Soft and Flexible 3D-Structured Device with Crack-Free Metal Patterns

This paper proposes a fabrication technique of 3-dimensional (3D) soft and flexible devices with embedded crack-free metal patterns. After the selective bonding between PDMS and parylene-C, additional MEMS techniques such as patterning of conductive lines and pads can be processed on a 2D plane before the transformation into a 3D structure. Moreover, the fabrication processes have been optimized to achieve crack-free metal patterns, because the microcracks in metal patterns could affect the electrical connections and the life-time of soft and flexible devices. Based on the advantageous material characteristics such as flexibility, softness, and biocompatibility, the 3D-structured devices are expected to be used as implantable biomedical devices for various prospective applications.