A method of evaluating a region of a sample, the method comprising: positioning a sample within a vacuum chamber; generating an electron beam with a scanning electron microscope (SEM) column that includes an electron gun at one end of the column and a column cap at an opposite end of the column; focusing the electron beam on the sample and scanning the focused electron beam across the region of the sample, while the SEM column is operated in tilted mode, thereby generating secondary electrons and backscattered electrons from within the region; and during the scanning, collecting backscattered electrons with one or more detectors while applying a negative bias voltage to the column cap to alter a trajectory of the secondary electrons preventing the secondary electrons from reaching the one or more detectors.

The present invention enables an overlay error between processors to be measured from a pattern image, the SN ratio of which is low. To this end, the present invention forms a secondary electron image 200 from a detection signal of a secondary electron detector 107, forms a reflected electron image 210 from a detection signal of a reflected electron detector 109, creates a SUMLINE profile 701 that is obtained by adding luminance information in the reflected electron image along the longitudinal direction of a line pattern, and calculates an overlay error of a sample by using position information about an upper layer pattern detected from the secondary electron image and position information about a lower layer pattern that is detected by using an estimation line pattern 801 estimated on the basis of the SUMLINE profile from the reflected electron image.

Methods and systems for detecting charged particles from a specimen are provided. One system includes a first repelling mesh configured to repel charged particles from a specimen having an energy lower than a first predetermined energy and a second repelling mesh configured to repel the charged particles that pass through the first repelling mesh and have an energy that is lower than a second predetermined energy. The system also includes a first attracting mesh configured to attract the charged particles that pass through the first repelling mesh, are repelled by the second repelling mesh, and have an energy that is higher than the first predetermined energy and lower than the second predetermined energy. The system further includes a first detector configured to generate output responsive to the charged particles that pass through the first attracting mesh.

Systems and methods of enhancing imaging resolution by reducing crosstalk between detection elements of a secondary charged-particle detector in a multi-beam apparatus are disclosed. The multi-beam apparatus may comprise an electro-optical system comprising a beam-limit aperture plate having a surface substantially perpendicular to an optical axis, the beam-limit aperture plate comprising a first aperture at a first distance relative to the surface of the beam-limit aperture plate, and a second aperture at a second distance relative to the surface of the beam-limit aperture plate, the second distance being different from the first distance. The first aperture may be a part of a first set of apertures of the beam-limit aperture plate at the first distance, and the second aperture may be a part of a second set of apertures of the beam-limit aperture plate at the second distance.

A scanning electron microscope (SEM) includes an electron gun, a deflector, an objective lens, first and second detectors each configured to detect emission electrons emitted from the wafer based on the input electron beam being irradiated on the wafer, a first energy filter configured to block electrons having energy less than a first energy among emission electrons emitted from a wafer based on an input electron beam from being detected by the first detector, and a second energy filter configured to block electrons having energy less than second energy among the emission electrons from being detected by the second detector.

A scanning electron microscope and a method for evaluating a sample, the method may include (a) illuminating the sample with a primary electron beam, (b) directing secondary electrons emitted from the sample and propagated above a first scintillator, towards an upper portion of the first scintillator, wherein the first scintillator and a second scintillator are positioned between the sample and a column electrode of the column; wherein the first scintillator is positioned above the second scintillator; (c) detecting the secondary electrons by the first scintillator; (d) directing backscattered electrons emitted from the sample towards a lower portion of the second scintillator; and (e) detecting the backscattered electrons by the second scintillator.

An ion implanter includes: a plurality of devices which are disposed along a beamline along which an ion beam is transported; a plurality of neutron ray measuring instruments which are disposed at a plurality of positions in the vicinity of the beamline and measure a neutron ray from a neutron ray source which is generated in the beamline due to collision of a high-energy ion beam; and a control device which monitors at least one of the plurality of devices, based on a plurality of measurement values measured by the plurality of neutron ray measuring instruments.

In order to allow detecting backscattered electrons (BSEs) generated from the bottom of a hole for determining whether a hole with a super high aspect ratio is opened or for inspecting and measuring the ratio of the top diameter to the bottom diameter of a hole, which are typified in 3D-NAND processes of opening a hole, a primary electron beam accelerated at a high accelerating voltage is applied to a sample. Backscattered electrons (BSEs) at a low angle (e.g. a zenith angle of five degrees or more) are detected. Thus, the bottom of a hole is observed using “penetrating BSEs” having been emitted from the bottom of the hole and penetrated the side wall. Using the characteristics in which a penetrating distance is relatively prolonged through a deep hole and the amount of penetrating BSEs is decreased to cause a dark image, a calibration curve expressing the relationship between a hole depth and the brightness is given to measure the hole depth.

When contamination or local electrification is generated during acquisition of a low-magnification image, if a high-magnification image contains both a portion in which the contamination or local electrification is generated and a portion in which the contamination or local electrification is not generated, a region whose image quality has changed due to the contamination or local electrification is erroneously recognized as a defect. Thus, defect detection fails or it may be impossible to correctly determine the feature quantity of a defect. The invention provides a defect observation system that acquires sample images at a low magnification and a high magnification, and sets the position or size of the field of view of the high-magnification image or the electron beam irradiation range during acquisition of the low-magnification image no that the image acquired at the high magnification does not contain the outer edge of the image acquired at the low magnification.

A system for imaging a sample through a protective pellicle is disclosed. The system includes an electron beam source configured to generate an electron beam and a sample stage configured to secure a sample and a pellicle, wherein the pellicle is disposed above the sample. The system also includes an electron-optical column including a set of electron-optical elements to direct at least a portion of the electron beam through the pellicle and onto a portion of the sample. In addition, the system includes a detector assembly positioned above the pellicle and configured to detect electrons emanating from the surface of the sample.