Gas assisted microstructuring of ceramic materials irradiated with excimer lasers

Because of their specific properties, i.e., emission of UV-radiation and pulse length in the range of several 10 ns which results in high intensities, excimer-lasers enable surface modification and micro processing of brittle and thermoshock sensitive materials. Surface treatment near the removal threshold generates a planarization or an increasing roughness, depending on the fluence. The generation of thin conductive layers is possible when radiating AlN-ceramics, with higher fluence and adapted feed rate. The influence of process parameters on the resistance is pointed out in the first part of this paper. With increasing fluence, a homogeneous removal with minimum dimensions of a few microns and high contour sharpness can be achieved. The gas ambience of the process can avoid or induce chemical reactions. The second part of this paper deals with the effect of process gas on the removal of ceramic materials. Using Si3N4 as an example, the influence of reactive gas on the removal geometry and the plasma formation is represented.