Connection Reliability of SnAgCu Solder Bump on Electroless CuNiP

Yoshimichi SOGAWA, Takao YAMAZAKI, Nobuaki TAKAHASHI
2008 Journal of The Japan Institute of Electronics Packaging  
A low-cost method for the electroless deposition of CuNiP without Au surface finishing has been developed with highly reliable under-bump metallization (UBM). When SnAgCu solder was connected to an electroless CuNiP alloy containing 45% Cu, formations of (Ni,Cu)3Sn4, Ni3P, Kirkendall void, and Au-Sn alloy did not occur. Consequently, this enabled a reliable and long-lasting connection for 750 hours at 175°C. The electroless CuNiP can be firmly connected to SnAgCu solder using active flux. The
more » ... NiP-UBM has relatively good corrosion resistance, and provides a durable barrier against SnAgCu solder.
doi:10.5104/jiep.11.292 fatcat:ntq2k5ttdngora3t45tbaedm4e