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 charted 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.

The present disclosure provides a technique for reducing man-hour of a user required for setting an automatic focused focal point search function of an electron beam and facilitating observation of a sample when reviewing a defect using an electron microscope. The present disclosure provides a technique in a charged particle beam system, in which an appropriate focal point position search width can be automatically set in consideration of convergence accuracy and an operation time based on a focal point measure distribution width for a focal point position acquired in advance under the same conditions and a difference between focal point positions before and after automatic focused focal point position search.

The present disclosure relates to an electron microscope having a deep learning module in which electron microscopy images and control parameters are used as training input information of the deep learning model, and the deep learning model trained using focus, contrast and brightness among the control parameters as targets of the deep learning model generates a command for optimal target it is possible to automatically provide a sample image with high quality based on data trained based on artificial intelligence without any manual manipulation of control parameter values, thereby allowing beginners as well as people with advanced skills to easily use the electron microscope, which contributes to thriving electron microscope market.

In the present invention, an electro-optical condition generation unit includes: a condition setting unit that sets, as a plurality of electro-optical conditions, a plurality of electro-optical conditions in which the combinations of the aperture angle and the focal-point height for an electron beam are different; an index calculating unit that determines a measurement-performance index in the electro-optical conditions set by the condition setting unit; and a condition deriving unit that derives an electro-optical condition, including an aperture angle and a focal-point height, so that the measurement-performance index determined by the index calculating unit becomes a prescribed value.

A multi charged particle beam apparatus irradiates a substrate placed on a stage with a multi charged particle beam through an illumination optical system including a plurality of components, and an objective lens successively. In one embodiment, an optical system adjustment method for the multi charged particle beam apparatus includes measuring positional deviation amounts of a plurality of individual beams included in the multi charged particle beam at two or more different heights in an optical axis direction of a measurement surface or an imaging position of the multi charged particle beam, calculating a normalized position difference based on the two or more heights and the positional deviation amounts, the normalized position difference being an illumination system aberration equivalent amount of the illumination optical system, and adjusting a set value for at least one of the plurality of components using a value of the normalized position difference.

Apparatus and methods are disclosed for particle beam focusing, suitable for use in sample preparation or test environments, including SEM-based nanoprobing platforms. With a particle beam incident on a sample surface, stage current is used as an indicator of spot size. By scanning or searching settings of a working distance control, a control value having maximum (or minimum) stage current is used to set the beam waist at the sample surface. Alternatively, minima (or maxima) of reflected current can be used. Stigmator controls can be adjusted similarly to reduce astigmatism. The scan of control settings can be performed concurrently with sweeping the beam across a region of interest on the sample. Curved sweep patterns can be used. Energy measurements can be used as an alternative to current measurement. Applications to a nanoprobing workflow are disclosed.

A method of imaging a sample with a charged particle beam device, comprising: determining a first focusing strength of an objective lens of the charged particle beam device, the first focusing strength being adapted to focus a charged particle beam on a first surface region of the sample; determining a first focal subrange of a plurality of focal subranges such that the first focusing strength is within the first focal subrange, wherein the plurality of focal subranges is associated with a set of values of a calibration parameter; determining a first value of the calibration parameter, the first value being associated with the first focal subrange; and imaging the first surface region with the first value.

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.

A multiple particle beam microscope and an associated method can provide a fast autofocus around an adjustable working distance. A system can have one or more fast autofocus correction lenses for adapting, in high-frequency fashion, the focusing, the position, the landing angle and the rotation of individual particle beams upon incidence on a wafer surface during the wafer inspection. Fast autofocusing in the secondary path of the particle beam system can be implemented in analogous fashion. An additional increase in precision can be attained via fast aberration correction mechanism in the form of deflectors and/or stigmators.