Field Risk Evaluation of Liquid Metal Interconnects in Microelectronics Applications

Gallium is one of the most desirable, yet less known, interconnects considered in the semiconductor industry. Good electrical conductivity and high stretchability of the liquid metal makes it very attractive for many applications. It allows components to be assembled or disaggregated like Lego blocks without any external forces or energy. The focus of this article is to shed light on intrinsic reliability degradation mechanisms for components that use liquid metal interconnects. As a starting reference to field reliability risk evaluations, the authors focus on common/controlled use conditions. Environments studied include standard test evaluation procedures like thermal aging (sustained exposure to high temperature over time), thermal cycling, current carrying capability, and finally functional product life cycle testing. Studies reveal that the interconnect has very distinct failure mechanisms and unique advantageous/disadvantageous over existing interconnects. Fundamental knowledge gained in this study is expected to help 1) drive future architectures, 2) material/design changes to address any limitations, and 3) finally new qualification methods/standards that account for the unique failure mechanisms.