175 nm period grating fabricated by i-line proximity mask-aligner lithography.

We report the fabrication of periodic structures with a critical dimension of 90 nm on a fused silica substrate by i-line (λ=365  nm) proximity mask-aligner lithography. This realization results from the combination of the improvements of the optical system in the mask aligner (known as MO exposure optics), short-period phase-mask optimization, and the implementation of self-aligned double patterning (SADP). A 350 nm period grating is transferred into a sacrificial polymer layer and coated with an aluminum layer.

Double-sided structured mask for sub-micron resolution proximity i-line mask-aligner lithography.

Diffractive mask-aligner lithography allows printing structures that have a sub-micrometer resolution by using non-contact mode. For such a purpose, masks are often designed to operate with monochromatic linearly polarized light, which is obtained by placing a spectral filter and a polarizer in the beam path. We propose here a mask design that includes a wire-grid polarizer (WGP) on the top side of a photo-mask and a diffractive element on the bottom one to print a 350 nm period grating by using a classical mask-aligner in proximity exposure mode.

250 nm period grating transferred by proximity i-line mask-aligner lithography.

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.

Direct nanopatterning of 100 nm metal oxide periodic structures by Deep-UV immersion lithography.

Deep-UV lithography using high-efficiency phase mask has been developed to print 100 nm period grating on sol-gel based thin layer. High efficiency phase mask has been designed to produce a high-contrast interferogram (periodic fringes) under water immersion conditions for 244 nm laser. The demonstration has been applied to a new developed immersion-compatible sol-gel layer.

100 nm period grating by high-index phase-mask immersion lithography.

The interferogram of a high index phase mask of 200 nm period under normal incidence of a collimated beam at 244 nm wavelength with substantially suppressed zeroth order produces a 100 nm period grating in a resist film under immersion. The paper describes the phase mask design, its fabrication, the effect of electron-beam lithographic stitching errors and optical assessment of the fabricated sub-cutoff grating.