A semiconductor package including a semiconductor chip; a lower redistribution layer on a lower surface of the semiconductor chip; a lower passivation layer on a lower surface of the lower redistribution layer; a UBM pad on the lower passivation layer and including an upper pad and a lower pad connected to the upper pad, the upper pad having a greater horizontal length at an upper surface thereof than a horizontal length at a lower surface thereof; a seed layer between the lower passivation layer and the UBM pad; and an external connecting terminal on a lower surface of the UBM pad, wherein the seed layer includes a first seed part covering a side surface of the upper pad, a second seed part covering a portion of the lower surface of the upper pad, and a third seed part covering a portion of a side surface of the lower pad.