As critical dimensions for leading-edge semiconductor devices shrink, the line-edge roughness (LER) requirements are pushing well into the single digit nanometer regime. At these scales many new sources of LER must be considered. In the case of extreme ultraviolet (EUV) lithography, modeling has shown the lithographic mask to be a source of significant concern. Here we present a correlation-based methodology for experimentally measuring the magnitude of mask contributors to printed LER. The method is applied to recent printing results from a 0.3 numerical aperture EUV microfield exposure tool. The measurements demonstrate that such effects are indeed present and of significant magnitude. The method is also used to explore the effects of illumination coherence and defocus and has been used to verify model-based predictions of mask-induced LER.
© 2009 Optical Society of America
Original Manuscript: March 20, 2009
Revised Manuscript: May 18, 2009
Manuscript Accepted: May 25, 2009
Published: June 10, 2009
Patrick P. Naulleau, "Correlation method for the measure of mask-induced line-edge roughness in extreme ultraviolet lithography," Appl. Opt. 48, 3302-3307 (2009)