As a chemically amplified resist, UVN30 has been evaluated for mask use in high density pattern rapid fabrication by
electron beam lithography. This resist displays excellent sensitivity and reasonable resolution for dense features. At
optimum conditions proximity effect is eliminated and 75 nm and 150 nm dense lines resolved in a 300 nm thick film
with writing field of 1mm<sup>2</sup>. With UVN30 mask, Si nanostructures are etched by non-switch DRIE etch chemistry
developed in this work, which achieves high etch rate and smooth sidewall. This method is a promising technique for fast
speed fabrication of nanophotonics, nanochannels and Si master stamps for nanoimprint.
This paper reviews our recent progress of micro and nanolithography techniques for the fabrications of planar photonic meta-materials and other nano photonic structures. The nanotechnologies involved in this development include the state-of-the-art electron-beam lithography (EBL), nanoimprint lithography (NIL), hot embossing, soft lithography and hybrid lithography, which is the combination of different lithography processes. Using these technologies, various meta-materials in sizes from micrometres down to sub-100 nm were successfully fabricated. Characterisations of these meta-materials have revealed a wealth of novel phenomena in nanophotonics. This paper will also discuss the advantages, disadvantages and suitability of each technology involved, trying to give a fair judgement for the applicability of the developed techniques. It can be concluded that micro and nanolithography are capable of achieving functional planar optic meta-materials in both single layer and multiple layer. Especially the developed manufacture processes using nanoimprint lithography and hot embossing technique may lead to fast speed patterning for high throughput and low cost mass production for broad applications.
Pattern placement error (or pattern distortion) caused by different thermal expansions between templates and substrates in nanoimprint lithography is experimentally investigated. Using fabricated nanorulers, placement errors are quantitatively measured. Our results prove that nanoimprint lithography (NIL) with a heat cycle does have considerable error of pattern placement. But that is not the case with imprints at room temperature. This indicates that low-temperature or room-temperature imprints should be effective solutions.
This paper proposes to apply nanoimprint and soft lithography to the manufacture of large area planar chiral photonic meta-materials. Both dielectric and metallic chiral structures in nanometre order were replicated by nanoimprint lithography (NIL). To carry out the NIL, a nanofabrication process for imprint templates with chiral features was developed. For the dielectric chiral structures, a single layer of thick hydrogen silsequioxane (HSQ) was used, and for metallic chiral ones a bi-layer PMMA/HSQ technique was employed. The polarization conversion capabilities of planar chiral structures (PCS) imprinted in dielectric materials have been experimentally observed. This indicates that the developed nanoimprint processes in this work have the prospect of manufacturing planar photonic meta-media in high volume at low cost. A hybrid lithography combing nanoimprint and soft lithography is proposed for the constructions of chiral cavities inside dielectric materials.