Thermoplastic packaging and embedding technology for ID-cards

State of the art ID-cards contain an RFID chip connected to a wired copper coil. For advanced smartcard applications the security-relevant data processing will be transferred from public terminals into the smartcards itself. In this paper we demonstrate the possibility to realize complex circuitries in polycarbonate based ID-cards by using a combination of printed circuit technology and conventional assembly-processes. With this approach a very high packing density for the circuitry consisting of the wiring architecture and components (active and passive) can be achieved. The realized ID-card demonstrator consists of a 125 m thick polycarbonate inlay containing active and passive components, an antenna, a capacitive key pad and an OLED-display. The inlay is encapsulated by lamination of polycarbonate foils resulting in an 800 m thick card body. The inlay is equivalent to a double sided printed circuit board. For its fabrication through holes are drilled in a copper-clad polycarbonate (125 m polycarbonate foil, with 12 m copper on both sides) and electroplated, followed by copper structuring and application of a silver finish. The chemical stability and handling of polycarbonate in PCB processing was excellent. Components are assembled using different types of conductive adhesives: ICA for passives, ACA for ICs, and ACF for OLED. Assembly of chips with fine contact structures was possible due to the precise Cu-structuring of the inlay: line/space is 50 m and 40 m, respectively. For the encapsulation cavities are milled into polycarbonate foils to accommodate component topographies. The prepared foils are then laminated onto the inlay to yield an 800 m thick ID-card. The electronic system is hermetically sealed and still flexible like a standard ID-card.