A semiconductor package includes a substrate which includes a chip mounting unit disposed on a first surface thereof and a pad forming unit disposed on an outer region of the chip mounting unit. The semiconductor package further includes a plurality of pads disposed on the pad forming unit of the substrate, a semiconductor chip disposed on the chip mounting unit of the substrate, a dam disposed on the first surface of the substrate between the semiconductor chip and the pad forming unit, and wherein the dam separates at least a portion of the pads from the semiconductor chip. In addition, the semiconductor package further includes an underfill material disposed between an active surface of the semiconductor chip and the first surface of the substrate and wherein an upper surface of the dam is rounded due to surface tension.