Regensburg 2019 – scientific programme
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 5: Instrumentation for Micro-/Nano-Analysis and Lithography/Structuring (joint session KFM/DS/O)
KFM 5.2: Talk
Monday, April 1, 2019, 15:30–15:50, PHY 5.0.21
Additive laser fabrication of silver and silver-composite 3D micro-structures — •Erik H. Waller1 and Georg von Freymann1,2 — 1Physics department and State Research Center OPTIMAS, Technische Universität Kaiserslautern, Kaiserslautern — 2Fraunhofer Institute for Industrial Mathematics (ITWM), Kaiserslautern
We present direct laser writing (DLW) of silver and silver-composite microstructures via photoreduction in liquid resists. Several photoresist compositions are compared based on visual inspection of 2D and 3D test structures complemented by EDS and spectral resonance measurements.
Compared to common approaches for additive manufacturing of 3D metallic structures, e.g., selective laser melting or sintering, DLW is a very precise fabrication technology allowing sub-micrometer feature sizes. However, structures fabricated by DLW are usually made of polymers. Renewed interest in DLW of metallic microstructures has emerged due to their potential, e.g., in plasmonics. The underlying principle of metal DLW is photo-induced reduction of a precursor to neutral metal within the laser focus. The metal particles subsequently agglomerate to form the building block of a structure. Adverse effects are mainly heating of and scattering by the evolving structure as well as low quantum yield and slow speed of the reaction. Thus, we here test different photoresist compositions with respect to the above mentioned criteria and identify key parameters to best control these photoreactions.