@misc{SchweigerMelnikovKochetal., author = {Schweiger, Severin and Melnikov, Anton and Koch, Sandro G. and Schenk, Harald}, title = {Two-Photon Lithography Parameter Study for Manufacturing of Acoustic Metamaterials on MEMS}, series = {MikroSystemTechnik Kongress 2021 : Mikroelektronik/Mikrosystemtechnik und ihre Anwendungen Innovative Produkte f{\"u}r zukunftsf{\"a}hige M{\"a}rkte 08. - 10. November 2021, Stuttgart-Ludwigsburg}, journal = {MikroSystemTechnik Kongress 2021 : Mikroelektronik/Mikrosystemtechnik und ihre Anwendungen Innovative Produkte f{\"u}r zukunftsf{\"a}hige M{\"a}rkte 08. - 10. November 2021, Stuttgart-Ludwigsburg}, publisher = {VDE-Verlag}, address = {Berlin ; Offenbach}, isbn = {978-3-8007-5656-8}, pages = {365 -- 368}, abstract = {Acoustic impedance matching structures can be used on capacitive micromachined ultrasonic transducers (CMUT) to increase acoustic energy transmission into the load medium. Our contribution contains a systematic study of the viability of the two-photon-polymerization lithography process for the fabrication of acoustic impedance matching metamaterials. For this purpose, acoustic simulations were conducted to find optimized dimensions of the matching structure. Based on the proposed dimensions, parameter sweeps were manufactured on substitute substrates, resulting in a viable parameter space for the direct fabrication on CMUT devices.}, language = {en} } @misc{SchweigerSchulzeSchlipfetal., author = {Schweiger, Severin and Schulze, Tim F. and Schlipf, Simon and Reinig, Peter and Schenk, Harald}, title = {Characterization of two-photon-polymerization lithography structures via Raman spectroscopy and nanoindentation}, series = {Journal of Optical Microsystems}, volume = {Vol. 2}, journal = {Journal of Optical Microsystems}, number = {3}, issn = {2708-5260}, doi = {10.1117/1.jom.2.3.033501}, abstract = {Additive manufacturing using two-photon polymerization (TPP) lithography is increasingly used in industry and research. Parameter sweeps of cuboid structures fabricated using TPP lithography were investigated across the parameters of the laser power and scan speed to find dependent mechanical material properties. The employed photoresists were examined using Raman spectroscopy to find the degree of conversion (DC) of monomer to polymer, and subsequently, micro- or nanoindentation was used to find Young's modulus (E). For the photoresist IP-Dip, the attained DC and E ranged from 20\% to 45\% and 1 to 2.1 GPa, respectively. The results were compared with reports found in the literature. For IP-Q, the attained DC and E ranged from 53\% to 80\% and 0.5 to 1.3 GPa, respectively. The characterized properties of IP-Q manifest as the current state of knowledge of the material.}, language = {en} } @misc{SchenkSchweigerKoch, author = {Schenk, Harald and Schweiger, Severin and Koch, Sandro G.}, title = {Two-Photon-Lithography Substrate Reflection and Absorption Compensation for Additive Manufacturing of Metamaterials on MEMS}, series = {2021 44th International Spring Seminar on Electronics Technology (ISSE)}, journal = {2021 44th International Spring Seminar on Electronics Technology (ISSE)}, isbn = {978-1-6654-1477-7}, issn = {2161-2536}, doi = {10.1109/ISSE51996.2021.9467575}, pages = {7}, abstract = {Structuring polymers on micro-electro-mechanical-systems (MEMS) for the manufacturing of acoustical and optical metamaterials using the two-photon polymerization process depends on reliable and controllable regulation of the intensity. Reflecting surfaces, diffracting elements and structures with poor heat dissipation can be problematic obstacles for the incident focused and pulsed laser beam. Thermal and optical simulations were performed and compared to test structures. A compensated fabrication approach was successfully applied to create optimized conditions in the polymerized volume.}, language = {en} }