Minimizing Defect on Ti Thin Film Laser Ablation using Square Flat-top NIR Femtosecond Laser for Thin Film Transistor of µ-LED Repair

In this paper, we report on the ablation of Ti thin films with a thickness of 100 nm, while minimizing defects. Ti thin films are used in the TFT of -LEDs, and repair processing is required to increase the production yield of -LEDs. The repair process involves selectively ablating specific regions with a femtosecond laser, which must be done with precision to ensure proper TFT operation. Precise ablation means that defects, such as burrs, ripples, and substrate ablation, do not occur. To implement minimizing defects, we conducted COMSOL Multiphysics simulations using both Gaussian and flat-top beams. We irradiated the sample with a laser under various conditions, including pulse fluence, number of pulses, and beam deformation, and assessed the resulting ablation quality. Through careful selection of the laser conditions, which include flat-top beam with 0.28 J/cm 2 fluence and 7 pulses, we were able to minimize burrs, ripples, and substrate ablation, resulting in neat and minimizing defect of 100 nm Ti ablation.