Orientation control materials for block copolymers used in directed self-assembly applications

摘要

An orientation control layer (OCL) for self-assembly of block copolymers comprises a random copolymer comprising a first repeat unit having an ethylenic backbone functional group and a side chain aromatic ring, a second repeat unit comprising an ethylenic backbone functional group and a side chain polycarbonate, and a third repeat unit comprising an ethylenic backbone functional group and a side chain ester or amide bearing an active group capable of forming a covalent bond with a substrate surface (e.g., a silicon wafer). The OCLs are neutral wetting to block copolymers having a high Flory-Huggins interaction parameter chi (χ) (“high-chi” block copolymers) such as a block copolymer comprising a polystyrene block and a polycarbonate block. The neutral OCL wetting properties allow for formation of lamellar domain patterns of the self-assembled high-chi block copolymers to be oriented perpendicular to the OCL surface.