In situ measurement of electromigration-induced transient stress in Pb-free Sn-Cu solder joints by synchrotron radiation based X-ray polychromatic microdiffraction [electronic resource].
- Berkeley, Calif. : Lawrence Berkeley National Laboratory. Advanced Light Source, 2009.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Additional Creators:
- Lawrence Berkeley National Laboratory
Lawrence Berkeley National Laboratory. Advanced Light Source
United States. Department of Energy. Office of Scientific and Technical Information
- Electromigration-induced hydrostatic elastic stress in Pb-free SnCu solder joints was studied by in situ synchrotron X-ray white beam microdiffraction. The elastic stresses in two different grains with similar crystallographic orientation, one located at the anode end and the other at the cathode end, were analyzed based on the elastic anisotropy of the β-Sn crystal structure. The stress in the grain at the cathode end remained constant except for temperature fluctuations, while the compressive stress in the grain at the anode end was built-up as a function of time during electromigration until a steady state was reached. The measured compressive stress gradient between the cathode and the anode is much larger than what is needed to initiate Sn whisker growth. The effective charge number of β-Sn derived from the electromigration data is in good agreement with the calculated value.
- Published through SciTech Connect.
Journal of Applied Physics ISSN 0021-8979; JAPIAU FT
Tamura, Nobumichi; Kunz, Martin; Tu, King-Ning; Chen, Kai; Lai, Yi-Shao.
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