A semiconductor package includes a first semiconductor structure including a first semiconductor layer having a first active surface and a first circuit device thereon and a first inactive surface and first bonding layer; a second semiconductor structure on the first semiconductor structure and including a second semiconductor layer having a second active surface and second circuit device thereon and a second inactive surface, a second frontside bonding layer, and a second backside bonding layer on the second inactive surface; and a third semiconductor structure on the second semiconductor structure and including a third semiconductor layer having a third active surface including a third circuit device thereon and a third inactive surface, and a third bonding layer, wherein the first bonding layer is bonded to the second frontside bonding layer, and the third bonding layer is bonded to the second backside bonding layer.