Moisture Related Low-K Dielectric Reliability Before and After Thermal Annealing

Abstract

A systematic investigation of moisture related SiOC:H low-k dielectric reliability before and after thermal annealing was conducted. With the physisorbed moisture desorbed by thermal annealing at 190degC, the SiOC:H low-k dielectric shows a reduced leakage current and an improved TDDB lifetime. However, due to some more tightly bound OH-groups in the dielectric, the SiOC:H low-k reliability is still far below that of an optimized integration scheme. The observed failure mechanism as indicated by TDDB thermal activation energy before and after annealing does not change. It is also found that the TDDB thermal activation energy is voltage (field) independent within confidence bounds, suggesting a mixing of disturbed bonds for SiOC:H low-k dielectric breakdown