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Characterization of the shape and line‐edge roughness of polymer gratings with grazing incidence small‐angle X‐ray scattering and atomic force microscopy
Author(s) -
Suh Hyo Seon,
Chen Xuanxuan,
Rincon-Delgadillo Paulina A.,
Jiang Zhang,
Strzalka Joseph,
Wang Jin,
Chen Wei,
Gronheid Roel,
de Pablo Juan J.,
Ferrier Nicola,
Doxastakis Manolis,
Nealey Paul F.
Publication year - 2016
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576716004453
Subject(s) - grazing incidence small angle scattering , optics , materials science , scattering , grating , surface finish , perpendicular , substrate (aquarium) , optoelectronics , physics , geometry , small angle neutron scattering , neutron scattering , composite material , oceanography , mathematics , geology
Grazing‐incidence small‐angle X‐ray scattering (GISAXS) is increasingly used for the metrology of substrate‐supported nanoscale features and nanostructured films. In the case of line gratings, where long objects are arranged with a nanoscale periodicity perpendicular to the beam, a series of characteristic spots of high‐intensity (grating truncation rods, GTRs) are recorded on a two‐dimensional detector. The intensity of the GTRs is modulated by the three‐dimensional shape and arrangement of the lines. Previous studies aimed to extract an average cross‐sectional profile of the gratings, attributing intensity loss at GTRs to sample imperfections. Such imperfections are just as important as the average shape when employing soft polymer gratings which display significant line‐edge roughness. Herein are reported a series of GISAXS measurements of polymer line gratings over a range of incident angles. Both an average shape and fluctuations contributing to the intensity in between the GTRs are extracted. The results are critically compared with atomic force microscopy (AFM) measurements, and it is found that the two methods are in good agreement if appropriate corrections for scattering from the substrate (GISAXS) and contributions from the probe shape (AFM) are accounted for.