High-Fidelity Directed Self-Assembly Using Higher-χ Polystyrene-Block-Poly(Methyl Methacrylate) Derivatives for Dislocation-Free Sub-10 nm Features

Abstract

Extreme ultraviolet (EUV) lithography currently enables the creation of ultrafine patterns. However, as miniaturization progresses, stochastic defects become a significant challenge. Directed self-assembly (DSA) of block copolymers (BCPs) has gained attention for pattern rectification to improve the quality of EUV patterns or for density multiplication to obtain sub-10 nm features. DSA is one of the most promising miniaturization processes because it does not cause stochastic defects. However, dislocation defects are an important issue in density multiplication using strongly segregating BCP. This study demonstrates the use of DSA on 300 mm silicon wafers with higher-Flory-Huggins interaction parameter (χ) polystyrene-block-poly(methyl methacrylate) derivatives for sub-10 nm features. These higher-χ polymers, synthesized from polystyrene-block-[poly(glycidyl methacrylate)-random-poly(methyl methacrylate)] (PS-b-PGM) and 2,2,2-trifluoroethanethiol (PS-b-PG_FM), show excellent reproducibility of perpendicular lamellae. Line patterns with a sub-10 nm half-pitch are successfully formed by DSA on 300 mm wafers. Line patterns without parallel-oriented structures or dislocations can be achieved by optimizing the chemical guides and annealing conditions. A polymer with a higher χN value exhibits improved roughness in the resulting line patterns.