A semiconductor package includes a package substrate, an interposer mounted on the package substrate via first conductive bumps; first and second semiconductor devices on the interposer and spaced apart from each other, mounted on the interposer via second conductive bumps and having concavo-convex patterns respectively formed in upper surfaces thereof; and a sealing member on the interposer covering the first and second semiconductor devices and exposing the concavo-convex patterns. The concavo-convex pattern of the first semiconductor device includes a plurality of first pillar structures provided in the upper surface of a first region of the first semiconductor device and having a first width, and a plurality of second pillar structures provided in the upper surface of a second region of the first semiconductor device and having a second width greater than the first width.