Production manner of glass substrate for information record media and production manner of information record media, and production manner of glass substrate for disk and production manner of disk.

摘要

PROBLEM TO BE SOLVED: To reduce a flying height and to prevent a head crash and an thermal asperity by bringing a glass substrate into contact with a chemically strengthening treatment solution containing a chemically strengthening salt and substituting ion in the substrate with ion having a larger ion diameter in the treatment solution. ;SOLUTION: A glass substrate such as aluminosilicate glass is immersed in and brought into contact with a chemically strengthening treatment solution containing a chemically strengthening salt cleaned by removing particles in a region not exceeding a glass transition temperature to give a glass substrate strengthened by substituting lithium ion, etc. in the substrate with ion having a larger ion diameter such as sodium ion. The chemically strengthening salt comprises sodium nitrate, potassium nitrate or their mixture, etc. is filtered in a dissolved state in water by a filter, etc. to remove particles. The amount of particles having ≥0.2 μm particle diameter is adjusted to ≤12,000 particles/ml. The obtained chemically strengthening salt is used.;COPYRIGHT: (C)2000,JPO