Disclosed is a semiconductor package with increased thermal radiation efficiency, which includes: a first die having signal and dummy regions and including first vias in the signal region, a second die on the first die and including second vias in the signal region, first die pads on a top surface of the first die and coupled to the first vias, first connection terminals on the first die pads which couple the second vias to the first vias, second die pads in the dummy region and on the top surface of the first die, and second connection terminals on the second die pads and electrically insulated from the first vias and the second vias. Each of the second die pads has a rectangular planar shape whose major axis is provided along a direction that leads away from the signal region.