Charged particle optical equipment and method for measuring lens aberration
AssigneeHitachi High-Technologies Corporation
InventorsTakaho Yoshida, Hisanao Akima
Life of this patent
Estimating the term…
Abstract
Beam scanning for obtaining a scanned image is performed by an aberration corrector, which is an aberration measured lens, and a scanning coil disposed above an objective lens, instead of a scanning coil ordinarily placed on the objective lens. Thus, distortion with an aberration of an aberration measured lens is scanned on the surface of a sample, and then a scanned image is formed from a scattered electron beam, a transmission electron beam, or a reflected/secondary electron beam that is generated by the scan, achieving a scanning aberration information pattern equivalent to a conventional Ronchigram. Such means is a feature of the present invention.
Claims9
A method for measuring a lens aberration in a charged particle optical device including means that focuses an electron beam for two-dimensional scanning on a sample,
- the charged particle optical device comprising:
- an electron source that emits an electron beam;
- sample mounting means for mounting the sample;
- electromagnetic lenses disposed between the electron source and the sample mounting part;
- electron beam scanning means that is provided on an electron-optical upstream side of aberration measured lenses of the electromagnetic lenses, and scans and deflect the electron beam;
- beam diaphragm means that is provided upstream of the electron beam scanning means and focuses the electron beam to a predetermined beam diameter;
- detecting means that detects an electron signal induced from the sample by the electron beam impinging onto the sample;
- and
- control means that controls the electron source, the electromagnetic lenses, the electron beam scanning means, and the detecting means,
- wherein the electron beam scanning means upstream of the measured lenses scans the electron beam from the electron source so as to two-dimensionally scan a beam probe on a surface of the sample, the beam probe being formed by the electromagnetic lenses,
- the detecting means detects at least one of signals including a secondary electron, a reflected electron, a transmitted electron, and a scattered electron that are induced by the beam probe projected with a distortion on the surface of the sample according to an aberration of the measured lens, and
- the control means calculates an aberration amount of the measured lens based on a two-dimensional image obtained in synchronization with scanning on the measured lens.
A charged particle optical device comprising:
- an electron source that emits an electron beam;
- sample mounting means for mounting a sample;
- electromagnetic lenses disposed between the electron source and the sample mounting part;
- electron beam scanning means that is provided on an electron-optical upstream side of aberration measured lenses of the electromagnetic lenses, and scans and deflect the electron beam;
- and
- control means that controls the electron source, the electromagnetic lenses, and the electron beam scanning means,
- wherein the electron beam scanning means upstream of the measured lenses scans the electron beam from the electron source so as to two-dimensionally scan a beam probe on a surface of the sample, the beam probe being formed by the electromagnetic lenses, and
- the charged particle optical device further comprises:
- detecting means that detects at least one of signals including a secondary electron, a reflected electron, a transmitted electron, and a scattered electron that are induced by the beam probe projected with a distortion on the surface of the sample according to an aberration of the measured lens;
- and
- measuring means that measures an aberration amount of the measured lens based on a two-dimensional image obtained in synchronization with scanning on the measured lens.
Dependencies are inferred from the claim text.