This book is a comprehensive overview of the discoveries in composition, growth and control of gold-aluminum intermetallic compounds in microelectronic interconnects known as purple plague. It focuses on the history of detection, theory, and understanding of the gold-aluminum interface reliability issues. Purple Plague in Microelectronics presents research on the phenomenon of purple plague from the earliest days to the present. The authors explain intricate scientific aspects to understand cause and effect of this reliability issue in microelectronics in a way that ensures the content is understandable to readers of various educational levels, novice to expert, while satiating the needs of the engineering personnel closely associated with work related to the gold-aluminum interfacial integrity. The discovery of void formation leading to porosity in the purple phase and the resulting joint failure is discussed, along with detailed analyses of the various phases, metallurgy characteristics, and diffusion phenomenon at the gold-aluminum interface. They provide detailed drawings, graphs, charts, models, and tables, which allow easy comprehension of concepts and phenomenon through visual aids. The book explains various methods for evaluating the quality and reliability of wire bond joints, highlighting the relative advantages of each approach. Techniques such as shear testing and bond resistance testing are discussed in detail. It also examines the role of ingredients used in packaging material and the gold wire itself, supported by relevant mathematical modelsIntended for electronic assembly engineers, design engineers, process development engineers, material scientists, electronic industry supervisors and managers, this book is an excellent reference for anyone involved in defect control and reliability in gold wire bonding.