Lithographic techniques, improved

Monodispersed particles can form close packed assemblies on nanostructured blend surfaces because of van der Waals interactions. The particle assemblies provide roughness to the underlying substrates. Further treatment, such as plasma etching [77] can also be applied to improve the surface roughness of blends. The colloidal particles can vary from polymer blends to inorganic spheres. Colloidal assembly is cost effective, since no expensive lithographic technique is required. This method is easy to master and to apply under laboratory conditions. 

In recent years, rapid progress has been made in lithographic technology along with a concomitant reduction in the minimun feature size. Ihe object of microphotolithography is to form high resolution resist patterns. Various techniques have been evaluated for improving the resolution of photoresist. 

It is also possible to smoothen the walls of patterned resist features, using standard post-lithographic processing techniques such as UV hardening, electron-beam irradiation, and thermal flow. The use of surfactant rinse liquids has also been shown to improve LER of patterned resist features to acceptable values. ... 

The route to generate aimed structures in general, and those of metal nanoparticles in particular, via the electro-oxidation of SAMs shows great promise. A series of examples other than those discussed here is available in Ref. [111]. Further developments of this strategy will be necessary to render it competitive by comparison with current lithographic methods. Although the generation of extended nanostructured surfaces by means of automated techniques has already been achieved [112], the use of multi-tip systems should lead to remarkable improvements in the efficiency of the technique. 

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