The article discusses the challenges of interconnect scaling in advanced CMOS circuits and the need for alternative metals to replace copper (Cu) in future technology nodes. As transistor scaling slows, interconnect scaling becomes the main driver for circuit miniaturization, but current Cu dual-damascene metallization faces increasing challenges due to reduced mechanical stability and reliability issues. Alternative metallization schemes are being researched to address these problems. The selection of alternative metals involves multiple criteria, including resistivity at nanoscale dimensions, reliability, thermal properties, and sustainability. The article introduces a multistage process for identifying, downselecting, and benchmarking alternative metals for interconnect applications. It covers materials close to manufacturing, those under research, and future directions for fundamental research. The article discusses the resistivity of metals at nanoscale dimensions, focusing on electron transport in bulk metals and nanostructures. It explains how the mean free path of charge carriers is a key parameter in determining resistivity, and how scattering effects at surfaces, grain boundaries, and alloy interfaces influence resistivity. Ab initio screening methods are used to compute the mean free path and identify metals with potentially lower resistivity than Cu at the nanoscale. The article also addresses interconnect reliability, including dielectric breakdown, electromigration, and self-heating. It discusses the need for barrier layers to prevent dielectric breakdown and the challenges of scaling down barrier and liner layers while maintaining interconnect performance. The article highlights the importance of materials with short mean free paths and low resistivity for future interconnect applications. The article concludes that alternative metals and metallization schemes can outperform Cu at sufficiently small line widths, and that the selection process is multifaceted, requiring consideration of various factors. The article emphasizes the importance of sustainability in the selection of alternative metals and introduces a life cycle assessment scheme for interconnect metals. The article also discusses the challenges of integrating alternative metals into future technology nodes and the need for further research in this area.The article discusses the challenges of interconnect scaling in advanced CMOS circuits and the need for alternative metals to replace copper (Cu) in future technology nodes. As transistor scaling slows, interconnect scaling becomes the main driver for circuit miniaturization, but current Cu dual-damascene metallization faces increasing challenges due to reduced mechanical stability and reliability issues. Alternative metallization schemes are being researched to address these problems. The selection of alternative metals involves multiple criteria, including resistivity at nanoscale dimensions, reliability, thermal properties, and sustainability. The article introduces a multistage process for identifying, downselecting, and benchmarking alternative metals for interconnect applications. It covers materials close to manufacturing, those under research, and future directions for fundamental research. The article discusses the resistivity of metals at nanoscale dimensions, focusing on electron transport in bulk metals and nanostructures. It explains how the mean free path of charge carriers is a key parameter in determining resistivity, and how scattering effects at surfaces, grain boundaries, and alloy interfaces influence resistivity. Ab initio screening methods are used to compute the mean free path and identify metals with potentially lower resistivity than Cu at the nanoscale. The article also addresses interconnect reliability, including dielectric breakdown, electromigration, and self-heating. It discusses the need for barrier layers to prevent dielectric breakdown and the challenges of scaling down barrier and liner layers while maintaining interconnect performance. The article highlights the importance of materials with short mean free paths and low resistivity for future interconnect applications. The article concludes that alternative metals and metallization schemes can outperform Cu at sufficiently small line widths, and that the selection process is multifaceted, requiring consideration of various factors. The article emphasizes the importance of sustainability in the selection of alternative metals and introduces a life cycle assessment scheme for interconnect metals. The article also discusses the challenges of integrating alternative metals into future technology nodes and the need for further research in this area.