High Thermal Conductivity Mold Compounds for Advanced Packaging Applications

Typical mold compounds with silica fillers have thermal conductivities (k) less than 1 W/mK. This paper will discuss one method to enhance k substantially with the addition of a small amount of graphene to batches of mold compounds with alumina fillers at different weight loading. Mixing techniques will be discussed together with characterization of properties (e.g., breakdown voltage, volume resistivity, and thermal conductivity) of the resulting composites. Several types of graphene powder were tested for these formulations of epoxy composites. A mold compound formulation with the highest k reported to date of 8.7 W/mK was obtained with less than 2wt% of graphene. Thermal resistance and MSL data with thermal test dies packaged in 8x8mm QFN will also be shown.