Accelerated resistance degradation in aluminum by pulsed power cycling

This work investigates the resistance degradation of AlCu resistors in CMOS backend during pulsed power cycling at extreme temperatures. Significant resistance increases ΔR up to 29% are observed in the interconnect. It is found that resistance degradation occurs ~ 100 times more rapidly under pulsed than under DC stress conditions. This accelerated resistance degradation is attributed to accelerated stress induced voiding. Interestingly, a peak in the aluminum resistance occurs after less than 10,000 high energy heating pulses. The resistance peak position and peak height are investigated under varying pulse conditions. The observed trends governing this resistance degradation mechanism can be used for accelerated lifetime predictions and are relevant for power cycling applications using devices with Al backend metal.