Abstract: A microscope system for flexibly, efficiently and quickly inspecting patterns and defects on extreme ultraviolet (EUV) lithography photomasks. The system includes a stand-alone plasma-based EUV radiation source with an emission spectrum with a freestanding line emission in the spectral range from 12.5 nm to 14.5 nm has a relative bandwidth of ?/??>1000, means for the broadband spectral filtering ?/??<50 for selecting the dominant freestanding emission line, means for suppressing radiation with wavelengths outside of the EUV spectral region, zone plate optics for magnified imaging of the object with a resolution which corresponds to the width of an outermost zone of the zone plate, a numerical aperture corresponding to more than 1000 zones, and a EUV detector array for capturing the patterned object.
Type:
Grant
Filed:
September 15, 2020
Date of Patent:
March 28, 2023
Assignee:
RI Research Institute GmbH
Inventors:
Rainer Lebert, Christoph Sebastian Phiesel, Thomas Missalla, Andreas Biermanns-Foeth, Christian Piel