Direct microfabrication using an x-ray micro-beam with a single refractive lens

A micro-beam of hard X-ray (10 keV) as small as 5 μm in diameter has been generated using a single refractive lens made of polymers (e.g. PMMA, PTFE) and been applied for direct writing, which may find possible applications in three-dimensional (3D) micro-fabrication. The refractive lenses are parabolic-shaped concave lenses with a radius of 4 μm and an aperture of 179 μm and have been produced using our high aspect-ratio techniques with synchrotron radiation (SR) of our home-made compact storage ring, AURORA-2S (electron energy of 0.7 GeV). The lenses have two parabolic curvatures (R=4 μm) with apertures A=2(2Rz)1/2=179 μm, thus the aspect-ratio z/R=250 for its curvatures, which is too great for traditional techniques to achieve. The transmissions of our lenses were measured to be 54-85%, which is higher than that of a zone plate and a compound refractive lens. (author)