Impedance Analysis as a Prognostics Technique for Detection of Interconnect Degradation
CALCE Team: M. H. Azarian and D. Kwon
Objectives: Quantify differences in time-to-failure between change in RF impedance and increase in DC resistance during creep and fatigue tests.Using failure analysis and experiments on model contact geometries, determine the extent of physical degradation required to produce RF impedance changes.
Abstract: Operating frequencies of communication and digital equipment are increasing, while critical dimensions of PCBs and components are shrinking. At high frequencies, signal propagation is concentrated in the surface of interconnects due to the skin effect. As signal frequencies of analog and digital equipment rise, electrical performance will exhibit increased sensitivity to interconnect degradation, which will precede loss of DC continuity. Results obtained in C07-16 demonstrate that RF impedance does respond to solder joint degradation earlier than DC resistance, showing that standard methods for monitoring solder joint reliability do not adequately detect initial stages of degradation, and may overestimate the lifetime of products used for high speed or high frequency applications. Building on the results of the first year’s research on this topic, this project will exploit high frequency metrics as a more sensitive measure of interconnect degradation, which should also provide more accurate assessments of reliability in high speed applications.