A semiconductor package includes a package substrate having a top surface and a bottom surface, and a stiffener ring mounted on the top surface of the package substrate. The stiffener ring includes a reinforcement rib that is coplanar with the stiffener ring on the top surface of the package substrate. At least two compartments are defined by the stiffener ring and the reinforcement rib. At least two individual chip packages are mounted on chip mounting regions within the at least two compartments, respectively, thereby constituting a package array on the package substrate.