@inproceedings{SignoriniPedronContietal.2018, author = {Signorini, Raffaella and Pedron, Danilo and Conti, Fosca and Hanss, Alexander and Bhogaraju, Sri Krishna and Elger, Gordon}, title = {Thermomechanical Stress in GaN LED Soldered on Copper Substrate Evaluated by Raman Measurements and Computer Modelling}, booktitle = {2018 24rd International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)}, publisher = {IEEE}, address = {Piscataway}, isbn = {978-1-5386-6759-0}, doi = {https://doi.org/10.1109/THERMINIC.2018.8593304}, year = {2018}, language = {en} } @inproceedings{BrugnolottoBhogarajuLiuetal.2019, author = {Brugnolotto, Enrico and Bhogaraju, Sri Krishna and Liu, E and Conti, Fosca and Pedron, Danilo and Signorini, Raffaella and Elger, Gordon}, title = {Investigation of thermomechanical local stress induced in assembled GaN LEDs}, booktitle = {2019 25th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)}, publisher = {IEEE}, address = {Piscataway}, isbn = {978-1-7281-2078-2}, doi = {https://doi.org/10.1109/THERMINIC.2019.8923629}, year = {2019}, language = {en} } @inproceedings{SignoriniContiBrugnolottoetal.2019, author = {Signorini, Raffaella and Conti, Fosca and Brugnolotto, Enrico and Pedron, Danilo and Liu, E and Bhogaraju, Sri Krishna and Elger, Gordon}, title = {Thermomechanical local stress in assembled GaN LEDs investigated by Raman optical spectroscopy}, booktitle = {Integrated Optics: Design, Devices, Systems, and Applications V}, editor = {Cheben, Pavel and Čtyrok{\´y}, Jiř{\´i} and Molina-Fern{\´a}ndez, I{\~n}igo}, publisher = {SPIE}, address = {Bellingham}, isbn = {978-1-5106-2729-1}, doi = {https://doi.org/10.1117/12.2520992}, year = {2019}, language = {en} } @inproceedings{PascucciContiBhogarajuetal.2021, author = {Pascucci, Jacopo and Conti, Fosca and Bhogaraju, Sri Krishna and Signorini, Raffaella and Liu, E and Pedron, Danilo and Elger, Gordon}, title = {Micro-Raman to detect stress phenomena in Si-chips bonded onto Cu substrates}, booktitle = {Integrated Optics: Design, Devices, Systems and Applications VI}, editor = {Cheben, Pavel and Čtyrok{\´y}, Jiř{\´i} and Molina-Fern{\´a}ndez, I{\~n}igo}, publisher = {SPIE}, address = {Bellingham}, isbn = {978-1-5106-4385-7}, doi = {https://doi.org/10.1117/12.2576414}, year = {2021}, language = {en} } @article{LiuContiBhogarajuetal.2020, author = {Liu, E and Conti, Fosca and Bhogaraju, Sri Krishna and Signorini, Raffaella and Pedron, Danilo and Wunderle, Bernhard and Elger, Gordon}, title = {Thermomechanical stress in GaN-LEDs soldered onto Cu substrates studied using finite element method and Raman spectroscopy}, volume = {51}, journal = {Journal of Raman Spectroscopy}, number = {10}, publisher = {Wiley}, address = {Chichester}, issn = {1097-4555}, doi = {https://doi.org/10.1002/jrs.5947}, pages = {2083 -- 2094}, year = {2020}, abstract = {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.}, language = {en} }