Nanooptics and photonics

Fabrication of micro-components for X-ray optic using proton beam writing technique.

A.G. Ponomarev, S.V. Kolinko, V.A. Rebrov, V.N. Kolomiets, S.N. Kravchenko
Institute of Applied Physics, National Academy of Sciences of Ukraine, 58, Petropavlivska St., 40000 Sumy, Ukraine. 
E-mail: ponom56@gmail.com

Using in an interferometric X-ray phase-contrast imaging method of objects visualization based on 3-phase diffraction gratings with certain physical and geometric parameters, it is possible to receive phase-contrast images of the object under study, using as a source of radiation an ordinary X-ray tube. This avoids the use of synchrotron coherent radiation. Typically, these gratings are made using LIGA technology which is a projection technology using high-cost masks. An alternative technology is the proton-beam writing technique, which provides direct exposure resistive material by means of the focused proton beam from electrostatic accelerator with an energy of several MeV. Proton beam writing is a direct writing techniques which gives possibility to fabricate in resistive materials of 3D micro- and nano-dimensions structures. The structures have high aspect ratio with vertical, smooth side walls and low line-edge roughness. 
This presentation describes the process of proton beam formation focused into a thin line using a triplet of magnetic quadrupole lenses. This significantly reduces the exposure time of the resistive material during fabrication of diffraction gratings. Images of diffraction gratings and their geometrical dimensions are given. The procedure of electroplating, which allows to fill the cavities obtained by the developing of the irradiated areas of the resist, is also considered.