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Laser technology has been applied in more and more areas of research. With its fast growth, faster and cheaper solution can be found in different industries. In this paper we present two applications of laser on LED and semi-conductor manufacturing. A new approach facilitated by laser micromachining for improving LED efficiency is introduced first. This is through change of stacking structure and the precision of up-to-date UV 355nm laser technology. The illumination area is increased due to the smaller connecting area (drilling size). Another work is the improving of leakage current of TiO2 film as dielectrics. Through the irradiation of 532nm DPSS laser the refractive index increases and the current leakage is reduced.

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Cracks induced by metal fatigue and structural aging effect can’t be fixed by traditional Gas Tungsten Arc Welding (GTAW), consequently cause the increasing of defect ratio. Although some cracks might be acceptable and qualified to field service standard subject to the military regulation, however, in certain areas, e.g. brazing and coating areas, the results are not ideal especially the HAZ and residual stress. In this study, Nd-YAG Laser welding and traditional GTAW processes were performed on Hastelloy X superalloy for comparison. Post-welding residual stress distribution was measured by X-ray diffraction method. Macro- and microstructure were observed by metallurgical OM and SEM in comparison to the hardness testing. Tensile test results show that traditional welding technology has better ultimate tensile strength and ductility. For the Nd:YAG laser welding, residual stress is limited to 3mm of the both sides of weld and drops drastically, while higher amplitude and widely spread in the GTAW welding. It is proposed that combining both methods, the repairing process can be optimized to reduce the defect ratio and save repairing time.