Method of operating a scanning electron microscope

A method of inspecting an object using a scanning particle beam microscope, the method comprising: operating the microscope in a high-resolution mode by laterally scanning a particle beam of the high-resolution mode; operating the microscope in a 3D-mode for acquiring a three-dimensional representation of the object by laterally scanning a particle beam of the 3D-mode; wherein the particle beam of the high-resolution mode and the particle beam of the 3D-mode have a same beam energy and a same focus distance; and wherein an aperture angle of the particle beam of the 3D-mode is at least 2 times greater, or at least 5 times greater, or at least 10 times greater, or at least 100 times greater than an aperture angle of the particle beam of the high-resolution mode.