The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 03, 2007
Filed:
Jul. 14, 2005
Toshihiro Tsumori, Fukui-ken, JP;
Toshihiro Tsumori, Fukui-ken, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
Proposed are a substrate that comprises an easily producible soft magnetic backing film and can reduce spike noise from the soft magnetic backing film, and a method for producing the substrate. More specifically, provided are a substrate for a perpendicular magnetic recording hard disk medium, comprising an Si single crystal substrate () having a diameter of 65 mm or less, a thickness of 1 mm or less and an average surface roughness (Rms) of 1 nm or more and 1000 nm or less; an under-plated layer () formed on the substrate, the layer () comprising one or more metals selected from a group consisting of Ni, Cu and Ag and having a thickness of 1 nm to 300 nm; and a plated soft magnetic layer () formed on the under-plated layer, the layer () having a thickness of 50 nm or more and less than 1000 nm, a coercivity of 20 Oe(oersteds) or less and a saturation magnetization of 1T or more, wherein the average surface roughness (Rms) of the plated soft magnetic layer is 0.1 nm or more and 5 nm or less.