Measurement and Analysis of the Impact of Micrometer Scale Cracks on the RF Performance and Reliability of Transmission Lines

Electronic systems are exposed to a variety of environmen-tal impacts causing multiple degradations of important charac-teristics such as signal propagation. Interconnect failures due to environmental stress are most often cracks. The ability to measure growing fatigue cracks on strip line conductive paths or solder joints is a desirable feature for reliability estimation of electronic assemblies. In this paper, we discuss the electrical, non-destructive measurement of micrometer scale crack propagation in func-tional signal paths. For this approach, electrical high frequen-cy scattering parameters of coplanar lines are investigated. Correlation calculations suppress parasitic noise and coupling effects and reduce the amount of data. The electrical mea-surement of degradations in micrometer dimensions is the first step to a novel generation of reliability monitoring systems.