Time-resolved microscopy and model-based analysis of Transparent Conductive Oxides thin-film ablation by spatial and temporal shaped ultrashort pulsed laser radiation

• Applicants: Professor Dr.-Ing. Arnold Gillner; Professor Dr. Heinz Paul Huber; Professor Dr. Wolfgang Schulz
• Subject Area: Production Automation and Assembly Technology
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 423531130

In this project, a basic understanding of the so-called partial and indirectly induced laser ablation of transparent, conductive layers using ultra-short pulsed laser radiation applied to ITO (Indium Tin Oxide) is to be developed. The result is a description in the form of a Metamodel, which is obtained from simulations and experimental data. By selective use of this laser-induced ablation, electrically conductive structures are separated or structured producing functional surfaces for components, such as front electrodes of a light-emitting diode. Since the end components often consist of several thin films with layer thicknesses in the range of a few tens to 100 nanometers, defects such as jumps in the edge area of the ITO layer removed can lead to short circuits and consequently to failure of the component. To manipulate or even prevent such defects, a thorough understanding of the ablation process and the physical interactions involved is necessary.In order to identify these mechanisms, the driving forces of the ablation process and to guide the development of a mathematical-physical model, experimental process observables are investigated, which describes both the dynamics and the energetics of the process. The simulative and experimental results are used for the iterative development of a Metamodel. A Metamodel is a computational look-up table for the continuous approximation of the relation between parameters and criteria (process map). Compared with the analysis of data from single simulation runs or experiments, the Metamodel allows a global analysis using rigorous, mathematical methods on interpolated, arbitrarily dense data. At the end of the project, the developed Metamodel is expected to predict measurable and verifiable target variables such as grating heights, substrate damage, insulation resistances and crack lengths as a function of the process parameters.

• DFG Programme: Research Grants