A method of determining aberrations in images obtained by a charged-particle beam tool, comprising: a) obtaining two or more images of a sample, wherein each image is obtained at a known relative difference in a measurement condition of the charged-particle beam tool; b) selecting an estimated aberration parameter for the aberrations of a probe profile representing the charged-particle beam used by the charged-particle beam tool; c) evaluating an error function indicative of the difference between the two or more images and two or more estimated images that are a function of the estimated aberration parameter and the known relative difference in the measurement condition; d) updating the estimated aberration parameter; e) performing processes c) and d) iteratively; f) determining the final aberration parameter as the estimated aberration parameter that provides the smallest value of the error function.

The invention relates to method of milling and imaging a sample. The method comprises the step of providing an imaging system, as well as a milling beam source. The method comprises the steps of milling, using a milling beam from said milling beam source, a sample to remove a layer of the sample; and imaging, using said imaging system, an exposed surface of the sample. As defined herein, the method further comprises the step of determining a relative position of said sample, and using said determined relative position of said sample in said milling step for positioning said sample relative to said milling beam. The relative position of said sample can be a working distance with respect to the imaging system, which can be determined by means of an autofocus procedure.

Provided is a charged particle beam device capable of focusing with high accuracy even when a charged particle beam has a large off-axis amount. The charged particle beam device generates an observation image of a sample by irradiating the sample with a charged particle beam, and includes: a deflection unit that inclines the charged particle beam; a focusing lens that focuses the charged particle beam; an adjustment unit that adjusts a lens strength of the focusing lens based on an evaluation value calculated from the observation image; a storage unit that stores a relationship between a visual field movement amount and the lens strength; and a filter setting unit that calculates the visual field movement amount based on an inclination angle of the charged particle beam and the relationship, and sets an image filter to be superimposed on the observation image based on the calculated visual field movement amount.

There is provided a technique capable of shortening a photographing time and obtaining a more accurate photographed image when photographing a sample SAM using a charged particle beam device 1. The charged particle beam device 1 includes an electron gun 3, an objective lens 6, a stage 8, detectors 10 and 11, an integrated control unit C0, a photographing function, and an autofocus function. Each of a plurality of photographing visual fields is focused in a focus value calculation visual field 64 adjacent to a designated visual field 61 designated as a photographing target among the plurality of photographing visual fields, and a focus value calculated in the focus value calculation visual field 64 is used for calculating focus values of each of the plurality of photographing visual fields.

Two types of operational parameters are used in a particle beam microscope. First parameters influence the image quality, and have settings that are alterable by a user in view of obtaining a better image quality. Second parameters characterize the mode of operation, and the image quality becomes poorer when these change. A mode of operation of the particle beam microscope includes: registering of settings of the first parameters and the second parameters, which the user undertakes in a period of time; analysing a plurality of recorded settings of the first parameters and of the second parameters; determining settings of the first parameters which are advantageous in view of the image quality on the basis of the current settings of the second parameters; and setting the determined advantageous settings of the first parameters.

The focused ion beam apparatus includes: an ion source configured to generate ions; a first electrostatic lens configured to accelerate and focus the ions to form an ion beam; a beam booster electrode configured to accelerate the ion beam to a higher level; one or a plurality of electrodes, which are placed in the beam booster electrode, and are configured to electrostatically deflect the ion beam; a second electrostatic lens, which is provided between the one or plurality of electrodes and a sample table, and is configured to focus the ion beam applied with a voltage; and a processing unit configured to obtain a measurement condition, and set at least one of voltages to be applied to the one or plurality of electrodes or a voltage to be applied to each of the first electrostatic lens and the second electrostatic lens, based on the obtained measurement condition.

A method of operating a charged particle beam device is disclosed, including focusing a charged particle beam onto a sample with an objective lens assembly; passing a reflected light beam through a bore of the objective lens assembly to an interferometer; and interferometrically determining a z-position of the sample with the interferometer. A charged particle beam device is disclosed, including a charged particle beam generator which has a charged particle source. A charged particle path for the charged particle beam extends through a bore of an objective lens assembly toward a sample stage. An interferometer is arranged to receive a reflected light beam which passes through the bore of the objective lens assembly.

When focus adjustment is performed according to the height of the surface of a sample at each inspection point in order to continuously inspect a plurality of inspection points on a wafer by using an electron microscope, even when the focus adjustment by an electrostatic lens in which a variation of heights of inspection points is greater than a predetermined range, and that can perform adjustment at a high speed and adjustment by an electromagnetic lens with a low speed are required to be used together, a flow of focus adjustment in which the number of times of the adjustment by the electromagnetic lens is reduced by using a relation of changes of heights at inspection points, an inspection order, and a range in which an electrostatic focus can be performed is realized, so that inspection with high throughput is made possible.

A method of automatically focusing a charged particle beam on a surface region of a sample is provided. The method includes acquiring a plurality of images for a corresponding plurality of focusing strength values; calculating a plurality of sharpness values based on the plurality of images, the plurality of sharpness values are calculated with a sharpness function provided as a sum in a frequency space based on the plurality of images; and determining subsequent focusing strength values of the plurality of focusing strength values with a golden ratio search algorithm based one the calculated sharpness values.

When a high-performance retarding voltage applying power supply cannot be employed in terms of costs or device miniaturization, it is difficult to sufficiently adjust focus in a high acceleration region within a range of changing an applied voltage, and identify a point at which a focus evaluation value is maximum. To address the above problems, a scanning electron microscope is provided including: an objective lens configured to converge an electron beam emitted from an electron source; a current source configured to supply an excitation current to the objective lens; a negative-voltage applying power supply configured to form a decelerating electric field of the electron beam on a sample; a detector configured to detect charged particles generated when the electron beam is emitted to the sample; and a control device configured to calculate a focus evaluation value from an image formed according to an output of the detector. The control device calculates a focus evaluation value when an applied voltage is changed, determines whether to increase or decrease an excitation current according to an increase or a decrease of the focus evaluation value, and supplies the excitation current based on a result of the determination.