As the demand for packaging more electronic capabilities into smaller packages rises, product developers must be more cognizant of how the system configuration will impact its performance. Practical Guide to the Packaging of Electronics: Second Edition, Thermal and Mechanical Design and Analysis provides a basic understanding of the issues that concern the field of electronics packaging. First published in 2003, this book has been extensively updated, includes more detail where needed, and provides additional segments for clarification. This volume supplies a solid foundation for heat transfer, vibration, and life expectancy calculations. Topics discussed include various modes of heat removal, such as conduction, radiation, and convection; the impact of thermal stresses; vibration and the resultant stresses; shock management; mechanical, electrical, and chemically induced reliability; and more. Unlike many other available works, it neither assumes the reader’s familiarity with the subject nor is it so basic that the reader may lose interest. Dr. Ali Jamnia has published a large number of engineering papers and presentations and is the holder of a number of patents and patent applications. He has been involved in the issues of electronics packaging since the early `90s and since 1995 has worked toward the development of innovative electronics systems to aid individuals with physical or cognitive disabilities. By consulting this manual, engineers, program managers, and quality assurance managers involved in electronic systems gain a fundamental grasp of the issues involved in electronics packaging, learn how to define guidelines for a system’s design, develop the ability to identify reliability issues and concerns, and are able to conduct more complete analyses for the final design.

Table of Contents:
INTRODUCTION Issues in Electronics Packaging Design Technical Management Issues Electronics Design Packaging / Enclosure Design Reliability BASIC HEAT TRANSFER: CONDUCTION, CONVECTION AND RADIATION Basic Equations and Concepts General Equations Non Dimensional Groups Nusselt Number Grashof Number Prandtl Number Reynolds Number CONDUCTIVE COOLING Thermal Resistance Sample Problem & Calculations Resistance Network Network Rules Sample Problem & Calculations Comparison with Exact Results Assumptions Temperature at Intermediate Points Exercise: IC Temperature Determination Heat Spreading Thermal Modeling Example Applications Junction-to-Junction Case Resistance Contact Interface Resistance Modeling the Interface Exercise – Calculate the Component Temperature First Approach A Second Approach A Third Approach A Word on Edge Guides 2-D or 3-D Heat Conduction Thermal Conductance Example RADIATION COOLING Factors Influencing Radiation Surface Properties View Factor Calculations View Factor Calculations In Electronics Packages Examples and Illustrations Electronics Packaging Problem Flow in a Vertical Open-ended Channel Cabinet Surface Temperature First Approach Second Approach FUNDAMENTALS OF CONVECTION COOLING Introduction Flow Regimes, Types & Influences Free (or natural) convection Estimates of Heat Transfer Coefficient Solution Procedure High Altitudes Board Spacing & Inlet-Outlet Openings Design Tips Cabinet Interior & Surface Temperature Calculating Surface Temperature Calculation of Internal Temperature Calculation of Component Temperature Fin Design Basic Procedure RF Cabinet Free Convection Cooling Analytical Approach Design Recommendations for This Example. A More Exact Procedure Forced Convection Direct Flow System Design Required Flow Rate Board Spacing & Configurations Flow Resistance Flow Networks Flow Rate Distribution Between Parallel Plates Optimum Board Spacing and Heat flow System’s Impedance Curve Sample Problem Fan-Selection, and Fan Laws Fan Performance Curve Fan Networks More on Fan Performance Curves Fan Laws Component Hot Spot Calculating hc Using Colburn Factor Calculating hc Using Flow Rate In-Direct Flow System Design Resistance Network Representation COMBINED MODES AS WELL AS TRANSIENT HEAT TRANSFER Total System Resistance Time Dependent Temperature Variation Temperature Rise of an Electronic Module BASICS OF VIBRATION AND ITS ISOLATION Periodic and Harmonic Motions Free Vibration First Application Example Second Application Mode Shapes Damped Vibration Impact of Damping Forced Vibration Engineering Applications Dynamic Magnification Factor Transmissibility Phase Angle Vibration Through Base Excitation Example Vibration Isolation Example 1 Example 2 Applications to Electronics Enclosures Maximum Deflection Typical Transmissibility Values in Electronics Enclosures Maximum Desired PCB Deflection Random Vibration Vibration Terminology Peak Value Average Value Mean Square Value Root Mean Square (RMS) Decibel Octave Spectral Density Solution Techniques For Random Vibration Excitation Spectrum Equipment Response Vibrations Due to Acoustics And Noise Multiple Degree of Freedom Systems BASICS OF SHOCK MANAGEMENT Pulse Shock Isolation Example 1 Example 2 System without Isolators System with Isolators Velocity Shock Isolation Example Maximum Desired PCB Deflection Equipment Design INDUCED STRESSES Forced Vibration Sample Problem Random Vibration Probability of Failure Example Shock Environment THE FINITE ELEMENT METHODS Some Basic Definitions THE FINITE ELEMENT ANALYSIS PROCEDURE Finite Element Formulation Formulation of Characteristic Matrix and Load Vector Direct Approach Variational (Energy) Approach Weighted Residual Approach Finite Element Formulation of Dynamic Problems Wave Propagation Type Vibration Type Methods of Solving This Equation: Example; Impact of Boundary Conditions; Uniform Bar Finite Element Formulation of Heat Conduction CAD to FEA Considerations CAD to FEA, Do’s and Do Not’s Criteria for Choosing an Engineering Software What types of Engineering programs are there? Computer Aided Design (CAD) and Computer Aided Manufacturing (CAM) Solid Mechanics and Stress Analysis - FEA Software Fluid Mechanics and Heat Transfer - CFD Software General Physics - CFD and/or FEA Which Software should I choose? Application Complete Package User Interface, Manuals and Training Customer Support Quality Assurance (QA) Maintenance Error Reports and Bug Fixes Software Performance Testing Validation Interfacing to Other Programs MECHANICAL AND THERMOMECHANICAL CONCERNS General Stress – Strain Relationship Anisotropic Behavior Orthotropic Behavior Isotropic Behavior Material Behavior and The Stress - Strain Curve Determining Deformations Under Application of General Loads Thermal Strains and Stresses Thermal Strains And Deflections Basic Equation Die Attachments IC Devices PCB Warpage Some Tips In Avoiding Temperature Related Failures Simplifications or Engineering Assumptions Linear Elasticity Geometric Simplifications Example Thickness Calculation Based Solely on Shear Thickness Calculation Based Solely on Back Plate Deflection MECHANICAL RELIABILITY Failure Modes Failures By Elastic Deflection Failures by Extensive Yielding Failures by Fracture Progressive Failures Life Expectancy Life Expectancy for Pure Fatigue Conditions Example Life Expectancy for In Random Vibration Example Life Expectancy for Pure Creep Conditions Life Expectancy for Creep-Fatigue Interactions Example 1 Example 2 ELECTRICAL RELIABILITY Basic Definitions Reliability Models Exponential Distribution Model Example 1 Example 2 Weibull Distribution Example Temperature, Electrical and Environmental Impacts on Reliability Temperature Effects Accelerated Testing Electrical Stress Effects Environmental Factors System Failure Rate Component Failure Rate System Failure Rate Example CHEMICALLY INDUCED RELIABILITY Electrochemical Attacks Corrosion Galvanic Cells Stress Cells Fretting Corrosion Chemical Attacks on Plastics Corrosion Control Through Proper Design Techniques Migration and Electromigration DESIGN CONSIDERATIONS IN AN AVIONICS ELECTRONIC PACKAGE Design Parameters Operational Characteristics Reference Documents Electrical Design Specifications Mechanical Design Specifications Electrical and Thermal Parameters Analysis Thermal Analysis Load Carrying and Vibration Analysis Reliability and MTBF Calculations First Year Electronic Failures APPENDIX A: DESCRIPTION OF FINITE ELEMENT MODEL APPENDIX B: STANDARD ATMOSPHERE SI Unit American (English) Unit APPENDIX C: TRANSIENT FLOW EMPERICAL FACTOR APPENDIX D: IMPACT OF CONVECTION ON SPREAD ANGLE APPENDIX E: HEAT TRANSFER COEFFICIENTS MODEL: NARROW GAP VS. WIDE GAP APPENDIX F: CREEP Stages of Creep Stress-Strain Relationship Impact of Creep in Electronics Packaging APPENDIX G: FATIGUE Mathematical Expressions for S-N Curves REFERENCES