Keywords: lithography, photoresists, molecular resists, POSS, nanopatterning, resist materials, nanotechnology, Greece, functionalised polycarbocycles, etch resistance additives, resist films
Materials for lithography in the nanoscale
Design and development of photoresists aiming at patterning in the nanoscale is reported. Functionalised polycarbocycle-based molecules and Polyhedral Oligomeric Silsesquioxane (POSS) containing (meth)acrylate copolymers are the basic components of the resist materials proposed for 193 nm and EUV lithography. The synthesis of new functionalised polycarbocycles aimed first at the development of etch resistance additives for 193 nm (meth) acrylate resists, since these compounds are characterised by moderate absorbance at 193 nm and by increased etch resistance due to the polyaromatic and cycloaliphatic rings they contain. Recently, additional functionalisation with appropriate imaging and hydrophilic groups advanced compounds of this class to become suitable main components of molecular resist compositions. On the other hand the incorporation of POSS groups in (meth)acrylate copolymers was studied first towards the development of 157 nm double layer resists, and recently, after the renewal of the semiconductor industry interest for 193 nm technology for double layer 193 nm resists. Characterisation methodologies for sub 100 nm thick resist films were also developed based on interferometry and used for the optimisation of the resist materials developed.