A semiconductor package is fabricated by attaching a first component to a second component. The first component is assembled by forming a first redistribution structure over a substrate. A through via is then formed over the first redistribution structure, and a die is attached to the first redistribution structure active-side down. The second component includes a second redistribution structure, which is then attached to the through via. A molding compound is deposited between the first redistribution structure and the second redistribution structure and further around the sides of the second component.