Directed Self-Assembly of Block Copolymer for Bit Patterned Media with Areal Density of 1.5 Teradot/Inch2 and Beyond
Figure 3
(a) Schematic representation of directed self-assembly of cylinder-forming PS-b-PMMA thin films by a 2D chemical prepattern. The density multiplication factor is 4 (). (A) Coating PS-OH brush layer on a substrate, (B) e-beam patterning with a pitch of and then O2 RIE etch, (C) stripping e-beam resist, (D) spin coating of PS-b-PMMA thin film, (E) thermal annealing BCP film, and (F) removal of PMMA block and the remaining PS block matrix. (b) Large-scale SEM image of PS-b-PMMA BCP pattern (hcp) with a pitch of 27.0 nm (1.0 Td/in2). The well-aligned BCP patterns are directed by a 2D chemical prepattern with a prepattern pitch of 54.0 nm (0.25 Td/in2, ). The insets are a magnified SEM image of BCP pattern and a 2D FFT graph.
