Moisture diffusion in epoxy molding compounds filled with particles

Mechanical reliability of epoxy molding compounds in plastic packages of in tegrated circuits (IC) is greatly affected by the compound ability to absor b moisture. Accordingly, the objective of the study is to evaluate the effe ct of moisture sorption on the mechanical properties of the compound. Exper imental studies were conducted to evaluate the moisture diffusion in compou nds with different, from moderate to high, concentration of silica and alum ina nitride fillers. The weight-gained analysis indicated that the moisture diffusion was of non-Fickian type and depended mainly on the specimen's re lative humidity and the filler concentration. We found that although the hy gro-thermal stresses, caused by moisture diffusion, were relatively low, su ch diffusion led to an appreciable decrease in the compound's strength. Moi sture diffusion can result also in a substantial increase in the material's plasticity. The obtained results can be helpful in the analysis of the mec hanical behavior of molding molding compounds employed in electronic packag ing. These results can be used to better understand and to improve the reli ability of plastic packages of IC devices.