A flip chip ball grid array (FCBGA) comprises a substrate, a cavity forming ring stiffener, an external heat sink, and a thermal interface material. The cavity forming ring stiffener is disposed on the substrate. The cavity forming ring stiffener has a segment which forms a cavity with the substrate, and exposes a top of the silicon chip. The external heat sink is disposed on the silicon chip and the segment of the cavity forming ring stiffener. A thermal interface material separates the segment of the cavity forming ring stiffener and the top of the silicon chip from the external heat sink and conducts heat from the silicon chip to the external heat sink.