Modeling of substrate related extrinsic oxide failure distributions

The extrinsic oxide failure distributions of 6.8 nm thermal oxide on Czochralski (CZ) silicon wafers was investigated in detail. Using superposition of intrinsic Weibull distributions folded with a normal distribution of oxide thinning in COPs, enables one to describe the cumulative failure distributions of splits with different hydrogen pre-anneals. Voltage acceleration of individual Weibull distributions allows one to model experimental data of wafer level step stress and long term package level tests. The features of the linear E-model, 1/E-model and power law model are discussed in terms of thickness dependence of voltage acceleration. The results indicate that substrate related defects cause extrinsic oxide breakdown only at the late stage of device operation, even if the conservative linear E-model is assumed.