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Title: Nanoimprint lithography using disposable masters
Author: Hubbard, Graham John
ISNI:       0000 0004 2741 4326
Awarding Body: University of Bath
Current Institution: University of Bath
Date of Award: 2011
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A novel imprint process, called Disposable Master Technology has been developed using disposable masters replicated from nickel masters using roll-to-roll printing. The disposable masters consist of a polyester terephthalate film coated with a photosensitive resin containing the inverse structure of the nickel master. The use of hydrophobic and oleophobic additives was found to improve release after imprinting. This has enabled structures of deeply submicron periodicity to be imprinted on silicon wafers up to 4" diameter with good reproducibility. Resist systems have been developed based on urethane acrylates plus a resist based on Oxetanyl Silsesquioxane which contains silicon for improved etch resistance, useful when transferring the imprinted structures into the substrate by reactive ion etching. The addition of fluorinated acrylates has been shown to improve the substrate coverage during spin coating and to ease disposable master release after imprinting. Silicone acrylate, used as an additive was found to improve the etch resistivity as well as also easing disposable master release. The generation of disposable masters from anodic porous alumina has been investigated. Aluminium sample pre-treatment has been optimized for 2 inch diameter aluminium discs to produce 100 nm and 200 nm spaced pores of 180 to 500 nm depth with conical or cylindrical shape. The self-ordered porous alumina has beef! replicated on to PET film creating polymer nanopillars of down to 50 nm in diameter. The resulting nanostructured polymer films can act as anti-reflection coatings. The angle dependent transmission of polymer films has been found to increase transmission by up to 2% at a normal angle of incidence and by 5% at 70Q, when compared to a control sample. Highly ordered mono-domain porous alumina templates were also demonstrated by pre- texturing the aluminium surface using disposable master technology, to provide another method of fabricating master moulds for disposable master technology
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available