| 摘要 |
PROBLEM TO BE SOLVED: To provide an electron beam illumination optical system that has small unevenness in illumination intensity on the illumination surface. SOLUTION: In the case of an electron beam optical system that irradiates the surface, uneven irradiation is brought about due to aberration or influence of aperture of the electron beam optical system. Therefore, as shown in Fig. if an electron gun which has a high electron emission density (current density) at a position that has a relatively wider angle than the immediate top of the axis is used, and the illumination surface is given Koehler illumination, the uneven irradiation due to aberration of the electron beam optical system is offset by the illumination unevenness caused by the current density angle distribution of the electron gun, and the illumination intensity unevenness can be reduced. Hence, an electron beam illumination optical system having small illumination unevenness on the illumination surface can be obtained. COPYRIGHT: (C)2003,JPO
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