US Patent 11710672 Microelectronic package with underfilled sealant

Embodiments may relate to a method of forming a microelectronic package with an integrated heat spreader (IHS). The method may include placing a solder thermal interface material (STIM) layer on a face of a die that is coupled with a package substrate; coupling the IHS with the STIM layer and the package substrate such that the STIM is between the IHS and the die; performing formic acid fluxing of the IHS, STIM layer, and die; and dispensing, subsequent to the formic acid fluxing, sealant on the package substrate around a periphery of the IHS.