Precision structuring and functionalization of ceramics with ultra-short laser pulses

High-performance ceramics have been firmly established for the manufacturing of tools and components in the modern electronics industry and mechatronics. Various components such as circuit boards, bearings, and sensors benefit from their specific characteristics, such as wear resistance, stiffness, and electrical neutrality. Apart from these advantages, the brittleness and hardness of ceramics turn the mechanical processing into a challenging and difficult task. Against this background, modern laser technologies have already been used to process ceramics for many years, enabling a contactless and wear-free machining. However, regarding high precision applications, for instance, the drilling of micro-holes or the fabrication of well-defined cavities and three-dimensional structures, conventional laser processes reach their limits. Especially due to thermal influences of the laser radiation, brittle edges, stresses, and redeposited layers emerge. Ultrashort pulse lasers enable completely new processing qualities in these fields. The extremely short pulse durations within the pico- and femtosecond range lead to nonlinear absorption mechanisms and an almost athermal material removal. Thereby, dielectric materials can be processed precisely and gently. In the course of a comprehensive process study, the beam–material interactions of ultrashort pulses with ceramics have been investigated. Besides the material properties, the ablation process is influenced by a multitude of laser parameters, such as wavelength, pulse overlap, and fluence. In order to reveal the most important variables, the experiments have been conducted by applying modern statistical methods. Using alumina (Al2O3) as an example, it is shown how different parameter regimes lead to disparate process qualities and efficiencies. The generated models have been used to optimize industrially interesting applications, from the separation of ceramic printed circuit boards to the realization of precise design structures.