Reconstruction of the in-depth profile of line gratings with critical dimension grazing incidence small angle x-ray scattering on laboratory equipment

Abstract

We present a reconstruction of the in-depth profile of line gratings using critical-dimension grazing incidence small angle x-ray scattering with a compact Cu-Kα x-ray source mounted on a laboratory small angle x-ray scattering (SAXS). By taking advantage of the grazing-incidence configuration and with a rotation of the gratings under the x-ray beam, several orders of the Bragg rods were probed and led to the extraction of the in-depth profile of the lines. The extracted in-depth profile is compared with 3D atomic force microscopy results. The methodology developed mimics the one of critical dimension SAXS measurements, in transmission, to enable future comparison between the two approaches as well as building complementary modeling. These results open new perspectives for in-line x-ray metrology since the Cu-Kα x-ray source is widely spread and used by the x-ray community.