The present invention relates to a reflow film containing a thermoplastic resin which is dissolvable in a solvent, and solder particles, wherein the solder particles are dispersed in the film, and also relates to a solder bump formation method which comprises: (A) a step of mounting the reflow film on the electrode surface side of a substrate, (B) a step of mounting and fixing a flat plate, (C) a step of heating, and (D) a step of dissolving and removing the reflow film, and herewith, a reflow film is provided which, by causing localization of the solder component on the electrodes of the substrate by self-assembly, exhibits excellent storage properties, transportability and handling properties during use, and can form solder bumps or solder joints selectively on only the electrodes.

Embodiments of the present disclosure are directed to integrated circuit (IC) package assemblies with magnetic contacts, as well as corresponding fabrication methods and systems incorporating such magnetic contacts. A first IC substrate may have a first magnet coupled with a first electrical routing feature. A second IC substrate may have a second magnet coupled with a second electrical routing feature. The magnets may be embedded in the IC substrates and/or electrical routing features. The magnets may generate a magnetic field that extends across a gap between the first and second electrical routing features. Electrically conductive magnetic particles may be applied to one or both of the IC substrates to form a magnetic interconnect structure that extends across the gap. In some embodiments, magnetic contacts may be demagnetized by heating the magnets to a corresponding partial demagnetization temperature (PDT) or Curie temperature. Other embodiments may be described and/or claimed.