Abstract Scope |
The development of three-dimensional integrated circuit (3D IC) triggers the reduction of solder bump size, causing a larger temperature gradient in the microbumps than flip chip solder joints. Thus, diffusion caused by temperature gradient can be a potential reliability issue in 3D IC packaging. Furthermore, with only a few micrometers of a solder bump, the anisotropic crystal structure of solder material can affect diffusion behavior. In this study, a temperature gradient is established on the symmetrical structure of Cu/In/Cu to investigate how grain orientation of In affects diffusion of Cu under bump metallization. The results shows asymmetrical In-Cu intermetallic compound (IMC) formation are found at two interfaces in some regions; however, symmetrical IMC formation is observed for other regions . The corresponding microstructure evolution and mechanism will be examined and discussed in details in this talk. |