A semiconductor package includes a first die, a plurality of second dies and a through via. The second dies are disposed over and electrically connected to the first die. The through via is disposed between the second dies and electrically connected to the first die. The through via includes a first portion having a first width and a second portion having a second width different from the first width and disposed between the first portion and the first die. The first portion includes a first seed layer and a first conductive layer, and the first seed layer is disposed aside an interface between the first portion and the second portion.