The present invention relates to a method for packaging a semiconductor die assembly. In one embodiment, a method is directed to packaging the semiconductor die assembly having a first die and a plurality of second dies arranged in a stack over the first die, wherein the first die has a peripheral region extending laterally outward from the stack of second dies. The method can comprise coupling a thermal transfer structure to the peripheral region of the first die and flowing an underfill material between the second dies. The underfill material is flowed after coupling the thermal transfer structure to the peripheral region of the first die such that the thermal transfer structure limits lateral flow of the underfill material.