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Advances on high current load effects on lead-free solder joints of SMD chip-size components and BGAs

Dániel Straubinger (Department of Electronics Technology, Budapest University of Technology and Economics, Budapest, Hungary)
Attila Géczy (Department of Electronics Technology, Budapest University of Technology and Economics, Budapest, Hungary)
András Sipos (Department of Electronics Technology, Budapest University of Technology and Economics, Budapest, Hungary)
András Kiss (Department of Electronics Technology, Budapest University of Technology and Economics, Budapest, Hungary)
Dániel Gyarmati (Department of Electronics Technology, Budapest University of Technology and Economics, Budapest, Hungary)
Oliver Krammer (Department of Electronics Technology, Budapest University of Technology and Economics, Budapest, Hungary)
Dániel Rigler (Department of Electronics Technology, Budapest University of Technology and Economics, Budapest, Hungary)
David Bušek (Department of Electrotechology, Czech Technical University in Prague, Faculty of Electrical Engineering, Prague 6, Czech Republic)
Gábor Harsányi (Department of Electronics Technology, Budapest University of Technology and Economics, Budapest, Hungary)

Circuit World

ISSN: 0305-6120

Article publication date: 25 February 2019

Issue publication date: 7 June 2019

160

Abstract

Purpose

This paper aims to present a novel approach on investigating critical current densities in the solder joints of chip-size surface-mounted components or device (SMD) components and ball grid array (BGA) lead-free solder joints with the focus of via-in-pad geometries. The investigation involves a numerical approach and a physical validation with selected geometry configurations and high current loads to reveal possible failure sources. The work is a continuation of a previous study.

Design/methodology/approach

Current density was investigated using finite element modeling on BGA joints. Dummy BGA components, 0402 and 0603 zero ohm jumper resistors, were used, both in daisy chain setups on standard FR4 printed circuit boards (PCBs). Respective physical loading experiments were set to find effects of elevated current density at hot zones of the joints. Cross-section analysis, scanning electron microscopy and shear force tests were used to analyze the joints.

Findings

The findings reveal alterations in the joints, while the current loading is not directly affecting the structure. The modeling reveals the current density map in the selected formations with increased current crowding zones. Overall, the degradation does not reach the level of electromigration (EM)-induced voiding due to the limiting factor of the FR4 substrate.

Practical implications

The heavy current load affects joint reliability, but there are limitations of EM-induced failures on PCB-based assemblies due to the thermomechanical weakness of the FR4 material.

Originality/value

The experiments investigate current density from a novel aspect on frequently used BGA surface mounted components with modeling configurations focusing on possible effects of via-in-pad structure.

Keywords

Acknowledgements

This paper was supported by Pro Progressio Foundation.

Citation

Straubinger, D., Géczy, A., Sipos, A., Kiss, A., Gyarmati, D., Krammer, O., Rigler, D., Bušek, D. and Harsányi, G. (2019), "Advances on high current load effects on lead-free solder joints of SMD chip-size components and BGAs", Circuit World, Vol. 45 No. 1, pp. 37-44. https://doi.org/10.1108/CW-11-2018-0088

Publisher

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Emerald Publishing Limited

Copyright © 2019, Emerald Publishing Limited

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