Organic-inorganic nanocomposites: Unique resists for nanolithography

Ultra large-scale integration (ULSI) should lead to 100 nm production circu its by 2006 as predicted by the Semiconductor Industry Association (SIA). F or-sub-100 nm lithography it is desirable to synthesize higher performance and higher contrast resists An optimum combination of high contrast necessa ry for sub-100 nm resolution, high sensitivity for high throughput can be a chieved by carefully engineering organic-inorgnnic nanocomposites, acting a s optimum resists for a given lithographic process This review outlines eme rging approaches towards the achievement of these goals A section also high lights Selected state-of-the-art resists. Nanocomposite resists for sub-100 nm features have included the incorporation of fullerene C-60 in a commerc ial resist ZEP520 (see Figure). Alternatively, nanoscale silica, particles :terre incorporated in the polymer backbone as covalently bonded pendant cl usters. The dispersion of 8-10 nm Silica particles in a chemically amplifie d resist has also been reported. In all these approaches, a higher softenin g temperature (T-g) and increased rigidity, due to increased density of the film resulted. Higher etch resistance as well as increased mechanical prop erties and also enhanced resist performance for nanometer pattern fabricati on have been obtained in these nanocomposites. Alternative approaches to co nventional lithography, based on self-assembled nanostructures, incorporati ng inorganic features as well as nanoimprinting via silicon polymer precurs ors, are also discussed.