| 摘要 |
PROBLEM TO BE SOLVED: To provide a cleaning resistance evaluation method of a photomask blank, which can simply evaluate an amount of changes in a critical dimension (CD) before and after the cleaning in a short time.SOLUTION: The cleaning resistance evaluation method of a photomask blank evaluates cleaning resistance of the photomask blank including an optical film on a transparent substrate. The method includes the steps of: measuring, in advance, an amount of change in an optical characteristic value and an amount of change in a CD before and after the cleaning of the optical film; obtaining a relational expression of the measured amount of change in the optical characteristic value and the measured amount of change in the CD; measuring the amount of change in the optical characteristic value before and after the cleaning of the optical film, of the evaluation target photomask blank depositing the optical film on the transparent substrate, when the cleaning resistance is evaluated; and converting the measurement value into the amount of change in the CD before and after the cleaning using the relational expression in advance obtained; and determining the photomask blank in which the converted CD is equal to or less than a certain value, as a non-defective product. |
