Stretchable electronics offer increased design freedom of electronic products. Typically, small rigid semiconductor islands are interconnected with thinmetal conductor lines on top of, or encapsulated in, a highly compliant substrate, such as a rubber material. A key requirement is large stretchability, i.e. the ability to withstand large deformations during usage without any loss of functionality. Stretching induced delamination is one of the major failure modes that determines the amount of stretchability that can be achieved for a given interconnect design. During peeltesting, performed to characterize the interface behaviour, the rubber is severely lifted at the delamination front while at the same time fibrillation of the rubber at the peel front is observed by ESEM analyses. The interface properties are established bycombining the results of numerical simulations and peeling experiments at two distinct scales: the global force-displacement curves and local rubber lift geometries. The thus quantified parameters are used to predict the delamination behaviour of zigzag and horseshoe patterned interconnect structures. The accuracy of these finite element simulations is assessed by a comparison of the calculated evolution of the shape of the interconnect structures and the fibrillation areas during stretching with experimentalresults obtained by detailed in-situ analyses.
Sluis, van der, O., Hsu, Y., Timmermans, P. H. M., Gonzalez, M., & Hoefnagels, J. P. M. (2011). Stretching induced interconnect delamination in stretchable electronic circuits. Journal of Physics D: Applied Physics, 44(3), 1-11. . https://doi.org/10.1088/0022-3727/44/3/034008