| 摘要 |
PURPOSE:To observe a sample by applying an electron beam to the sample in a good focusing state. CONSTITUTION:An autofocusing method consists of a process of surface scanning on the sample surface W with an electron beam EL, a process of shifting to graphic scanning CS for detecting of a focusing state of the electron beam EL, a process of operating a detection signal SG and making it store operation value AV, a process of making a change of the operation value AV get within a preset range and a process of controlling the focusing state of the electron beam EL to change stepwise in order to find the maximum value MC of the operation value AV. |
