Magnetic-disk substrate, magnetic disk, and method for manufacturing magnetic-disk substrate
AssigneeHoya Corporation
InventorsMasanobu ITAYA, Kinobu OSAKABE
Life of this patent
Estimating the term…
Abstract
A magnetic-disk substrate has a pair of main surfaces and arithmetic average roughnesses Ra of the main surfaces are each 0.11 nm or less. Also, in surface unevenness of the main surfaces, an average area of regions occupied by a plurality of protrusions having a height of 0.1 [nm] or more from an average plane of the surface unevenness is 25 [nm2/protrusion] or less. The arithmetic average roughness Ra and the surface unevenness are measured using an atomic force microscope with a probe having a probe tip provided with a carbon nanofiber rod-shaped member.
Claims20
A magnetic-disk substrate, comprising:
- a pair of main surfaces,
- an arithmetic average roughness Ra of each of the main surfaces being 0.11 nm or less, and
- the arithmetic average roughness Ra being a value obtained through measurement using an atomic force microscope provided with a probe having a probe tip provided with a carbon nanofiber rod-shaped member.
A magnetic-disk substrate, comprising:
- a pair of main surfaces,
- in surface unevenness of the main surfaces, an average area of regions occupied by a plurality of protrusions having a height of 0.1 [nm] or more from an average plane of the surface unevenness being 25 [nm2/protrusion] or less, and
- the surface unevenness of the main surfaces being a value obtained through measurement using an atomic force microscope provided with a probe having a probe tip provided with a carbon nanofiber rod-shaped member.
A method for manufacturing a magnetic-disk substrate, comprising:
- after grinding a pair of main surfaces of a substrate, polishing the main surfaces of the substrate with a machining allowance of 30 μm or less such that an average area of regions occupied by a plurality of protrusions having a height of 0.1 [nm] or more from an average plane of surface unevenness of the main surfaces is 25 [nm2/protrusion] or less, the surface unevenness having been measured using an atomic force microscope provided with a probe having a probe tip provided with a carbon nanofiber rod-shaped member.
Dependencies are inferred from the claim text.