Effect of dissolution and intermetallic formation on the reliability of FC joints
Abstract
The dissolution processes and subsequent intermetallic reactions between high tin solder bump alloys and Cu‐ or Ni‐based UBM‐metallisations were investigated both theoretically and experimentally. The results showed that when the Cu UBM layer is used together with eutectic or higher Sn‐based solder alloys the dissolution of Cu and the rate of the Cu6Sn5 formation is too high for reliable interconnections. On the contrary, Ni provides feasible solution for UBM/high tin solder applications. Although there is strong chemical interaction between nickel and high Sn solder bump alloys, the dissolution and subsequent Ni3Sn4 layer growth rates are very low. Thus, a thin Ni layer can sustain interactions with high Sn liquid as well as solid solders during high temperature use. On the basis of the results obtained flip chip bonding with Ni‐based UBM structures provides a viable interconnection solution for reliable fine‐pitch applications.
Keywords
Citation
Kulojärvi, K., Vuorinen, V. and Kivilahti, J. (1998), "Effect of dissolution and intermetallic formation on the reliability of FC joints", Microelectronics International, Vol. 15 No. 2, pp. 20-24. https://doi.org/10.1108/13565369810215582
Publisher
:MCB UP Ltd
Copyright © 1998, MCB UP Limited