Microstructural evaluation of interfacial intermetallic compounds in Cu wire bonding with Al and Au pads

作者：Kim Hyung Giun; Kim Sang Min; Lee Jae Young; Choi Mi Ri; Choe Si Hyun; Kim Ki Hong; Ryu Jae Sung; Kim Sangshik; Han Seung Zeon; Kim Won Yong; Lim Sung Hwan^*

来源：Acta Materialia, 2014, 64: 356-366.

DOI：10.1016/j.actamat.2013.10.049

• Copper wire bonding
• Interfacial microstructure
• Intermetallic compounds
• Phase transformation
• Transmission electron microscopy

A comparative study on the difference in interfacial behavior of thermally aged Cu wire bonding with Al and Au pads was conducted using transmission electron microscopy. During high-temperature lifetime testing of Cu wire bonding with Al and Au pads at 175 degrees C for up to 2000 h, different growth rates and growth characteristics were investigated in the Cu-Al intermetallic compounds (IMCs), including CuAl2, CuAl and Cu9Al4, and in the Cu-Au IMCs, including (Au,Cu), Cu3Au and (Cu,Au). Because of the lower growth rates and greater ductility of Cu-Au IMCs compared to those of Cu-Al IMCs, the Cu wire bonding with the Au pad showed relatively better thermal aging properties of bond pull strength and ball shear strength than those with the Al pad counterpart. In this study, the coherent interfaces were found to retard the growth of IMCs, and a variety of orientation relationships between wire, pad and interfacial IMCs were identified.

• 出版日期2014-2