An electron beam system for wafer inspection and review of 3D devices provides a depth of focus up to 20 microns. To inspect and review wafer surfaces or sub-micron-below surface defects with low landing energies in hundreds to thousands of electron Volts, a Wien-filter-free beam splitting optics with three magnetic deflectors can be used with an energy-boosting upper Wehnelt electrode to reduce spherical and chromatic aberration coefficients of the objective lens.

An electron beam system for wafer inspection and review of 3D devices provides a depth of focus up to 20 microns. To inspect and review wafer surfaces or sub-micron-below surface defects with low landing energies in hundreds to thousands of electron Volts, a Wien-filter-free beam splitting optics with three magnetic deflectors can be used with an energy-boosting upper Wehnelt electrode to reduce spherical and chromatic aberration coefficients of the objective lens.

Systems and methods are provided for compensating dispersion of a beam separator in a single-beam or multi-beam apparatus. Embodiments of the present disclosure provide a dispersion device comprising an electrostatic deflector and a magnetic deflector configured to induce a beam dispersion set to cancel the dispersion generated by the beam separator. The combination of the electrostatic deflector and the magnetic deflector can be used to keep the deflection angle due to the dispersion device unchanged when the induced beam dispersion is changed to compensate for a change in the dispersion generated by the beam separator. In some embodiments, the deflection angle due to the dispersion device can be controlled to be zero and there is no change in primary beam axis due to the dispersion device.

Systems and methods are provided for compensating dispersion of a beam separator in a single-beam or multi-beam apparatus. Embodiments of the present disclosure provide a dispersion device comprising an electrostatic deflector and a magnetic deflector configured to induce a beam dispersion set to cancel the dispersion generated by the beam separator. The combination of the electrostatic deflector and the magnetic deflector can be used to keep the deflection angle due to the dispersion device unchanged when the induced beam dispersion is changed to compensate for a change in the dispersion generated by the beam separator. In some embodiments, the deflection angle due to the dispersion device can be controlled to be zero and there is no change in primary beam axis due to the dispersion device.

There is provided an ultrafast electron diffraction apparatus including: a photoelectron gun configured to emit an electron beam; a bending portion for emitting the electron beam emitted from the photoelectron gun by changing a travel direction of the electron beam by a predetermined angle; and a sample portion including a sample to be analyzed by the electron beam emitted from the bending portion. The electron beam reaches the sample portion in a state that a pulse of the electron beam is compressed and the timing jitter between the pumping light and probe electron pulse is completely reduced as the travel direction of the electron beam is changed by the predetermined angle through the bending portion.

There is provided an ultrafast electron diffraction apparatus including: a photoelectron gun configured to emit an electron beam; a bending portion for emitting the electron beam emitted from the photoelectron gun by changing a travel direction of the electron beam by a predetermined angle; and a sample portion including a sample to be analyzed by the electron beam emitted from the bending portion. The electron beam reaches the sample portion in a state that a pulse of the electron beam is compressed and the timing jitter between the pumping light and probe electron pulse is completely reduced as the travel direction of the electron beam is changed by the predetermined angle through the bending portion.

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.

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.

The present disclosure proposes a crossover-forming deflector array of an electro-optical system for directing a plurality of electron beams onto an electron detection device. The crossover-forming deflector array includes a plurality of crossover-forming deflectors positioned at or at least near an image plane of a set of one or more electro-optical lenses of the electro-optical system, wherein each crossover-forming deflector is aligned with a corresponding electron beam of the plurality of electron beams.

A magnetic apparatus and a method of operating the magnetic apparatus can include a scanning electromagnet that redirects a beam of charged particles, a vacuum chamber that prevents the atmosphere from interfering with the charged particles, and, a parallelizing permanent magnet array for parallelizing the beam of charged particles. The parallelizing permanent magnet array can be located proximate to a target comprising a Bremsstrahlung target or an object that is being irradiated. The magnetic field of the scanning electromagnet can be variable to produce all angles necessary to sweep the beam of charged particles across the target and the parallelizing permanent magnet array can be configured from a magnetic material that does not require an electric current.