A study of moisture diffusion in polymeric packaging materials especially at high temperatures

Abstract

Accurate characterizing of moisture diffusion properties of polymeric packaging materials at high temperatures has been a challenge. In this research, the technique of Karl Fischer Titration (KFT) was explored, through comparing with conventional testing technique TGA (Thermo-gravimetric Analysis). Moisture desorption experiments was performed with 3 types of polymeric packaging materials: molding compound, underfill and die attach materials.The outgassing of volatiles at high temperatures has been confirmed by using Gas Chromatography/Mass Spectrometry (GC/MS), which is likely the main cause for significant differences observed between the results of TGA and KFT. KFT is not affected by the outgassing and it is reliable for characterizing moisture diffusion at high temperatures. Both Fickian and non-Fickian behaviors were observed in moisture desorption experiments. The results show Ed above Tg is much lower than that below Tg. Moisture absorption experiments were carried out using various polymeric packaging materials. The effects of fillers on moisture diffusion and aging in polymeric packaging materials were discussed.