Experimental and FEM studies have been under-taken in order to characterize the non-Fickian behavior of moisture absorption, temperature-dependent residual moisture content and hygroscopic swelling of epoxy molding compounds exposed to moist environments. Moisture absorption and desorption tests of two molding compounds and two IC packages using these materials have been carried out by gravimetric methods. Finite element analysis has been performed to simulate the anomalous dual-stage moisture absorption. To consider the residual moisture remaining in the package after the desorption process, a simple method has been developed, which allows for consideration of bake-out conditions and provides much more flexibility, enabling calculation of the non-Fickian moisture desorption with a specific residual moisture content. The Coefficient of Moisture Expansion (CME) has been also measured by coupling the results of Thermal Mechanical Analyzer (TMA) and Thermal Gravitational A nalyzer (TGA) at different temperatures. It has been shown that the moisture desorption model of this study can be used as an alternative for TGA. ©2008 IEEE

cous filled resin and subsequent curing does also cause intrin-The universal applicability of polymeric materials in mi-sic stress in the materials, what can be of importance in studies crosystem technology is based on a wide adaptability of their of the mechanical performance. thermo-mechanical as well as their electric/dielectric characThe computational design of reliable packages and interteristics. However, as they are generally sensitive to tempera-connects can minimize prototype development and testing cost. ture and moisture, obey a misfit in thermal expansion to other Accordingly, finite element (FE-) modeling is widely used to electronic materials, and lack a high mechanical strength they perform parametric studies on the thermo-mechanical behavior. are often the weakest link in packaging applications. Finite-Since the assemblies of interest are material compounds, faelement analyses (FEA) are in widespread use to determine the tigue, delamination and interface cracking are the most frethermo-mechanical performance of the precision material quently observed failure modes, induced by the stress originatcompounds. In theoretical strength analyses the property de-ing from various loadings.

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