| 摘要 |
PROBLEM TO BE SOLVED: To achieve a uniform illuminance distribution by suppressing uneven illumination on an exposed surface, so as to sufficiently cope with required delicate micro-machining. SOLUTION: A illuminator is provided with a correction optical system 10 in addition to various kinds of optical systems which are the components of a stepper. When, for example, the nitrogen in a room 10b is partially replaced with oxygen, light absorption occurs in the room 10b as luminous fluxes La, Lb, and Lc pass through the room 10b. Since the distances of the fluxes La, Lb, and Lc when they pass through the room 10b are La<Lb<Lc, the absorbed amounts of the fluxes La, Lb, Lc become different from each other and the illuminance distribution on the light emitting surface of the correction optical system 10 shows a descending distribution towards right side. A uniform illuminance distribution is obtained by changing the oxygen concentration of the optical system 10 or the wavelength of a light source, so that the uneven illuminance on the surface of a wafer which is a surface to be irradiated may be offset by utilizing this nature. |
