X-ray microscopy in Zernike phase contrast mode at 4 keV photon energy with 60 nm resolution

Abstract

We report on x-ray microscopy of advanced microelectronic devices imaged in Zernike-type phase contrast mode at 4 keV photon energy. Fresnel zone plates were used as high resolution x-ray objectives providing 60 nm spatial resolution. Integrated circuit copper interconnect structures were imaged in positive as well as negative phase contrast. In both cases the phase contrast in the x-ray images is about five times higher than the pure absorption contrast.

X-ray mosaic nanotomography of large microorganisms

“…On the other hand, hard X-ray microscopes with efficient tomographic capabilities usually operate in projection mode (Mokso et al, 2007) or full-field mode (Andrews et al, 2010;Neuhausler et al, 2003) and typically in the range of 6-20 keV with a penetration depth of up to several millimeters, granting therefore insight into larger samples made of materials with higher atomic numbers. In projection mode at 17-29 keV, with inherent propagation-based phase contrast, a spatial resolution of 180 nm in 3D has been reported in Requena et al (2009).…”

Condenser Optics in the X-ray Microscope

“…We were especially interested in the contrast among them, so all of them were operated in Zernike phase-contrast mode [7,8], i.e., a ring-shaped direct light not scattered by a sample meets a phase plate at the back focal plane of the OZP. This phase plate attenuates the direct light and gives /4 or 3/4 phase delay, depending upon the positive or the negative phase contrast.…”

Compact phase-contrast soft X-ray microscopy

“…Zernike phase contrast is an established technique in x-ray microscopy when using an arrangement where a phase ring phase-shifts the undiffracted light [11,12]. However, in soft x-ray microscopy, focal lengths are short which makes a phase ring more difficult to implement.…”