The electric field dependence of Cu migration induced dielectric failure in interlayer dielectric for integrated circuits

The Cu migration-induced failure of the interlayer dielectric in integrated circuits was studied using the time-dependent dielectric breakdown (TDDB) test and one dimensional (1D) finite difference method (FDM) simulation. A metal-insulator-semiconductor structure with a Cu electrode was used for the TDDB tests. A 1D FDM simulation was performed while considering the space charge effect due to the Cu ions that migrated into the dielectric. Both the TDDB and FDM simulation showed the linear dependence of the times to failure (TTFs) on the applied electric field in accelerating conditions. However, the extrapolation of the lifetime under low field service conditions using the 1D FDM showed a deviation from the E model in the case of the TTFs.