Thermal pathway engineering in epoxy molding compounds via high-loading SiO₂-embedded carbon nanofibers fabricated by syringeless electrospinning

In this study, carbon nanofibers (CNFs) with high SiO₂ loading are developed as thermally conductive additives for epoxy molding compounds (EMCs) used in advanced semiconductor packaging. A syringeless electrospinning strategy is employed to fabricate high-content SiO₂-embedded CNFs, while interfacial engineering of SiO₂ via silane treatment is introduced to control precursor-stage rheological behavior. Specifically, amine-functionalized SiO₂-embedded CNFs exhibit the highest increase in precursor viscosity due to enhanced polymer–particle interactions, allowing uniform SiO₂ embedding along the CNF backbone at an optimal loading amount of 20 wt%. When incorporated into EMC at 0.6 wt%, the additive exhibits the highest mechanical strength and thermal conductivity enhancement. The superior performance originates from the synergistic contributioon of continuous heat-dissipation pathways provided by the carbon framework and the optimized packing factor achieved by SiO₂ embedding. Infrared thermography further confirms enhanced heat transport, showing a 9.4 °C higher surface temperature compared with pristine EMC after 3 min of heating. These findings highlight that the structural evolution of CNFs with embedded inorganic fillers, combined with precursor-stage interfacial and rheological engineering, provides a new design strategy of carbonaceous material for thermally and mechanically stable EMC systems.