) Materials .............................. 703
References .................................................... 708
Index ......................................................... 711
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