Transmission hard X-ray microscope with increased view field using planar refractive objectives and condensers made of SU-8 polymer

Abstract

Planar X-ray refractive lenses in crossed geometry providing 2D focusing are fabricated from SU-8 polymer using tilted deep X-ray lithography. The profiles of the objective lens elements are parabolic. The lens elements for the condensers were designed with a power of the surface function of 1.5, 1.7 and 2 to vary the field of views for a transmission X-ray microscope (TXM). With these lenses a TXM was set up at the ESRF beamline BM-5 for a photon energy of 15 keV. Different test nanostructures were imaged with this TXM using inline phase-contrast, with X-ray magnification factors of 29, demonstrated spatial detail resolution of 100 nm (half-period of lines and spaces) and exposure times around 10 s. Further improvement of a TXM based on the SU-8 lenses using refractive condensers with large apertures is considered with the aim to reduce exposure times.