A Study on the Board-Level Thermomechanical Reliability of Flip-Chip Chip Scale Package (FCCSP)

This study explores the thermomechanical reliability of Flip-Chip Chip Scale Package (FCCSP) technology, a critical enabler for compact and high-performance electronic devices. The research addresses reliability challenges caused by mismatches in the coefficient of thermal expansion (CTE) among silicon dies, substrates, and printed circuit boards (PCBs), which induce thermal stresses and lead to solder joint fatigue under temperature cycling. Through a combination of experimental tests and advanced finite element analysis (FEA), the study develops a comprehensive simulation framework that integrates multi-scale modeling, material characterization, and failure prediction techniques. Key contributions include the introduction of an equivalent material layer to reduce computational complexity, sub-modeling of high-stress solder joints for precise reliability analysis, and the use of the Darveaux fatigue model to predict solder joint lifespan under various thermal cycling conditions. This work offers practical insights into material and design strategies for enhancing FCCSP reliability, advancing the durability of next-generation electronic packaging technologies.