Fabrication of Silica X-Ray Micro-Lenses by Ion-Beam Lithography

The paper presents the results of development and fabrication of X-ray micro-lenses from X-ray amorphous material, silica, by ion-beam lithography based on systems combining a focused ion beam and a scanning electron microscope. The possibility of fabrication of glass microlenses with a concave parabolic profile and curvature radii from two to 30 μm and an aperture of 20 μm is demonstrated. A method for removing the redeposited layer using 5% hydrofluoric acid is tested. The achieved accuracy of parabolic microlens profile fabrication was less than 30 nm (minimum–maximum scatter), and the RMS roughness of the optical surface was less than 10 nm. The optical characteristics of silica micro-lenses for high-resolution X-ray microscopy applications for new-generation synchrotron sources are evaluated.