Patent ID: 7901840
Filing Date: 2011-03-08
Classification: G03F

Abstract:
1. A method of manufacturing a mask blank transparent substrate, comprising: a preparation step of preparing a transparent substrate having a precision-polished main surface; a surface shape information obtaining step of obtaining, as surface shape information of the main surface, height information from a reference plane at a plurality of measurement points provided in a predetermined region on the main surface of the transparent substrate that contacts a mask stage of an exposure apparatus; a simulation step of obtaining, based on the surface shape information obtained in the surface shape information obtaining step and shape information of the mask stage including a region where the mask stage contacts the main surface of the transparent substrate, height information from the reference plane at the plurality of measurement points by simulating the state where the transparent substrate is set in the exposure apparatus; a flatness calculation step of deriving, based on the height information from the reference plane obtained in the simulation step, a difference between a maximum value and a minimum value in a predetermined region including a transfer region of an exposure mask to thereby obtain a flatness of the transparent substrate when the transparent substrate is set in the exposure apparatus; and a judging step of judging whether or not the flatness calculated in the flatness calculation step satisfies a specification, wherein the height information in the simulation step is determined based upon a deflection differential equation in mechanics of materials, the deflection differential equation comprising at least (1) the height information obtained in the surface shape information obtaining step, (2) a warp of the transparent substrate along an X-direction with respect to the mask stage as fulcrums, and (3) a deflection of the transparent substrate along the X-direction due to gravity, and wherein the X-direction is a direction perpendicular to a longitudinal direction of the mask stage.