Solders have given the designer of modern consumer, commercial, and military electronic systems a remarkable flexibility to interconnect electronic components. The properties of solder have facilitated broad assembly choices that have fueled creative applications to advance technology. Solder is the electrical and me chanical "glue" of electronic assemblies. This pervasive dependency on solder has stimulated new interest in applica tions as well as a more concerted effort to better understand materials properties. We need not look far to see solder being used to interconnect ever finer geo metries. Assembly of micropassive discrete devices that are hardly visible to the unaided eye, of silicon chips directly to ceramic and plastic substrates, and of very fine peripheral leaded packages constitute a few of solder's uses. There has been a marked increase in university research related to solder. New electronic packaging centers stimulate applications, and materials engineering and science departments have demonstrated a new vigor to improve both the materials and our understanding of them. Industrial research and development continues to stimulate new application, and refreshing new packaging ideas are emerging. New handbooks have been published to help both the neophyte and seasoned packaging engineer. Front Matter....Pages i-xxi Flux Reactions and Solderability....Pages 1-37 Solder Paste Technology and Applications....Pages 38-91 Technical Considerations in Vapor Phase and Infrared Solder Reflow Processes....Pages 92-116 Optimizing the Wave Soldering Process....Pages 117-142 Post-Solder Cleaning Considerations....Pages 143-172 Scanning Electron Microscopy and Energy Dispersive X-ray (SEM/EDX) Characterization of Solder Solderability and Reliability....Pages 173-224 The Role of Microstructure in Thermal Fatigue of Pb-Sn Solder Joints....Pages 225-265 Microstructure and Mechanical Properties of Solder Alloys....Pages 266-278 The Interaction of Creep and Fatigue in Lead-Tin Solders....Pages 279-305 Creep and Stress Relaxation in Solder Joints....Pages 306-332 Effects of Strain Range, Ramp Time, Hold Time, and Temperature on Isothermal Fatigue Life of Tin-Lead Solder Alloys....Pages 333-360 A Damage Integral Methodology for Thermal and Mechanical Fatigue of Solder Joints....Pages 361-383 Modern Approaches to Fatigue Life Prediction of SMT Solder Joints....Pages 384-405 Predicting Thermal and Mechanical Fatigue Lives from Isothermal Low Cycle Data....Pages 406-454 Static and Dynamic Analyses of Surface Mount Component Leads and Solder Joints....Pages 455-507 Integrated Matrix Creep: Application to Accelerated Testing and Lifetime Prediction....Pages 508-544 Solder Attachment Reliability, Accelerated Testing, and Result Evaluation....Pages 545-587 Surface Mount Attachment Reliability and Figures of Merit for Design for Reliability....Pages 588-613 Back Matter....Pages 615-631 This chapter attempts, on the basis of experimental results available, to explain the mechanism, for those fluxes that have been studied, by which they appear to work.
