An electronic device is attached to a first surface of a board which includes vias. A heat sink precursor for the electronic device is attached to the second surface of the electronic board. The heat sink precursor includes a cavity facing the vias. A wave of solder paste is applied to the second surface. The solder paste penetrates into the cavity of the heat sink precursor and flows by capillary action through the vias to weld a thermal radiator and/or electronic contact of the electronic device to the vias. The solder paste further remains in the cavity to form a corresponding heat sink.