Production of specific 3D nano-particles and nano-structures for the development of an automated optical characterization using high-resolution interference microscopy

• Applicants: Professor Dr. Hartmut Hillmer; Professor Dr.-Ing. Peter Lehmann
• Subject Area: Measurement Systems
• Term: from 2017 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 390307847

This project is about the production and interferometric characterization of curved structures in the micro- and nanometer range. The structures are produced using nanoimprint lithography (NIL) and measured using a novel characterization method based on a Linnik white-light interferometer. The aim is to expand the NIL process with regard to the variety of shapes and materials to complex 3D structures and to establish a fast, non-contact but high-resolution method, with which even difficult geometries can be measured. When developing the measurement setup and methodology, selected structures with defined geometries and materials are used. In this way, both working groups involved complement each other and develop beneficial synergies.In the first phase of the project, the production of semi-ellipsoidal structures using isotropic dry etching was already demonstrated. Furthermore, a NIL process to produce 3D metal structures through precise multiple imprinting was established. To characterize the structures, an “adaptive” measurement concept based on a Linnik interferometer was developed and implemented. Using a reference object with a geometry that is adapted to the geometry of the measuring object it can detect deviations in the nanometer range. These can be accessed and evaluated by use of an in-house developed software. The renewal proposal presented here connects directly to the results already achieved in the first funding period. Via substrate conformal nanoimprint lithography (SCIL), metal structures are supposed to be fabricated on top of curved semi-ellipsoidal structures made of polymer. On the one hand, this is aimed at the production of hybrid material structures, on the other hand, a sub-structuring can take place by NIL on curved surfaces and thus opens up new paths towards geometrically demanding structures. The focus will be i. a. on producing a special SCIL stamp that prevents the residual layer from curing during the imprint process.The measurement of differently scaled parts of one structure and the combination of different materials is also a huge challenge for the interferometric measurement system. The goal is to adopt the adaptive concept to a broader variety of measurement geometries and scales. One focus lies on the integration of immersion objectives. This provides the possibility to enhance the resolution of the system and at the same time gain new detailed insight in the behaviour of interferometric measurements in immersion media. Additionally, the system is supposed to be upgraded in order to benefit from polarization dependent effects even under UV-illumination.

• DFG Programme: Research Grants