Reconstruction of sub-wavelength features and nano-positioning of gratings using coherent Fourier scatterometry

Nitish Kumar, Peter Petrik, Gopika K.P. Ramanandan, Omar El Gawhary, Sarathi Roy, Silvania F. Pereira, Wim M.J. Coene, H. Paul Urbach

Research output: Article

23 Citations (Scopus)

Abstract

Optical scatterometry is the state of art optical inspection technique for quality control in lithographic process. As such, any boost in its performance carries very relevant potential in semiconductor industry. Recently we have shown that coherent Fourier scatterometry (CFS) can lead to a notably improved sensitivity in the reconstruction of the geometry of printed gratings. In this work, we report on implementation of a CFS instrument, which confirms the predicted performances. The system, although currently operating at a relatively low numerical aperture (NA = 0.4) and long wavelength (633 nm) allows already the reconstruction of the grating parameters with nanometer accuracy, which is comparable to that of AFM and SEM measurements on the same sample, used as reference measurements. Additionally, 1 nm accuracy in lateral positioning has been demonstrated, corresponding to 0.08% of the pitch of the grating used in the actual experiment.

Original languageEnglish
Pages (from-to)24678-24688
Number of pages11
JournalOptics Express
Volume22
Issue number20
DOIs
Publication statusPublished - okt. 6 2014

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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    Kumar, N., Petrik, P., Ramanandan, G. K. P., El Gawhary, O., Roy, S., Pereira, S. F., Coene, W. M. J., & Urbach, H. P. (2014). Reconstruction of sub-wavelength features and nano-positioning of gratings using coherent Fourier scatterometry. Optics Express, 22(20), 24678-24688. https://doi.org/10.1364/OE.22.024678