Analysis of thermal effect on transparent conductive oxide thin films ablated by UV laser

Transparent conductive oxide thin films are applied to many computer, communication and consumer electronics products including thin film transistor liquid crystal displays, organic light emitting diodes, solar cells, mobile phones, and digital cameras. The laser direct write patterning of the indium tin oxide (ITO) thin film processing technique produces a heat affected zone that has an enormous effect on the electro-optical efficiency of transparent conductive oxide films. This is because direct laser writing patterning in thermal machining process can create debris and micro-cracks in the substrate. Therefore, this study establishes the ultraviolet (UV) laser ablation of temperature model on the polycarbonate and soda-lime glass substrates using the finite element analysis software ANSYS, and measures the temperature field based on the laser micro-patterning process. The meshing model determines the structure of the pre-processors and parameters were set with ANSYS parameter design language. This study also simulates the Gaussian distribution laser irradiation on the pre-processor structure. A UV laser processing system made micro-patterning on ITO thin films to analyze which conditions damaged the substrates. Comparing the simulation and experiment results reveals the minimum laser ablation threshold of the ITO thin films with the melting and vaporization temperatures. Simulation results show that the temperature distribution on PC and soda-lime glass substrates after laser irradiation of 1.05 μs with a laser output power of 0.07 W produces temperatures of approximately 52 °C, 54 °C and 345°Cand 205 °C at the laser output power of 0.46 W. The experiment results show that the patterning region is similar to the simulation results, and the lower laser power does not damage the substrates.