An integrated circuit has a substrate and an interconnect region disposed on the substrate. The interconnect region includes a plurality of interconnect levels. Each interconnect level includes interconnects in dielectric material. The integrated circuit includes a thermal via in the interconnect region. The thermal via extends vertically in at least one of the interconnect levels in the interconnect region. The thermal via includes a cohered nanoparticle film in which adjacent nanoparticles are cohered to each other. The thermal via has a thermal conductivity higher than dielectric material touching the thermal via. The cohered nanoparticle film is formed by a method which includes an additive process.