A microelectronic package is provided. The microelectronic package includes a substrate, a die coupled to a top surface of the substrate and a integrated heat spreader thermally coupled to the die, wherein the integrated heat spreader comprises integrated heat spreader walls. The microelectronic package also includes a thermal interface material disposed between the die and the integrated heat spreader and an underfill material disposed between the integrated heat spreader and the substrate, wherein the underfill material is disposed within gaps between the integrated heat spreader walls, the die and the thermal interface material.