Patent · US Active

Method of automatically focusing a charged particle beam on a surface region of a sample, method of calculating a converging set of sharpness values of images of a charged particle beam device and charged particle beam device for imaging a sample

US11610755B2 · kind B2 · utility

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2References
22Claims
0Family size

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Key dates

Filing dateOct 21, 2021
Grant dateMar 21, 2023
Priority date
Expiry dateOct 21, 2041

Classification

  • Technology area (CPC H)Electricity
  • CPC primaryH01J2237/216
  • WIPO fieldElectrical machinery, apparatus, energy
  • WIPO sectorElectrical engineering

Abstract

A method of automatically focusing a charged particle beam on a surface region of a sample is provided. The method includes acquiring a plurality of images for a corresponding plurality of focusing strength values; calculating a plurality of sharpness values based on the plurality of images, the plurality of sharpness values are calculated with a sharpness function provided as a sum in a frequency space based on the plurality of images; and determining subsequent focusing strength values of the plurality of focusing strength values with a golden ratio search algorithm based one the calculated sharpness values.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.