Micromachining of Transparent, Semiconducting and Metallic Substrates Using Femtosecond Laser Beams

Cutting and drilling of different materials (dielectrics, metals and semiconductors) up to 2.5 milimeters thick was carried out by laser ablation with focused femtosecond laser pulses beneath a water layer which covered the samples. The applied method demonstrated good results in term of fabrication throughput and end-quality compared to conventional fabrication in air. The improved fabrication outcomes are related to the nonlinear transformation of the femtosecond beam and enhanced removal of ablation debris by cavitation bubble collapse. We demonstrate actual cutting speeds as high as 0.3 mm/s for transparent materials (1 mm thick), 0.15 mm/s for metals (1 mm thick), 3 mm/s for semiconducting samples (0.4 mm thick). In addition, the through-cuts have a tapper angle below 2 % and surface roughness equals approximately 5 μm.