Interfacial reactions between pure indium solder and Au/Ni metallization

Thermal interface material (TIM) attracts considerable attention as the increasing demands for efficient heat dissipation in high-performance microelectronic packages. Due to high thermal conductivity, pure indium is a promising candidate of TIM. The TIM joint between two adjoining components is constructed by solid-liquid interdiffusion (SLID) reaction between indium and Au/Ni metallization on the adjoining surfaces. An understanding of the formation and growth kinetics of the intermetallic compounds (IMCs) at the In/Au/Ni interface is crucial for the reliability assessment of the TIM joints. In this study, the interfacial reactions between indium and Au/Ni in the SLID and thermal aging processes at 220-260 degrees C and 100-150 degrees C, respectively, are investigated. The metallographic analysis indicates that the thin Au layer dissolves rapidly into the molten indium matrix, leaving only one IMC at the In/Ni interface in the SLID and aging reactions. Compositional and crystallographic analyses both confirm that the IMC is Ni28In72 incorporated with a small amount of Au solubility. The thickness evolution of Ni28In72 displays a linear relationship with the square root of reaction time, indicating a diffusion-controlled growth behavior.

Automated summary

Thermal interface material (TIM) is receiving significant attention due to the increasing demand for efficient heat dissipation in high-performance microelectronic packages. This study investigates the interfacial reactions between indium and Au/Ni in the solid-liquid interdiffusion (SLID) and thermal aging processes. The results provide important insights for the reliability assessment of TIM joints.