Contributions to EUV mask metrology infrastructure

There is a strong demand for stand alone actinic tools for high volume manufacturing of EUV mask infrastructure. Among such metrology tools reflectometry, blank inspection, mask defect and pattern inspection are of special need to be in pilot lines of EUVL roadmaps expected to prepare production in 2012 to 213. With existing lab sources and metrology tool technology we expect to make significant contributions. With the existing EUV-reflectometer developed for mask blank characterization accuracies of < 0.1 % in peak reflectivity precision and 0.002 nm for centroid wavelength (CWL-50. 1 ) are routinely achieved on both reflective multilayer coated and absorbers coated blanks. Furthermore, new upgrades for fiducial mark detection in the reflectometer allow for measurements on structured masks with precise positioning (better than 50 m). Meanwhile, detail studies on reproducibility and sensibility of measurement versus tilt angle have been performed. These studies shows le ss than 1% change in peak reflectometry due to 500 rad tilt, while accuracy of alignment is <100 rad. We will demonstrate our recent achievements and further plans to along the roadmap requirements. Actinic mask blank defect inspection is considered crucial and is required at mask blank suppliers and perhaps in mask houses. For this aim, a proof of concept experiment based on an EUV microscope has been set up. The first results are presented together with tool extrapolation. We analyze the achievable defect resolving power and its localization with limited performance state-of-the-art collecting objectives. Possible alternative approaches are discussed.