Abstract: Optical scattering disk, use and wavefront measuring apparatus. The optical scattering disk includes a transparent substrate (1) and a light scattering layer (2) adjoining a surface of the substrate and having light-scattering-active particles (3). The light scattering layer has an embedding medium (4) which is optically denser than air and directly adjoins the facing surface of the substrate without intervening air gaps and by which the light-scattering-active particles are surrounded. Such optical scattering disks may be used, e.g., in apparatuses for wavefront measurement of high-aperture microlithography projection objectives employing lateral shearing interferometry.

Abstract: A measurement apparatus which measures spatial coherence in an illuminated plane illuminated by an illumination system, comprises a measurement mask which has at least three pinholes and is arranged on the illuminated plane, a detector configured to detect an interference pattern formed by lights from the at least three pinholes, and a calculator configured to calculate the spatial coherence in the illuminated plane based on a Fourier spectrum obtained by Fourier-transforming the interference pattern detected by the detector.

Abstract: A phase imaging method for an optical wavefront acquires a plurality of phase images of the optical wavefront using a phase imager. Each phase image is unique and is shifted with respect to another of the phase images by a known/controlled amount that is less than the size of the phase imager's pixels. The phase images are then combined to generate a single high-spatial resolution phase image of the optical wavefront.

Abstract: One embodiment of the invention provides a lens-testing apparatus being used for testing a lens device. The lens-testing apparatus comprises a light module, at least one first and second image sensors, and at least one image sensor module. The light module generates a patterned light beam passing the lens device. The first and second image sensors receive first and second portions of the patterned light beam; the first image sensor is disposed between the second image sensor and the lens device. The image sensor module receives a substantially parallel third portion of the patterned light beam, and comprises a third image sensor and a collimator. The third portion of the patterned light beam is focused onto the third image sensor by the collimator; the distance between the first image sensor and the lens device is smaller than the distance between the second image sensor and the lens device.

Abstract: A method of testing a convex mirror surface figure in which an optical quality substrate material is used having a convex front surface and a rear surface polished to a precise optical figure to create a lens. The lens is then tested by a standard interferometric or wavefront lens-testing method and the convex surface coated once a desired curvature is obtained. Null testing may be attained by passing a collimated interferometer beam through a focusing lens shaped to counter the predicted spherical aberration introduced by a perfect convex mirror/lens. A nominal rear surface figure of the mirror/lens may be used if a precisely figured test window is contacted with the rear surface using a refractive index-matching substance with an index of refraction closely matching the index of refraction of the test optic.

Abstract: A system and method forming near diffraction limited size beacon for adaptive optical system using a temporally partially coherent laser source. Comprises projection of laser beams through turbulent medium having non-cooperative target using combination of adaptive optical system and short temporal coherence length laser source forming controllable focused laser target beacon. Combines adaptive optical system technology using any wavefront sensing technique making complex field measurements with short coherence length and associated broad spectral bandwidth. The partially coherent laser source forms narrow (near diffraction limited) size region of coherent laser light at target. The coherent region of return dominates signal for any measurement technique computing average of field over wavelength bandpass and can be used to pre-compensate either the partially coherent laser beam, a long coherence length beam of different wavelength or wavelength in bandpass, or both.

Abstract: A measurement method of measuring a wavefront aberration of an optical system to be measured, comprising a first measurement step of measuring wavefronts of the optical system to be measured with respect to linearly polarized light beams along at least three different azimuths, a first calculation step of calculating a wavefront of the optical system to be measured with respect to non-polarized light and a birefringent characteristic of the optical system to be measured, based on the wavefronts of the optical system to be measured, which are measured in the first measurement step, and a second calculation step of calculating a wavefront of the optical system to be measured with respect to arbitrary polarized light, based on the wavefront and the birefringent characteristic of the optical system to be measured, which are calculated in the first calculation step.

Abstract: Interferometric scanning method(s) and apparatus for measuring test optics having aspherical surfaces including those with large departures from spherical. A reference wavefront is generated from a known origin along a scanning axis. A test optic is aligned on the scanning axis and selectively moved along it relative to the known origin so that the reference wavefront intersects the test optic at the apex of the aspherical surface and at one or more radial positions where the reference wavefront and the aspheric surface intersect at points of common tangency (“zones”) to generate interferograms containing phase information about the differences in optical path length between the center of the test optic and the one or more radial positions. The interferograms are imaged onto a detector to provide an electronic signal carrying the phase information.

Abstract: A measurement method for measuring a wavefront aberration of a target optical system using a measurement apparatus that measures the wavefront aberration of the target optical system by detecting an interference pattern includes the steps of measuring as a system parameter a shift from a design value of a value that defines a structure of the measurement apparatus and the target optical system, and measuring the wavefront aberration of the target optical system using the system parameter.

Abstract: A method for approximating an influence of an optical system on the state of polarization of optical radiation comprises the steps of providing incoming optical radiation for the optical system in several incoming states of polarization, including at least one incoming state having circularly polarized radiation components; directing the incoming optical radiation onto the optical system; measuring at least one characteristic, including a phase distribution, of a resulting outgoing optical radiation emerging from the optical system with respect to each of the incoming states of polarization; and approximating the influence of the optical system on the state of polarization of optical radiation by evaluating the measured characteristics of the outgoing optical radiation.

Abstract: A device and method for the interferometric measurement of phase masks, particularly from lithography. Radiation passing through a coherence mask is brought to interference by a diffraction grating. A phase mask is arranged in or near the pupil plane of the first imaging optics which can be positioned exactly in the x-y direction by which interferograms are generated which are phase-shifted in the x-y direction by translational displacement of the coherence mask or of the diffraction grating. The interferograms are imaged onto the spatially resolving detector by second imaging optic and the phase and transmission functions of the phase mask are determined by an evaluation unit. The invention can, of course, generally be applied to planar phase objects, such as biological structures, for example, points of establishment with respect to an interference microscope.

Abstract: The present invention provides a method including measuring a wavefront aberration of the optical system to be measured on a measurement surface, measuring a pupil transmittance distribution of the optical system determining a pupil function of the optical system based on the wavefront aberration and the pupil transmittance distribution, and performing imaging computation using the pupil function to obtain a light intensity distribution formed on an image plane of the optical system, and calculating a flare, generated in the optical system, from the light intensity distribution.

Abstract: Light emitted from a light source is formed into parallel light beams, the parallel light beams are divided into two light beams, and one of the divided light beams is converted by a conical lens to light (beam) having an energy density on an optical axis maximized over a distance, and is applied to a surface of a measuring object, with another one of the divided light beams being applied to a reference mirror, so that, by detecting an interfered light beam between rearward scattered light of the light (beam) applied to the surface of the measuring object and reflected light from the reference mirror, a shape of the measuring object is measured.

Abstract: A system for evaluation of optical quality of an optical device includes a light source configured to generate light, the generated light be received by an optical device. An interferometric lens apparatus is removably mounted to the optical device to generate interference fringes. A camera device is configured to receive and display the interference fringes, and a computer configured to analyze the interference fringes received from the camera device to determine aberrations of the optical device and generate a recommendation to correct the determined aberrations. Methods for evaluating the optical quality of an optical device are also described.

Abstract: A measuring system for the optical measurement of an optical imaging system, which is provided to image a pattern arranged in an object surface of the imaging system in an image surface of the imaging system, comprises an object-side structure carrier having an object-side measuring structure, to be arranged on the object side of the imaging system; an image-side structure carrier having an image-side measuring structure, to be arranged on the image side of the imaging system; the object-side measuring structure and the image-side measuring structure being matched to each other in such a way that, when the object-side measuring structure is imaged onto the image-side measuring structure with the aid of the imaging system, a superposition pattern is produced; and a detector for the locally resolving acquisition of the superposition pattern. The imaging system is designed as an immersion system for imaging with the aid of an immersion liquid.

Abstract: A method for measuring wavefront information of a projection optical system includes arranging a first diffraction grating having a pitch P1 on a side of an object plane of the projection optical system; arranging a second diffraction grating having a pitch P2 which is ½ of a pitch of an image of the first diffraction grating formed by the projection optical system, on a side of an image plane of the projection optical system PL; illuminating the first diffraction grating with an illumination light; receiving interference fringes of a shearing interference light composed of two pairs of diffracted lights formed by the illumination light from the second diffraction grating via the first diffraction grating and the projection optical system; and determining the wavefront information of the projection optical system based on the received interference fringes. The wavefront information of the projection optical system can be measured highly accurately.

Abstract: A measurement method for measuring a shape of a target using an interference pattern includes the steps of converting a first interference pattern into a first shape of the target (S103 to S105), obtaining a second interference pattern at a position where the target moves in an optical axis direction of the reference surface (S107, S108), unwrapping the second interference pattern after aligning a phase of the first interference pattern with a phase of the second interference pattern (S109), converting the unwrapped second interference pattern into a second shape of the target (S110), determining whether or not the first shape of the target coincides with the second shape (S111), and calculating the shape of the target by adding the integral multiple of a wavelength of the light source to the unwrapped second interference pattern if the first shape does not coincide with the second shape (S112).

Abstract: Characterization of an optical system is quickly and easily obtained in a single acquisition step by obtaining image data within a volume of image space. A reticle and image plane are positioned obliquely with respect to each other such that a reticle having a plurality of feature sets thereon, including periodic patterns or gratings, is imaged in a volume of space, including the depth of focus. Metrology tools are used to analyze the detected or recorded image in the volume of space through the depth of focus in a single step or exposure to determine the imaging characteristics of an optical system. Focus, field curvature, astigmatism, spherical, coma, and/or focal plane deviations can be determined. The present invention is particularly applicable to semiconductor manufacturing and photolithographic techniques used therein, and is able to quickly characterize an optical system in a single exposure with dramatically increased data quality and continuous coverage of the full parameter space.

Abstract: A measuring system (100) for the optical measurement of an optical imaging system (150), which is provided to image a pattern arranged in an object surface (155) of the imaging system in an image surface (156) of the imaging system, comprises an object-side structure carrier (110) having an object-side measuring structure (111), to be arranged on the object side of the imaging system; an image-side structure carrier (120) having an image-side measuring structure (121), to be arranged on the image side of the imaging system; the object-side measuring structure and the image-side measuring structure being matched to each other in such a way that, when the object-side measuring structure is imaged onto the image-side measuring structure with the aid of the imaging system, a superposition pattern is produced; and a detector (130) for the locally resolving acquisition of the superposition pattern. The imaging system is designed as an immersion system for imaging with the aid of an immersion liquid (171).

Abstract: A measurement method of measuring a wavefront aberration of an optical system to be measured, comprising a first measurement step of measuring wavefronts of the optical system to be measured with respect to linearly polarized light beams along at least three different azimuths, a first calculation step of calculating a wavefront of the optical system to be measured with respect to non-polarized light and a birefringent characteristic of the optical system to be measured, based on the wavefronts of the optical system to be measured, which are measured in the first measurement step, and a second calculation step of calculating a wavefront of the optical system to be measured with respect to arbitrary polarized light, based on the wavefront and the birefringent characteristic of the optical system to be measured, which are calculated in the first calculation step.

Abstract: A wavefront measurement system includes a source of electromagnetic radiation. An illumination system delivers the electromagnetic radiation to an object plane. A source of a diffraction pattern is in the object plane. A projection optical system projects the diffraction pattern onto an image plane, which includes a mechanism (e.g., a shearing grating) to introduce the lateral shear. A detector is located optically conjugate with the pupil of the projection optical system, and receives an instant fringe pattern, resulting from the interference between sheared wavefronts, from the image plane. The diffraction pattern is dynamically scanned across a pupil of the projection optical system, and the resulting time-integrated interferogram obtained from the detector is used to measure the wavefront aberration across the entire pupil.

Abstract: A measurement apparatus includes a first mask that is arranged on an object plane of a target optical system, and has a window that transmits measurement light, a second mask that has a reflection surface for reducing coherence of the measurement light, and a diffraction grating configured to split the measurement light that has been reflected on the second mask, has passed the first mask and the target optical system, wherein a distance Lg between the diffraction grating and an image plane of the target optical system satisfies Lg=m·Pg2/? where Pg is a grating pitch of the diffraction grating, ? is a wavelength of the measurement light, and m is an integer except for 0.

Abstract: A relationship between surface decenter of a lens 1 under test and surface-decenter comatic aberration and a relationship between surface tilt of the lens 1 under test and surface-tilt comatic aberration are calculated by computer simulation. The surface tilt of the lens 1 under test is calculated by measuring a transmissive wavefront of a projecting portion 3, and comatic aberration of the lens 1 under test is calculated by measuring a transmissive wavefront of a lens portion 2. The surface-decenter comatic aberration that occurs due to the surface decenter is calculated by subtracting the surface-tilt comatic aberration from the calculated comatic aberration. The surface decenter of the lens 1 under test is calculated based on the calculated surface-decenter comatic aberration.

Abstract: A measuring system for the optical measurement of an optical imaging system, which is provided to image a pattern arranged in an object surface of the imaging system in an image surface of the imaging system, comprises an object-side structure carrier having an object-side measuring structure, to be arranged on the object side of the imaging system; an image-side structure carrier having an image-side measuring structure, to be arranged on the image side of the imaging system; the object-side measuring structure and the image-side measuring structure being matched to each other in such a way that, when the object-side measuring structure is imaged onto the image-side measuring structure with the aid of the imaging system, a superposition pattern is produced; and a detector for the locally resolving acquisition of the superposition pattern. The imaging system is designed as an immersion system for imaging with the aid of an immersion liquid.

Abstract: A measuring device for measuring a wavefront aberration of an optical system includes a first mask for defining light that enters the optical system, and a second mask having first to fourth openings. The first opening transmits a component of the light passing through the optical system without removing information about the wavefront aberration of the optical system, and the second to fourth openings transmit components of the light passing through the optical system having the information about the wavefront aberration of the optical system removed.

Abstract: The disclosure describes obtaining a first reference wavefront generated from a object plane mask slit, obtaining a second reference wavefront generated from a first image plane mask slit, measuring a wavefront of a target optical system including a reference wavefront error, and subtracting the first and the second reference wavefronts from the target optical system include the reference wavefront error.

Abstract: A method includes calculating destructive interference conditions between two linearly s-polarized waves and between two linearly p-polarized waves, respectively, in dependence on varying parameters of the s- and p-polarized waves, representing the destructive interference conditions in a diagram, setting an optical radiation field to be used in the optical imaging process, and comparing the optical radiation field with the diagram.

Abstract: The invention provides a measurement apparatus which measures a wavefront aberration of an optical system to be measured, the apparatus includes a measurement mask which is inserted on an object plane of the optical system to be measured, and includes a plurality of reflection units configured to generate spherical waves by reflecting light, the measurement mask including a reflection layer configured to reflect the light, a first layer which is stacked on the reflection layer, has a plurality of openings, and is made of a first substance, and a second layer which is stacked on the first layer, has a window configured to expose a region in which the plurality of openings are arrayed, and is made of a second substance different from the first substance, wherein the plurality of reflection units are formed by portions of the reflection layer, which are exposed through the plurality of openings.

Abstract: Modified MZ (Mach-Zender) interferometers preferably are utilized to analyze the transmitted, aspherical wavefront of an ophthalmic lens by mounting the lens in a cuvette having a rotatable carousel that can hold multiple lenses. Fresh, temperature controlled, saline solution is circulated about the lenses, and the cuvette is positioned in a vertical test arm of the interferometer configuration. Reverse raytracing preferably is utilized to remove aberrations induced into the wavefront as it is imaged from immediately behind the lens to the detector of the interferometer.

Abstract: An exposure apparatus including an illumination system which illuminates an original, and projection optics which project a pattern of the original illuminated by the illumination system onto a substrate. The apparatus includes an interferometer which forms an interference pattern including aberration information on the projection optics using a polarized light beam emitted from the illumination system, in which the interferometer is a common path interferometer in which two light beams forming interference pattern pass along a path in the projection optics, and a processor which calculates optical characteristics of the projection optics on the basis of the interference pattern formed by the interferometer. The illumination system including a polarization controller which sequentially generates at least three difference polarized light beams with respective polarization states different from each other.

Abstract: A refractive-index measurement system includes a light source, a first beam splitter, a first reflective mirror, a second reflective mirror, a second beam splitter, a container, a first polarizer, and a second polarizer. The first beam splitter splits light emitted from the light source into first and second light beams. The first light beam and the second light beam are reflected by the first reflective mirror and the second reflective mirror, respectively, incident into the second light beam splitter. The container is positioned along an optical pathway of first light beam. The container accommodates a lens and is filled with a medium having a refractive index substantially the same as a theoretical refractive index of the lens. The first polarizer is positioned along the optical pathway of the first light beam. The second polarizer is positioned along an optical pathway of the second light beam.

Abstract: A measurement method for measuring a wavefront aberration of a target optical system using a measurement apparatus that measures the wavefront aberration of the target optical system by detecting an interference pattern includes the steps of measuring as a system parameter a shift from a design value of a value that defines a structure of the measurement apparatus and the target optical system, and measuring the wavefront aberration of the target optical system using the system parameter.

Abstract: An imaging system for obtaining interferometric measurements from a sample spherical surface has a light source for providing an incident light beam, a beamsplitter disposed to direct the incident light beam toward the sample spherical surface and to direct a test light reflected from the sample spherical surface and a reference light reflected from a reference spherical surface toward an interferometric imaging apparatus. There is a lens assembly in the path of the incident light beam, with at least one lens element, wherein one of the at least one lens elements has an aspheric surface and wherein one of the at least one lens elements further provides the reference spherical surface facing the sample spherical surface. A reference plate is temporarily disposed in the path of the incident light beam for measuring the aspheric surface itself and is removable from the path of the incident light beam for obtaining interferometric measurements from the sample spherical surface.

Abstract: An optical system representing the configuration of a tested element disposed therein is provided. The optical system comprises a light source emitting a spatial-incoherent light having a phase shifting scheme toward the tested element and then forming an image with a transverse ray aberration on the image plane of the tested element; a spatial filter on the image plane to spatially filter the image formed by the tested element; and a detection module comprising a detector for receiving the spatially filtered image.

Abstract: A measuring device for measuring a wavefront aberration of an optical system includes a first mask for defining light that enters the optical system, and a second mask having first to fourth openings. The first opening transmits a component of the light passing through the optical system without removing information about the wavefront aberration of the optical system, and the second to fourth openings transmit components of the light passing through the optical system having the information about the wavefront aberration of the optical system removed.

Abstract: An exposure apparatus for exposing a pattern of a mask onto an object using light from a light source, includes a projection optical system for projecting the pattern onto the object, and a measuring apparatus for measuring, as an interference fringe, optical performance of the projection optical system using the light, wherein the measuring apparatus is a point diffraction interferometer that has a pinhole to form an ideal spherical wave, a line diffraction interferometer that has a slit to form an ideal cylindrical wave or an ideal elliptical wave, or a shearing interferometer that utilizes a shearing interferometry.

Abstract: An analyzer plate positioned between a projection system and a radiation sensor is illuminated by a projected beam of radiation. The analyzer plate includes two crossing regions, each of which transmits radiation with a different polarization direction. The beam of projection radiation is patterned without influencing the polarization of the beam. By patterning the beam of projection radiation so that one region receives more radiation than the other region, the radiation sensor is given polarization selectivity.

Abstract: A measurement method for measuring a wavefront aberration of a target optical system using a measurement apparatus that measures the wavefront aberration of the target optical system by detecting an interference pattern includes the steps of measuring as a system parameter a shift from a design value of a value that defines a structure of the measurement apparatus and the target optical system, and measuring the wavefront aberration of the target optical system using the system parameter.

Abstract: A method of positioning optical elements relative to each other uses an interferometer apparatus comprising a plurality of holograms generating beams of adjustment measuring light which are incident on optical surfaces of the optical elements. Interference patterns generated by superimposing adjustment measuring light of the beams reflected from the surfaces are indicative of positioning errors of the optical elements. The beams of adjustment measuring light may comprise focused beams forming a point focus on the optical surface and beams of light which is orthogonally incident on extended portions on the optical surface.

Abstract: A method for measuring a wavefront of an optical system. A first step of the method includes directing electromagnetic radiation uniformly at an object plane having a first grating positioned therein. Lines of the first grating comprise a plurality of dots. A second step of the method includes projecting an image of the first grating onto a focal plane having a second grating positioned therein. A third step of the method includes measuring the wavefront of the optical system based on a fringe pattern produced by the second grating.

Abstract: An exposure apparatus, which equipped with a projection optical system that is configured to project a pattern of an original onto a substrate, includes an interferometer configured to measure a wavefront in a first direction and a wavefront in a second direction of light passed through the projection optical system; a focus detecting unit configured to detect focus positions in the first and second directions of the projection optical system; and a calculating unit configured to calculate wavefront aberration of the projection optical system on the basis of the measurement result of the interferometer and the detection result of the focus detecting unit.

Abstract: An apparatus measuring wavefront aberration of an optical system includes a first mask in an object plane and having plural openings, an illumination optical system illuminating the openings of the first mask by using light from a light source, a second mask in an image plane and having an opening allowing passage of light containing aberration of the optical system and a pinhole/slit. The apparatus takes an image of interference fringe generated by light having passed through the optical system and the pinhole/slit and the light having passed through the optical system and the opening of the second mask, calculates an evaluation value to evaluate a state of the interference fringe by using image data of the image, determines, based on the evaluation value, whether the wavefront aberration of the inspected optical system is to be calculated, and calculates the wavefront aberration of the optical system from the image data.

Abstract: A method of manufacturing an optical component comprising a substrate and a mounting frame with plural contact portions disposed at predetermined distances from each other is provided. The method comprises providing a measuring frame separate from the mounting frame for mounting the substrate, which measuring frame comprises a number of contact portions equal to a number of the contact portions of the mounting frame, wherein respective distances between the contact portions of the measuring frame are substantially equal to the corresponding distances between those of the mounting frame, measuring a shape of the optical surface of the substrate, while the substrate is mounted on the measuring frame, and mounting the substrate on the mounting frame such that the contact portions of the mounting frame are attached to the substrate at regions which are substantially the same as contact regions at which the substrate was attached to the measuring frame.

Abstract: A measurement apparatus which measures a wavefront aberration of an optical system to be measured, the apparatus comprises a detection unit configured to detect an interference pattern formed by light having passed through a mask inserted on an object plane of the optical system to be measured, and a mask inserted on an image plane of the optical system to be measured.

Abstract: A measuring device for measuring a wavefront aberration of an optical system includes a first mask for defining light that enters the optical system, and a second mask having first to fourth openings. The first opening transmits a component of the light passing through the optical system without removing information about the wavefront aberration of the optical system, and the second to fourth openings transmit components of the light passing through the optical system having the information about the wavefront aberration of the optical system removed.

Abstract: A method and apparatus for measuring the chromatic response of lithographic projection imaging systems is described. An apparatus for determining the lens aberrations for a lithographic projection lens is provided. A substrate coated with a suitable recording media is provided. A series of lithographic exposures are performed using an exposure source with variable spectral settings. The exposures are measured, and the measurements are used to determine a chromatic response of the projection imaging system.

Abstract: The invention relates to a method for interferometrically measuring large optics. A combination of a method known as stitching technique, during which the sub-interferograms are determined on partial surfaces of measuring area and are joined in a software-controlled manner and which, as a result, enables the use of small, more cost-effective interferometers, however polished surfaces of the test piece being assumed, together with an immersion method, during which, in fact, lower demands for the surface quality of the test piece exist that, however, is accompanied by edge faults. In order to make this combination possible, a modification of the stitching technique is developed, during which the measuring area (CA) is completely covered by a film consisting of an immersion liquid.

Abstract: A measurement method for measuring a wavefront aberration of a target optical system using an interference pattern formed by a light from a first image side slit, and a light from a second image side slit, the first and second image side slits being located at an image side of the target optical system, the first image side slit having, in a shorter direction, a width equal to or smaller than a diffraction limit of the target optical system, and the second image side slit having, in a shorter direction, a width greater than the diffraction limit of the target optical system includes the steps of obtaining three or more primary wavefronts of the target optical system from different measurement directions, and calculating a wavefront aberration of the target optical system based on the three or more primary wavefronts obtained by the obtaining step.

Abstract: A point diffraction interferometer for measuring properties of a spatial impulse response function, the interferometer including: a source for generating a source beam; an optical system; an optical element including a test object located in an object plane of the optical system, the test object including a diffraction point for generating from the source beam a measurement beam that passes through the optical system, wherein the optical element also generates from the source beam a reference beam that is combined with the measurement beam to generate an interference pattern in an image plane of the optical system, the interference pattern representing the spatial impulse response function of the optical system.

Abstract: A substrate inspection method includes: generating primary charged particle beams; applying the generated primary charged particle beams to an inspection target of a substrate; condensing first secondary charged particle beams including at least one of secondary charged particles, reflected charged particles, and back scattering charged particles which have been generated from the substrate, or first transmitted charged particle beams which have transmitted the inspection target, a phase difference being generated between the secondary charged particle beams or between the transmitted charged particle beams in accordance with a structure of the inspection target; imaging the secondary charged particle beams or the transmitted charged particle beams; detecting the imaged secondary charged particle beams or transmitted charged particle beams and outputting a signal of a secondary charged particle beam image or a transmitted charged particle beam image including information on the phase difference; and detecting