Meaning
The spatial variation in the movement of atoms leads to localized depletion or accumulation within a conductive metal line. Detecting flux divergence indicates where a metal track is thinning out under the influence of current flow. When atoms enter a segment slower than they exit it, the resulting gap causes an open circuit.
The process stops when the electrical stress is removed or the temperature drops below the mobility threshold.
Atom Depletion
Voids grow in size as the net difference in atom flow stays positive over many hours. Continuous flux divergence eventually reaches a critical mass that interrupts current transmission. High concentrations of copper vacancies are visible under electron microscopy at these locations.
Interface Disruption
Changes in metal grain orientation create boundaries where flow rates fluctuate wildly. Because flux divergence peaks at these transitions, failures typically happen near vias or contact pads. These points are the weakest links in the entire interconnect network.
Failure Prediction
Measuring the time until the first resistance spike allows for the estimation of total system reliability. Analysis of flux divergence helps set the safe operating limits for consumer electronics. If the divergence stays low, the component operates for its full intended lifespan without incident.
