Thermoelastic Behavior of Filled Molding Compounds: Composite Mechanics Approach

Abstract

Abstract Reliability of epoxy molding compounds used in plastic packages of integrated circuit (IC) devices depends on the level of thermal stresses caused by the thermal expansion (contraction) mismatch of the epoxy and the silicon materials. In this analysis we asses the effect of silica fillers on the thermal stresses. We conclude that thermal stresses in the epoxy molding compound (composite) can be indeed reduced by the application of appropriate fillers. We found, however, that the volume concentration of the fillers, does not have to be larger than 0.3 to keep the thermal stresses at a sufficiently low level. This number is close to the fillers volume concentration (c = 0.336–0.390) in actual commercially available molding compounds. The obtained results and recommendations can be helpful in the analysis of stresses and physical design of plastic packages of IC devices.