Effect of High-Temperature Exposure on the Thermo-Mechanical Behavior of Epoxy Molding Compound and Warpage of Molded Wafers

Abstract

The warpage behavior of the electronic packages is hard to be predicted because epoxy molding compound (EMC), a major component of the electronic packages, shows complex thermo-mechanical behavior. Therefore, it is possible to establish a warpage reduction strategy only when the thermo-mechanical behavior of the EMC is accurately understood. In this study, the shrinkage behavior of EMC by oxidation, which occurs at high temperatures such as solder reflow temperature, was measured and applied to reduce the warpage of the molded wafer structure. About 0.43 % of the shrinkage of the fully cured EMC at 250°C for 6 hours was accurately measured through the digital image correlation (DIC) method, and the warpage change due to oxidation shrinkage was quantitatively predicted from an accurate database on the amount of shrinkage. In addition, changes in thermal expansion properties such as coefficient of thermal expansion (CTE) and glass transition temperature by oxidation were measured, and the effect of changes in properties on CTE mismatch-induced thermal warpage behavior was analyzed. These analyses suggested the possibility of EMC oxidation as a thermo-mechanical behavior for warpage control of electronic packages.