Flexible and stretchable redistribution layer with embedded chips for human-machine interface

Suitable stretchable electronics is the key to promote future human-machine collaboration to facilitate processes in daily life. Sensors and actuators on humans will enable a close and yet unhesitating interaction with robots by translating data between biological and technical systems. This paper describes our first approach for chip integration and stretchable interconnect manufacturing in order to achieve reliable stretchable interconnects. Therefore inkjet printed silver horseshoe-interconnects with a radius of 500µm on spin coated polyurethane substrate are tested on a self-developed stretch test setup. More than 400 stretch and release cycles on 10% and 20% stretching were achieved. Furthermore, a polymer chip-embedding process by polymer casting is shown to apply fan-out redistribution layer directly on thin chip carrier. Those carriers can be integrated in stretchable foils in order to achieve miniaturized and low-profile assemblies for human-machine interfaces.