Using scatterometry based on Spectroscopic Ellipsometry, a complete study of Gate lithography level measurement on standard products has been conducted. Experiments were done on typical ST batches for 120, 90, and 65 nm nodes. KLA-Tencor SpectraCD SE system is used to collect and analyze line critical dimensions and profiles. A systematic correlation with Scanning Electron Microscope (SEM) is done, completed by a cross section analysis. The study also takes into account lithography defect anlysis using a specific targets with intentionally generated process failures. Our objective is to determine the sensitivity window of such measurment technique to process defect and marginal process conditions. We show that KLA-Tencor SpectraCD allows a full reconstruction of the line profile - as well as the film stack underneath it - with values that are in agreement with production control. Cpm values obtained on products demonstrate that SE based scatterometry fulfils all requirements to be integrated in a production envrionemnt and provides suitable metrology for advanced lithography process monitoring.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.