Built-in reliability design of highly integrated solid-state power switches with metal bump interconnects

Li, Jianfeng; Castellazzi, Alberto; Dai, Tianxiang; Corfield, Martin; Solomon, Adane Kassa; Johnson, Christopher Mark

Abstract

A stacked substrate–chip–bump–chip–substrate assembly has been demonstrated in the construction of power switch modules with high power density and good electrical performance. In this paper, special effort has been devoted to material selection and geometric shape of the bumps in the design for improving the thermomechanical reliability of a highly integrated bidirectional switch. Results from3-D finite-element simulation indicate that for all design cases the maximum von Mises stresses and creep strain accumulations occur in the solder joints used to join bumps on IGBTs during a realistic mission profile, but occur in the solder joints used to join bumps on DBC substrates during accelerated thermal cycling. The results from both the simulation and the accelerated thermal cycling experiments reveal that selection of Cu/Mo/Cu composite brick bumps in the stacked assembly can significantly improve the thermomechanical reliability of both the solder joints and the DBC substrates when compared to Cu cylinder bumps and Cu hollow cylinder bumps reported in previous work. Such results can be attributed to the effective reduction in the extent ofmismatch of coefficients of thermal expansion between the different components in the assembly.

Citation

Li, J., Castellazzi, A., Dai, T., Corfield, M., Solomon, A. K., & Johnson, C. M. (2015). Built-in reliability design of highly integrated solid-state power switches with metal bump interconnects. IEEE Transactions on Power Electronics, 30(5), https://doi.org/10.1109/TPEL.2014.2357334

• Journal Article Type: Article
• Acceptance Date: Sep 2, 2014
• Online Publication Date: Sep 11, 2014
• Publication Date: May 1, 2015
• Deposit Date: Sep 15, 2015
• Publicly Available Date: Sep 15, 2015
• Journal: IEEE Transactions on Power Electronics
• Print ISSN: 0885-8993
• Electronic ISSN: 1941-0107
• Publisher: Institute of Electrical and Electronics Engineers
• Peer Reviewed: Not Peer Reviewed
• Volume: 30
• Issue: 5
• DOI: https://doi.org/10.1109/TPEL.2014.2357334
• Keywords: Cu/Mo/Cu composite, finite-element (FE) method, integration, thermal cycling, wirebond-less packaging
• Public URL: https://nottingham-repository.worktribe.com/output/983894
• Publisher URL: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6895288
• Contract Date: Sep 15, 2015