Eliminating the trade-off between throughput and pattern quality of directed self-assembly via warm solvent annealing

Abstract

Directed self-assembly (DSA) of block copolymers (BCPs) has been suggested as one of the promising nanofabrication solutions for resolving the resolution limit of optical lithography. However, further improvement of pattern quality such as line edge roughness and manufacturability remains as a critical challenge. Although the use of BCPs with a large Flory-Huggins interaction parameter (χ) was suggested as a potential solution, practical self-assembly route has not been developed yet due to their extremely slow self-assembly kinetics which brings about low throughput compared to low-χ BCPs. In this study, we report that warm solvent annealing (WSA) under controlled environment can markedly improve both self-assembly kinetics and pattern quality compared to a room-temperature process and can eliminate the undesirable trade-off between pattern quality and self-assembly speed occurring for conventional solvent vapor annealing. As a result, we demonstrate the formation of well-defined 13-nm-wide self-assembly patterns (3σ line edge roughness of ~ 2.5 nm) in treatment times of 30 s (for 360-nm-wide templates). We also provide self-consistent field theory (SCFT) simulation results to elucidate the mechanism of pattern quality improvement by WSA. This method will provide a new opportunity for high-χ BCPs self-assembly.