Experimental and numerical study of package moisture diffusion

Many researches were done on the mechanism of moisture diffusion in molding compound, but there are few results on the mechanism of moisture behavior in plastic package, which is more complex than that of molding compound because of the multi-materials and interfaces in plastic package. In this study, an experimental method was developed to study the moisture invasion path and moisture distribution in plastic package. A package moisture imaging method was proposed. Nuclear Magnetic Resonance (NMR) technique and supper absorption polymer (SAP) doping were combined to gain the direct evidence of the moisture in package. Numerical simulation was performed to analyze the moisture behavior in plastic package. Based on the quantitative results of moisture distribution in package, a virtual interfacial material was introduced into numerical analysis to describe the effect of bimaterial interface on moisture diffusion behavior within a plastic package. The results show that the moisture diffusion behavior in plastic package can be predicted more exactly.