Effect of temperature on the variance of the log‐normal distribution of failure times due to electromigration damage

To predict interconnect reliability, the mean time to failure, nature of failure time distribution, and the variance in the distribution at operating conditions must be known. The first two pieces of data can be obtained using the well‐established mean time to failure technique. It is demonstrated the effect of temperature on the variance of the failure time distribution can be found from data obtained from temperature‐ramp resistance analysis to characterize electromigration. The predicted variance is lowest at temperatures near where data were gathered, but the variance increases as the temperature approaches operating conditions.