| 摘要 |
<p>PROBLEM TO BE SOLVED: To form a self-standing film or a membrane having an appropriate area and strength and in-plane uniformity by forming a window material or a filter of a composite film composed of a plurality of kinds of films. SOLUTION: A window material or a filter 23 through which light passes before irradiating a first optical element is formed of a composite film composed of a plurality of kinds of films. The first film 21 of the composite film is formed as a self-standing film or a membrane having an appropriate area and strength and in-plane uniformity by using an element which is selected as to make the absorption coefficient of the film or membrane to light having a wavelength between 100nm and about 50nm as small as possible. On the first film 21, a second film 22 which does not absorb exposure light having a prescribed wavelength, but well absorbs light having a wavelength longer than the prescribed one is formed. Therefore, the exposure illuminance on the surface of a mask can be improved and the in-plane distribution of the film thickness of the filter can be reduced.</p> |
