Sonochemical Synthesis of Submicrometer Ga-Based Particles for Cu-to-Cu Interconnection

Heterogeneous integration has been the most important electronic packaging technology, with the emerging needs of miniaturization of electronic devices. Conventional solders are gradually unable to meet the requirements of advanced electronic interconnection, e.g., 3D IC and high-power devices, which are operated in extreme conditions. We previously proposed gallium (Ga)-based transient liquid phase bonding for forming face-centered cubic solid-solution joints without the formation of intermetallic compounds, which guarantees thermal stability and reliability. However, a scalable transfer technology and the associated material are required to realize its industrial applications. Herein, we synthesized Ga-based submicrometer particles (SMPs) by a sonochemical process as the filler material for Ga-based paste. With the Ga-based paste, high-strength, thermally stable, and low-resistance Cu-to-Cu bonding is achieved with a relatively low processing temperature and short bonding time. We demonstrated the potential and feasibility of a Ga-based SMP for high-performance Cu-to-Cu bonding.