Hoya Corporation

Wd Media (singapore) Pte. Ltd.

Hoya Magnetics Singapore Pte. Ltd.

Masafumi Ishiyama

Teiichiro Umezawa

Kenji Ayama

Tokichiro Sato

Takahiro Onoue

Hiroshi Tomiyasu

Junichi Horikawa

Takashi Morikawa

Koichi Shimokawa

Kazuaki Sakamoto

Kong Kim

Toshiaki Tachibana

Provided is a mask blank in which a thin film for transfer pattern formation is provided on a main surface of a transparent substrate. The thin film is made of a material containing a transition metal and silicon and further containing at least one of oxygen and nitrogen. The thin film has as its surface layer an oxide layer with an oxygen content higher than that of the thin film of a region other than the surface layer. The thin film is formed so that the thickness of its outer peripheral portion is greater than that of its central portion on the main surface side. The oxide layer is formed so that the thickness of its outer peripheral portion is greater than that of its central portion on the main surface side.

Mask blank and transfer mask

Mask blank, transfer mask, and methods of manufacturing the same

A perpendicular magnetic recording medium includes a substrate, a soft magnetic layer, a pre-underlayer, an underlayer, and a main recording layer serving as a magnetic recording layer. The pre-underlayer contains seed crystal grains that serve as a base for crystal grains of the underlayer, and an addition substance that is added between the seed crystal grains and composed of an element having an atomic radius smaller than that of an element forming the seed crystal grains.

Perpendicular magnetic recording medium and method of manufacturing the same

A perpendicular magnetic recording medium with SNR improved by reducing noise due to an auxiliary recording layer so that a higher recording density can be achieved. The perpendicular magnetic recording mediumincludes a base, at least a magnetic recording layerhaving a granular structure in which a non-magnetic grain boundary portion is formed between crystal particles grown in a columnar shape; a non-magnetic split layerdisposed on the magnetic recording layerand containing Ru and oxygen; and an auxiliary recording layerthat is disposed on the split layerand that is magnetically approximately continuous in an in-plane direction of a main surface of the base

Perpendicular magnetic recording medium and process for manufacture thereof

A perpendicular magnetic recording medium of the invention is characterized by having, on a disk substrate, a soft magnetic layer, a magnetic recording layer, a continuous layermagnetically continuous in the in-plane direction of the substrate, a blocking layerfor blocking shock imposed on the continuous layer, and a medium protective layercontaining carbon formed on the blocking layer.

Perpendicular magnetic recording medium and manufacturing method of the same

In a magnetic disk having a magnetic layer, a protection layer, and a lubrication layer formed on a substrate in this order, a surface free energy &#x3b3;S of a surface of the magnetic disk derived by an extended Fowkes equation is greater than 0 and no greater than 24 mN/m. &#x3b3;Sd (dispersion force component of surface free energy) forming the surface free energy &#x3b3;S is greater than 0 and no greater than 17 mN/m, &#x3b3;Sp (dipole component of surface free energy) forming the surface free energy &#x3b3;S is greater than 0 and no greater than 1 mN/m, and &#x3b3;Sh (hydrogen bonding force component of surface free energy) forming the surface free energy &#x3b3;S is greater than 0 and no greater than 6 mN/m.

Magnetic disk and manufacturing method thereof

An object of the present invention is to provide a method of manufacturing a perpendicular magnetic recording medium () in which both of a coercive force Hc and reliability can be achieved at a higher level even with heating at the time of forming a medium protective layer () and to provide the perpendicular magnetic recording medium (). Thus, in a typical structure of the present invention, in the method of manufacturing the perpendicular magnetic recording medium () including at least a magnetic recording layer (), which is a ferromagnetic layer of a granular structure in which a non-magnetic grain boundary part is formed between crystal grains each grown in a columnar shape, and a medium protective layer () with carbon hydride as a main component in this order on a disk base (), the method includes a magnetic recording layer forming step of forming the magnetic recording layer () so that the grain boundary part contains oxides of a plurality of types and a medium protective layer forming step of forming the medium protective layer () in a state where the disk base () having the magnetic recording layer () formed thereon is heated at 160 to 200 degrees Celsius.

Method of manufacturing perpendicular magnetic recording medium and perpendicular magnetic recording medium

Provided is a magnetic disk () for a magnetic recording, which comprises a magnetic layer () for a magnetic recording, a protecting layer () formed over the magnetic layer () for protecting the magnetic layer (), and a lubricating layer () formed over the protecting layer (). The protecting layer () is a layer composed substantially of carbon, hydrogen and nitrogen. The atomic ratio (N/C) of nitrogen and carbon, which was calculated from the spectral intensities of N1s and C1s detected for a detection angle of 7 degrees of photoelectrons by an angularly resolved X-ray photoelectron spectroscopy, is 0.15 to 0.25. This constitution of the protecting layer () is excellent in wear resistance and sliding characteristics even for a film thickness of 3 nm or less and provides a magnetic disk which can avoid a high fly write trouble or the like.

Magnetic disk and magnetic disk manufacturing method

A vertical magnetic recording disc () includes a base (), a magnetic recording layer (), and a medium protection layer (). The magnetic recording layer () is a ferromagnetic layer having a granular structure where a granular portion is formed. The medium protection layer () contains nitrogen (N) atoms and carbon (C) atoms with a number ratio (N/C) in a range from 0.050 to 0.150. In a Raman spectrum obtained by exciting the medium protection layer () by argon ion laser light of wavelength 514.5 nm, from which a fluorescence is removed, the peak ratio Dh/Gh is in a range from 0.70 to 0.95, when a D peak Dh appearing in the vicinity of 1350 cmis separated from G peak Gh appearing in the vicinity of 1520 cmby the Gauss function.

Provided is a magnetic recording medium which maintains high S/N ratio and coercive force (Hc) and has high recording density, even with fine magnetic particles, by further improving crystal orientation of a magnetic recording layer. The magnetic recording medium is provided with an orientation control layer (), a nonmagnetic under layer (), and a magnetic recording layer () on a substrate. The orientation control layer () has an fcc structure and a (111) plane parallel to the substrate. The under layer () has an hcp structure and a (0001) plane parallel to the substrate. An atomic distance of the (111) plane of the orientation control layer () is &#x2212;0.2 &#x212b; to +0.15 &#x212b; to a lattice spacing of the under layer ().

Magnetic recording medium

A protection layer containing carbon as a major component is deposited by plasma CVD. The protection layer has film quality such that, when a spectrum is obtained by excluding photoluminescence from a Raman spectrum in a wavenumber band from 900 cmto 1800 cmobtained by exciting the protection layer with an argon ion laser beam having a wavelength of 514.5 nm and the spectrum is subjected to waveform separation by the Gaussian function to split a D peak appearing around 1350 cmand a G peak appearing around 1520 cm, the ratio Dw/Gw between a half width Dw of the D peak and a half width Gw of the G peak exceeds 0 and is not greater than 2.7.

Magnetic disk, method of manufacturing the magnetic disk and method of evaluating the magnetic disk

The present invention provides a perpendicular magnetic recording medium that can reduce noise by further size reduction and isolation of magnetic grains in a magnetic recording layer and can increase the recording density by improvement of the SNR. A typical configuration of a perpendicular magnetic recording medium according to the present invention is a perpendicular magnetic recording medium having a magnetic recording layer with a granular structure in which non-magnetic grain boundary portions are formed between magnetic grains that have grown continuously in a columnar shape, wherein the grain boundary portions contain a plurality of kinds of oxides.

Perpendicular magnetic recording medium

A magnetic disk comprises a magnetic layer and a protective layer sequentially formed on a disk-shaped substrate and has a principal surface to which data is recorded, and a side surface portion both of which are coated with the protective layer. The protective layer on the side surface portion is thinner than the protective layer on the principal surface. Preferably, the side surface portion includes a side wall surface, and a chamfered surface lying between the side wall surface and the principal surface, and at least the protective layer on the chamfered surface is thinner than the protective layer on the principal surface.

In a method of evaluating surface tension of a solid body surface, selection is made of at least three liquid samples having different surface tensions, and contact angles between the respective liquid samples and the solid body surface are measured. Thereby, a correlation between cosines (Y) of the contact angles and surface tensions (X) of the liquid samples is derived as a logarithmic function. Surface tension of the solid body surface is evaluated by the use of a value of X that is calculated by substituting 1 for Y in the correlation. When evaluated by the foregoing evaluation method, a magnetic disk has a surface where the value of X, when 1 is substituted for Y, is greater than 0 and no greater than 17 mN/m.

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Singapore, Singapore

Masafumi Ishiyama