Implementation of background scattering variance reduction on the RapidNano particle scanner
conference paper
The background in simple dark field particle inspection shows a high scatter variance which cannot be distinguished from signals by small particles. According to our models, illumination from different azimuths can reduce the background variance. A multi-azimuth illumination has been successfully integrated on the Rapid Nano particle scanner. This illumination method reduces the variance of the background scattering on substrate roughness. It allows for a lower setting of the detection threshold, resulting in a more sensitive inspection system. By implementing this system the lower detection limit of the scanner was reduced from 59 nm to 42 nm LSE. A next improvement, a change of the inspection wavelength to 193 nm will bring the detection limit to sub 20 nm. © 2014 SPIE.
TNO Identifier
507118
ISSN
1996756X
ISBN
9780819499738
Publisher
SPIE
Article nr.
905033
Source title
SPIE Advanced Lithography Conference, Metrology, Inspection, and Process Control for Microlithography XXVIII, 23-27 February 2014, San Jose, CA, USA