Titania doped quartz glass and making method

摘要

On an EUV light-reflecting surface of titania-doped quartz glass, an angle (θ) included between a straight line connecting an origin (O) at the center of the reflecting surface to a birefringence measurement point (A) and a fast axis of birefringence at the measurement point (A) has an average value of more than 45 degrees. Since fast axes of birefringence are distributed in a concentric fashion, a titania-doped quartz glass substrate having a high flatness is obtainable which is suited for use in the EUV lithography.

主权项

1. A method for manufacturing a titania-doped quartz glass, comprising the steps of subjecting a feed of a silicon-providing reactant gas and a titanium-providing reactant gas to oxidation or flame hydrolysis with the aid of a combustible gas and a combustion-supporting gas by using a burner, to form synthetic silica-titania fine particles, depositing the silica-titania fine particles on a rotating target, and concurrently melting and vitrifying the particles to form a titania-doped quartz glass ingot, wherein
during the ingot formation, the molten face of the ingot is maintained in an oblong shape having a major axis aligned with the growth axis direction of the ingot so that a molten face sector of the ingot has a length “a” in the growth axis direction of the ingot and a radius “b” in a radial direction of the ingot perpendicular to the growth axis direction, which meet the relationship: 0.3<1−(b/a)<0.67, and wherein said burner comprises a central multi-fold tube section A including at least three tubes at the center and a multi-nozzle section B enclosing section A, a multiplicity of combustion-supporting gas feed tubes in the multi-fold tube section B being disposed in five or six rows concentric with the central multi-fold tube.