Ultra slim RF package for ultrabooks and smart phones

A semiconductor device package having reduced form factor and a method for forming said semiconductor device are disclosed. In an embodiment, an active die is embedded within a cavity in the core layer of the package substrate, wherein an in-situ electromagnetic shield is formed on the sidewalls of the cavity. In another embodiment, a crystal oscillator is at least partially embedded within the core layer of the package substrate. In another embodiment, a package having a component embedded in the core layer is mounted on a PCB, and a crystal oscillator generating a clock frequency for the package is mounted on the PCB. By embedding components within the core or removing components from the package to be mounted directly on the PCB, the x, y, and z dimensions of a package may be reduced. In addition, in-situ electromagnetic shield may reduce EM noise emitted from the active die.