| 摘要 |
PURPOSE:To prevent a photomask from making incorrect application in error about its front/back, up/down or right/left by forming a square photomask base board forming a shape different from the shapes of other corners on one corner at least out of four corners and a photomask holding groove with which the base board is to be engaged. CONSTITUTION:When the square photomask base board 1 is to be formed by working a transparent plane member consisting of quartz or the like as a square form, a notch 3 is formed on one corner out of four corners and the width l1 of the base board 1 is set up differently from the width l2. The groove 5 of the holding part of a photomask holder 4 is formed similarly to the shape of the base board 1 with slightly larger size. At the fitting of the base board 1 to the holder 4, the base board 1 is engaged and fixed with the groove 5. |
