| 摘要 |
PURPOSE:To make the handling of a reticle frame easy and correctly set the position of the reticle at all times by using a brittle material having a specified Young's modulus and a specified Poisson's ratio to form the frame. CONSTITUTION:Reticle frame 2 is made of brittle material such as glass or stone having 6,000-8,000kg/mm.<2> Young's modulus and 0.18-0.25 Poisson's ratio. The material is roughly worked by cutting and finished to the specified size by polishing or other method. In case the material is hit against an article, it is chipped 9 without causing plastic deformation. Even if chipped frame 2 is used, space T between the upper surface of lens-barrel 3 and reticle 1 agrees with the thickness of original frame 2. Reticle 1 is set to the desired position, and the image is correctly projected on a mask dry plate. |
