Reliability of interfaces for lead-free solder bumps
This study aims at a better understanding of the reliability of lead-free solder bumps for flip-chip applications. Without the presence of lead, copper in the under bump metal (UBM) layer dissolves extensively into the molten solder during reflow, which forms a thick intermetallic layer at the inter...
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Published in | 5th International Conference on Thermal and Mechanical Simulation and Experiments in Microelectronics and Microsystems, 2004. EuroSimE 2004. Proceedings of the pp. 615 - 619 |
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Main Authors | , , , , |
Format | Conference Proceeding |
Language | English |
Published |
IEEE
2004
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Subjects | |
Online Access | Get full text |
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Summary: | This study aims at a better understanding of the reliability of lead-free solder bumps for flip-chip applications. Without the presence of lead, copper in the under bump metal (UBM) layer dissolves extensively into the molten solder during reflow, which forms a thick intermetallic layer at the interface. It was found that with a annealing step before reflow, the thickness of the intermetallic layer can be reduced. When nickel is used as the UBM and SnAgCu is used as the bump material, (Cu,Ni)/sub 6/Sn/sub 5/ ternary intermetallic is formed at the interface. The ternary intermetallic increased the chance of failure at the interface during ball shear test. After thermal cycling, the probability of failure at the interface further increased. |
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ISBN: | 9780780384200 0780384202 |
DOI: | 10.1109/ESIME.2004.1304100 |