Reliability and Microstructure of Au-Al and Au-Cu Direct Bonding Fabricated by the Surface Activated Bonding

SAB (Surface Activated Bonding) method has been introduced as the most appropriate interconnection method for the next generation of electronic packaging because of room temperature process and other advantages. Thus it is important to study the reliability of SAB interconnection in long term life test. In this paper, SAB interconnection interface between Au and Al or Cu during high temperature thermal aging was investigated. The degradation of interface microstructure, and some properties for the interconnection during aging process were studied to investigate the failure mechanism of the interconnection. IMC (Intermetallic compounds) layer of Au-Al or Au-Cu were found formed during thermal aging, and that caused the failure mode of the interconnection changing in shear test. The results reveal that SAB method is highly reliable compared with other high temperature bonding methods such as wire bonding and soldering as there is no IMC layer in bonding process for SAB whereas others have.