The invention provides a semiconductor package assembly. The semiconductor package assembly includes a first semiconductor package and a second semiconductor package overlying a portion of the first semiconductor package. The first semiconductor package includes a first redistribution layer (RDL) structure, a first semiconductor die and a molding compound. The first semiconductor die is disposed on a first surface of the first RDL structure and electrically coupled to the first RDL structure. The molding compound is positioned overlying the first semiconductor die and the first surface of the first RDL structure. The second semiconductor package includes a first memory die and a second memory die vertically stacked on the first memory die. The second memory die is electrically coupled to first memory die by through silicon via (TSV) interconnects formed passing through the second memory die.