Impact of interconnect length on BTI and HCI induced frequency degradation

The dependence of Bias Temperature Instability (BTI) and Hot Carrier Injection (HCI) induced frequency degradation on interconnect length has been examined for the first time. Experimental data from 65nm test chips show that frequency degradation due to BTI decreases monotonically with longer wires because of the shorter effective stress time, while the HCI-induced component has a non-monotonic relationship with interconnect length due to the combined effect of increased effective stress time and decreased effective stress voltage. A simple aging model is proposed to capture the distinct BTI and HCI effects in global interconnect drivers.