CHARACTERIZATION OF HYGROSCOPIC SWELLING AND THERMO-HYGRO-MECHANICAL DESIGN ON ELECTRONIC PACKAGE

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. Hygro-mechanical properties, such as the coefficient of moisture expansion (CME), were determined through Thermo-Mechanical Analyzer (TMA) and Themo-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 oil the FE software ANSYS were developed to predict the thermal-induced strain, hygroscopic swelling deformation, and residual thermo-hygro-mechanical stress distributions. Reliability analysis at three JEDEC preconditioning standards 60 degrees C60%RH, 85 degrees C60%RH and 85 degrees C85%RH was carried out. A series of comprehensive parametric studies were conducted in this research.