Scanning electron microscope measurement of width and shape of 10nm patterned lines using a JMONSEL-modeled library

The width and shape of 10nm to 12nm wide lithographically patterned SiO2 lines were measured in the scanning electron microscope by fitting the measured intensity vs. position to a physics-based model in which the lines' widths and shapes are parameters. The approximately 32nm pitch sample was...

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Bibliographic Details
Published in:Ultramicroscopy 2015-07, Vol.154, p.15-28
Main Authors: Villarrubia, J.S., Vladár, A.E., Ming, B., Kline, R.J., Sunday, D.F., Chawla, J.S., List, S.
Format: Article
Language:English
Subjects:
Asymmetry
Computer simulation
Critical dimension (CD)
Critical dimension small angle x-ray scattering (CD-SAXS)
Dimensional metrology
Fittings
Libraries
Mathematical models
Model-based dimensional metrology
Monte Carlo methods
Scanning electron microscopy
Scanning electron microscopy (SEM)
Simulation
State of the art
Transmission electron microscopy (TEM)
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Summary:The width and shape of 10nm to 12nm wide lithographically patterned SiO2 lines were measured in the scanning electron microscope by fitting the measured intensity vs. position to a physics-based model in which the lines' widths and shapes are parameters. The approximately 32nm pitch sample was patterned at Intel using a state-of-the-art pitch quartering process. Their narrow widths and asymmetrical shapes are representative of near-future generation transistor gates. These pose a challenge: the narrowness because electrons landing near one edge may scatter out of the other, so that the intensity profile at each edge becomes width-dependent, and the asymmetry because the shape requires more parameters to describe and measure. Modeling was performed by JMONSEL (Java Monte Carlo Simulation of Secondary Electrons), which produces a predicted yield vs. position for a given sample shape and composition. The simulator produces a library of predicted profiles for varying sample geometry. Shape parameter values are adjusted until interpolation of the library with those values best matches the measured image. Profiles thereby determined agreed with those determined by transmission electron microscopy and critical dimension small-angle x-ray scattering to better than 1nm.
ISSN:0304-3991
1879-2723
DOI:10.1016/j.ultramic.2015.01.004