Prestrain-free Fabrication of Stretchable Wavy Metal Interconnections on Elastomeric Substrates

C.W. Park, S.W. Jung, S.C. Lim, J.-Y. Oh, B.S. Na, J.B. Koo
Electronics and Telecommunications Research Institute, KR

Keywords: stretchable, wavy, interconnection

Summary:

Here we provide a new process for fabricating well-controlled wavy surface structures only within selected regions of an elastomeric substrate, as the platform for stretchable electronic circuits. In this process, the wavy structure of several micrometer scales is first produced within a rigid Si mold by conventional photolithography, dry etching, and photoresist coating processes, and is transferred on to an elastomeric polydimethylsiloxane (PDMS) substrate. As the wavy structure is defined by photolithography, we can locally form some flat island regions within the wavy substrate. Within the flat regions, we can locate active devices so that the influence of an external stress can be minimized, while most stress is absorbed by the wavy interconnecting region. On the one-dimensional wavy structured-PDMS surface, we can produce Au/Cr interconnects providing good stretchability (~15% resistance increase at 20% tensile strain) without any pre-stretching step. The effects of various parameters such as metal deposition condition, the configuration or dimension of wavy structures have also been investigated quantitatively.