Herein we describe the annealing behavior of copper Through Silicon Vias (TSVs) in a series of experiments. Temperatures ranged from 150°C to 450°C and the dwell of the temperature varied between 30 min and 4 h. Copper protrusion, test samples warpage and the copper microstructure were examined in a subsequent characterization. Combining the results of these measurements enables the determination of an optimized temperature and dwell set, which avoids further protrusion and minimizes stress after annealing. Additionally, the data analysis shows a temperature- and dwell-dependency of copper protrusion and die warpage. Electron backscatter diffraction (EBSD) measurements on TSV cross sections show changes of the micro structure. Hence it could be verified that copper underwent grain growth during annealing. The described investigations represent a new systematic approach for the characterization of the copper annealing behavior in TSVs. The evaluation of the specific expe riments and the comparison between different annealing conditions enable insights into the structural changes of the material during the annealing process. With help of the implemented characterization this approach succeeds in giving optimized settings for the TSV annealing process. Based on the measurement data it is possible to choose a suitable temperature and dwell process set depending on subsequent redirection layer (RDL) processing steps. Furthermore a model for the annealing procedure in TSVs is derived from the measurement results

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This paper focuses on the characterization and Finite Element (FE) simulation of thermo-mechanical loads in Through Silicon Vias (TSVs), which emerge due to the annealing process after electro chemical deposition (ECD) of copper. For this purpose a FE-model has been implemented, which calculates the stress state of TSV structures after annealing. To validate the model, measurements using -Raman spectroscopy (RS) were carried out. Results from Finite Element Modeling (FEM) were converted into their corresponding Raman-Shifts to make it comparable to RS measurements. Additionally warpage and copper protrusion were measured to receive a complete picture of the occurring mechanisms and boundary conditions