Flexible printed circuits (FPCs) are widely used in electronic devices such as movable part line or wearable sensor. Inkjet printing is attracting attention because it can draw electric lines of any shape without a photo mask. The mechanical characteristics such as flexibility or durability of electric lines have been evaluated by bending and tensile tests. Moreover, the reliability characteristics of metal particle ink lines under electric current loading have been recently evaluated. However, the electronic line has not been evaluated under both the mechanical stress due to bending deformation and the electrical stress due to electric current. According to scaling down of electric devices, the current density and Joule heat in interconnect line increase and electromigration (EM) damage becomes a serious problem. EM is a transportation phenomenon of metallic atoms caused by electron wind under high-density electric current. Reducing EM damage is extremely important to enhance device reliability. In this study, high-density current loading tests of flexible electronic line were conducted under bending deformation of the substrate in order to investigate the effect of mechanical stress on the EM damage of the electronic line.
As the results of current loading tests, the specimens with bending deformation became open circuits in shorter time than that without bending deformation. Therefore, it is considered that the bending deformation is affected on the electric reliability characteristic of the flexible electronic lines reflecting EM damage.