Crystals 2016, 6(1), 12; https://doi.org/10.3390/cryst6010012
Formation Mechanism of Porous Cu3Sn Intermetallic Compounds by High Current Stressing at High Temperatures in Low-Bump-Height Solder Joints
Jie-An Lin 1
, Chung-Kuang Lin 1, Chen-Min Liu 1, Yi-Sa Huang 1, Chih Chen 1,*
, David T. Chu 2 and King-Ning Tu 2
, Chung-Kuang Lin 1, Chen-Min Liu 1, Yi-Sa Huang 1, Chih Chen 1,*
, David T. Chu 2 and King-Ning Tu 21
Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
2
Department of Materials Science and Engineering, University of California at Los Angeles, Los Angeles, CA 90095-1595, USA
*
Author to whom correspondence should be addressed.
Academic Editor: Duc Nguyen-Manh
Received: 22 November 2015 / Revised: 4 January 2016 / Accepted: 11 January 2016 / Published: 16 January 2016
(This article belongs to the Special Issue Intermetallics)
Abstract
Electromigration tests of SnAg solder bump samples with 15 μm bump height and Cu under-bump-metallization (UBM) were performed. The test conditions were 1.45 × 104 A/cm2 at 185 °C and 1.20 × 104 A/cm2 at 0 °C. A porous Cu3Sn intermetallic compound (IMC) structure was observed to form within the bumps after several hundred hours of current stressing. In direct comparison, annealing alone at 185 °C will take more than 1000 h for porous Cu3Sn to form, and it will not form at 170 °C even after 2000 h. Here we propose a mechanism to explain the formation of this porous structure assisted by electromigration. The results show that the SnAg bump with low bump height will become porous-type Cu3Sn when stressing with high current density and high temperature. Polarity effects on porous Cu3Sn formation is discussed. View Full-Text
Figure 1
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Lin, J.-A.; Lin, C.-K.; Liu, C.-M.; Huang, Y.-S.; Chen, C.; Chu, D.T.; Tu, K.-N. Formation Mechanism of Porous Cu3Sn Intermetallic Compounds by High Current Stressing at High Temperatures in Low-Bump-Height Solder Joints. Crystals 2016, 6, 12.
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