| 摘要 |
An electron beam apparatus for providing an evaluation of a sample, such as a semiconductor wafer, that includes a micro-pattern with a minimum line width not greater than 0.1 mum with high throughput. A primary electron beam generated by an electron gun is irradiated onto a sample and secondary electrons emanating from the sample are formed into an image on a detector by an image projection optical system. An electron gun 61 has a cathode 1 and a drawing electrode 3 , and an electron emission surface 1 a of the cathode defines a concave surface. The drawing electrode 3 has a convex surface 3 a composed of a partial outer surface of a second sphere facing the electron emission surface 1 a of the cathode and an aperture 73 formed through the convex surface for passage of the electrons. An aberration correction optical apparatus comprises two identically sized multi-polar Wien filters arranged such that their centers are in alignment with a 1/4 plane position and a ¾ plane position, respectively, along an object plane-image plane segment in the aberration correction optical apparatus, and optical elements having bidirectional focus disposed in an object plane position, an intermediate image-formation plane position and an image plane position, respectively, in the aberration correction optical apparatus.
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