Electron beam apparatus
AssigneeHitachi High-Tech Corporation
InventorYu Yamazawa
Life of this patent
Estimating the term…
Abstract
In an electron beam apparatus performing angular scanning that changes an incident angle of an electron beam incident at a predetermined incident position on a sample, when a correction coil is provided in a gap portion of a yoke (magnetic path) of an objective lens, spherical aberration can be corrected by following a deflection signal even if a deflection frequency increases. Therefore, a main control unit that controls an electron optical system sets predetermined phase change amounts a, b with respect to control of a scanning coil in control of the correction coil, and the predetermined phase change amounts a, b are made different depending on a plurality of scanning modes having different scanning speeds.
Claims13
An electron beam apparatus configured to perform angular scanning that changes an incident angle of an electron beam incident at a predetermined incident position on a sample, and having a plurality of scanning modes having different scanning speeds of the angular scanning, the electron beam apparatus comprising:
- a scanning coil configured to deflect the electron beam;
- an objective lens configured to swing back the electron beam deflected to the outside of an optical axis by the scanning coil;
- a correction coil disposed in a gap portion of a magnetic pole of the objective lens;
- and
- a main control unit
- configured to set predetermined phase change amounts with respect to control of the scanning coil in control of the correction coil, and the predetermined phase change amounts differ depending on the plurality of scanning modes.
An electron beam apparatus configured to perform angular scanning that changes an incident angle of an electron beam incident at a predetermined incident position on a sample, and having a plurality of scanning modes having different scanning speeds of the angular scanning, the electron beam apparatus comprising:
- a scanning coil configured to deflect the electron beam;
- an objective lens configured to swing back the electron beam deflected to the outside of an optical axis by the scanning coil;
- a correction coil disposed in a gap portion of a magnetic pole of the objective lens;
- and
- a main control unit configured to set predetermined phase change amounts with respect to control of the scanning coil in control of the correction coil, and the predetermined phase change amounts differ depending on the plurality of scanning modes;
- and
- wherein
- the scanning coil includes a first scanning coil configured to deflect the electron beam in an X direction and a second scanning coil configured to deflect the electron beam in a Y direction, the first scanning coil is controlled by a first scanning coil signal IX, and the second scanning coil is controlled by a second scanning coil signal IY,
- the correction coil is controlled by a correction coil signal Icor, and
- the main control unit is configured to use, as a control amount of the correction coil signal Icor, a function of a product of spherical aberration coefficient Cs of the objective lens and {(IX−a)2+(IY−b)2}, in which a and b represent the predetermined phase change amounts.
Dependencies are inferred from the claim text.