| 摘要 |
<p>An optical element according to an embodiment comprises a substratum for support; multilayer film (30) capable of reflecting extreme ultraviolet rays, supported by the substratum; and alloy layer (20) interposed between the multilayer film and the substratum, wherein the alloy layer (20) is a thin film of alloy. The alloy layer (20) has a tensile internal stress, reducing the compressive internal stress of the multilayer film (30). Consequently, any deformation of optical element (100) can be inhibited, thereby realizing desirable optical characteristics. Further, on the alloy layer (20), the surface roughness can be minimized. Accordingly, in the forming of the multilayer film (30) on the alloy layer (20), any disordering of the structure of the multilayer film (30) can be suppressed and any deterioration of optical characteristics can be prevented. Thus, the resolving power of exposure unit (400) can be maintained. Further, the life duration of optical element (100) eventually exposure unit (400) can be prolonged.</p> |
