Semiconductor package devices and methods of forming the semiconductor package devices are provided. The semiconductor package devices may include a lower package including a lower semiconductor chip on a lower substrate, an upper package including an upper semiconductor chip on an upper substrate. The upper substrate may include a protruding part corresponding to the lower semiconductor chip and a connection part that has a bottom surface lower than a bottom surface of the protruding part and is disposed around the protruding part. The semiconductor package devices may also include a heat dissipation part in a space between the lower semiconductor chip and the protruding part on the upper substrate and a package connection pattern electrically connecting the lower package to the upper package.