In one embodiment, a method of forming a semiconductor device includes stacking a second wafer with a first wafer and forming a through via extending through the second wafer while the second wafer is stacked with the first wafer. In another embodiment, a method of forming a semiconductor device includes singulating a first wafer into a first plurality of dies and attaching the first plurality of dies over a second wafer having a second plurality of dies. The method further includes forming a through via extending through a die of the first plurality of dies after attaching the first plurality of dies over the second wafer.