Screen-Printed Stretchable Interconnects

This article focuses on characterization of screen printed electrical interconnects for wearable applications. The interconnects are screen printed with stretchable silver-based ink on a thermoplastic polyurethane film. By optimizing the process parameters, we were able to fabricate 200 μm line widths with spacing of 200 μm. The average sheet resistance is 36.2 mΩ/□, however a significant lot-to-lot deviation was noted. In the strain tests, half of the samples have lost conductivity when 74.1% strain is reached. The normalized resistances of the samples rise linearly to approximately 30 % strain, after which the growth rate and deviation between samples increases significantly. It was also discovered that no cracking can be found from the traces while subjected to strains under 30%.