Underfill dispense at substrate aperture

Disclosed are methods for dispensing underfill material in an IC assembly having a die mounted on a substrate with a gap therebetween. One or more aperture is provided in the substrate for receiving underfill material into the gap. Underfill material is dispensed into the gap through the one or more apertures, thereby filling the gap with underfill material and providing a favorable flow rate and improved underfilling. Embodiments of the invention are disclosed in which capillary action, a vacuum, or positive pressure, are used to assist in the flow of the underfill material.