| 摘要 |
Methods and devices are provided for performing adjustments of illumination uniformity obtained from a charged-particle illumination-optical system as used, e.g., in a charged-particle-beam (CPB) microlithography apparatus. The adjustments are based on measurements of illumination-beam current density. The device includes an aperture plate (desirably a silicon membrane), defining a tiny measurement aperture (desirably about 1 mum diameter), mounted on the reticle stage at the reticle plane. The illumination beam is scanned over the aperture. Charged particles of the beam passing through the aperture are directed to a beam-current detector on or at the substrate stage. The membrane desirably has a thickness of about 1 to 3 mum. The measurement aperture allows the distribution of current density of the illumination beam to be measured highly accurately. The thinness of the membrane allows the membrane to scatter incident CPB radiation rather than absorbing the radiation, thereby preventing thermal deformation of the membrane.
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