Research progress of low-temperature Cu-Cu bonding technology for advanced packaging

Low-temperature Cu-Cu bonding technology is the core technology for advanced packaging. Compared with the mainstream Sn-based soldering process, it can achieve finer pitch, higher electrical and thermal conductivity. In this paper, low-temperature Cu-Cu bonding technology for advanced packaging is reviewed. The research progress of low-temperature Cu-Cu bonding realized by thermal compression bonding and hybrid bonding is systematically summarized from the aspects of process flow, bonding mechanism and performance characterization. The advantages of the newly-developed nanomaterial sintering process in reducing bonding temperature and process requirements are further expounded. Mechanism of patterned nanowires, nano-porous frameworks and nanoparticles for low-temperature bonding are summarized. Low-temperature Cu-Cu bonding technology for advanced packaging are forecast.