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 μm and the smallest linewidth of the finger electrodes realized is 90 μm. 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.