Fabrication of Molded Interconnection Devices by Ultrasonic Hot Embossing on Thin Polymer Films

Ultrasonic hot embossing allows fabrication of metal patterns onto a polymer film with a low cost and rapid process. A polymer layer with a thin metal film on top is welded onto the polymer substrate where there are protruding micro structures on the tool. Edges around the protruding structures cut the metal layer and ensure electrical insulation. The entire process performs in a few seconds. The non-welded areas are mechanically removed after this process. An antenna of a radio frequency identification device (RFID) and a flexible membrane keyboard were fabricated by embossing 10- mum-thick conductive paths from an aluminum foil onto polypropylene films, 150 and 250 mum in thickness. Antenna circuits have been proven to show the expected resonance frequencies and the keyboard was successfully employed as an input device for a PC.