The electromigration damage response time and implications for DC and pulsed characterizations

摘要

A measurement interference for highly accelerated electromigration stress tests is identified. Measurements of the median-time-to-failure, t/sub 50/ for DC and for pulsed current stress as a function of pulse repetition frequency, reveal that highly accelerated stress tests may overestimate metallization reliability if t/sub 50/ is comparable with the response time of the vacancy concentration. Techniques necessary to make reliable wafer-level t/sub 50/ measurements are described.