| 摘要 |
A method for focusing a charged particle beam, the method includes: (a) altering a focal point of a charged particle beam according to a first focal pattern while scanning a first area of a sample and collecting a first set of detection signals; (b) altering a focal point of a charged particle bean according to a second focal pattern while scanning a second area that is ideally identical to the first area and collecting a second set of detection signals; and (c) processing the first and second set of detection signals to determine a focal characteristic; whereas the first focal pattern and the second focal pattern differ by the location of an optimal focal point.
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