A pattern inspection apparatus includes an actual outline image generation circuit to generate an actual outline image of a predetermined region defined by a function, where the gray scale value of each pixel in the predetermined region including plural actual image outline positions on an actual image outline of a figure pattern in an inspection image is dependent on a distance from the center of a pixel concerned to the closest actual image outline position in the plural actual image outline positions, and a reference outline image generation circuit to generate a reference outline image of the predetermined region defined by the function, where a gray scale value of each pixel in the predetermined region is dependent on a distance from the center of a pixel concerned to the closest reference outline position in plural reference outline positions on a reference outline to be compared with the actual image outline.

Improved aberration correction in multipass electron microscopy is provided by having Fourier images of the sample (instead of real images) at the reflection planes of the resonator. The resulting −1 magnification of the sample reimaging can be compensated by appropriate sample placement or by adding compensating elements to the resonator. This enables simultaneous correction of lowest order chromatic and spherical aberration from the electron objective lenses. If real images of the sample are at the reflection planes of the resonator instead, only the lowest order chromatic aberration can be corrected.

Diffraction patterns of a sample at various tilt angles are acquired by irradiating a region of interest using a first charged particle beam. Sample images are acquired by irradiating the region of interest using a second charged particle beam. The first and second charged particle beams are formed by splitting charged particles generated by a charged particle source.

A drift amount computing device (100) computes an amount of drift between a first image and a second image, and comprises a correlation function computing section (112) for calculating a correlation function between the first and second images, a local maximum position searching section (114) for searching a range of positions of the correlation function for local maximum positions, a local maximum position determining section (116) for assigning weights to intensities of plural local maximum positions according to the distance from the center of the correlation function, comparing the weighted intensities of the local maximum positions, and determining one of the maximum local positions which corresponds to the amount of drift, and a drift amount computing section (118).

The disclosure relates to a method of imaging a specimen using a transmission charged particle microscope, said method comprising providing a specimen, and providing a charged particle beam and directing said charged particle beam onto said specimen for generating a flux of charged particles transmitted through the specimen. The method comprises the step of generating and recording a first energy filtered flux of charged particles transmitted through the specimen, wherein said first energy filtered flux of charged particles substantially consists of non-scattered and elastically scattered charged particles. The method as disclosed herein comprises the further step of generating and recording a second energy filtered flux of charged particles transmitted through the specimen, wherein said second energy filtered flux of charged particles substantially consists of inelastically scattered charged particles. Said first and second recorded energy filtered flux are then used for imaging said specimen with increased contrast.

The disclosure relates to a method of imaging a specimen using a transmission charged particle microscope, said method comprising providing a specimen, and providing a charged particle beam and directing said charged particle beam onto said specimen for generating a flux of charged particles transmitted through the specimen. The method comprises the step of generating and recording a first energy filtered flux of charged particles transmitted through the specimen, wherein said first energy filtered flux of charged particles substantially consists of non-scattered and elastically scattered charged particles. The method as disclosed herein comprises the further step of generating and recording a second energy filtered flux of charged particles transmitted through the specimen, wherein said second energy filtered flux of charged particles substantially consists of inelastically scattered charged particles. Said first and second recorded energy filtered flux are then used for imaging said specimen with increased contrast.

Diffraction patterns of a sample at various tilt angles are acquired by irradiating a region of interest using a first charged particle beam. Sample images are acquired by irradiating the region of interest using a second charged particle beam. The first and second charged particle beams are formed by splitting charged particles generated by a charged particle source.

Techniques of using a Transmission Charged Particle Microscope for diffraction pattern detection are disclosed. An example method including irradiating at least a portion of a specimen with a charged particle beam, using an imaging system to collect charged particles that traverse the specimen during said irradiation, and to direct them onto a detector configured to operate in a particle counting mode, using said detector to record a diffraction pattern of said irradiated portion of the specimen, recording said diffraction pattern iteratively in a series of successive detection frames, and during recording of each frame, using a scanning assembly for causing relative motion of said diffraction pattern and said detector, so as to cause each local intensity maximum in said pattern to trace out a locus on said detector.

There is provided a method of image acquisition capable of reducing the effects of diffraction contrast. This method of image acquisition is implemented in an electron microscope for generating electron microscope images with electrons transmitted through a sample. The method starts with obtaining the plural electron microscope images while causing relative variations in the direction of incidence of an electron beam with respect to the sample. An image is generated by accumulating the plural electron microscope images.

Improved aberration correction in multipass electron microscopy is provided by having Fourier images of the sample (instead of real images) at the reflection planes of the resonator. The resulting 1 magnification of the sample reimaging can be compensated by appropriate sample placement or by adding compensating elements to the resonator. This enables simultaneous correction of lowest order chromatic and spherical aberration from the electron objective lenses. If real images of the sample are at the reflection planes of the resonator instead, only the lowest order chromatic aberration can be corrected.