Metrology is needed to characterize structure and composition in emerging integrated circuits at the nano-scale. Interconnect technology has been identified as the largest single factor limiting both performance, power, and reliability of emerging devices. The artifacts of interest may be exposed or embedded and may occur at any stage of device fabrication. We are particularly interested in metrology for the accurate understanding and quantification of the reliability issues associated with interconnect metallization in emerging nanoelectronic devices. In this regard, we have developed a suite of broadband microwave (RF)-based metrology techniques to non-destructively identify, measure, and characterize performance-limiting defects in emerging nanoelectronic devices. These RF based metrology tools offer several advantages over the traditional techniques and are uniquely suitable for studying the kinds of problems we are interested in. For example, the traditional low-frequency resistance (RDC) measurements, commonly used for electromigration, are based on changes in the resistance of conductive pathways. So long as there are contiguous electrical paths, the devices under test will not fail the RDC test. In contrast, changes in RF insertion losses offer early prognostics.

In this talk, we describe the application of a suite of broadband microwave-based techniques to the interconnect reliability assessment of integrated circuits. We discuss how microwave propagation characteristics have been used to study the impact of thermal aging on phenomena such as stress-induced failures, electromigration, and corrosion of the interconnects in 3D-ICs. We will also compare the mechanistic insights obtained from the traditional resistance increases in low-frequency direct current to those from high-frequency measurements.