Fabrication of well-controlled wavy metal interconnect structures on stress-free elastomeric substrates

[Display omitted] •A method for forming elastomeric substrates with wavy surface profiles is proposed.•The wavy profile is formed on a stress-free substrate without any pre-straining.•Waves of arbitrary sizes and orientations can be formed only within selected areas.•The wavy substrate is employed as a platform for stretchable metal interconnects.•Metal interconnects on the wavy substrate show a good stretching performance. We propose a new technique for fabricating well-controlled wavy surface structures on an elastomeric substrate at a few-micrometer scale without any pre-stretching and deposition steps, as the platform for stretchable metal interconnects. In this process, the wavy structure is defined by photolithography on a stress-free elastomeric substrate, so that we can provide various types of wavy profiles for metal interconnects with arbitrary sizes and orientations within a single substrate. As the wavy structures can be formed only within selected regions while keeping the whole substrate area free of strain, it may be possible to fabricate entire circuitry including active devices directly on the elastomeric substrate with no need for mechanical transfer steps. The present technique can provide a practical strategy for realizing large-area stretchable electronic circuits, for various applications such as stretchable display or wearable electronic systems.