| 초록 |
Achieving sub-10 nm high-aspect-ratio patterns from diblock copolymer self-assembly requires both a high interaction parameter (χ, determined by the incompatibility between the two blocks) and a perpendicular orientation of microdomains. We firstly realize a fully perpendicular orientation of a high-χ block copolymer, poly(styrene-block-dimethylsiloxane) (PS-b-PDMS), using partially hydrolyzed polyvinyl alcohol (PVA) top coats with a solvent annealing process, despite the large surface energy differences between PS and PDMS. The PVA top coat on the block copolymer films under a solvent vapor atmosphere not only significantly reduces the interfacial energy difference between two blocks at the top surface but also provides sufficient solvent concentration gradient in the through-thickness direction and appropriate solvent evaporation rates within the film to promote a perpendicular microdomain orientation. We also introduce top coats of polyvinyl acetate (PVAc) on PS-b-PDMS film to form the perpendicular orientation of BCP microdomains and induce dewetting process for the laterally aligned BCP patterns during the solvent annealing. |
