A solid-state drive (SSD) includes a main printed circuit board (PCB), and a first semiconductor package and a second semiconductor package respectively mounted on a top surface and a bottom surface of the main PCB. Each of the first and second semiconductor packages has a surface on which connection pads corresponding to a package ball map are disposed. The package ball map includes cells arranged in a plurality of rows and a plurality of columns, and one signal corresponds to each of the cells of the package ball map. The package ball map includes first signals corresponding to at least some of cells included in a selected reference column from among the plurality of columns, and at least one pair of second signals respectively corresponding to cells that are symmetrical to each other with respect to the reference column. The pair of second signals are swappable signals, and the first signals are not swappable signals.