KLA Corporation
Wave-Front Aberration Metrology of Extreme Ultraviolet Mask Inspection Systems

Abstract:

A metrology system for measuring wave-front aberration of an extreme ultraviolet (EUV) mask inspection system is disclosed. The test mask includes a substrate formed from a material having substantially no reflectivity for EUV illumination, and one or more patterns formed on the substrate, the one or more patterns having a reflective portion configured to reflect EUV illumination, positioned in a common plane with an absorption portion having substantially no reflectivity for EUV illumination, on or above the substrate.