Short, Stretchable Molded Interconnect reliability under 10% cyclic elongation

SMI (Stretchable Molded Interconnect) technology allows for realization of PCB-like manufactured electronic systems with intrinsic ability to be bent and locally stretched multiple times. The elasticity is obtained by introduction of meandered, electrical tracks that have the ability to follow the deformation of its PDMS encapsulation without electrical failure. This work investigates the endurance of 4 different meander-based interconnect types in a cyclic stretching test until 10% elongation. By modeling the failures of the unsupported copper interconnect (e.g. no polyimide support) with Weibull distribution we show that it can sustain up to 5000, 10% elongation cycles below 1% failure probability. Parameters of the distributions are compared between different interconnect geometries. SMI processing parameters critical to reliability are indicated based on failure analysis of poorly performing interconnects.