1-Second Rapid Shear-Rolling Process for Unidirectionally Aligned and Perpendicularly Oriented Block Copolymer Nano-patterns for a Roll-to-Roll Scale*

Directed self-assembly of block copolymer (BCP) has been noticed in next-generation lithography as an alternative patterning method. The shear alignment attracts much attention as it can realize macroscopic unidirectional alignment of BCP microdomains. However, static shearing proceeds at a relatively low temperature due to the threat of macroscopic peeling, so the orientation is relatively poor. In the case of soft-shear or laser-shear using a temperature gradient, it is difficult to control the expansion direction of the PDMS located on the top. Moreover, only a unidirectional structure of parallel-oriented cylinders could be realized due to preferential wetting at the upper PDMS interface. Recently, our group realized a unidirectional alignment in a 4-inch scale by developing a shear-rolling process that can sequentially and massively apply shear stress to the BCP films, but it was still a low-temperature process, so repeated rolling was required for high-quality orientation.

In this presentation, we introduce the 1-second rapid shear-rolling process at very high temperatures to achieve highly & unidirectionally aligned perpendicular lamellar structures of PS-b-PMMA without special surface treatment even in contact with a PDMS pad. In addition, we confirmed our approach also worked with several neutral approaches and various lamellar BCP films. Finally, we successfully demonstrate the roll-to-roll process for unidirectional perpendicular alignment of the BCP films on flexible substrates.