ITO patterning by a low power Q-switched green laser and its use in the fabrication of a transparent flow meter

A new ITO patterning method is reported and then applied for fabricating a transparent gas flow meter. Laser-induced backside wet etching using a low power green laser (visible-LIBWE) was used for direct-write ITO patterning. The obtained ablation result shows a smoother surface and less debris than that obtained from front-side laser ablation. Surface quality was examined by SEM, energy dispersive spectroscopy, electron spectroscopy for chemical analysis and surface profiler, and was compared to the etching result by UV and IR lasers. Electrical isolation was obtained using this new ITO ablation method. The method was then utilized in fabricating a transparent gas flow meter. The gas flow was measured by monitoring the resistance change of ITO micro strips by a multimeter. The flow meter's detection limit was estimated to be 0.24 ml min −1 and its response time was 2.6 s.