Reliability Analysis of 2.5D Package Structure Based on Thermal-Moisture-Mechanical Coupling

With the widespread application of 2.5D packaging in high-end devices, comprehensive analysis of packaging reliability has become increasingly important. This paper addresses the limitations of previous studies that focused solely on thermal field analysis for evaluating the reliability of 2.5D packaging. It integrates moisture-mechanical models, thermo-mechanical models, and thermal-moisture-mechanical coupling models to conduct a multi-physics coupling analysis, investigating the impact of humidity on 2.5D packaging. The simulation models undergo temperature humidity bias testing and thermal cycling testing after moisture preconditioning to analyze the reliability of the packaging under hygro-thermal expansion stresses. The research results indicate that thermal-moisture stress is more significant in the upper-layer microbumps relative to the lower ones, with the greatest reliability risk occurring at the apex corners of the outer circumference of the solder ball array. Concurrently, under thermal cycling test conditions,it is observed that the maximum equivalent stress induced under the combined influence of thermal and humidity loads escalates by 63.6% in comparison to the maximum equivalent stress induced by thermal loads alone. This article provides certain insights into the reliability of 2.5D packaging in thermo-hygro environments, aiding design professionals in a more thorough assessment of reliability within packaging design.