A substrate processing apparatus includes a chamber providing a space for performing a semiconductor process on a semiconductor substrate, and a substrate stage configured to support the semiconductor substrate. The substrate stage includes a platen having a seating surface to support the semiconductor substrate, the platen having a resistance heater and an RF electrode adjacent to the seating surface, a shaft under the platen, the shaft having a first through hole in a central region and a plurality of second through holes in a peripheral region surrounding the central region, an RF rod spaced apart from an inner wall of the first through hole, the RF rod electrically connected to the RF electrode, and a plurality of heater rods respectively within the plurality of second through holes and electrically connected to the resistance heater.