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
Assignee
Inventors
Key dates
| Filing date | Oct 21, 2021 |
| Grant date | Mar 21, 2023 |
| Priority date | — |
| Expiry date | Oct 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.