Evaluation of interface delamination in IC packages by considering swelling of the molding compound due to moisture absorption

Adhesion strength evaluation of molding compounds is a critical issue in both structural design and material selection of plastic IC packages. We previously proposed a new adhesion test method that can separate residual stress from adhesion strength, and we confirmed that the measured true adhesion strength can be applied to the quantitative prediction of interface delamination in a dry package. This paper describes the influence of moisture absorbing conditions on true adhesion strength determined by this method. The drop of true adhesion strength of a specimen that has absorbed moisture at 50/spl deg/C is about 40 percent of that of a specimen at 85/spl deg/C. This suggests that the general moisture condition (85/spl deg/C/85%) accelerates the damage to plastic IC packages when compared to the case of moisture absorption at room temperature. We also evaluated interface delamination in a moisture-absorbed package by considering the swelling of the molding compound due to moisture absorption. The predicted results agree well with the experimental data for moisture-absorbed packages.