Laser-microfabrication with accurate positioning and metrological traceability

The positioning range of ultra precise positioning systems is restricted to certain hundreds of micrometers in lateral direction due to the application of piezoelectrical stages. Using galvanometer scanner, the range is limited even to tens of micrometer or by restriction of accuracy. Direct laser writing processes can be done with a combination of both positioning techniques, but structures in the millimeter range can only be achieved by using stiching methods. The nanopositioning and nanomeasuring machine NMM-1, developed at TU Ilmenau together with SIOS Meβtechnik GmbH, provides a large positioning volume of 25 mm × 25 mm × 5 mm with a positioning resolution in the sub-nanometer range. A combination of this precise positioning machine with common laser writing tools like UV direct laser writing or two-photon polymerization enables to produce structures with metrological traceability. The laser writing techniques base on both one-photon absorption and two-photon processes in the used photosensitive materials. Therefore, a 405 nm fiber-coupled laser diode for the one-photon processes and a 805 nm femtosecond laser are guided through an objective onto the positioning stage of the NMM-1. In first experiments, structures with sub-10 μm linewidths could be achieved. Furthermore, a probe system consisting of a hologram laser unit with a wavelength of a 650 nm is applied to the setup to control the focus spot of the machining laser onto the sample’s surface. That leads to a further decrease in the linewidths of the structures.