title: 250  nm period grating transferred by proximity i-line mask-aligner lithography.
abstract: This Letter, describes a fabrication method based on a high refractive index binary phase mask combined with a suitable illumination setup, which produces a close to normal incidence illumination, to fabricate sub-micrometer diffraction gratings. The method uses the i-line (365 nm) of a mercury lamp spectrum in a mask-aligner in proximity mode, to avoid any contact between the mask and the wafer, which is normally used to produce high resolution structures. The transfer of the structure in a fused silica wafer demonstrates that mask-aligner lithography can produce high aspect ratio sub-wavelength structures without resorting to any contact between mask and wafer.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Bourgin
authors.forename: Thomas
authors.initials: T
authors.lastname: Käsebier
authors.forename: Uwe D
authors.initials: UD
authors.lastname: Zeitner