Micro devices integration with stretchable spring embedded in long PDMS-fiber for flexible electronics

This study presents a PDMS (Polydimethylsiloxane) fiber integrated with multi devices scheme using stretchable electroplating copper spring. Each device was located on the node and embedded in PDMS-fiber. Thus, devices are mechanically connected by PDMS-fiber and electrically connected by inner stretchable spring. Thus, large-area and flexible applications can be achieved. Advantages of this approach: (1) length magnification by stretchable spring; (2) thicker stretchable spring embedded in PDMS provides well mechanical and electrical characteristics; (3) node acts as a hub for devices implementation and integration; (4) partially stretched spring could reduce the resistance variation by external loads. A 6.2cm PDMS-fiber with sensors and LED is implemented using a 2.4cm node-spring components fabricated on 4-inch wafer. PDMS-fiber longer than 30cm can be achieved using different spring design.