Inkjet printing and argon plasma sintering of an electrode pattern on polymer substrates using silver nanoparticle ink

Inkjet printing and plasma sintering of a silver electrode pattern on polymer substrates for applications in microfluidic systems is presented. The pattern consists of several finger electrodes and contact pads that exhibit lateral dimensions of 30 × 80 mm2 The pitch between neighboring finger electrodes is 270 m and the smallest linewidth of the finger electrodes realized is 90 m. Commercially available silver nanoparticle dispersion is used as ink. The electrode layout is printed onto a cyclic olefin polymer (COP) substrate. Prior to printing the substrate is activated using argon plasma in order to ensure good wetting. The as-printed features are then sintered using argon plasma. This sintering technique enables sintering of the nanoparticles in a selective manner without heating the substrate above its glass transition temperature. Sintering times are in the range of 5 to 15 minutes and the resulting resistivity of the printed features is approximately 57 times the bulk silver value.