A semiconductor substrate and a stackable semiconductor package and a fabrication method thereof which make it possible to form a highly-integrated semiconductor module within a limited area. The semiconductor substrate includes a non-conductive substrate main body having a plurality of patterned conductive wires formed therein, a cavity formed in an upper center portion of the substrate main body, and a plurality of via holes which perpendicularly pass through edge portions of the substrate main body. A stackable semiconductor package includes the above-described semiconductor substrate, having a semiconductor device positioned in its cavity with a molding compound, the semiconductor device being electrically connected to the conductive wires formed in the semiconductor substrate. Plural stackable semiconductor packages may be stacked such that the via holes are aligned, and a conductive material such as solder can be placed in the via holes to ensure electrical connection. Additionally, conductive external terminals may be positioned on upper and lower surfaces of the substrate main body of the upper and lower stackable semiconductor packages.