Thermally induced self-assembly of poly(4-(tert-butyldimethylsiloxy) styrene-b-2-vinylpyridine) with extremely reduced roughness of patterns

Directed self-assembly (DSA) of block copolymers (BCPs) is among the best alternative methods for achieving traditional top-down lithography because BCPs can form well-ordered nanostructures, such as spheres, cylinders, gyroids, and lamellae, with a controlled domain size (d) of 10-50 nm. However, regarding the pattern quality, further development of BCPs to satisfy industrial demands is still necessary. Here, a well-defined BCP, poly(4-(tert-butyldimethylsiloxy)styrene b-2-vinylpyridine) (P4BDSS-b-P2VP), was synthesized to investigate the relationship between the Flory-Huggins interaction parameter (chi) and the self-assembled pattern quality by comparing it with poly(styrene b 4 (ten butyldimethylsiloxy)styrene) (PS-b-P4BDSS). It was confirmed that the higher chi value of P4BDSS-b-P2VP (0.128 at 25 degrees C) than that of PS-b-P4BDSS (0.0525 at 25 degrees C) calculated based on small-angle X-ray scattering (SAXS) analysis and Leibler's mean field theory was beneficial to pattern quality in DSA. The line edge roughness (LER) and line width roughness (LWR) of P4BDSS-b-P2VP were 1.33 and 2.73 nm, respectively, which were lower than those of PS-b-P4BDSS (2.29 and 3.52 nm, respectively).