Impact of Reaction Shrinkage on Stress in Semiconductor Packages
The reliability of a semiconductor package is strongly influenced by the adhesion and temperature behavior of the package encapsulant. This study considers the effect of mold shrinkage during the encapsulation molding process. Four commercially available molds were investigated using warpage and thermomechanical analysis. It could be demonstrated that, for all four types, when molded on a silicon substrate, the temperature at which no stress occurred was in a range of 28–60°C above the molding temperature. This is caused by the shrinkage due to a crosslinking reaction of the mold polymer during the molding process. For a more precise understanding and simulation of the stress behavior inside a molded package, the effect of reaction shrinkage has to be considered.