A semiconductor device having one or more through-silicon vias (TSVs) is provided. The TSVs are formed such that sidewalls of the TSVs have a scalloped surface. In an embodiment, the sidewalls of the TSVs are sloped wherein a top and bottom of the TSVs have different dimensions. The TSVs may have a V-shape wherein the TSVs have a wider dimension on a circuit side of the substrate, or an inverted V-shape wherein the TSVs have a wider dimension on a backside of the substrate. The scalloped surfaces of the sidewalls and/or sloped sidewalls allow the TSVs to be more easily filled with a conductive material such as copper.