Role of Cu in TDDB of low-k dielectrics

Abstract

The role of Cu in the time dependent dielectric breakdown (TDDB) performance of Cu/Low-k integrated systems was studied. Interdigitated comb capacitors with and without Cu incorporated in the structure were temperature bias stressed (BTS). The Cu containing structures failed in a fraction of the time of the Cu-free samples. Annealing for 1200+ hours without bias did not change the failure times as compared to a 5 minute anneal, indicating that diffusion of neutral Cu does not play a role in TDDB. The results can be attributed to field enhanced Cu diffusion in the framework of an "Impact Damage" TDDB failure model. ©2007 IEEE.