Bit-patterned media magnetic recording disk with two sizes of dots and imprint template made with directed self-assembly (DSA) of block copolymers

摘要

A bit-patterned media (BPM) magnetic recording disk has two sizes of dots of magnetic material. The large and small dots are formed together in a hexagonal-close-packed (HCP) pattern. In the data regions none of the larger sized dots are adjacent one another; however in the servo regions some of the larger sized dots are adjacent one another. The adjacent larger sized dots form blocks that provide large amplitude “bursts” as the readback signal, as required for servo burst fields. The disk is made by imprint lithography using an imprint template, which can be made by directed self-assembly (DSA) of a block copolymer (BCP). The imprint template has two sizes of recesses, resulting in BPM disks with two sizes of dots. After the disks are imprinted they are exposed to a DC magnetic field, which magnetizes all the dots in the same direction.

主权项

1. A bit-patterned-media magnetic recording disk having a substrate and a magnetic recording layer on the substrate, the recording layer comprising two sizes of generally circularly-shaped magnetic dots forming a plurality of radially-spaced tracks having data sectors and servo sectors, wherein the data sectors contain dots of both sizes arranged together in a generally hexagonal-close-packed pattern, wherein the servo sectors extend radially across the tracks and contain dots of both sizes arranged together in a generally hexagonal-close-packed pattern, the servo sectors including at least two circumferentially-adjacent burst regions, each burst region containing a pattern of radially-spaced blocks of at least four adjacent larger sized dots that form the burst, each burst block extending across at least two tracks and together with surrounding smaller sized dots forming part of a hexagonal-close-packed pattern, and wherein the pattern of burst blocks in one of said at least two circumferentially-adjacent burst regions is radially spaced from the pattern of burst blocks in the other of said at least two circumferentially-adjacent burst regions.