Parametric studies on pulsed near ultraviolet frequency tripled Nd:YAG laser micromachining of sapphire and silicon

The use of a near ultraviolet Nd:YAG laser for rapid micromachining of sapphire and silicon has been systematically investigated. Cutting, marking and surface ablation of both materials have been produced by direct writing using a high-speed x-y galvanomechanical beam positioner. Machining results such as ablation rate and efficiency are discussed. The results show that the quality and efficiency of the laser machining depend on several factors, including focus length, beam feed rate (cutting speed) and the pulse repetition rate. The surface morphology and ablation rate indicate that the laser ablation process of sapphire could be a mixed photothermal and photochemical process, while that of silicon appears be dominated by a photothermal process when using a near UV nanosecond pulses.