| 摘要 |
PROBLEM TO BE SOLVED: To provide a polishing method which allows a main surface of a quartz glass substrate to have a flatness of 0.3 μm or less after polishing.SOLUTION: A method of mechanically polishing a main surface of a quartz glass substrate 10 by using polishing slurry having cerium oxide as a main component, includes implementation of each of following processes at least once: a first polishing process of mechanically polishing the main surface of the quartz glass substrate 10 under conditions in which a zeta potential of cerium oxide 30 is negative and an absolute value of the zeta potential becomes greater than 5 mV; and a second polishing process of mechanically polishing the main surface of the quartz glass substrate 10 under conditions in which the zeta potential of the cerium oxide is positive and the absolute value of the zeta potential becomes greater than 5 mV. |
