Self-assembly and self-interconnection of thin RFID devices on plasma-programmed foil substrates

The paper reports on a self-assembly process that enables both self-alignment of microelectronic devices and self-interconnection of devices with the surrounding electrical wiring. The complete process was successfully demonstrated using state-of-the-art RFID devices (radio frequency identification device) which were self-connected to four metal pads on polymer foil substrates. The new self-assembly concept comprises the following steps: mask-less plasma patterning process to define target areas for die assembly on polymer tapes, application and self-alignment of a liquid assembly medium at the target area, dropping of the chip device onto the assembly liquid, self-orientation of the chip with respect to the contact pads and finally heat induced bonding and interconnection of the device.