Investigation of Ag-Cu Alloys for Interconnects in IC

Copper (Cu) has been the standard material of choice for interconnects in integrated circuits for decades because it has low resistivity (~1.68 µΩ·cm), high electrical conductivity, and is cost-effective. With the transition to newer downscaled technologies, scaling restrictions, higher nanoscale-sized resistivity, electromigration, and thermal requirements become major problems. This paper explores alternative materials-silver (Ag), and silver-copper (Ag-Cu) alloys that have shown potential benefits compared to copper for deep-submicron IC technology. Silver is an ideal material for high-performance interconnects because it has a lower resistivity (~1.59 µΩ·cm), a higher thermal conductivity (~429 W/m·K), and a better capacity to transmit current (~10¹² A/m²) than copper (~385 W/m·K, ~10 11 A/m²). Ag- Cu alloys tend to be a viable substitute material for next-generation semiconductor nodes because they provide a reliable balance between the high electrical conductivity of silver and the affordability and robustness of copper. In addition to reviewing the materials' diffusion behavior, resistance to electromigration, and integration issues, this study compares them based on their electrical, thermal, and physical characteristics. The results show how Ag and Ag-Cu alloys enhance IC performance and reliability in next-generation semiconductor technology by overcoming the drawbacks of copper.