We propose using angular scatterometry as a means to investigate LWR (line-width roughness) and CD (critical dimension). The grating target is illuminated by a single wavelength light source which has large angular aperture both in incidence angle θ and azimuth angle φ. A preliminary scatterometry model was first built by assuming perfect critical dimension printed without any line-width roughness. The difference between the model prediction and actual measurement is cased by line-width roughness contribution. We developed a calibration curve as a function of line-width roughness based on the statistical quantity of the incidence and azimuth angle dependence. The results demonstrate that scatterometry can indeed be used to extract line-width roughness and critical dimension information in production line with nano-scale resolution.

Date Published: 5 April 2007
PDF: 10 pages
Proc. SPIE 6518, Metrology, Inspection, and Process Control for Microlithography XXI, 65184G (5 April 2007); doi: 10.1117/12.711734

Published in SPIE Proceedings Vol. 6518:
Metrology, Inspection, and Process Control for Microlithography XXI
Chas N. Archie, Editor(s)