Research fields

FUNDAMENTALS OF PLASMA-BASED MACHINING PROCESSES

The focus is on research into plasma-based processes for modifying solid surfaces. The focus is on gaining fundamental knowledge about the processes taking place on the surface. The object of investigation are local plasma dry etching processes for the material removal of preferably optical materials (e.g. Si, SiC, glasses, glass ceramics), processes for the local deposition of thin layers for the purpose of shaping as well as the chemical modification and functionalization of surfaces (cleaning, sterilization, chemical functionalization). A wide range of effects can be achieved with the aid of various precursor gases and plasma excitation methods. For this purpose, investigations are carried out on material removal, application and functionalization depending on a wide range of parameters (e.g. type of plasma excitation, gas type and flows, surface temperature, processing geometry, substrate material and chemical and physical surface condition). The research results are evaluated with a view to potential applications.

REACTIVE ATMOSPHERIC PRESSURE PLASMA JET SOURCES

In this focus area, atmospheric pressure plasma jet sources and the associated control electronics and high-frequency generators are developed, which are primarily specified for the application field of ultra-precision surface processing. As a rule, these plasma sources are excited at high frequency (MHz-GHz) and can be operated with reactive gases. The aim of the work is to develop sources for the generation of temporally and spatially highly stable plasma jets for specific applications such as local etching and deposition processes as well as for surface cleaning, decontamination and chemical functionalization. Simulation tools for modeling energy and mass flows at the sources are also used for development. Plasma jet sources and their necessary peripherals are integrated into systems and transferred into industrial practice together with company partners.

BASIC PRINCIPLES OF ION-BEAM SUPPORTS uLTRAPRACTION FORMATION AND CORRECTION OF OPTICAL SURFACES

Ion beam-assisted surface treatment is a process for ultra-precise shaping and correction of surfaces in which low-energy intergas ions (Ar+, Xe+) with energies between 200 eV and 2000 eV are accelerated onto the surface to be treated and remove material via a physical sputtering process. Material removal can also be supported by chemically reactive components. Depending on the surface topography to be corrected, the ion beam is guided over the surface under dwell time control. Together with the Leibniz Institute for Surface Modification in Leipzig (IOM), the UPB Chair is researching and developing various aspects of this process, e.g. interaction mechanisms between the ion beam and the surface, algorithms for efficient process control, new ion beam sources and simulation algorithms for calculating the local dwell times. The investigations are also aimed at the processing of materials that were previously not easily accessible, such as metals. In particular, the ion beam processing of aluminum as a material for the production of optical mirrors is being investigated and methods for shape correction and smoothing of complex-shaped surfaces are being developed.

PROCESS CHAIN DEVELOPMENT FOR ULTRA-PRECISION MACHINING

The work deals with the development and optimization of innovative plasma-based process chains for ultra-precision shaping depending on the material to be processed and the required surface specification and taking into account upstream and downstream process steps. Plasma processes can also be optionally combined with laser beam or ion beam processes.