A semiconductor package which includes a first substrate having a pre-designed pattern formed thereon; a first chip mounted by a flip chip method on one side of the first substrate; a support formed to a predetermined thickness on an edge of the first substrate; an interposer having an edge thereof placed on the support, such that the interposer covers the first substrate and forms a cavity between the interposer and the first substrate, and having a pre-designed pattern formed respectively on both sides thereof; a via penetrating the support and the interposer; a second chip mounted on one side of the interposer facing the first substrate; a second substrate placed on the other side of the interposer with at least one conductive ball positioned in-between; and a third chip mounted on the second substrate.