1. A semiconductor structure, comprising:a substrate having a front side surface and a back side surface;
at least one semiconductor device disposed on the front side surface;
a through-substrate via (TSV) disposed in the substrate, wherein the TSV is exposed by the front side surface and the back side surface, and the TSV is electrically connected to the semiconductor device;
a shield structure disposed in the substrate and surrounding the TSV, wherein the shield structure is exposed by the front side surface, the shield structure is electrically isolated from the TSV, and the shield structure and the TSV having bottom ends at different heights; and
a first dielectric layer covering a side surface and a bottom surface of the shield structure, wherein the back side surface of the substrate is lower than a bottom surface of the first dielectric layer.