Abstract: An electron microscope is offered which facilitates aberration correction even during high-magnification imaging. The microscope has a spherical aberration corrector, a transfer lens system mounted between the corrector and an objective lens, an aperture stop mounted in a stage preceding the corrector so as to be movable relative to the optical axis, and an angular aperture stop mounted at or near the principal plane of the transfer lens system movably relative to the optical axis to adjust the angular aperture of the electron beam.

Abstract: The present disclosure provides an electron beam column with substantially improved resolution and/or throughput for inspecting manufactured substrates. The electron beam column comprises an electron gun, a scanner, an objective lens, and a detector. In accordance with one embodiment, the electron gun includes a gun lens having a flip-up pole piece configuration. In accordance with another embodiment, the scanner comprises a dual scanner having a pre-scanner and a main scanner, and the detector may be configured between the electron gun and the pre-scanner. In accordance with another embodiment, the electron beam column includes a continuously-variable aperture configured to select a beam current. Other embodiments relate to methods of using an electron beam column for automated inspection of manufactured substrates. In one embodiment, for example, an aperture size is adjusted to achieve a minimum spot size given a selected beam current and a column-condition domain being used.

Abstract: A scanning transmission electron microscope for imaging a specimen includes an electron beam source to generate an electron beam. Beam optics are provided to converge the electron beam. A stage is provided to hold a specimen in the path of the electron beam. A beam scanner scans the electron beam across the specimen. A controller may define one or more scanning areas corresponding to locations of the specimen, and control one or more of the beam scanner and stage to selectively scan the electron beam in the scanning areas. A detector is provided to detect electrons transmitted through the specimen to generate an image. The controller may generate a sub-image for each of the scanning areas, and stitch together the sub-images for the scanning areas to generate a stitched-together image. The controller may also analyze the stitched-together image to determine information regarding the specimen.

Abstract: The invention relates to an environmental cell for use in e.g. an electron microscope. The environmental cell shows an aperture (15) for passing the beam produced by the electron microscope to a sample (6) placed inside the environmental cell. The environmental cell according to the invention is characterized in that a part of the environmental cell (14) is transparent to secondary radiation such as back-scattered electrons or X-rays. This enables the detection of this radiation by a detector placed outside the environmental cell and thus a much simpler construction of the cell.

Abstract: Provided is a circuit-pattern inspection device which enables efficient inspection of a semiconductor wafer by selectively inspecting areas on the semiconductor wafer, such as boundaries between patterns thereon, where defects are likely to occur during the step of producing the semiconductor wafer while changing the beam scanning direction for each area. Two-dimensional beam-deflection control is employed for inspection operations in a continuous-stage-movement-type circuit-pattern inspection device in which only one-dimensional scanning has been employed conventionally. That is, by employing a combination of an electron-beam-deflection control in a first direction parallel to the stage-movement direction and an electron-beam-deflection control in a second direction intersecting the stage-movement direction, it is possible to obtain an image of any desired area for inspection that is set within a swath.

Abstract: There is provided a technique that is capable of attracting a sample without making the voltage applied to an electrostatic chuck unnecessarily large. Attraction experiments with respect to the electrostatic chuck are performed using a testing sample whose degree of warp and pattern of warp are known, and a critical application voltage at which the attraction state changes from “bad” to “good” is found. When measuring an inspection target sample, the flatness of the inspection target sample is measured, and the degree of warp and pattern of warp of the inspection target sample are detected. Based on the degree of warp and pattern of warp of the inspection target sample and on the known critical application voltage, the application voltage for the electrostatic chuck is set.

Abstract: A method of examining a sample using a spectroscopic apparatus, comprising the following steps: Mounting the sample on a sample holder; Directing a focused input beam of radiation onto a location on the sample, thereby producing an interaction that causes a flux of stimulated photonic radiation to emanate from said location; Examining said flux using a multi-channel photon-counting detector, thus accruing a measured spectrum for said location; Automatically repeating said directing and examining steps for a series of successive locations on the sample, which method comprises the following steps: Choosing a beam parameter of the input beam that will influence a magnitude of said flux of stimulated photonic radiation; For each location within a first set of locations on the sample, accruing a spectrum using a first value of said beam parameter; For each location within a second set of locations on the sample, accruing a spectrum using a second value of said beam parameter, different from said first value.

Abstract: The charged particle beam device has a problem that a symmetry of equipotential distribution is disturbed near the outer edge of a specimen, an object being evaluated, causing a charged particle beam to deflect there. An electrode plate installed inside the specimen holding mechanism of electrostatic attraction type is formed of an inner and outer electrode plates arranged concentrically. The outer electrode plate is formed to have an outer diameter larger than that of the specimen. The dimensions of the electrode plates are determined so that an overlapping area of the outer electrode plate and the specimen is substantially equal to an area of the inner electrode plate. The inner electrode plate is impressed with a voltage of a positive polarity with respect to a reference voltage and of an arbitrary magnitude, and the outer electrode is impressed with a voltage of a negative polarity and of an arbitrary magnitude.

Abstract: An inspection device carries out beam scanning on a stable scanning cycle by enabling flexible change of various scanning sequences according to inspection conditions thereof, and at the same time, eliminates as much unevenness as possible in scanning cycle which hinders stabilization of charging. A beam scanning scheduler schedules beam scanning based on an inputted scanning condition, and a programmable sequencer carries out beam scanning control according to a beam scanning schedule generated by the beam scanning scheduler. The scanning scheduler calculates scanning line reference coordinates on a scanning-line-by-scanning-line basis, based on the scanning condition, and issues a scanning cycle trigger. The programmable sequencer controls supply timing of the scanning line reference coordinates and a scanning position on an in-line pixel-by-pixel basis, based on line scanning procedure information and the scanning cycle trigger provided from the beam scanning scheduler.

Abstract: It is an object of the present invention to provide a technique capable of accurately inspecting a circuit pattern in which the contrast of an observation image is not clear, like a circuit pattern having a multilayer structure. A pattern inspection method according to the present invention divides a circuit pattern using the brightness of a reflection electron image and associates the region in the reflection electron image belonging to each division with the region in a secondary electron image.

Abstract: A method for manufacturing a transmission electron microscope (TEM) micro-grid is provided. A support ring and a sheet-shaped carbon nanotube structure precursor are first provided. The sheet-shaped carbon nanotube structure precursor is then disposed on the support ring. The sheet-shaped carbon nanotube structure precursor is cut to form a sheet-shaped carbon nanotube structure in desired shape. The sheet-shaped carbon nanotube structure is secured on the support ring.

Abstract: A sample holding apparatus for electron microscope includes: a sample holding assembly including an assembly of three components of an upper diaphragm holding part, a sample holding plate and a lower diaphragm holding part; and a holding part that holds the sample holding assembly replaceably. The sample holding assembly includes a cell defined between a diaphragm of the upper diaphragm holding part and a diaphragm of the lower diaphragm holding part, and a flow channel connected to the cell, in which a sample mounted at a protrusion of the sample holding plate is placed. The diaphragm of the upper diaphragm holding part, the sample and the diaphragm of the lower diaphragm holding part are disposed along an optical axis of an electron beam.

Abstract: A system includes a particle optical system and a photosensitive detector. The particle optical system includes a charged particle beam source and an objective lens. The charged particle beam source is configured to generate a charged particle beam that travels along a particle beam path, and the objective lens is configured to focus the particle beam onto an object plane of the particle optical system. The system is configured such that a light beam path of the system extends from the object plane to the photosensitive detector.

Abstract: The invention relates to a multiple beam charged particle optical system, comprising an electrostatic lens structure with at least one electrode, provided with apertures, wherein the effective size of a lens field effected by said electrode at a said aperture is made ultimately small. The system may comprise a diverging charged particle beam part, in which the lens structure is included. The physical dimension of the lens is made ultimately small, in particular smaller than one mm, more in particular less than a few tens of microns. In further elaboration, a lens is combined with a current limiting aperture, aligned such relative to a lens of said structure, that a virtual aperture effected by said current limiting aperture in said lens is situated in an optimum position with respect to minimizing aberrations total.

Abstract: The charged particle beam apparatus having an opening formation member formed with an opening for passage of a charged particle beam emitted from a charged particle source, and either a detector adapted to detect charged particles having passed through the passage opening or a detector adapted to detect charged particles resulting from bombardment on another member of the charged particles having passed through the opening, comprises an aligner for aligning charged particles discharged from the sample and a control unit for controlling the aligner, wherein the control unit controls the aligner to cause it to shift trajectories of the charged particles discharged from the sample so that length measurement may be executed on the basis of detection signals before and after the alignment by the aligner.

Abstract: A system and method for transmission electron microscopy (TEM) of a photocatalyst sample exposed to UV and/or visible light at irradiance levels comparable to those provided by irradiation with sunlight or at least 1,000 W/cm2 while maintaining the spatial resolution of interrogation of at least 0.14 nm. Light is delivered to the sample substantially transversely to the sample's surface from an external broadband source through an optical fiber with an output facet formed at an acute angle with respect to the fiber axis. The light delivery system is adapted to not interrupt an operation of auxiliary TEM systems responsible for changing the TEM-chamber environment.

Abstract: Provided is a composite charged particle beam apparatus, including: an electron beam column for irradiating a sample with an electron beam; an ion beam column for irradiating the sample with an ion beam to perform etching processing; a sample stage drive portion for moving a sample stage in an irradiation axis direction of the electron beam; and a column adjusting portion for moving the ion beam column relatively to a sample chamber such that the sample is irradiated with the ion beam at a position irradiated with the electron beam.

Abstract: A transmission electron microscope comprises a high-voltage source for outputting a high voltage at two high-voltage outputs and outputting a control signal at a controller output; a focusing lens for focusing a beam; a monochromator which allows only those particles of the particle beam to pass whose kinetic energy is within an adjustable energy interval; an energy-dispersive component which deflects particles of different kinetic energies differently; a detector; and a controller connected to the controller output, which controls a beam deflector, arranged between the energy-dispersive component and the detector, the monochromator, or the energy-dispersive component in dependence on the control signal, or superposes plural of intensity distributions detected by the detector with an offset relative to one another, which offset is set in dependence on the control signal.

Abstract: A method and electron microscope system of performing three-dimensional imaging using an electron microscope. At least some of the illustrative embodiments are methods comprising generating an electron beam, and creating a hollow-cone electron beam (by passing the electron beam through an annular aperture), focusing the hollow-cone electron beam to form a probe, scanning a specimen using the probe; and performing three-dimensional imaging based on the scanning.

Abstract: An electron microscope assembly suitable for enhancing an image of a lithography tool includes an electron microscope configured for positioning below a lithography stage of an e-beam lithography tool, the lithography stage of the e-beam lithography tool including an aperture for providing the microscope line-of-sight to the lithography optics of the lithography tool, a translation unit configured to selectively translate the microscope along the optical axis of the lithography optics of the lithography tool responsive to a translation control system, the translation unit further configured to position the microscope in an operational state such that the optics of the microscope are positioned proximate to the lithography optics, a docking unit configured to reversibly mechanically couple the microscope with the lithography tool, the microscope configured to magnify a virtual sample plane image generated by the lithography tool.

Abstract: (1) part or all of the number, coordinates and size/shape and imaging sequence of imaging points each for observation, the imaging position change method and imaging conditions can be calculated automatically from CAD data, (2) a combination of input information and output information for imaging recipe creation can be set arbitrarily, and (3) decision is made of imaging or processing at an arbitrary imaging point as to whether to be successful/unsuccessful and in case a failure is determined, a relief process can be conducted in which the imaging point or imaging sequence is changed.

Abstract: Provided is a charged particle beam apparatus adapted so that even when an additional device is not mounted in the charged particle beam apparatus, the apparatus rapidly removes, by neutralizing, a local charge developed on a region of a sample that has been irradiated with a charged particle beam. After charged particle beam irradiation for measurement of the sample, the apparatus controls a retarding voltage or/and an accelerating voltage at a stage previous to a next measurement, and then neutralizes an electric charge by reducing a difference between a value of the retarding voltage and that of the accelerating voltage to a value smaller than during the currently ongoing measurement. The charged particle beam achieves neutralizing without reducing throughput, since the local charge developed on the region of the sample that has been irradiated with the charged particle beam is removed, even without an additional device mounted in the apparatus.

Abstract: An elongated member is formed which has a frontal and a distal end, and a length axis. The frontal end satisfies vacuum sealing and maneuverability specifications of a sample holder for a particle beam microscope. The elongated member includes a tubular section defining an axial cavity along the length axis, and having an orifice toward the distal end of the elongated member. The resulting device is characterized as being a sample holder for use in particle beam microscopes. The sample holder enables the examination of high aspect ratio samples by accommodating them in its axial cavity. The examination can take place without prior modification of the high aspect ratio samples.

Abstract: The invention relates to a blocking member to be placed in the diffraction plane of a TEM. It resembles the knife edge used for single sideband imaging, but blocks only electrons deflected over a small angle. As a result the Contrast Transfer Function of the TEM according to this invention will equal that of a single sideband microscope at low frequencies and that of a normal microscope for high frequencies. Preferable the highest frequency blocked by the blocking member is such that a microscope without the blocking member would show a CTF of 0.5.

Abstract: Provided is a high-resolution scanning electron microscope with minimal aberration, and equipped with an electro-optical configuration that can form a tilted beam having wide-angle polarization and a desired angle, without interfering with an electromagnetic lens. In the scanning electron microscope, an electromagnetic deflector (201) is disposed above a magnetic lens (207), and a control electrode (202) that accelerates or decelerates electrons is provided so at to overlap (in such a manner that the height positions overlap with respect to the vertical direction) with the electromagnetic deflector (201). In wide field polarization, electrodes are accelerated, and in tilted beam formation, electrons are decelerated.

Abstract: A method for adjusting or aligning one or more optical elements in a Transmission Electron Microscope (TEM) is disclosed. The TEM is equipped with an objective lens for guiding a beam of electrons to a sample, a diffraction plane in which at least a beam of unscattered electrons is focused and a structure to enhance the Contrast Transfer Function (CTF) which is situated in the diffraction plane or an image thereof.

Abstract: System and method for EMI shielding for a CD-SEM are described. One embodiment is a scanning electron microscope (“SEM”) comprising an electron gun for producing an electron beam directed toward a sample; a secondary electron (“SE”) detector for detecting secondary electrons reflected from the sample in response to the electron beam; and a dual-layer shield disposed around and enclosing the SE detector. The shield comprises a magnetic shielding lamina layer and a metallic foil layer.

Abstract: A background reduction system may include, but is not limited to: a charged particle source configured to generate a charged-particle beam; a louvered structure including one or more apertures configured to selectively transmit charged particles according to their angle of incidence; and a charged-particle detector configured to receive charged particles selectively transmitted by the louvered structure.

Abstract: An ultrafast electron diffraction device for irradiating a sample with a bunch of electrons in an ultrashort pulse in order to perform an ultrafast analysis of the sample. The ultrafast electron diffraction device includes: a) a laser emitter for delivering an ultrashort pulse laser having a pulse width of not more than 1 ps onto a target which is a material for generating electrons at an intensity of not less than 1017 W/cm2; and b) a pulse compressor for rotating, in a magnetostatic field, a bunch of electrons generated from the target onto which the ultrashort pulse laser has been delivered so as to suppress the spread of the bunch of electrons in their traveling direction. The pulse compressor is composed of an entrance-side parallel-plate static magnet, one end of which is placed on the course of the bunch of electrons, and an exit-side parallel-plate static magnet.

Abstract: In order to provide a charged particle beam apparatus that can detect charged particle beam signals in discrimination into a plurality of energy bands, and obtain high-resolution images for each of the energy bands using the signals, the charged particle beam apparatus has a charged particle source (12-1); an aperture (16) that limits the diameter of the charged particle beam (4); optics (14, 17, 19) for the charged particle beam; a specimen holder (21); a charged particle detector (40) that detects secondary charged particles and reflected charged particles from a specimen; and signal calculation unit that processes the output signal from the charged particle detector.

Abstract: Methods for spatially resolved alignment of independent spectroscopic data from scanning transmission electron microscopes (STEMs) are provided. One such method includes performing a first scan of a first area of a first sample using a STEM configured to capture a first signal having a first image profile, performing a second scan of a second area of a second sample using the STEM configured to capture a second signal having a second image profile, selecting a subset region from one of the first and second profiles, correlating the selected subset region from the one of the first and second profiles and the other of the first and second profiles, and selecting, based on the correlating, a portion of the other of the first and second profiles such that the selected subset region and the portion of the other of the first and second profiles are about equal.

Abstract: The invention relates to a method for determining a reconstructed image using a particle-optical apparatus. The particle-optical apparatus comprises a particle source for producing a beam of particles, an object plane on which an object to be imaged may be placed, a condenser system for illuminating the object plane with the beam of particles, a projection system for forming an image of the object plane by imaging particles transmitted through the object on an image plane, and a detector for detecting the image, the detector comprising a semiconductor sensor having an array of pixels for providing a plurality of pixel signals from respective pixels of the array in response to particles incident on the detector.

Abstract: Observation fields of an electron microscope image and an optical magnifying observation image are smoothly switched. A magnifying observation apparatus includes: a pair of end-face plates closes end faces of a body portion; an electron beam imaging device mounted on a first position of a cylindrical shaped outer surface of the body portion; an optical imaging device mounted on a second position being different from the first position in the outer surface; a rotating device that rotates the both imaging devices along the outer surface such that a distance from each of the both imaging devices to a common rotation axis of the both imaging devices is kept constant and optical axes of the both imaging devices are oriented toward the rotation axis; a specimen stage that is disposed in the chamber, and arranged to a position that is substantially the same to a height of the rotation axis.

Abstract: A method and apparatus for reducing drift in a charged particle beam system. The method includes providing a charged particle beam column including a charged particle beam, a lens system, and a sample chamber; disposing a temperature-controlled device between the lens system and the sample chamber to control heat transfer between the lens system and the sample chamber; and controlling the temperature of the temperature-controlled device to reduce or eliminate the thermal drift of the position of a sample within the sample chamber relative to the position of the charged particle beam.

Abstract: An object of the present invention is to provide a pattern measuring apparatus which performs high-accuracy concavity/convexity determination (e.g., distinguishing between a line segment and space) while simultaneously reducing the dose of a beam falling onto a pattern to be measured. To attain the object, this invention proposes a pattern measuring apparatus which specifies a pattern in a measurement object area by scanning a tilted bean with respect to another area different from the measurement object area and then performs measurement based on the pattern-specifying result. With such arrangement, it becomes possible to perform measurement without the risk of wrong pattern designation while lowering the dose of a beam hitting the measurement object area.

Abstract: The present invention provides a charged particle beam apparatus which employs LVSEM to inspect sample surface with a throughput much higher than the prior art. The high throughput is realized by providing a probe current and a FOV both several times of those of the prior art. Accordingly several means are proposed to avoid obvious degradation of image resolution due to the increases in Coulomb effect and geometric aberrations, and increase efficiency and uniformity of secondary charged particle collection.

Abstract: In a direct electron detector, backscattering of electrons into the detector volume from below the sensor is prevented. In some embodiments, an empty space is maintained below the sensor. In other embodiments, a structure below the sensor includes geometry, such as multiple high aspects ratio channels, either extending to or from the sensor to trap electrons, or a structure of angled surfaces to deflect the electrons that pass through the sensor.

Abstract: Disclosed are embodiments of an ion beam shield for use in an ion beam sample preparation apparatus and methods for using the embodiments. The apparatus comprises an ion beam irradiating means in a vacuum chamber that may direct ions toward a sample, a shield blocking a portion of the ions directed toward the sample, and a shield retention stage with shield retention means that replaceably and removably holds the shield in a position. The ion beam shield has datum features which abut complementary datum features on the shield retention stage when the shield is held in the shield retention stage. The shield has features which enable the durable adhering of the sample to the shield for processing the sample with the ion beam. The complementary datum features on both shield and shield retention stage enable accurate and repeatable positioning of the sample in the apparatus for sample processing and reprocessing.

Abstract: An object of the present invention is related to detecting of a detection signal at an optimum position in such a case that a sample plane is inclined with respect to a charged particle beam. The present invention is related to a charged particle beam apparatus for irradiating a charged particle beam to a sample, in which a detector is moved to a plurality of desirable positions around the sample so as to optimize positions of the detector. In accordance with the present invention, since it is possible to obtain an optimum detection signal in response to an attitude and a shape of the sample, a highly accurate sample observation, for instance, an SEM observation, an STEM observation, and an FIB observation can be carried out. Moreover, in an FIB-SEM apparatus, it is possible to highly accurately detect an end point of an FIB process.

Abstract: A seal member to be contacted with an observation object is provided at an open end of a lens barrel so that the observation object can be attracted to the lens barrel via the seal member and fixed in direct and close contact with the lens barrel when a vacuum is created in the lens barrel by a vacuum pump. In other words, instead of providing a sample chamber, the observation object is fixed in close contact with the lens barrel to prevent relative movement therebetween by a suction force even without a sample chamber. In this configuration, the interior of the lens barrel can be maintained in a vacuum state despite the absence of a sample chamber and no adverse effect occurs during observation because the lens barrel and the observation object are not moved relative to each other by vibration.

Abstract: A method of controlling particle absorption on a wafer sample and charged particle beam imaging system thereof prevents particle absorption by grounding the wafer sample and kept electrically neutral during the transfer-in and transfer-out process.

Abstract: Cryogenic manipulation of a material sample with an in situ probe is enabled with a novel cooled probe design. A material sample mounted on a cryo-stage in a vacuum chamber is cooled to a cryogenic temperature. In addition, a nano-manipulator probe inside the sample chamber is also cooled to cryogenic temperature. A specific sample site is milled in the chamber using a focused ion beam and attached to the cooled probe by vapor deposition. After releasing the sample, the sample site is attached to a destination surface such as a transmission electron microscope (TEM) grid and the probe is then detached from the sample using the focused ion beam.

Abstract: In accordance with an embodiment, a defect inspection apparatus includes a charged beam irradiation unit, a detection unit, an energy filter, and an inspection unit. The charged beam irradiation unit generates a charged beam and irradiates a sample including a pattern as an inspection target thereon with the generated charged beam. The detection unit detects secondary charged particles or reflected charged particles generated from the sample by irradiation of the charged beam and outputs a signal. The energy filter is arranged between the detection unit and the sample to selectively allow the secondary charged particles or the reflected charged particles with energy associated with an applied voltage to pass therethrough. The inspection unit applies voltages different from each other to the energy filter and outputs information concerning a defect of the pattern from an intensity difference between signals obtained under application voltage different from each other.

Abstract: An electron beam is irradiated on an observation region of a sample surface. An image (SEM image) is acquired based on a detection signal of secondary electrons from a detector disposed obliquely above the observation region. A length of a shadow of a pattern appearing in the image is detected. Then, a height H of the pattern is calculated by a formula H=L×tan ? on the basis of the detected length L of the shadow and an apparent angle ? of the detector to the sample surface obtained in advance. An intensity distribution of the secondary electrons on a line orthogonal to an edge of the pattern is extracted, and the length L of the shadow of the pattern is obtained as a distance between two points where a recess portion of the intensity distribution intersects a predetermined threshold.

Abstract: A transmission electron microscope in which a sample is positioned in a sample plane 9b comprises an objective lens 11b, a first projection lens system 61b having plural lenses, a second projection lens 63b system having plural lenses, and an analyzing system. The sample plane 9b is imaged into an intermediate image plane 71, a diffraction plane 15b of the objective lens 11b is imaged into an intermediate diffraction plane 67b, and either a) the intermediate image plane is imaged into an entrance image plane of the analyzing system and the intermediate diffraction plane is imaged into an entrance pupil plane of the analyzing system, or b) the intermediate image plane 71 is imaged into the entrance pupil plane 65b and the intermediate diffraction plane 67b is imaged into the entrance image plane 21b.

Abstract: A scanning transmission electron microscope includes an electron beam source to generate an electron beam. Beam optics are provided to converge the electron beam to a probe, such as for example a longitudinally stretched probe. A stage is provided to hold a specimen in the path of the electron beam. The specimen may include one or more elongated objects, such as for example polymers to be sequenced. A beam scanner scans the electron beam across the specimen. A controller may define one or more scanning areas corresponding to the locations of the elongated objects, and control one or more of the beam scanner and stage to selectively scan the electron beam probe in the scanning areas. The controller may also tune the beam optics during imaging. One or more detectors are provided to detect electrons transmitted through the specimen to generate an image for each of the scanning areas.

Abstract: A correlation standard for calibrating a scanning electron microscope is provided. The correlation standard comprises a pellet and a metal stub. The pellet comprises a compressed mixture of carbon powder and alumina powder. The pellet is attached to the metal stub with a conductive adhesive.

Abstract: A phase plate, specifically a Zernike type phase plate, for use in an electron microscope, comprises a central hole, and a thin film causing a phase shift of the electrons passing through said film. This phase shift causes the Contrast Transfer Function (CTF) to change from a sine-like function to a cosine-like function. The phase plate is equipped with a film in the form of an annulus, carried by a much thinner film. As a result only in a small spatial frequency range (for low frequencies) the phase is changed (and thus the CTF), and for other spatial frequencies the phase shift is negligible, and thus the CTF remains unchanged. Due to the much smaller thickness of the carrier film the scattering of electrons is negligible as well.

Abstract: In an interference electron microscope, a first electron biprism is disposed between an acceleration tube and an illumination-lens system, a mask is disposed between the acceleration tube and the first electron biprism, and the first electron biprism is arranged in a shadow that the mask forms. Current densities of first and second electron beams on a parabolic surface of an objective lens system where a sample is positioned are controlled by a control system by an optical action of the illumination-lens system, the mask is imaged on the parabolic surface of the objective lens system, and an electro-optical length between the first electron biprism and the parabolic surface of the objective lens where the sample is positioned is controlled without generating Fresnel fringes on a sample surface from the mask and the first electron biprism.

Abstract: The monochromator for reducing energy spread of a primary charged particle beam in charged particle apparatus comprises a beam adjustment element, two Wien-filter type dispersion units and an energy-limit aperture. In the monochromator, a dual proportional-symmetry in deflection dispersion and fundamental trajectory along a straight optical axis is formed, which not only fundamentally avoids incurring off-axis aberrations that actually can not be compensated but also ensures the exit beam have a virtual crossover which is stigmatic, dispersion-free and inside the monochromator. The present invention also provides two ways to build a monochromator into a SEM, in which one is to locate a monochromator between the electron source and the condenser, and another is to locate a monochromator between the beam-limit aperture and the objective. The former provides an additional energy-angle depending filtering, and obtains a smaller effective energy spread.