Higher, more precise, multifunctional - From micro- to mesoscale structures through 'next-level laser lithography' as the core building block of a high-performance process technology (mesoTrace)

• Subject Area: Microsystems
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 497866273

The possibilities for the lithographic fabrication of functional structures with profile heights in the dimensions from a few tens to several hundred micrometers, which simultaneously meet very high accuracy requirements and extend over large lateral ranges, are currently very limited. These structures, which address the transition between the micro- and the mesoscale, offer a very high potential, especially in optics and semiconductor technology, to provide properties that were previously not or only insufficiently attainable. Examples from optics are: (i) diffractive structures simultaneously utilizing high and low diffraction orders, (ii) hybrid elements of diffractive structures on free-form curved refractive surfaces, or (iii) deep, tailored microlens arrays with statistical or periodic distribution and varying lens geometry. In semiconductor technology, mesoscale mask structures can be used e.g. for doping power semiconductor devices that are necessary for efficient energy conversion in the field of renewable energies. This project aims to significantly exceed previous limits in the manufacturability of functional structures in the transition range from the micro- to the mesoscale and to fundamentally explore the usable technologies. The primary objective of the project is the acquisition of a state-of-the-art direct-writing laser lithography system.The project mainly follows three scientific aspects: A) Overcome previous limitations of laser lithography. This concerns the considerable increase of achievable profile heights into the range up to 180 µm, a reduction of disturbing 'stitching' effects as well as the reduction of surface roughness, over extended areas. B) Combination of laser lithography with subsequent plasma etching processes: The limits of the structure transfer for deep and highly precise photoresist structures by dry etching processes are investigated. C) Properties and functionalities of the elaborated 'mesoscale' structures. Finally, the newly available structures will be used for ongoing scientific projects, in particular for hyperspectral and multimodal optical instrumentation and for ion-irradiated semiconductor devices.The team consists of four partners whose competences complement each other excellently: Professors Brunner, Rüb and Schie (EAH-Jena) combine relevant experience in the fabrication of nano- and microstructures and their use in multimodal optical systems as well as in semiconductor manufacturing. The competence profile of Prof. Dr. H. Hillmer (University of Kassel) offers excellent synergies to micro- and nanotechnology as well as to the research of micro-optical structures for spectral sensing applications.

• DFG Programme: Major Instrumentation Initiatives
• Major Instrumentation: Laserlithografieanlage
• Instrumentation Group: 0930 Spezialgeräte der Halbleiterprozeßtechnik
• Applicant Institution: Ernst-Abbe-Hochschule Jena
• Leader: Professor Dr. Robert Brunner