Available at: http://digitalcommons.calpoly.edu/theses/21
Date of Award
MS in Electrical Engineering
Mobile and handheld electronics devices such as digital cameras, cell phones, and personal digital assistants (PDAs) are prone to be dropped in their lifetime. The drop event may result in failure of solder joints inside these devices. The importance and widespread use of these devices in both business and leisure activities continues to increase, so device failure is increasingly costly and inconvenient. Recently the European Union (EU) Restriction of Hazardous Substances (RoHS) and other countries' lead-free directives banned the use of lead in consumer electronics products. While this is a responsible environmental change for the electronics industry, it requires the introduction of new solders and soldering processes, and signals a major change in production methods as lead-based solders are no longer used in these devices. Thus, it is critical to study the drop impact reliability of lead-free solder joints. This thesis discusses the reliability of Chip Scale Packages (CSPs) in drop impact, with and without the CSPs being edge-bonded, using two failure detection systems and presents the component failure sequence as observed by each system. To enable this study a high-speed data acquisition system, capable of in-situ detection of transitional solder interconnect failure, was developed at Cal Poly for drop impact reliability testing. Edge-bonding is shown to significantly improve drop impact reliability of CSPs.