ABSTRACT
Polymers naturally have low thermal conductivity. Polymer composites with practical high dielectric strength are required to have relatively high thermal conductivity. When polymers are loaded with high thermally conductive inorganic micro-fillers, resulting composites have high thermal conductivity due to percolation effect of micro-fillers. However, they often suffer from reduced dielectric breakdown strength. In order to overcome this reduction, a certain nanotechnology method has been explored using nanofillers. Thermal conductivity is governed by phonon flow. Increase in thermal conductivity of composites by infilling high-thermal-conductivity fillers is governed by propagation speed of phonon and percolation. This chapter explores why high-dielectric-constant materials (high-k) and low-dielectric-constant materials (low-k) are needed for the downsizing and high-density mounting of LSI. The reduction in permittivity dielectric constant by the use of a nanocomposite is considered attributable to the influence of the area restricted by molecular chains due to strong particle-base material bonds on the nanoparticle interface.
