TY - GEN
T1 - The growth and segregation of intermetallic compounds in the bulk of flip chip Sn2.4Ag solder joint under electrical current stressing
AU - Wang, Wei Chieh
AU - Lin, Kwang-Lung
AU - Chiu, Ying Ta
AU - Lai, Yi Shao
PY - 2013/9/9
Y1 - 2013/9/9
N2 - This paper reports a peculiar growth and segregation behavior of IMC in a flip chip joint with Sn2.4Ag solder bump under electrical current stressing. A set of two neighboring solder joints were adopted for investigation at 1.5∼3.0×104 A/cm2 of current stressing at various temperatures up to 180°C. One of the joint experiences current flow from substrate to the Si chip while opposite for the other joint. The size analysis with SEM imaging shows that the Ag3Sn IMCs formed in the bulk during current stressing grows following the empirical equation Δr (radius change) = ktn with n =1.1, indicating a reaction controlled kinetics. The activation energy of the Ag3Sn IMC growth was estimated to be 11.5 (at 3.0 × 104 A/cm2) ∼14.0 (at 1.0×104 A/cm2) kJ/mole. Both Cu6Sn 5 and Cu3Sn were formed at the joint/metallization interface, while only Cu6Sn5 were found in the bulk. The SEM investigation at various cross sections from center to one end of the hemisphere for a joint, current stressed with 1.5×104A/cm 2 at 180°C for 330 hours, shows a serious segregation of the Cu6Sn5 IMC closing to the end portion of the bump. A mechanism incorporating IMC dissolution, electromigration, and thermomigration was proposed to explain the segregation behavior.
AB - This paper reports a peculiar growth and segregation behavior of IMC in a flip chip joint with Sn2.4Ag solder bump under electrical current stressing. A set of two neighboring solder joints were adopted for investigation at 1.5∼3.0×104 A/cm2 of current stressing at various temperatures up to 180°C. One of the joint experiences current flow from substrate to the Si chip while opposite for the other joint. The size analysis with SEM imaging shows that the Ag3Sn IMCs formed in the bulk during current stressing grows following the empirical equation Δr (radius change) = ktn with n =1.1, indicating a reaction controlled kinetics. The activation energy of the Ag3Sn IMC growth was estimated to be 11.5 (at 3.0 × 104 A/cm2) ∼14.0 (at 1.0×104 A/cm2) kJ/mole. Both Cu6Sn 5 and Cu3Sn were formed at the joint/metallization interface, while only Cu6Sn5 were found in the bulk. The SEM investigation at various cross sections from center to one end of the hemisphere for a joint, current stressed with 1.5×104A/cm 2 at 180°C for 330 hours, shows a serious segregation of the Cu6Sn5 IMC closing to the end portion of the bump. A mechanism incorporating IMC dissolution, electromigration, and thermomigration was proposed to explain the segregation behavior.
UR - https://www.scopus.com/pages/publications/84883327640
UR - https://www.scopus.com/pages/publications/84883327640#tab=citedBy
U2 - 10.1109/ECTC.2013.6575785
DO - 10.1109/ECTC.2013.6575785
M3 - Conference contribution
AN - SCOPUS:84883327640
SN - 9781479902330
T3 - Proceedings - Electronic Components and Technology Conference
SP - 1600
EP - 1605
BT - 2013 IEEE 63rd Electronic Components and Technology Conference, ECTC 2013
T2 - 2013 IEEE 63rd Electronic Components and Technology Conference, ECTC 2013
Y2 - 28 May 2013 through 31 May 2013
ER -