標題: Mechanism of electromigration-induced failure in flip-chip solder joints with a 10-mu m-thick Cu under-bump metallization
作者: Nah, Jae-Woong
Chen, Kai
Tu, K. N.
Su, Bor-Rung
Chen, Chih
材料科學與工程學系
Department of Materials Science and Engineering
公開日期: 1-三月-2007
摘要: The electromigration-induced failure in flip-chip eutectic SnPb solder joints with a 10-mu m-thick Cu under-bump metallization (UBM) was studied without the effect of current crowding in the solder region. The current crowding occurred inside the UBM instead of in the solder joint at the current density of 3.0 x 10(4) A/cm(2) because of the spreading of current in the very thick Cu UBM. In these joints, the failure occurred through a two-stage consumption of the thick Cu UBM in the joint where electrons flowed from the chip to the substrate. In the first stage, the Cu UBM dissolved layer by layer rather uniformly across the entire Cu UBM-solder interface. In the second stage, after half of the Cu UBM was dissolved, an asymmetrical dissolution of Cu UBM took place at the corner where electrons entered from the Al interconnect to the Cu UBM. Experimental observation of dissolution steps of the 10-mu m-thick Cu UBM is presented. The transition from the first stage to the second stage has been found to depend on the location of current crowding in the flip-chip joints as the UBM thickness changes during the electromigration test. The current distribution in the flip-chip solder joints as a function of UBM thickness was simulated by three-dimensional finite element analysis. The dissolution rate of Cu UBM in the second stage was faster than that in the first stage. The mechanism of electromigration-induced failure in the flip-chip solder joints with a 10-mu m-thick Cu UBM is discussed.
URI: http://dx.doi.org/10.1557/jmr.2007.0084
http://hdl.handle.net/11536/11076
ISSN: 0884-2914
DOI: 10.1557/jmr.2007.0084
期刊: JOURNAL OF MATERIALS RESEARCH
Volume: 22
Issue: 3
起始頁: 763
結束頁: 769
顯示於類別:期刊論文


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  1. 000244672900030.pdf