A semiconductor device, a formation method thereof, and a package structure are provided. The semiconductor device comprises: a semiconductor substrate in which a metal-oxide-semiconductor field-effect transistor (MOSFET) is formed; a dielectric layer, provided on the semiconductor substrate and covering the MOSFET, wherein a plurality of interconnection structures are formed in the dielectric layer; and at least one heat dissipation path, embedded in the dielectric layer between the interconnection structures, for liquid or gas to circulate in the heat dissipation path, wherein openings of the heat dissipation path are exposed on the surface of the dielectric layer. The present invention can improve heat dissipation efficiency, and prevent chips from overheating.