Automatic Extraction Methodology for Accurate Measurements of Effective Channel Length on 65-nm MOSFET Technology and Below

The length of MOSFET channels is an important circuit design parameter, and this paper focuses on a new industrially-compatible technique using gate-to-channel measurements C-gc(V-g) to provide accurate extraction of the channel length. Thanks to fully-automatic probers, the technique provides large scale extractions and so, statistical-based results can be extracted with a maximized reliability. An in-depth study of parasitic capacitances has been performed to improve the extraction accuracy to within a few nanometers. The proposed methodology has been upgraded to in-line monitoring tests and deployed in a 300-mm semiconductor manufacturing facility. The pertinence of accurate channel length extraction has finally been proved by experimental studies (hot carrier injection lifetime), validating the coherence and the reliability of this technique.