Facile and Fast Interfacial Engineering Using a Frustrated Interfacial Self‐Assembly of Block Copolymers for Sub‐10‐nm Block Copolymer Nanopatterning

A requisite for successful nanopatterning is a precise interface control to meet the adequate surface energies. In block copolymer (BCP) nanopatterning, the interfaces need to be neutralized, promoting both blocks to wet the substrate, and thus realizing the perpendicular orientation of BCPs. However, conventional methods for surface neutralization are expensive and require complex multi‐step processes, which hinders the application of BCP to continuous lithography processes. In this study, the simplest method for controlling the out‐of‐plane domain orientation using frustrated interfacial self‐assembly (FISA) of BCPs is introduced. The FISA layer is a randomly segregated structure that is readily created from the air/water interface. The FISA layer can be transferred to any target substrate, neutralizing both free and substrate interfaces. Employing FISA, the highly aligned and perpendicularly oriented sub‐10‐nm BCP patterns are produced with exceptional simplicity. Frustrated interfacial self‐assembly (FISA) of block copolymers creates a molecular‐level thick ultrathin neutralization layer enabling perpendicularly oriented sub‐10‐nm BCP nanopatterning. The randomly segregated structure of the FISA provides compositional randomness with 10‐nm scale. Furthermore, The Langmuir–Blodgett method‐based FISA process is compatible with roll‐to‐roll process, which makes the FISA a promising candidate for scale‐up of BCP nanopatterning.