The directed self-assembly (DSA) of block copolymers (BCPs) has been suggested as a promising nanofabrication solution. However, further improvements of both the pattern quality and manufacturability remain as critical challenges. Although the use of BCPs with a high Flory-Huggins interaction parameter () has been suggested as a potential solution, this practical self-assembly route has yet to be developed due to their extremely slow self-assembly kinetics. In this study, it is reported that warm solvent annealing (WSA) in a controlled environment can markedly improve both the self-assembly kinetics and pattern quality. A means of avoiding the undesirable trade-off between the quality and formation throughput of the self-assembled patterns, which is a dilemma which arises when using the conventional solvent vapor treatment, is suggested. As a demonstration, the formation of well-defined 13-nm-wide self-assembled patterns (3 sigma line edge roughness of approximate to 2.50 nm) in treatment times of 0.5 min (for 360-nm-wide templates) is shown. Self-consistent field theory (SCFT) simulation results are provided to elucidate the mechanism of the pattern quality improvement realized by WSA.