Niklas Kardatzki –
Nanostructures such as nanopillars/-holes, nanoline structures, or nanoparticles have proven to be highly effective in fields such as photonics, MEMS/MOEMS/NEMS, biocompatible sensors, and quantum sensing. A crucial step in this process is the structuring of host materials like silicon (Si) and silicon carbide (SiC). To transfer and implement the required nanostructures, lithographic techniques such as electron beam lithography (EBL), photolithography, scanning probe lithography, and nanoimprint lithography (NIL) are employed. Among these, NIL stands out due to its high resolution and throughput combined with low cost. NIL uses a UV-curable resist (UV-NIL) into which nanoscale patterns are imprinted via a stamp. The patterned resist then serves as a mask in subsequent dry etching processes or as the application itself. Thus, a primary focus is the development and optimization of UV-sensitive resists to achieve layer properties witch high homogeneity, high etch selectivity and a minimal residual layer thickness. Moreover, these resists must be compatible with the stamp material and substrate surface. To address these challenges, a new type of resist, specifically developed for UV-NIL, named mr-NIL213FC-100 nm, has been introduced which aims for a significant improvement of its etch-resistance in dry plasma processes. This work investigates this novel resist with the goal of developing and optimizing process parameters for imprinting using UV-NIL. Initially, the fundamental process parameters for imprinting with the new resist were determined. In the first step, a spin curve of mr-NIL213FC-100 nm on silicon was recorded, and the resulting edge bead was characterized. Subsequently, the adhesion properties between mr-NIL213FC and silicon were tested based on various pretreatment steps. An optimized surface treatment was identified to improve adhesion between the resist and the substrate. Furthermore, the behavior of mr-NIL213FC during the imprint process was analyzed, with particular focus on the residual resist layer and its correlation with the applied resist volume. The influence of the flow behavior of mr-NIL213FC, as well as the type of stamp and pattern geometries, on the success of the imprint process, was also examined. As a result, the critical properties of the newly developed resist for successful imprinting processes were established. Based on these findings, the feasibility of transferring nanoscale structures into SiC without using metallic masks was demonstrated. SiC is one of the most promising materials for high-power, high-frequency, and high-temperature semiconductor devices, as well as for photonics, optoelectronics, and quantum sensing applications. It was shown that starting from mr-NIL213FC, 125 nm deep and 200 nm wide lines&spaces structures could be transferred into a SiC substrate using
mr-NIL213FC as a dry etching mask.
type
Bachelor thesis
status
finished
contact
Dr. Marina Scharin-Mehlmann
Fraunhofer IISB
Prof. Dr.-Ing. Jörg Schulze
Professors