A semiconductor package structure includes a first redistribution layer, a first semiconductor die, a first through via with a first width and a second through via with a second width different than the first width, and a second redistribution layer. The first semiconductor die is disposed over the first redistribution layer. The first through via and the second through via are disposed between the first redistribution layer and the first semiconductor die. The bottom end of the first through via is substantially level with the bottom end of the second through via. The second redistribution layer is disposed over a surface of the first semiconductor die that is opposite to the first redistribution layer.