Apparatus and method for E-beam dark field imaging
AssigneeKLA-Tencor Technologies Corporation
InventorsDouglas K. Masnaghetti, Eric Munro, Gabor D. Toth, Jeffrey Keister
Life of this patent
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Abstract
One embodiment disclosed relates to a scanning electron beam apparatus including an objective lens, scan deflectors, de-scan deflectors, an energy-filter drift tube, and a segmented detector. The objective lens may be an immersion lens configured with a high extraction field so as to preserve azimuthal angle discrimination of the electrons scattered from the specimen surface. The de-scan deflectors may be used to compensate for the scanning of the incident electron beam. The energy-filter drift tube is configured to align the scattered electrons according to polar angles of trajectory from the specimen surface.
Claims25
A scanning electron beam apparatus comprising:
- an objective lens configured to focus an incident electron beam onto a specimen surface and to extract a secondary electron beam therefrom;
- scan deflectors configured to deflect the incident electron beam so as to scan the incident electron beam over the specimen surface;
- de-scan deflectors configured to deflect the secondary electron beam so as to compensate for the scanning of the incident electron beam;
- an energy-filter drift tube positioned to receive the secondary electron beam after the de-scan deflectors;
- and
- a segmented detector positioned to receive the secondary electron beam after the energy-filter drift tube,
- wherein the segmentation of the detector provides angular discrimination based on electron landing positions.
A method of imaging using a scanning electron beam;
- the method comprising:
- deflecting an incident electron beam so as to scan the incident electron beam over a specimen surface;
- focusing the incident electron beam onto the specimen surface;
- extracting a secondary electron beam from the specimen surface;
- deflecting the secondary electron beam so as to compensate for the scanning of the incident electron beam;
- aligning electrons in the secondary electron beam according to polar angles of trajectory from the specimen surface;
- and
- detecting the secondary electron beam using a segmented detector,
- wherein the segmentation of the detector provides angular discrimination based on electron landing positions.
A scanning electron microscope comprising:
- means for deflecting an incident electron beam so as to scan the incident electron beam over a specimen surface;
- means for focusing the incident electron beam onto the specimen surface;
- means for extracting a secondary electron beam from the specimen surface;
- means for deflecting the secondary electron beam so as to compensate for the scanning of the incident electron beam;
- means for aligning electrons in the secondary electron beam according to polar angles of trajectory from the specimen surface;
- and
- means for detecting the secondary electron beam using a segmented detector;
- wherein the segmentation of the detector provides angular discrimination based on electron landing positions.
Dependencies are inferred from the claim text.