Avoiding Inelastic Strains in Solder Joint Interconnections of IC Devices - Avoiding Inelastic Strains in Solder Joint Interconnections of IC Devices -

Analytical Modeling, Its Role and Significance Method of Interfacial Compliance Introduction Stresses in the Midportion of a Multimaterial Body Subjected to a Change in Temperature Bimaterial Assembly: Interfacial Shearing Stresses Bimaterial Assembly: Interfacial Peeling Stresses Trimaterial Assembly: Interfacial Shearing Stresses Trimaterial Assembly: Interfacial Peeling Stresses Numerical Example Bimaterial Assembly Subjected to Thermal Stress: Propensity to Delamination Assessed Using the Interfacial Compliance Model Background/Incentive Strain Energy Release Rate (SERR) Computed Using the Interfacial Compliance Approach Adequate SERR Specimen’s Length Numerical Example #1 Numerical Example #2 Probabilistic Approach: Application of the Extreme Value Distribution Probabilistic Approach: Numerical Example Appendix A: Convolution of Extreme Value Distribution with a Normally Distributed Variable Appendix B: A Numerical Integration Example References Thermal Stress in Assemblies with Identical Adherends Introduction Bell Labs Si-on-Si multi-chip flip-chip Packaging Technology Simplest Elongated Assembly with Identical Adherends Assembly with Identical Adherends Subjected to Different Temperatures: Thermal Stresses in a Multileg Thermoelectric Module Design Motivation Background Basic Equation Theorem of Three Axial Forces Special Cases Homogeneously Bonded Assembly Assembly Bonded at the Ends (Two-Legged TEM)Midportion of a Long Multilegged Assembly TEM Designs in Figures 3.11 and 3.12 TEM Designs in Figures 3.11 and 3.12 Design in Figure 3.12 for a High-Temperature Power Generation TEM Ultrathin and Long (Beam-Like) Legs Predicted thermal stress in a circular bonded assembly with identical adherends Motivation Assumptions Basic Equation Solution to the Basic Equation Large and/or Stiff Assemblies Normal Stresses in the Bonding Layer Bow Bending Stresses in the Adherends Peeling Stress Numerical Example References Inelastic Strains in Solder Joint Interconnections Background/Motivation Assumptions Shearing Stress Basic Equation Boundary Conditions Elasto-Plastic Solution Possible Numerical Procedure for Solving the Elasto-Plastic Equations Predicted Lengths of the Plastic Zones Based on an Elastic Solution Peeling Stress Basic Equation Solution to the Basic Equation Numerical Example The Case of a BGA Assembly Background/Motivation Basic Equation Numerical Example #1 (PCB Substrate)Numerical Example #2 (Ceramic Substrate)Probabilistic Palmgren-Miner Rule for Solder Materials Experiencing Elastic Deformations Background/Incentive Probabilistic Palmgren-Miner Rule Remaining Useful Life Rayleigh Law for the Random Amplitude of the Interfacial Shearing Stress Numerical Example References Elevated Stand-Off Heights Can Relieve Thermal Stress in Solder Joints Background/Motivation Stresses in a Short Beam Subjected to Bending Caused by its End Offset Interfacial Stresses in Assemblies with Small Stand-off Heights Head-In-Pillow Problem Motivation Background Interfacial Stresses and Warpage Numerical Example References Stress Relief in Soldered Assemblies by Using Inhomogeneous Bonds Background/Incentive Assembly’s Midportion Assembly’s Peripheral Portion(s) and Forces at the Boundaries Interfacial Stresses Numerical Example Optimized Design Optimization Condition Peripheral Material with a Low Fabrication Temperature Peripheral Material with a Low Parameter of the Interfacial Shearing Stress Peripheral Material with a Low Parameter of the Interfacial Shearing Stress and Low Fabrication Temperature Conclusions References Thermal Stresses in a Flip-Chip Design Background/Incentive Thermal Stress Model for a Typical Flip-Chip Package Design Approach Forces Acting in the Midportion of the Assembly Located at the Design’s Midportion Peripheral Portions of the Design Numerical Examples Design with an Organic Lid: Midportion of the Design Design with an Organic Lid: Peripheral Portion of the Design Design with a Copper Lid: Midportion of the Design Design with a Copper Lid: Peripheral Portions of the Design Is it Really Important that the Entire Underchip Area is Encapsulated (“Underfilled”)?Stress Relief in an FC Design Due to the Application of an Inhomogeneous Solder Joint System Effect of the Underfill Glass Transition Temperature Background Assumptions Thermally Induced Forces and Interfacial Stresses Thermally Induced Forces in the Midportion of a Long Flip-Chip/Substrate Assembly Distributed Thermally Induced Forces Interfacial Shearing Stresses Numerical Example References Assessed Interfacial Strength and Elastic Moduli of the Bonding Material from Shear-Off Test Data Background/Incentive Basic Equation Solution to the Basic Equation Interfacial Shearing Stress Shear Modulus of the Bonding Material Numerical Example Possible Characterization of the Solder Material Properties CONCLUSION References Board-Level Dynamic Tests Background Drop Testing Role Of Modeling Linear Response Nonlinear Response Solder Joints Board-Level Testing Conclusions Appendix A: Exact Solution to the Problem of the Nonlinear Dynamic Response of a PCB to the Drop Impact during Board-Level Drop Tests A.1. Background/Initiative A.2. Assumptions A.3. Kinetic and Strain Energies A.4. Condition of Nondeformability of the PCB Support Contour A.5. Stress (Airy) Function A.6. In-plane (membrane) Stresses and Strains A.7. Parameter of Nonlinearity A.8. Basic Equation and Its Solution A.9. Vibration Amplitude A.10. Effective Initial Velocity A.11. Nonlinear Frequency A.12. Bending Moments A.13. Equivalent Static Loading A.14. Numerical Example References Appendix References Failure-Oriented-Accelerated-Testing and Multiparametric Boltzmann–Arrhenius–Zhurkov Equation Accelerated Testing FOAT, Its Significance, Attributes, and Role Multiparametric BAZ Equation Temperature Cycling: Predicted Time-to-failure Incentive for Mechanical Prestressing of Accelerated Test Specimens Background/Incentive Basic Equations Boundary Conditions Solutions to the Basic Equations Constants of Integration Numerical Example Accelerated Testing of Solder Joint Interconnections: Incentive for Using a Low-Temperature/Random- Vibrations Bias Background/Incentive Methodology Reduction to Practice Calculation Procedure Numerical Example Testing Facility and Procedure Conclusion Possible Next-Generation QT Appendix A: Elastic Stability of the Specimen as a Whole Appendix B: Approximate Formula for the Interfacial Peeling Stress and Elastic Stability of the Compressed Component #1 References Probabilistic Design for Reliability Background/Incentive PDfR and its “ten commandments”Design for Reliability of Electronic Products: Deterministic and Probabilistic Approaches Some simple PDfR examples Adequate Heat Sink Reliable Seal Glass Extreme Response in Temperature Cycling The Total Cost of Reliability could be Minimized: Elementary Example Required Repair Time to Assure the Specified Availability Background/Incentive Analysis Numerical Example Conclusion Burn-in Testing of Electronic and Photonic Products: To BIT or not to BIT?Background/Initiative Objective Information Based on the Available BTC Conclusion APPENDIX A: RELIABILITY OF AN ELECTRONIC PRODUCT COMPRISED OF MASS-PRODUCED COMPONENTS A.1. Summary A.2. Background/Incentive A.3. Analysis A.3.1. Analytical Bathtub Curve (Diagram)A.3.2. Statistical Failure Rate A.3.3. The Case When Random SFR isNormally Distributed A.3.4. The Case When Random SFR is Distributed in Accordance with the Rayleigh Law A.3.5. Probability of Nonfailure A.4. Conclusions References Appendix References Fiber Optics Systems and Reliability of Solder Materials Background/Objective Fiber Optics Structural Analysis (FOSA) in Fiber Optics Engineering: Role and Attributes Fibers Soldered into Ferrules Thermal Stresses in a Cylindrical Soldered TriMaterial Body with Application to Optical Fibers Background/Incentive Analysis Numerical Example Conclusion References