SCANNING ELECTRON MICROSCOPE

摘要

An out-lens objective lens and a snorkel objective lens have advantages and disadvantages respectively. The configuration for an objective lens and a detector capable of obtaining advantages of both the snorkel objective lens and the out-lens objective lens is required in order to obtain high resolution and desired image quality for a widely used scanning electron microscope. According to the present invention, the magnetic-field property of an objective lens (7) is simulated and the shape of the objective lens (7) is determined from the orbit (26) of a backscattered electron due to a leakage magnetic field from the objective lens (7). Thereby, the effect on the orbit of a backscattered electron due to the leakage magnetic field of an objective lens is reduced while image quality change due to a change in the operation distance of an objective lens is minimized, so that a high-yield and high-resolution image can be obtained as with a snorkel objective lens.