Stock material or miscellaneous articles – Magnetic recording component or stock – Thin film media
Reexamination Certificate
2011-08-23
2011-08-23
Rickman, Holly (Department: 1785)
Stock material or miscellaneous articles
Magnetic recording component or stock
Thin film media
C428S800000, C428S817000, C428S836000
Reexamination Certificate
active
08003236
ABSTRACT:
A method for making a master mold to be used for nanoimprinting patterned-media magnetic recording disks results in a master mold having topographic pillars arranged in a pattern of annular bands of concentric rings. The ratio of circumferential density of the pillars to the radial density of the concentric rings in a band is greater than 1. The method uses sidewall lithography to first form a pattern of generally radially-directed pairs of parallel lines on the master mold substrate, with the lines being grouped into annular zones or bands. The sidewall lithography process can be repeated, resulting in a doubling of the number of lines each time the process is repeated. Conventional lithography is used to form concentric rings over the radially-directed pairs of parallel lines. After etching and resist removal, the master mold has pillars arranged in circular rings, with the rings grouped into annular bands. The master mold may be used to nanoimprint the disks, resulting in disks having a BAR greater than 1, wherein BAR is the ratio of data track spacing in the radial direction to the data island spacing in the circumferential direction.
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Albrecht Thomas R.
Stipe Barry Cushing
Yang Henry Hung
Berthold Thomas R.
Chau Lisa
Hitachi Global Storage Technologies - Netherlands B.V.
Rickman Holly
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