| 摘要 |
PURPOSE:To prevent adhesion of dust, and to prevent the quality of a material from being deteriorated, by covering the surface of a reticle by sealing it up tightly by a parallel plane plate, and constituting its parallel plane plate of an inorganic material having an ultraviolet-ray transmissivity. CONSTITUTION:Far ultraviolet rays are emitted from an excimer laser 1, and radiated to a reticle 3 through an illuminating optical system 2. On its reticle 3, a parallel plane plate 5 is provided through a spacer 4, and the reticle 3 is sealed up tightly and covered with the parallel plane plate 5. Also, on the lower face of the reticle 3, a pattern 8 is formed, and its pattern 8 is made to form an image on a wafer 7 by a projection optical system 6. In such a case, the parallel plane plate 5 is constituted of an inorganic material for allowing ultraviolet rays to transmit through, for instance, quartz, etc. Also, thickness of the spacer 4 is set to depth of focus or above of the projection optical system 6. Accordingly, since the inorganic material for allowing far ultraviolet rays transmit through is used, a drop of the light quantity of the far ultraviolet rays is prevented, adhesion of dust is prevented without deteriorating the parallel plane plate, and also, it is possible not to allow an unnecessary part to form an image on the wafer. |
