|
Polymeric materials with an imaging chemistry based on the main chain cleavage under the influence of photogenerated acid are a promising resist platform for EUV lithography. Backbone scission resist materials are, in principle, capable of creating very small structures due to the fact that the removing parts can have dimensions in the order of the monomers that they consist of. Nevertheless, in the case of the commonly used non-chemically amplified materials of this type, issues like sensitivity and poor etch resistance limit their applications, whereas inadequate etch resistance and non-satisfactory process reliability are the usual problems encountered in acid-catalyzed materials based on main chain scission. In this work, we report on optimization of the formulation of new high-sensitive polymeric materials for EUV lithography by tuning the ratio between the photoacid generator (PAG) and the base quencher. In our material design, the acid-catalyzed chain cleavable polymers contain very sensitive acid-labile bonds in their backbone while they remain intact in alkaline ambient. These photoresists were evaluated with several PAG and base quencher (BQ) loadings. The PAG ratio spans from 4% to 7% with respect to polymer weights, whereas the BQ ratio tuned to 5%, 10%, and 15% with respect to PAG weight. High-performance patterning capabilities were achieved for linesspaces down to 22 nm half-pitch using EUV interference lithography. We report linewidth roughness versus dose-to-size for 25 nm and 22 nm half-pitch for different PAG and BQ loadings and provide a comparison.
|
