Flexible Microsystems Using Over-molding Technology

Abstract Today’s world is full of intelligent electronics and with the development of flexible printed electronics technologies, different integration approaches are of high demand. The combination of electronics with polymer is a new technology platform as it integrates multiple functionalities into plastic products. This work shows preliminary results in the integration of electronic components (e.g. NFC chips and LEDs) using over-molding technology. A significant degree of freedom in product design is obtained resulting in a low-cost fabrication of flexible smart objects. The integration is achieved by using adhesion between flexible circuits and injection molded plastics. In order to check the adhesion performance between the flexible circuit and polymer injected, the polyimide foils with patterned copper cladding were over-molded with different engineering plastics into the form of peel test specimens. The technology was shown by the realization of a demonstrator, in which LEDs are wirelessly powered using an NFC antenna and a chip. The NFC antenna is executed in the copper layer and the LEDs and NFC chip are soldered on the foil. The antenna and NFC chip can harvest the energy from (e.g. a smartphone) in order to power the LEDs. This is a simple example of wireless energy transfer that could be used to power circuits and readout sensor values using NFC without the need of having an integrated battery.