Fast and rigorous use of thermal time constant to characterize back end of the line test structure in advanced technology

Thermal time constant analysis (TTC) opens a wide range of applications: structure identification, 3D localization for very deep micron technologies. In this paper, we describe a new analysis methodology for TTC signatures induced by modulated thermal laser stimulation (TLS). Previous approaches did not allow a fast and rigorous method to acquire and treat transient TLS signals. To overcome these limitations we have done a theoretical study, based on the Fourier transform of an analytical model describing temporal dependency of the TLS signal, which is powerful for signature interpretation. This analysis flow is applied to 65 nm reliability test structure.