This paper discusses a successful experimental procedure to determine the hygroscopic swelling property of polymeric materials used in electronic packaging. Saturated moisture concentration and moisture diffusivity were determined by measuring the weight gain during moisture absorption. Hygromechanical properties, such as the coefficientof moisture expansion (CME), were determined through Thermo-Mechanical Analyzer (TMA) and Thermo-Gravimetric Analyzer (TGA) techniques. Fick's law of transient diffusion is solved by using finite element (FE) analysis to evaluate the overall moisture distributions. Both two-dimensional and three-dimensional models based on the FE software ANSYS were developed to predict the thermal-induced strain, hygroscopic swelling deformation, and residual thermohygro-mechanicalstress distributions. Reliability analysis at three JEDEC preconditioning standards 60°C60%RH, 85°C60%RH and 85°C85%RH was carried out. A series of comprehensive parametric studies were conducted in this research.
