The Influence Of Complex Geometries And Stress Non-Uniformity On Reliability

This paper describes a general method and a model for lifetime extrapolations which can account for stress non-uniformities caused by complex geometries or also geometrical variations due to the manufacturing process. The effect of these non-uniformities combined with different materials involved in a stacked geometry on the overall back end of line (BEOL) dielectric reliability are considered theoretically and illustrated via simulations. The key idea behind this is to consider test structures from a system level viewpoint rather than from a single component viewpoint. The effects of variation in the line-to-line spacings between the metal lines and those of the sidewall angle are considered as well as variations due to the positions across the wafer.