Semiconductor materials are still the material of choice also in many microsystems applications. This is mainly justified by the availability of mature processes and equipment originally developed for microelectronics fabrication. However, for microsystems more flexible requirements have to be fulfilled and new tools have to be developed especially with regard to smaller part numbers than in microelectronics. But also in microelectronics, conventional machines have often reached their limits in semiconductor processing which leads to the requirement of new processes. Lasers are generally able to ablate semiconductor materials. Especially ultrafast lasers are able to perform processes with high efficiency and accuracy. One of the most challenging conditions is not to influence the bulk material. Within this paper, the general interaction of ultrafast lasers with semiconductors is investigated. The ablation process is outlined and beam parameters influencing the removal and especially the cutting process are described, and potential applications are shown.