Low-temperature copper sinter-joining technology for power electronics packaging: A review

Low-temperature copper (Cu) sinter-joining technology has attracted increasing attention in high-power electronic device packaging because of its low material cost, good electrical and thermal conductivity, lowtemperature joining processes, and high-temperature service characteristics. However, due to the high oxidation risk and agglomeration tendency of Cu particles, the stability of Cu pastes is poor, the sinter-joining conditions become harsh, and the performances of sintered parts could be better. These defects heavily hinder the application of low-temperature Cu sinter-joining technology in power electronic packaging. In this review, the research of the low-temperature Cu sinter-joining technology is reviewed, including its background, development, challenges, and perspectives. Based on the sinter-joining mechanism, the advanced progress of Cu paste formulas and sintering processes are described in detail, and the mainstream strategies for improving Cu paste's stability and oxidation resistance are discussed, highlighting scientific issues and advocating for best practices in conducting low-temperature Cu sinter-joining technology. In addition, the reliability and failure mechanisms of sintered Cu joints are summarized, which provides theoretical support for further improving the performance and service life of the joint. Finally, the development trend and future research directions of low-temperature Cu sinter-joining technology are described.