An RF semiconductor package includes a substrate having generally planar top and bottom surfaces. The substrate includes a metallic base region and one or more metallic signal terminal regions extending from the top surface to the bottom surface, and an insulative material separating the metallic regions from one another. The bottom surface of an RF semiconductor die is surface-mounted to the base region at the top substrate surface. The RF semiconductor die has a terminal pad disposed at a top surface of the RF semiconductor die. The terminal pad is electrically connected to one of the signal terminal regions at the top substrate surface. A lid is attached to the top substrate surface so that the RF semiconductor die is enclosed by the lid to form an open-cavity around the RF semiconductor die. The base and signal terminal regions are configured for surface-mounting at the bottom substrate surface.