The European Union’s directive banning the use of lead-based (Pb) solders in electronic consumer products has created an urgent need for research on solder joint behavior under various driving forces in electronic manufacturing, and for development of lead-free solders. This book provides a comprehensive examination of advanced materials reliability issues related to copper-tin reaction and electromigration in solder joints, and presents methods for preventing common reliablity problems.
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.
Introduction Advanced Surface Mount Technology and Die Attach Techniques Solder Material Soldering Chemistry Solderability Microstructure of Solders Aqueous-Cleaning Manufacture No-Clean Manufacture Protective and Reactive Atmosphere Soldering Surface Mount Fine Pitch Technology Surface Mount-BGA/PAC Technology Soldering Methodology and Equipment Soldering and Soldering Related Issues Strengthened Solders Lead-Free Solders Solder Joint Failure Mode Solder Joint Failure Assessment-Case Studies Solder Joint Quality and Reliability New and Emerging Specifications and Standards Future Trends.
One of the strongest trends in the design and manufacture of modern electronics packages and assemblies is the utilization of surface mount technology as a replacement for through-hole tech nology. The mounting of electronic devices and components onto the surface of a printed wiring board or other substrate offers many advantages over inserting the leads of devices or components into holes. From the engineering viewpoint, much higher lead counts with shorter wire and interconnection lengths can be accommo dated. This is critical in high performance modern electronics packaging. From the manufacturing viewpoint, the application of automated assembly and robotics is much more adaptable to high lead count surface mounted devices and components. Indeed, the insertion of high lead count parts into fine holes on a substrate might often be nearly impossible. Yet, in spite of these surface mounting advantages, the utilization of surface mount technology is often a problem, primarily due to soldering problems. The most practical soldering methods use solder pastes, whose intricacies are frequently not understood by most of those involved in the engineering and manufacture of electronics assemblies. This publication is the first book devoted exclusively to explanations of the broad combination of the chemical, metallurgical, and rheological principles that are critical to the successful use of solder pastes. The critical relation ships between these characteristics are clearly explained and pre sented. In this excellent presentation, Dr. Hwang highlights three impor tant areas of solder paste technology.
Introduction Advanced Surface Mount Technology and Die Attach Techniques Solder Material Soldering Chemistry Solderability Microstructure of Solders Aqueous-Cleaning Manufacture No-Clean Manufacture Protective and Reactive Atmosphere Soldering Surface Mount Fine Pitch Technology Surface Mount-BGA/PAC Technology Soldering Methodology and Equipment Soldering and Soldering Related Issues Strengthened Solders Lead-Free Solders Solder Joint Failure Mode Solder Joint Failure Assessment-Case Studies Solder Joint Quality and Reliability New and Emerging Specifications and Standards Future Trends.
Managers, engineers and technicians will use this book during industrial construction of electronics assemblies, whilst students can use the book to get a grasp of the variety of methods available, together with a discussion of technical concerns. It includes over 200 illustrations, including a photographic guide to defects, and contains many line drawings, tables and flow charts to illustrate the subject of electronics assembly. Soldering in Electronics Assembly looks theoretically at everything needed in a detailed study, but in a practical manner. It examines the soldering processes in the light of electronic assembly type; solder; flux; and cleaning requirements. It has information on every available process, from the most basic hand soldering through to latest innovatory ones such as inert atmosphere wave soldering and zoned forced convection infra-red machines. The book provides a detailed analysis of solder and soldering action; purpose of flux and relevant flux types for any application; classification of assembly variants; assessment and maintenance of solderability. There is also a detailed analysis of soldering process defects and causes. In addition, Soldering in Electronics Assembly contains a new chapter on Ball Grid Array (BGA) technology. A practical guide for the industry covering all the main soldering processes currently in use Cleaning, faults, troubleshooting and standards are all major topics Considers safety and solder process quality assessment
This book presents a systematic approach in performing reliability assessment of solder joints using Finite Element (FE) simulation. Essential requirements for FE modelling of an electronic package or a single reflowed solder joint subjected to reliability test conditions are elaborated. These cover assumptions considered for a simplified physical model, FE model geometry development, constitutive models for solder joints and aspects of FE model validation. Fundamentals of the mechanics of solder material are adequately reviewed in relation to FE formulations. Concept of damage is introduced along with deliberation of cohesive zone model and continuum damage model for simulation of solder/IMC interface and bulk solder joint failure, respectively. Applications of the deliberated methodology to selected problems in assessing reliability of solder joints are demonstrated. These industry-defined research-based problems include solder reflow cooling, temperature cycling and mechanical fatigue of a BGA package, JEDEC board-level drop test and mechanisms of solder joint fatigue. Emphasis is placed on accurate quantitative assessment of solder joint reliability through basic understanding of the mechanics of materials as interpreted from results of FE simulations. The FE simulation methodology is readily applicable to numerous other problems in mechanics of materials and structures.
This unique book provides an up-to-date overview of the concepts behind lead-free soldering techniques. Readers will find a description of the physical and mechanical properties of lead-free solders, in addition to lead-free electronics and solder alloys. Additional topics covered include the reliability of lead-free soldering, tin whiskering and electromigration, in addition to emerging technologies and research.
The book is important because it reflects a trend, especially in microelectronics manufacture toward recyclability. Europe and Asia are moving towards legislation to ban the use of lead in solders and public demand in the US will likely have the same result. Producers of solders and manufacturers who use them will have to invent and employ suitable substitutes and A Guide to Lead-free Solders will show them how to do so.
