An electronic assembly includes a substrate, a device attached to the substrate, and a thermally conductive heat spreader covering the device and at least a portion of the substrate. A metal substantially fills the space between the device and the thermally conductive heat spreader. A method includes attaching at least one die to a substrate, placing a thermally conductive heat spreader over the die, and injecting a molten metal material into the space between the thermally conductive heat spreader and the die.