Line width roughness (LWR) is usually estimated simply as three standard deviations of the line width. The effect of image noise upon this metric includes a positive nonrandom component. The metric is therefore subject to a bias or ?systematic error? that we have estimated can be comparable in size to the roughness itself for samples as smooth as required by the industry roadmap. We illustrate the problem using scanning electron microscope images of rough lines. We propose simple changes to the measurement algorithm that, if adopted by metrology instrument suppliers, would permit estimation of LWR without bias caused by image noise. (11 references)
Proceedings of SPIE
February 27-March 4, 2005
San Jose, CA, USA
Metrology, Inspection, and Process Control for Microlithography XIX, Richard M. Silver, Editor, May 2005
and Bunday, B.
Unbiased Estimation of Linewidth Roughness, Proceedings of SPIE, San Jose, CA, USA, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=822373
(Accessed December 6, 2023)