A semiconductor package comprises a top package and a bottom package with a plurality of fan-out interconnect structures. A plurality of inter-package connectors are formed inside a gap between the top package and the bottom package. A conductive protection layer is formed over the semiconductor package, wherein the conductive protection layer seals the gap around its perimeter, wherein the conductive protection layer covers an upper surface and a side wall of the top package, and wherein the conductive protection layer covers portions of an upper surface of the bottom package that extend beyond a boundary of the top package and a top portion of a side wall of the bottom package.