Provided is a semiconductor package including a lower semiconductor chip including a lower semiconductor substrate, a rear surface protecting layer covering a non-active surface of the lower semiconductor substrate, a plurality of lower via electrodes, and a plurality of rear surface signal pads and a plurality of rear surface thermal pads arranged on the rear surface protecting layer; an upper semiconductor chip including an upper semiconductor substrate, a wiring structure on an active surface of the upper semiconductor substrate, a front surface protecting layer that covers the wiring structure and has a plurality of front surface openings, and a plurality of signal vias and a plurality of thermal vias that fill the front surface openings; and a plurality of signal bumps connecting between the rear surface signal pads and the signal vias and a plurality of thermal bumps connecting between the rear surface thermal pads and the thermal vias.