Method for manufacturing a titanium-doped silica glass mirror substrate blank for EUV lithography and system for determining the position of defects in the blank

摘要

The present invention relates to a method for producing a mirror substrate blank made of titanium-doped silica glass for EUV lithography having a thickness of at least 40 mm, comprising the following method steps: (a) surface polishing of the surface of the blank (B) determining the defect data in the surface of the blank, wherein (b1) the light is incident on the blank at a predetermined angle of incidence of less than 90 ° at the flat surface of the blank; (b2) The light is scattered on the defects in the blank, and (b3) the scattered light is detected by light detection means provided vertically above it at a distance x from the transmission point on the surface of the blank, ( c) a step of determining the position of the defect in the surface layer based on the data obtained in the process of the method step (b); Removed, forming a mirror substrate blank. [Selection] Figure 1a