| abstract |
The present inventions relate generally to methods for packaging integrated circuits using thin foils that form electrical interconnects for the package. The foil includes a base layer (such as copper) with an optional plating layer (such as silver) suitable for improving adhesion of the bonding wires (or other connectors) to the foil. The base layer (or the plated surface if the foil is preplated) of the foil is patterned by laser ablation to define components (e.g. contacts) of a device area. The patterning is arranged to ablate entirely through selected portions of the plating layer and part, but not all, of the way through corresponding underlying portions of the base layer. In some embodiments, the metallic foil is partially etched after the laser ablation in order to deepen the trenches that define the patterning of the foil. Multiple dice may then be attached to die attach pad areas of the plated foil and electrically coupled to electrical contacts. Some embodiments contemplate encapsulating the dice, bonding wires, and portions of the plated foil with a plastic molding material. Portions of the metallic foil may then be removed by etching, laser ablation, or grinding. The resulting structure may then be singulated to form individual integrated circuit packages. |