Method of manufacturing glass substrate for recording medium, glass substrate for recording medium, recording medium and holding jig
Provided is a method of manufacturing a glass substrate efficiently via prevention of foreign matter adhesion to a glass substrate as to chemical strengthening. Disclosed is a method of manufacturing a glass substrate for a recording medium possessing the step of conducting a chemical strengthening process by which a glass substrate held by a holding jig and the holding jig are immersed in a chemical strengthening solution, and 1 st alkali metal ion on a surface of the glass substrate is substituted by 2 nd alkali metal ion having a larger ion diameter than that of 1 st alkali metal ion contained in the chemical strengthening solution, wherein the holding jig possesses a member of material made of a metal comprising an alkali metal element, or a metal film comprising an alkali metal element to cover a surface of the holding jig from the very beginning of the chemical strengthening process.
1. A method of manufacturing a glass substrate for a recording medium comprising:
conducting a first lapping process of polishing a first surface of a glass substrate and polishing a second surface of the glass substrate to adjust parallelism, flatness and thickness of the first surface and the second surface;
subsequent to completion of the first lapping process, conducting a second lapping process of polishing the first surface and polishing the second surface to finely adjust parallelism, flatness and thickness of the first surface and the second surface;
subsequent to completion of the second lapping process, conducting a chemical strengthening process by which the glass substrate, held by a holding jig, and the holding jig are immersed in a chemical strengthening solution, and a first alkali metal ion on the first surface of the glass substrate is substituted by a second alkali metal ion contained in the chemical strengthening solution and having a larger ion diameter than that of the first alkali metal ion, wherein the holding jig comprises a member of material, made of a metal comprising an alkali metal element; and
subsequent to completion of the chemical strengthening process, conducting a polishing process by precisely polishing the first surface and precisely polishing the second surface to complete the glass substrate for use with a recording medium.
2. A method of manufacturing a glass substrate for a recording medium comprising:
conducting a first lapping process of polishing a first surface of a glass substrate and polishing a second surface of the glass substrate to adjust parallelism, flatness and thickness of the first surface and the second surface;
subsequent to completion of the first lapping process, conducting a second lapping process of polishing the first surface and polishing the second surface to finely adjust parallelism, flatness and thickness of the first surface and the second surface;
subsequent to completion of the second lapping process, conducting a chemical strengthening process by which the glass substrate, held by a holding jig, and the holding jig are immersed in a chemical strengthening solution, and a first alkali metal ion on the first surface of the glass substrate is substituted by a second alkali metal ion contained in the chemical strengthening solution and having a larger ion diameter than that of the first alkali metal ion, wherein the holding jig comprises a metal film comprising an alkali metal element to cover a surface of the holding jig from the very beginning of the chemical strengthening process; and
subsequent to completion of the chemical strengthening process, conducting a polishing process by precisely polishing the first surface and precisely polishing the second surface to complete the glass substrate for use with a recording medium.
3. The method of claim 2 , wherein the metal film is a metal film formed via immersion of the metal film in the chemical strengthening solution.
4. The method of claim 2 , wherein the metal film has a thickness of 0.05-10 μm.
5. The method of claim 1 , wherein when the holding jig and glass substrate are simultaneously immersed in the chemical strengthening solution the holding jig does not generate foreign matter that is deposited on the glass substrate in an amount that would affect the efficacy of the glass substrate when used as a recording medium.
6. The method of claim 5 , wherein the substitution of the second alkali metal ion on the surface of the glass substrate inhibits elution of material of the holding jig into the chemical strengthening solution since the second alkali metal ions are present in the chemical strengthening solution, whereby generation of foreign matter in the chemical strengthening solution is suppressed.
7. The method of claim 2 , wherein when the holding jig and glass substrate are simultaneously immersed in the chemical strengthening solution the holding jig does not generate foreign matter that is deposited on the glass substrate in an amount that would affect the efficacy of the glass substrate when used as a recording medium.
8. The method of claim 7 , wherein the substitution of the second alkali metal ion on the surface of the glass substrate inhibits elution of material of the holding jig into the chemical strengthening solution since the second alkali metal ions are present in the chemical strengthening solution, whereby generation of foreign matter in the chemical strengthening solution is suppressed.