Ablation morphology and defect analysis of Ti thin film irradiated by femto- and picosecond laser for fine ablation of Micro-LED display thin film transistor repair

The titanium (Ti) thin film is a material used in the thin-film transistor (TFT) of Micro-LED display and require partial processing during repair processes. For a suitable repair process, defects such as particles, droplets, and burrs should not be present during processing. In this study, Ti with a thickness of 100 nm was ablated by varying pulse duration and fluence with a wavelength of 1026 nm. In case of the pulse duration, it was set to 190 fs, 1 ps, 10 ps. Ablation thresholds of 0.116 J/cm² for 190 fs, 0.124 J/cm² for 1 ps, and 0.13 J/cm² for 10 ps were obtained. The Two-Temperature Model (TTM) equation was applied to simulate the ablation using COMSOL Multiphysics. Based on the simulation, it was observed that short pulse durations and low fluences near the ablation threshold can suppress burrs, particles, and droplets. Although various defects need to be addressed still exist, this foundational processing is expected to be helpful to study for Micro-LED display TFT repairing.