Pursuing the critical dimension in etched patterns using X-ray scattering*

As the lithographically manufactured nanostructures are shrinking in size, conventional techniques, such as microscopies (SEM, AFM) reach their resolution limits. The Critical Dimension Small-Angle X-ray Scattering (CD-SAXS) has emerged as a promising technique to extract the profile of line gratings. With the advent of high brightness sources and fast detectors, there is a possibility for combining fast X-ray acquisition with high-speed data treatment to reach the timescale for an effective in-line characterization method.
We have developed two tools for analyzing etched patterns, which are integrated in our plugin based graphical toolkit: Xi-CAM. First, fast algorithms were implemented into Xi-CAM, in collaboration with NIST, in order to provide a user-friendly interface, as well as a high throughput CD-SAXS tool. Then, a high performance Grazing Incidence SAXS simulation tool was developed, consisting on recording full Bragg rods thanks to a continuous rotation of the sample and then reconstructing the profile of etched patterns.