Undercooled liquid metal particles as gateway to low-temperature processing and non-equilibrium dynamics.

The continuous need to overcome thermal and miniaturization challenges in the fabrication of integrated circuits calls for novel alternative pathways to device and interconnect manufacturing. Efforts to achieve this goal, however, have been challenging due to limitations of the traditional equilibrium-based (Gibbsian) view of metal processing. This perspective demonstrates the application of metastable-metal processing as a platform for low-temperature and heatless solders with their subsequent effects on interconnect formation. In the process of realizing the solder, new understanding of non-equilibrium thermodynamics has emerged primarily around the solidification of deeply undercooled metals. This has led to resolution of the Kauzmann paradox (entropy catastrophe) through expansion of associated phase space to capture the contribution of tensions that drive deep undercooling.