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US 4,071,765 AGranted
Electron microscope
AssigneeU.S. Philips Corporation
InventorsKarel Jan van Oostrum, Gerardus Gegorius Petrus VAN Gorkom
Life of this patent
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Abstract
In an electron beam apparatus corrections are made for vibrations and field disturbances which cause a lateral beam shift. A detector is arranged in an intermediate image near the beam path and a signal derived therefrom is used for controlling a beam deflection device. When a second beam deflection device is added, the undesired deflection in a scanning electron microscope can be distinguished from the deflection caused by the scanning.
Claims9
Electron beam apparatus, comprising:
- an electron-optical lens system for forming a final image of an object with an electron beam, said system also forming with the electron beam at least one intermediate image of the object;
- electron detection apparatus at the periphery of the intermediate image for detecting the difference between the actual position of the intermediate image and a reference position, said detection apparatus producing a signal indicative of the difference;
- and
- beam deflection apparatus responsive to said signal for automatically deflecting the electron beam in a
- direction which compensates for the difference, whereby the position of the final image of the object is thereby stabilized against movements of the object relative to the electron-optical lens system.
2 more elements
Dependencies are inferred from the claim text.