Electromigration Lifetime Optimization by Uniform Designs and a New Lifetime Index

In this paper, we report electromigration (EM) reliability optimizations using highly efficient uniform design (UD). Considering the large error that results from using a single lifetime index, and the different EM failure modes, we introduce a new proportion index incorporating early failures to compensate for the shortage of using a single traditional intrinsic lifetime index in our Design of Experiments (DOE). Applying a supersaturated UD DOE, we greatly reduce ( > 70% savings) the number of wafers used in experiments, comparing to the classical RSM design. This very economic experiment has successfully maximized EM lifetimes, which are more than 10 times longer, and without early failure, in a much shorter period of time.