| 摘要 |
PURPOSE:To expose patterns with high accuracy over the entire surface on a circular disk surface by will maintaining the flatness of a circular reticule. CONSTITUTION:The circular reticule R is imposed on the holding part 4 of a rotary driving section 3 and a flat plate 5 is disposed on the circular reticule R apart a slight spacing therefrom. Gas of a prescribed pressure is supplied between the flat plate 5 and the circular reticule R via a through-hole 5c in the central part of the flat plate 5. The circular reticule R is attracted to the plane plate 5 by Bernoulli theorem, by which the deflection of the circular reticule R is corrected. |
