A method of, and a detector for, performing energy sensitive imaging of ionizing radiation are provided, including acquiring a first frame having a plurality of pixels, each pixel of the plurality having an energy of detection and a location; grouping, into a cluster, pixels of the plurality having an energy of detection above a predetermined threshold and a location along with at least one other pixel also having an energy of detection above the predetermined threshold and being within a predetermined distance of the location; summing the energy of detection of all pixels within the grouped cluster to determine a cluster energy; determining a location of the cluster based on a distribution and an intensity of the summed energy of detection; and generating an image of the cluster based on the determined cluster energy and the determined location of the cluster.

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 method of determining a number of charged particles incident on a detector within a period may include generating a first signal that is based on a charged particle impacting a sensing element of the detector, performing processing using the first signal based on a predetermined characteristic of a charged particle arrival event on the detector, and outputting a count signal based on the processing.

The present invention concerns a method of determining alignment of electron optical components in a charged particle apparatus. The charged particle apparatus comprising: an aperture array and a detector configured to detect charged particles corresponding to beamlets that pass through the corresponding apertures in the aperture array. The method comprises: scanning each beamlet in a plane of the aperture array over a portion of the aperture array in which a corresponding aperture of the aperture array is defined so that charged particles of each beamlet may pass through the corresponding aperture; detecting during the scan any charged particles corresponding to each beamlet that passes through the corresponding aperture; generating a detection pixel for each beamlet based on the detection of charged particles corresponding to each beamlet at intervals of the scan; and collecting information comprised in the detection pixel such as the intensity of charged particles.

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.

A method and system for analyzing a specimen in a microscope are disclosed. The method comprises: acquiring a series of compound image frames using a first detector and a second detector, different from the first detector, wherein acquiring a compound image frame comprises: causing a charged particle beam to impinge upon a plurality of locations within a region of a specimen, the region corresponding to a configured field of view of the microscope, the microscope being configured with a set of microscope conditions, monitoring, in accordance with the configured microscope conditions, a first set of resulting particles generated within the specimen at the plurality of locations using the first detector so as to obtain a first image frame, monitoring, in accordance with the configured microscope conditions, a second set of resulting particles generated within the specimen at the plurality of locations using the second detector, so as to obtain a second image frame, wherein each image frame comprises a plurality of pixels corresponding to, and derived from the monitored particles generated at, the plurality of locations within the region, for each pixel of the second image frame, if the configured microscope conditions are the same as those for a stored second image frame of an immediately preceding acquired compound frame in the series, and if the respective pixel corresponds to a location within the region to which a stored pixel comprised by said stored second image frame corresponds, combining said stored pixel with the pixel so as to increase the signal-to-noise ratio for the pixel, and combining the first image frame and second image frame so as to produce the compound image frame, such that the compound image frame provides data derived from, for each of the plurality of pixels, the particles generated at the corresponding location within the region and monitored by each of the first detector and second detector; and displaying the series of compound image frames in real-time on a visual display.

A method of calibrating analog-to-digital converters, ADCs, of a charged particle-optical device comprises: providing, for each of the ADCs, image data of charged particles detected from a sample output by the ADC; calculating, for each of the ADCs, at least one statistical value from a distribution of the image data output by the ADC; and changing at least one setting of at least one of the ADCs based on the calculated at least one statistical values so as to compensate for any mismatch between the at least one statistical value of the ADCs.

Systems and methods are provided for charged particle detection. The detection system can comprise a signal processing circuit configured to generate a set of intensity gradients based on electron intensity data received from a plurality of electron sensing elements. The detection system can further comprise a beam spot processing module configured to determine, based on the set of intensity gradients, at least one boundary of a beam spot; and determine, based on the at least one boundary, that a first set of electron sensing elements of the plurality of electron sensing elements is within the beam spot. The beam spot processing module can further be configured to determine an intensity value of the beam spot based on the electron intensity data received from the first set of electron sensing elements and also generate an image of a wafer based on the intensity value.

There is provided a charged particle beam apparatus capable of obtaining a high SN ratio with a small electron irradiation amount. The charged particle beam apparatus includes a charged particle detection device. The charged particle detection device detects an analog pulse waveform signal (110) in a detection of emitted electrons (1 event) when one primary electron enters a sample, converts the analog pulse waveform signal (110) into a digital signal (111), perform a wave height discrimination (112) with the use of a unit peak corresponding electron, and outputs the digital signal (111) as a multilevel count value.

Techniques for acquiring an electron energy loss spectrum in two dimensions are disclosed herein. The technique at least includes exposing an electron sensor to an electron spectrum projected in two dimensions, wherein one of the two dimensions corresponds to a dispersive axis, and the other of the two dimensions corresponds to a non-dispersive axis, receiving an electron sensor readout frame from the electron sensor, where the electron sensor readout frame comprises a plurality of values representative of the electron spectrum in each of the two dimensions, and reducing a resolution of the electron sensor readout frame in at least one of the two dimensions, where reducing the resolution includes reducing the number of values in the at least one of the two dimensions, where the electron sensor readout frame comprises a plurality of values in each of the two dimensions after the reduction in resolution.