Design and Fabrication of Elastic Interconnections for Stretchable Electronic Circuits

Abstract

For biomedical and textile applications, the comfort of the user will be enhanced if the electronic circuits are not only flexible but also elastic. This letter reveals a simple mouldedinterconnect-device technology for the construction of elastic point-to-point interconnections, based on 2-D spring-shaped metallic tracks, which are embedded in a highly elastic silicone film. Metal interconnections of 3-cm long were constructed with an initial resistance of about 3 Ω, which did not significantly increase (< 5%) when stretched. A stretchability above 100% in one direction has been demonstrated.

Amorphous carbon interlayers for gold on elastomer stretchable conductors

“…To date, this has only been attempted for uni-axial loading conditions. Moreover, many groups have used photolithography and finite element modeling [20][21][22] to minimize in-plane strains. Despite these intense efforts, little is known about the metal/elastomer interface, which has been scarcely investigated, to date.…”

Interface Integrity in Stretchable Electronics

“…These interconnects are often very stretchable but the conductivity is low which limits frequency of the electronic signals. Designs following the second path mostly use metals for the interconnects adding stretchability by structuring the interconnects in mechanistic patterns which locally reduce the deformation, when they are stretched globally, similar to a helical telephone cord [5][6][7]. Although, both design paths have reliability issues, this paper focuses mainly on issues related to the second design path.…”

Solderable and electroplatable flexible electronic circuit on a porous stretchable elastomer

“…To date, several flexible or stretchable electronics for biomedical or industrial applications [3][4][5][6][7][8][9][10][11] have been developed. Metal thin-film deposition on a flexible substrate, such as polyimide (PI), has been a standard approach [12][13][14][15][16][17][18] , although the elasticity of PI is limited and thin metal patterns can tolerate only limited deformation before breaking. Metal deposition and patterning on polydimethylsiloxane (PDMS) has received attention because PDMS is stretchable and is broadly used in biomedical applications, which makes it appropriate for attaching to the skin or for implanting into the body and has been extensively applied in the biomedical field.…”

“…Metal films on PDMS, however, can sustain only limited stretching, and the stable and durable deposition of metal onto PDMS surfaces poses a great challenge. Several ingenious solutions to this problem have been described, including an accordionlike structure 18,19 , a meandering-shaped thin metal conductor on the PDMS surface 3,12,17,[19][20][21] , bonding of two-dimensional stretchable Si nanomembranes onto elastomeric PDMS slabs, or printing of elastic conductors comprising single-walled nanotubes on elastic substrates [22][23][24] . Although these technologies have contributed greatly to the development of flexible electronics, each of them still has their limits (for example, complicated fabrication processes, and direct bonding of commercialized components on highly stretching substrates).…”

“…Although several methods to bond solid island circuits to the meandering-shaped thin metal conductor by soldering [16][17][18]31 exist, they need to be encapsulated with PDMS. Thus a new paradigm is required for the direct bonding.…”