| 摘要 |
A inspection system includes: a lens arrangement adapted to generate a substantially symmetrical electrostatic field about an optical axis and to direct a primary electron beam towards an object that is oriented in relation to the optical axis at a non-normal angle; and at least on additional electrode, positioned outside the lens arrangement such as to increase symmetry of an electromagnetic field in the vicinity of an interaction point between the primary electron beam and the object. A method for inspecting an object includes: passing a primary electron beam, along an optical axis, through a substantially symmetrical electrostatic field defined within an electron lens arrangement; and propagating the primary electron beam from the lens arrangement towards an interaction point with an object that is oriented in relation to the optical axis at a non-normal angle, while maintaining, by at least one additional electrode positioned outside the lens arrangement, a substantially symmetrical electrical field in a vicinity of the interaction point.
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