MANUFACTURING METHOD FOR MAGNETIC DISK GLASS SUBSTRATES, MANUFACTURING METHOD FOR MAGNETIC DISK, AND POLISHING PAD

摘要

The present invention provides a manufacturing method for magnetic disk glass substrates such that micro-waviness in a range of 50-150 μm in a profile can be reduced. In the present invention, the amount of sinkage into a polishing pad when a circular section of a cylindrical indenter with a diameter of 50 μm is pressed with a load of 2.5 mN from the surface of the polishing pad is measured consecutively on the polishing pad surface in 50 μm intervals at 12 points, and a polishing pad which has a standard deviation of 0.15 μm acquired from data for sinkage amounts for 10 points excluding the largest value and the smallest value of the acquired sinkage amounts is used in the polishing treatment.