Use of Resistance-Evolution Dynamics During Electromigration to Determine Activation Energy on Single Samples

In this paper, we present an analysis of resistance change events that are occurring during the degradation of interconnects. The events analyzed are the following: 1) a step jump in resistance and 2) a subsequent progressive linear increase of resistance. We first find that the height of the step is correlated with time to fail. We show that the occurrence of a step is likely due to the vertical growth of a void, and the variation of the resistance-step amplitude is due to the variation of the length of the void from sample to sample. We then find that resistance-increase rate of the progressive part is correlated with copper drift velocity. Thus, we show that it is possible to determine an activation energy on every sample, which is performing temperature change during the progressive part of the resistance increase.