Embodiments of a method of attaching an integrated circuit (IC) die to a substrate are disclosed. In one embodiment, at a first temperature, a solder disposed between the IC die and substrate is reflowed. The reflowed solder is allowed to solidify to form electrical connections between the IC die and substrate. At a second temperature less than the first temperature, a liquid curable underfill material is placed in a gap between the IC die and substrate, and this underfill material may be placed in the gap, at least in part, by capillary action. The second temperature is maintained while curing the underfill material, and this second temperature is below a melting temperature of the solidified solder. Other embodiments are described and claimed.