Patent ID: 8475669
Filing Date: 2013-07-02
Classification: G11B

Abstract:
1. A method of forming a patterned media master pattern and magnetic media disks, comprising: (a) using e-beam lithography to form a chemical contrast pattern of concentric rings on a disk, where a spacing of the concentric rings is equal to an integral multiple of a target track pitch, the rings including regions within servo sector headers where the rings are continuous and offset radially by a fraction of a track pitch, including providing a substrate with chemical contrast that provides different wetting affinities to constituent materials of a block copolymer to direct assembly of the block copolymer, and the patterned media comprises discrete track media; (b) forming the chemical contrast pattern by depositing a polymer brush film on the substrate, applying e-beam resist on the polymer brush film to form and develop open areas in the e-beam resist, such that the open areas in the e-beam resist expose portions of the polymer brush film, chemical properties of the polymer brush film are altered in the open areas where the polymer brush film is not covered by e-beam resist, and removing the e-beam resist to form the substrate with chemical contrast pattern between the chemically modified polymer brush areas and unmodified areas; (c) performing self-assembly to form a new ring pattern at the target track pitch on top of the chemical contrast pattern, including the radial offsets in the servo sector headers; and (d) transferring the new ring pattern to magnetic media disks to form data tracks on the magnetic media disks that are separated by nonmagnetic grooves, with the nonmagnetic grooves and the data tracks including radial offset regions.