1 October 2010 Statistical- and image-noise effects on experimental spectrum of line-edge and line-width roughness
Atsushi Hiraiwa, Akio Nishida
Author Affiliations +
Abstract
The accuracy of estimated line-edge-roughness and line-width-roughness (LER and LWR) statistics is mostly determined by the noise inherent in experimental power spectral densities (PSDs). One type of noise is statistical noise, a kind of jagged structure, that is caused by the finiteness of a number NL of line segments used in analyses. To keep the estimation error below 5%, the ratio of sampling interval to correlation length should be 0.3 or smaller, and NL needs to be larger than 100 under the condition that the length of line segments is 2000 nm or larger, in compliance with the Semiconductor Equipment and Materials International standard. Another noise type is scanning-electron-microscope image noise. It causes edge-detection errors and induces an additional variation in LER/LWR. This variation raises the minima of PSDs and accordingly enhances the errors. The factor of the error enhancement is suppressed below 1.5 by controlling the ratio of image-noise-induced LER/LWR variance to the true variance below 0.6. This is achieved by averaging image pixels perpendicularly to fine lines, and is free from any appreciable drawbacks. The experimental results agree well with analytical approximations to Monte-Carlo results that are separately obtained. This leads us to obtain more general guidelines for accurate analyses by using the analytical formulas.
©(2010) Society of Photo-Optical Instrumentation Engineers (SPIE)
Atsushi Hiraiwa and Akio Nishida "Statistical- and image-noise effects on experimental spectrum of line-edge and line-width roughness," Journal of Micro/Nanolithography, MEMS, and MOEMS 9(4), 041210 (1 October 2010). https://doi.org/10.1117/1.3504358
Published: 1 October 2010
Lens.org Logo
CITATIONS
Cited by 18 scholarly publications.
Advertisement
Advertisement
RIGHTS & PERMISSIONS
Get copyright permission  Get copyright permission on Copyright Marketplace
KEYWORDS
Statistical analysis

Line width roughness

Error analysis

Solids

Edge detection

Fourier transforms

Microelectromechanical systems

Back to Top