TY - JOUR A1 - Liu, E A1 - Conti, Fosca A1 - Bhogaraju, Sri Krishna A1 - Signorini, Raffaella A1 - Pedron, Danilo A1 - Wunderle, Bernhard A1 - Elger, Gordon T1 - Thermomechanical stress in GaN-LEDs soldered onto Cu substrates studied using finite element method and Raman spectroscopy JF - Journal of Raman Spectroscopy N2 - Local thermomechanical stress can cause failures in semiconductor packages during long-time operation under harsh environmental conditions. This study helps to explain the packaging-induced stress in blue GaN-LEDs soldered onto copper substrates using AuSn alloy as lead-free interconnect material. Based on the finite element method, a virtual prototype is developed to simulate the thermomechanical behavior and stress in the LED and in the complete LED/AuSn/Cu assembly considering plastic and viscoplastic strain. The investigations were performed by varying the temperature between −50°C and 180°C. To validate the model, the simulation results are compared to experimental data collected with Raman spectroscopy. Studies of the urn:x-wiley:03770486:media:jrs5947:jrs5947-math-0003 phonon mode of GaN semiconductor are elaborated to understand the induced thermomechanical stress. The model enables evaluation of the stress in the interfaces of the assembly, which otherwise cannot be accessed by measurements. It serves to predict how assemblies would perform, before committing resources to build a physical prototype. UR - https://doi.org/10.1002/jrs.5947 KW - finite element method KW - gallium nitride (GaN) KW - LED KW - semiconductor KW - thermomechanical stress Y1 - 2020 UR - https://doi.org/10.1002/jrs.5947 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-9438 SN - 1097-4555 VL - 51 IS - 10 SP - 2083 EP - 2094 PB - Wiley CY - Chichester ER - TY - CHAP A1 - Conti, Fosca A1 - Liu, E A1 - Bhogaraju, Sri Krishna A1 - Wunderle, Bernhard A1 - Elger, Gordon T1 - Finite Element simulations and Raman measurements to investigate thermomechanical stress in GaN-LEDs T2 - 2020 IEEE 8th Electronics System-Integration Technology Conference (ESTC) UR - https://doi.org/10.1109/ESTC48849.2020.9229843 KW - finite element method KW - gallium nitride (GaN) KW - LED KW - Raman spectroscopy KW - semiconductor KW - thermomechanical stress Y1 - 2020 UR - https://doi.org/10.1109/ESTC48849.2020.9229843 SN - 978-1-7281-6293-5 PB - IEEE CY - Piscataway ER - TY - CHAP A1 - Tavakolibasti, M. A1 - Meszmer, P. A1 - Kettelgerdes, Marcel A1 - Böttger, G. A1 - Elger, Gordon A1 - Erdogan, Hüseyin A1 - Seshaditya, A. A1 - Wunderle, Bernhard T1 - Structural-thermal-optical-performance (STOP) analysis of a lens stack for realization of a digital twin of an automotive LiDAR T2 - 2022 23rd International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE) UR - https://doi.org/10.1109/EuroSimE54907.2022.9758897 KW - thermo-mechanical simulation KW - optical simulation KW - digital twin KW - structural thermal optical performance analysis Y1 - 2022 UR - https://doi.org/10.1109/EuroSimE54907.2022.9758897 SN - 978-1-6654-5836-8 PB - IEEE CY - Piscataway, NJ ER - TY - CHAP A1 - Kettelgerdes, Marcel A1 - Mezmer, Peter A1 - Haeussler, Michael J. A1 - Böttger, Gunnar A1 - Tavakolibasti, Majid A1 - Pandey, Amit A1 - Erdogan, Hüseyin A1 - Elger, Gordon A1 - Schacht, Ralph A1 - Wunderle, Bernhard T1 - Realization, multi-field coupled simulation and characterization of a thermo-mechanically robust LiDAR front end on a copper coated glass substrate T2 - Proceedings: IEEE 73rd Electronic Components and Technology Conference, ECTC 2023 UR - https://doi.org/10.1109/ECTC51909.2023.00131 KW - LiDAR KW - Reliability KW - Thermo-mechanical Simulation KW - Optical Simulation KW - VCSEL KW - Lifetime Testing KW - Glass Packaging Y1 - 2023 UR - https://doi.org/10.1109/ECTC51909.2023.00131 SN - 979-8-3503-3498-2 SN - 2377-5726 SP - 753 EP - 760 PB - IEEE CY - Piscataway ER - TY - CHAP A1 - Pandey, Amit A1 - Unruh, Denis A1 - Kettelgerdes, Marcel A1 - Wunderle, Bernhard A1 - Elger, Gordon ED - Matoba, Osamu ED - Shaw, Joseph A. ED - Valenta, Christopher R. T1 - Evaluation of thermally-induced change in sharpness of automotive cameras by coupled thermo-mechanical and optical simulation T2 - SPIE Future Sensing Technologies 2023 UR - https://doi.org/10.1117/12.2665475 Y1 - 2023 UR - https://doi.org/10.1117/12.2665475 SN - 978151065723 SN - 9781510657229 IS - 123270U PB - SPIE CY - Bellingham ER - TY - JOUR A1 - Liu, E A1 - Bhogaraju, Sri Krishna A1 - Wunderle, Bernhard A1 - Elger, Gordon T1 - Investigation of stress relaxation in SAC305 with micro-Raman spectroscopy JF - Microelectronics Reliability UR - https://doi.org/10.1016/j.microrel.2022.114664 Y1 - 2022 UR - https://doi.org/10.1016/j.microrel.2022.114664 SN - 0026-2714 VL - 2022 IS - 138 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Tavakolibasti, M. A1 - Meszmer, P. A1 - Böttger, G. A1 - Kettelgerdes, Marcel A1 - Elger, Gordon A1 - Erdogan, Hüseyin A1 - Seshaditya, A. A1 - Wunderle, Bernhard T1 - Thermo-mechanical-optical coupling within a digital twin development for automotive LiDAR T2 - 2021 22nd International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE) UR - https://doi.org/10.1109/EuroSimE52062.2021.9410831 KW - Couplings KW - Laser radar KW - Digital twin KW - Thermomechanical processes KW - Adaptive optics KW - Optical coupling KW - Real-time systems Y1 - 2021 UR - https://doi.org/10.1109/EuroSimE52062.2021.9410831 SN - 978-1-6654-1373-2 PB - IEEE CY - Piscataway ER -