Patent ID: 8499583
Filing Date: 2013-08-06
Classification: C03C,G11B

Abstract:
1. A method of manufacturing a magnetic-disk glass substrate, the method including a chemical strengthening process of chemically strengthening the glass substrate, wherein: the chemical strengthening process comprises at least two steps; a first step brings the glass substrate into contact with a chemical strengthening treatment solution containing first ions having an ionic radius larger than an ionic radius of ions contained in the glass substrate, thereby causing ion exchange to occur; and a second or subsequent step brings the glass substrate into contact with a treatment solution containing second or subsequent ions being bivalent ions, wherein the second or subsequent step of bringing the glass substrate into contact with the treatment solution containing second or subsequent ions being bivalent ions is carried out to suppress excessive chemical strengthening due to the treatment solution adhering to a surface portion of the glass substrate after the first step and to prevent formation of fine waviness on the glass substrate, wherein a maximum value of the fine waviness of a main surface of the glass substrate is less than 5 nm in a rectangular measurement range having sides of 800 um and 980 um.