Reliability of Electroplated Sn-37Pb Solder Bumps with Different Under Bump Metallizations (UBMs) during High Temperature Storage Test
The interfacial reactions and shear properties of Sn-37Pb (wt.%) solder bumps with two different under bump metallizations (UBMs), Cu and Ni, were investigated after high temperature storage (HTS) tests at 150 C for up to 65 days. Two different intermetallic compounds (IMCs), Cu6Sn5 and Cu3Sn, were formed at the bump/Cu interface, whereas only a Ni3Sn4 IMC layer was formed at the bump/Ni interface. The thicknesses of these IMCs increased linearly with the square root of duration time. The IMC growth rate at the bump/Cu UBM interface was much greater than that at the bump/Ni UBM interface. The shear properties of the bumps with the Cu UBM were greatly decreased with increasing duration time, compared with those with the Ni UBM.
Byung Tae Ahn, Hyeongtag Jeon, Bo Young Hur, Kibae Kim and Jong Wan Park
J. M. Koo et al., "Reliability of Electroplated Sn-37Pb Solder Bumps with Different Under Bump Metallizations (UBMs) during High Temperature Storage Test", Solid State Phenomena, Vols. 124-126, pp. 5-8, 2007