A method for manufacturing a flip chip package includes preparing an IC chip that includes an active surface on which electrode pads are formed, attaching a heat dissipater to a backside of the IC chip with a thermal interface material (TIM), providing a flux filler layer on a substrate, where the substrate includes a plurality of land pads each corresponding to each of the plurality of electrode pads, and mounting the IC chip to the substrate with the active surface facing the substrate. The method further includes forming metal connectors on each of the corresponding plurality of electrode pads of the IC chip, and forming an electrical interconnection between the land pads of the substrate and the plurality of metal connectors by soldering the metal connectors to the land pads. The heat dissipator may be a hermetic heat spreader having a pair of opposite ends bent toward the substrate, which are hermetically sealed to the substrate.