Magnetic disk substrate and production method of magnetic disk
View Patent ↗The invention can provide a production method for a magnetic disk substrate capable of reducing the number of surface defects of a glass substrate. When a magnetic disk is produced by using the resulting magnetic disk substrate, the yield and, furthermore, the reliability can be improved. When a surface of a magnetic disk substrate is washed after it is polished, the glass substrate is dipped into a washing solution while the surface of the glass substrate polished is held under a wet condition. The wet condition of the surface of the glass substrate includes a condition in which the glass substrate is dipped into water that may contain a surfactant, and a condition in which a liquid film is formed substantially on the entire surface.
1. A production method for a magnetic disk substrate wherein a surface of a glass substrate is washed after it is polished, comprising wetting said glass substrate between polishing and washing, with a wetting solution comprised of water and a carboxylic acid, and dipping the wetted glass substrate into a washing solution while the surface of said polished glass substrate is kept in a wet condition by the wetting solution.
2. The production method of a magnetic disk substrate according to claim 1 , wherein the wet condition of the surface of said polished glass substrate is a dip condition into water containing the carboxylic acid or containing the carboxylic acid and a surfactant.
3. The production method of a magnetic disk substrate according to claim 1 , wherein the wet condition of the surface of said polished glass substrate is a condition where a liquid film of water containing the carboxylic acid or containing the carboxylic acid and a surfactant, is formed substantially on the entire surface.
4. The production method of a magnetic disk substrate according to claim 2 , wherein, immediately after polishing, said glass substrate is dipped into water, containing the carboxylic acid or containing the carboxylic acid and a surfactant.
5. The production method of a magnetic disk substrate according to claim 2 , wherein said carboxylic acid is a mono- or poly-chain carboxylic acid.
6. The production method of a magnetic disk substrate according to claim 5 , wherein said poly-chain carboxylic acid is oxalic acid, citric acid, tartaric acid, malic acid or malonic acid.
7. The production method of a magnetic disk substrate according to claim 6 , wherein said poly-chain carboxylic acid is oxalic acid.
8. The production method of a magnetic disk characterized in that a magnetic recording layer is formed on said magnetic disk substrate according to claim 1 .