Measurement of copper drift in methylsilsesquiazane-methylsilsesquioxane dielectric films

Measurement of Cu drifts in methylsilsesquiazane-methylsilsesquioxane diele ctric films in the presence of an electric field was conducted using bias-t emperature stress (BTS) and capacitor-voltage (CV) analysis as well as time dependent dielectric breakdown (TDDB) stress. The amount of Cu ions in the dielectric films can be estimated making use of the flatband voltage shift Delta V-FB from the BTS. Comparing the flatband voltage measured by CV ana lysis with the leakage current integrated over time, it is found that the m ain content of the leakage current during BTS is ionic current that can be attributed to the drift of Cu and mobile ions. The Cu ions cause the leakag e current during TDDB stress to increase. The drift rate of Cu in methylsil sesquioxane is lower than the reported values in polyarylene ether (PAE) an d fluorinated polyimide (FPI), and larger than that in plasma enhanced chem ical vapor deposition (PECVD)-SiON.