A comprehensive review of challenges and potential solutions associated with the impact of downscaling of integrated circuit (IC) feature sizes on on-chip interconnect materials is presented. The adoption of Moore's Law has led to developments and manufacturing of transistors with nanoscale dimensions, faster switching speeds, lower power consumption, and lower costs in recent generations of IC technology nodes. However, shrinking dimensions of wires connecting transistors have resulted in degradations in both performance and reliability, which in turn limit chip speed and lifetime. Therefore, to sustain the continuous downward scaling, alternative interconnect conductor materials to replace copper (Cu) and tungsten (W) must be explored to meet and overcome these challenges.