Towards alternative 3D nanofabrication in macroscopic working volumes

Abstract

This paper gives an overview of the research carried out at TU Ilmenau towards the development and application of tip- and laser-based nanofabrication on flat and curved surfaces in extended macroscopic working areas. It is shown that sub-10 nm structures can be fabricated by scanning probe lithography (SPL). The use of soft stamps has revealed their suitability for nanoimprinting on curved surfaces. Laser-based methods for a maskless exposure of resist on curved surfaces utilising 405 nm laser diodes have already been tested successfully. Furthermore, the current work deals with two-photon polymerisation, which has great potential with regard to the fabrication of sub-wavelength structures. At present, the methods mentioned have all been applied only in working ranges <100 × 100 μm2 in the plane and <10 μm in height. To overcome these limitations, the nanofabrication techniques are now being integrated in the nanopositioning and measuring machines (NPMMs) developed at TU Ilmenau. They offer working volumes of up to 200 × 200 × 25 mm3 with a positioning resolution of 20 pm. To provide access to any geometry elements in the 3D space with nanometre precision, the machine concepts as well as the metrological concepts are further developed. Due to the increased demands of lowest trajectory deviations within the fabrication process, new real-time controllers for probing and fabrication systems are investigated, as well as interactions in combined force and positioning sensors. Further important research is carried out into interference lithography, to enable an exposure of non-planar substrates and to improve the lateral structure resolution at the same time. A mix-and-match combination of such methods that allows the simultaneous exposure of large substrate regions with nanofabrication methods such as SPL becomes possible on the basis of the NPMMs, and is another area of great potential with regard to the research work presented in this paper.