A semiconductor device includes an integrated circuit structure and a thermal pillar over the integrated circuit structure. The integrated circuit structure includes a semiconductor substrate including circuitry, a dielectric layer over the semiconductor substrate, an interconnect structure over the dielectric layer, and a first thermal fin extending through the semiconductor substrate, the dielectric layer, and the interconnect structure. The first thermal fin is electrically isolated from the circuitry. The thermal pillar is thermally coupled to the first thermal fin.