Reducing Line Edge Roughness of PS-b-PMMA pattern by inducing hydrogen bonding at the interface of the block copolymer microdomains

Sharp interface between two blocks in block copolymer nano pattern is one of the important issues in industrial applications to nano-patterning. We utilized hydrogen bonding between N-(4-aminomethyl-benzyl)-4-hydroxymethyl-bezamide (BA) and urea (U) at the interface of polystyrene-\textit{block}-poly(methyl methacrylate) copolymer (PS-PMMA). For this purpose, we first synthesized PS by ATRP, then the end group was converted to amino group. Next, it was reacted with BA, followed by reaction with 4-pentynoic acid, resulting in alkyne-terminated group (PS-U-BA-alkyne). Also, azide-terminated PMMA was prepared by anionic polymerization followed by end functionalization. Finally, by the azide-alkyne click reaction between PS-U-BA-alkyne and PMMA-azide, PS-U-BA-PMMA was synthesized. We prepared vertical oriented lamellar nanopatterns on pre-patterned wafers and investigated line edge roughness (LER) after removing PMMA block by dry etching process. We found that LER was reduced compared with PS-PMMA without hydrogen bonding.