| 摘要 |
A method and apparatus for generating an image of a sample with a electron beam apparatus is disclosed. The image is generated from a portion of the sample with a measurement device having a source unit for directing an electron beam substantially towards the sample. The measurement device also has a detector for detecting particles that are emitted from the sample, an electrode proximal to the sample having a hole through which the electron beam and a portion of the emitted particles may pass, and an image generator for generating the image of the sample from the detected particles. A first voltage is applied to the electrode when the electron beam is substantially in a center of the hole. The first voltage is selected to control positive charge build up on the sample. A second voltage is applied to the electrode when the electron beam is deflected a predetermined distance from the center of the hole. The second voltage is selected to allow a significant amount of emitted particles to reach the detector to facilitate image generation while maintaining charge control.
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