Research on fatigue of TSV-Cu under thermal and vibration coupled load based on numerical analysis

The three-dimensional (3D) integrated packaging technology based on through-silicon-via (TSV) is recognized as a new packaging technology which is most likely to exceed Moore's Law and complies with the requirements of smaller size, higher performance, lighter weight and lower power consumption. However, its failure mechanism and reliability problems during the long-term service process have not been fully elucidated, which hinders its widespread application. There is plenty of literature about the reliability of the TSV structure under thermal load, but the literature considering vibration loads is extremely rare. On the other hand, most of the previous literature focuses on the reliability of the TSV structure in manufacturing processes (such as annealing), but little attention was paid to their reliability assessment during service life. As the fundamental structure of 3D integrated packaging, TSV reliability will undoubtedly play a pivotal role in the long-term service reliability of the chip. The TSV structure needs to withstand various complex loads during service, such as thermal load, vibration load, electric load, etc., so it is necessary to consider the coupling of various loads to scientifically and effectively evaluate its reliability life. In this paper, the fatigue theory and multi-field coupled numerical analysis theory were summarized in detail. On this basis, a numerical analysis method for thermal-vibration coupling of TSV copper (TSV-Cu) was proposed. The typical TSV microstructure model was established and the fatigue life of electroplated copper under thermal and vibration coupled loads was calculated based on E-N curve. The influence of loading parameters on fatigue life was explored and compared. The results show that the effects of different load forms and parameter conditions on the fatigue life of TSV-Cu are significantly different.