The observation of mobile ion of 40nm node by Triangular Voltage Sweep

Abstract

Using the different test structures, we investigated the Triangular Voltage Sweep (TVS) variables, e.g. temperature, capacitor area & voltage sweep rate to observe the mobile ion in dielectric layer for Back-end process. We found that temperature 125°C could activate mobile ions. The amount of mobile ion is strongly correlated with tested topology. The amount of mobile ion is also dependent on the voltage sweep rate. Time-dependent dielectric breakdown (TDDB) lifetime will reduce 1 order when mobile ion concentration raise 1 order. It is extremely important to specify the reasonable dielectric area of test structure (intra-metal comb length) for both of TDDB and TVS.