(53e) Time Dependent Dielectric Breakdown of Interlayer Dielectrics with Barriers

A charge transport model was developed to simulate time dependent dielectric breakdown of interlayer dielectrics when a metallic barrier material is present. The barrier serves to separate the copper metallization layer from the dielectric. This paper summarizes the behavior of the model for a generic barrier system and shows that the most important parameters are the ratio of diffusivities and solubilities in the barrier and dielectric. The model is then applied to the specific barriers, TaN and Ru(P). A comparison with experimental data for SiO2 without a barrier and for SiO2 with TaN and Ru(P) barrier systems showed excellent agreement with the experimental data of Hwang et al [1] and Henderson and Ekerdt [2]. The model was able to simulate the data for all three systems using the same set of physical parameters with one exception. The parameter, γ, outlining the dependence of the time-to-failure on the applied electric field was larger for the barrier system than the no-barrier case. This is believed to reflect the barrier properties for Cu as well as the oxidizing agent necessary to form the Cu ion required to break down the dielectric.

1. Hwang, S.S., Jung, S.Y., and Joo, Y.C., J. Appl. Phys. 101, 074501 (2007).

2. Henderson, L.B. and Ekerdt, J.G., Thin Solid Films, 517, 1645 (2009).