The invention provides a semiconductor package with a through silicon via (TSV) interconnect. An exemplary embodiment of the semiconductor package with a TSV interconnect includes a semiconductor substrate, having a front side and a back side. A contact array is disposed on the front side of the semiconductor substrate. An isolation structure is disposed in the semiconductor substrate, underlying the contact array. The TSV interconnect is formed through the semiconductor substrate, overlapping with the contact array and the isolation structure.