Increase of Depth of Focus (DOF) and higher Numerical Aperture (NA), make of immersion lithography a sub-50nm
technology node enabler. At the same time it introduces a range of new defect types, also known as immersion defects.
According to the ITRS roadmap, the Smallest Defect Of Interest (SDOI) for the 45nm node has a size of 30nm  which
is the minimal defect size which poses risk to the integrity of the post litho chain processes. A novel approach of
Immersion Defectivity Baseline creation and monitoring has been developed for the 45nm technology node by ASML,
supported by Applied Materials. An Immersion Defectivity Baseline consists of: a qualified stack, a dedicated
defectivity reticle, a Defect Inspection Tool with an optimized inspection recipe, a Defect Review SEM with an
optimized defect review recipe and a defect qualification scheme. The new approach to Immersion Defectivity Baseline
creation is based on the combined capabilities of highest resolution bright-field inspection and SEM (Scanning Electron
Microscopy) review that are available today, with a unique qualification methodology using printed programmed defects
that cover the full printable size range. The inspection tool's SDOI detection sensitivity has been optimized for
engineering, production as well as monitoring modes, with negligible nuisance rate and basic classification capability
followed by highly accurate SEM review and classification. As a result, it enables a stringently controlled, highly
efficient, automated defect classification for baseline monitoring and increased productivity. The SEM material analysis
sub-apparatus complete the control loop for baseline creation and excursion control. This paper presents a protocol for
Immersion Defectivity Baseline creation and control methodologies used for the latest ASML immersion scanner.