Design and performance of metal conductors for stretchable electronic circuits

Purpose - The purpose of this paper is to present an update on the progress of the design and reliability of stretchable interconnections for electronic circuits. Design/methodology/approach - Finite element modelling (FEM) is used to analyse the physical behaviour of stretchable interconnects under different loading conditions. The fatigue life of a copper interconnect embedded into a silicone matrix has been evaluated using the Coffin-Manson relation and FEM. Findings - The mechanical properties of the substrate and the design of the metal interconnection play an important role on the fatigue lifetime of circuit. In the case of copper embedded into a PDMS Sylgard 186, more than 2,500 tensile cycles have been observed for a periodic deformation of 10 per cent. Research limitations/impiications - Reliability results are limited and need further work to create a more accurate empirical model to estimate the lifetime of stretchable interconnections. Originality/value - The combined use of FEM and experimental analysis enable a more reliable design of the stretchable metal interconnections. The proposed horseshoe design offers the benefit of reduced permanent damage during elongation.