Simulations of the optical intensity within Nano Imprint Lithography (NIL) mask features have been made for patterned quartz masks having ultrathin film coatings with different indices of refraction. Fractionally fluorine terminated surfaces, previously proposed for improving the yield of NIL processes, are briefly reviewed. Optical intensity solutions within the feature were obtained using Panoramictech Maxwell solver software for variances in the optical constants of the coating films, aspect ratio, feature size, and wavelength.. The coated masks have conformal surface, higher index of refraction under-layer coating and a fractional terminated fluorine hydrocarbon (FHC) monomolecular layer. The values of optical constants for the FHC layers are unknown, so a range of ad-hoc values were simulated. Optical constants for quartz mask and Al<sub>2</sub>O<sub>3</sub>, TiO2 and Si under-layer films are taken from the literature. Wavelengths were varied from 193nm to 365nm. The question of photo-dissociation of the FHC layer for higher energy photons is addressed from first principles, with the result that the F-terminated layers are stable at higher wavelengths. Preliminary simulations for features filled with resist over various substrates are dependent on the antireflection character of the underlying film system. The optical intensity is generally increased within the simulated mask feature when coated with a higher index/FHC films relative to the uncoated reference quartz mask for ~5nm physical feature sizes.
A structure and method for coating Nano Imprint Lithography (NIL) masks is described. The approach uses conformal ALD layering methods and sequential monomolecular depositions. The processes describe chemically bonded, high density, smooth coatings having <i>fractional</i> fluorine terminations. Various molecular precursor mixtures or various reactive surface site chemical functionalization schemes allow the attainment of controlled percentages of <i>fractional</i> F-terminations. The percentage of fluorine terminations is adjustable and controllable from 0% to 100%. Chemistries are described that result in coating layers of the order of ~1nm. These fractional F-terminated coatings may be useful for the reduction and minimization of defects in advanced imprint lithography processes.
Future semiconductor manufacture includes challenging requirements to maintain film interface quality and minimize contamination. In addition, there will also be a drive to reduce costs by reducing the number of operational steps or by increasing throughput. Processes driven by yield considerations are metal stacks, poly-metal dielectric (cluster tools exist today) and, in the future perhaps, gate stacks, poly emitters, and salicide contacts. Processes driven to reduce operational expenses are those that are used many times, such as lithocells (track and exposure tools) and, perhaps, metrology cells. This paper reviews the status and process intent of typical cluster tools and their architectures. It addresses many of the issues that exist and provides a theme that much learning is required to achieve a substantial cluster tool environment in a future factory environment.