Weight-scale, XRR and corona charge method on back-end dielectrics for 65 and 45nm technology nodes

The monitoring of the back-end dielectrics for 65 and 45nm technology nodes is of great interest to ensure the integration of those materials into damascene structure. Several metrology methods were compared for density and k value measurements. It was shown that the densities measured with XRR and weight-scale were identical and that density could be correlated to corona charge method k value thanks to a Clausius-Mosotti-like relation. According to these results, it appeared that, for uniformly deposited and stable materials, weight-scale measurements can give accurate and fast monitorings. On the contrary, non-homogeneous materials should preferably be monitored with XRR or corona charge method depending on the controlled parameter.